Oz Report

topic: tail (45 articles)

A tail for Aeros gliders?

Tue, Mar 17 2009, 9:21:55 am EDT

Is a designer getting smart, or is this a marketing move, or a response to recent incidents?

Aeros Ltd|tail

I wrote earlier about tails for flex wing gliders in relation to a tucking and tumbling incident at Manila on an Aeros glider. Aeros apparently has a number of gliders with tails at the DHV for testing. But the difference in sprog settings for the Combat L 13 07 with and without a tail is miniscule so it is unclear what the point of the tail would be. There is a little greater difference in sprog settings with and without the tail for the 09 version.

The argument against tails is that the wing tips are as far back as a tail would be given a normal keel length. Given that, there is no reason why you could expect a damping effect of a tail, that the outer wing area could not give you. I wrote earlier that you would need a longer keel.

You can see a long discussion of this here.

2 topics in this article: Aeros Ltd, tail

Fatality Report

Learning from an aerotowing accident from last year

Mike Haas

Tue, Aug 30 2005, 2:00:00 pm GMT

Angelo Mantas «Angelomant» writes:

Analysis - Mike Haas Fatality

Scenario - Mike’s accident happened during midday thermal conditions. He was flying a Moyes 147 Litesport, aerotowing it off of a launch dolly. Several witnesses saw the accident, but I give Dave Whedon’s account the most weight, because a) He saw the entire event, from start to finish, and b) He was watching several tows intently to see what conditions were like, since he hadn’t towed in a while.

The tug was given the “go” signal. Dave said that almost as soon as Mike launched off the cart, he appeared to be having difficulty with both pitch and roll control. Then, at around 50' - 60’, the glider pitched up radically and started arcing to the left. Somewhere around this time the weak link broke, or the pilot released. The glider continued rotating left and dove into the ground, first hitting the left wing tip, then nose. The glider’s pitch was near vertical on impact, confirmed by the fact that the control bar, except for a bend in one downtube, was basically intact, whereas the keel and one leading edge snapped just behind the nose plate junction. This all happened fairly quickly. Based on witness and tug pilot accounts, the glider was never over 100’.

Despite help reaching him almost instantly, attempts to revive him proved futile. Mike suffered a broken spinal cord and was probably killed instantly.

Causes - In examining the circumstances surrounding the accident, it seems to me that several factors, which by themselves might not cause major problems, combined to lead to Mike's losing control of the glider.

1) New, high performance glider.

2) Larger size glider than what he was used to.

3) A fast flying tug (Kolb)

4) Flying through a thermal just after launching.

5) A rearward keel attachment point on the “V” bridle.

Mike had only one previous flight on his new Litesport, in laminar coastal ridge soaring conditions. Although he flew over two hours, he probably never flew the glider at the speeds encountered when aerotowing. Mike had many aerotows on a Moyes Xtralite, but according to Matt Taber, the Litesport doesn’t track as well at high speed. The Litesport was also bigger than his Xtralite, which would make it less responsive and harder to control.

The tug used was a Kolb ultralight. Although this tug had an increased wing span than normal Kolbs, it still tows at a higher speed than a Dragonfly. I can tell you from my own experience that it is harder to tow behind a faster tug.

Soon after launching, the glider and tug flew through a strong thermal. This is confirmed by witnesses watching the tug, and the tug pilot’s reporting a strong spike in climb rate.

Here is where some controversy might come in: on examining the wreckage, Arlan (tug pilot) saw where the upper “V” bridle was attached, and immediately felt that that was a possible cause of the accident. It was attached at the hang point, and in his opinion, was too far back for a stable tow. Since then, there has been debate on whether or not that was a safe attachment point. That positioning on the keel was recommended to him by the seller, and apparently many other pilots have towed a Litesport from the same position. Shortly after the accident, some pilots in Wisconsin did an aerotow of a Litesport from slightly behind the hang point, and reported it towed fine.

I agree with Arlan that the upper bridle attachment point contributed to the accident. The test done in Wisconsin was done early in the morning in stable conditions, and the pilot weighed 50 more pounds than Mike. Just because others have managed to tow with this upper bridle position, doesn’t mean it’s safe, especially for pilots on the light end of the weight range.

To sum up, Mike was flying a glider that was bigger than what he was used to, with less stability at the higher speeds needed to stay behind the Kolb. Even with Mike’s hang gliding experience, these factors would tax his abilities. These difficulties would be magnified by the de-stabilizing effect of the rearward keel bridle attachment and the faster speed of the Kolb tug. Already struggling (as witnesses state), when Mike hit the thermal, a difficult situation became impossible. Mike lost control, and either locked out or stalled, leading to his dive into the ground.

How can we prevent this from happening in the future?

A proper keel attachment would have made the glider fly faster without a lot of bar pressure. It also would have made the glider more stable in yaw, because the tow force would be farther in front of the CG. My own experience has been that since moving my keel attachment further forward, tows are much more stable.

Using a tail fin - Tail fins definitely help stabilize gliders on aerotow, especially high performance gliders that may be less stable in yaw. A too rearward keel bridle attachment can be overcome with a fin. Many aerotow parks use tail fins on their demo gliders. The downside to fins is that they can make thermaling difficult on many gliders, but they can still be a valuable tool to make your glider safer while you figure out where your keel bridle attachment should be.

First tows of new gliders in smooth conditions. It is much easier to aerotow a new glider when the air is smooth. Learn how the glider tows in calm air, make any equipment adjustments necessary, then later tow in midday, thermal air.

Practice flying your glider fast before aerotowing it. If you foot launch or static tow your glider, you can literally fly for years without ever flying at the speeds involved with aerotowing. Even platform/payout winch towing doesn't involve those speeds. Practice pulling in the bar and keep it there. Easy? Now try to make a small heading correction and keep it. Good chance you’ll be PIOing all over. This kind of practice definitely pays off.

Wind streamers along runway. It’s agreed that Mike hit a strong thermal shortly after launching. Placing streamers on both sides of the runway, at regular intervals, would help detect if a thermal is coming through the takeoff area. If all the streamers are pointing the same way, it’s safe to launch. If some of the streamers start moving other directions or reversing, it’s obvious some kind of turbulence is coming through. This is not a new idea, it’s not expensive (wood stakes and surveyor's tape) yet I’ve never seen anyone do this. Maybe it’s time we start.

Mike was a Hang IV pilot with over twenty years experience. He was not a “hot dog” and was very safety conscious. No one who knew Mike could believe that this happened to him. Although I feel I have a better understanding now of what happened, I can’t help feeling that if this could happen to him, none of us are safe.

(editor's noticed: There was an earlier, and different accident report published in June in HG/PG Magazine.)

Discuss "Fatality Report" at the Oz Report forum link»

21 topics in this article: accident, aerotow, Angelo Mantas, bridle, cart, Dave Whedon, Dragonfly, equipment, fatality, foot launch, HG & PG Magazine, Matt Taber, Mike Haas, Moyes Litesport, Moyes Xtralite, safety, tail, tow, tug, ultralite, winch

Tucks, tumbles, and tails (spins, too)

Mon, Jun 28 2004, 1:00:01 pm EDT

So what has the tail done for the flying wing set?

tails

Ron Gleason|tuck|tumble|tail|video

http://splorg.org/lectures/dyson.html

"In science, it is better to be wrong than to be vague."

Kari's recent tumble at the Worlds has reminded me that I should go back and look at how things have changed in hang gliding since the introduction of the horizontal tail in rigid wing hang gliders. To do that, I'm going to make a series of statements which may or may not be true, go over some of the history of this hang gliding innovation, and then sharpen up those statements a bit (in the next article), so that they can be proven, disproven or further clarified.

1. Horizontal tails of four or five square feet in area attached near the ends of hang glider keels significantly increase the pitch stability and pitch dampening of both flex wing and rigid wing hang gliders.

2. Rigid wing hang gliders (the ATOS V and VX) with tails are significantly more pitch stable and have significantly more pitch dampening than high performance topless flex wing hang gliders without tails in certified configurations. The gap between the rigids and flexies increases significantly if flex wing pilots lower their sprogs below certified levels.

3. There is a range of conditions in the air that will cause a topless flex wing hang glider without a tail to tuck and tumble. Within a "significant" portion of that range a rigid wing hang glider with a tail (an ATOS V, for example) will recover from a tuck and not tumble.

4. The ATOS V and VX are significantly more difficult to spin than the ATOS C (without a tail) and comparable to flex wing hang gliders in their spin characteristics.

Tails were reintroduced a few years ago into production flex hang gliders with the advent of the modern topless flex wing hang glider, especially after it was shown that they significantly reduced the speed of rotation occurring after a stall. Due to their cost, inconvenience, fragility, and assumed bad effects on glider ratio, they were abandoned when it was felt that internal sprog systems were sufficient to provide the required pitch dampening and stability.

A few months after I tucked and tumbled an ATOS C in Australia in January, 2002 tails were adapted, developed, tested and became available for use with rigid wing hang gliders. It was felt that because of their higher aspect rations, relative small surface area and small cord length, that rigid wing hang gliders had less pitch stability and pitch dampening than topless flex wing hang gliders and would benefit significantly from the addition of horizontal tails (see articles below addressing these concerns).

Let me step back a bit and give a few definitions. A hang glider is pitch stable if when glider is displaced away from trim there is a force which brings it back to trim (to an angle of attack that has the wing flying). The glider is more stable if the force increases as the displacement increases. It is also more stable if the force continues to operate over a larger range of displacements from trim.

For example, if the glider's nose rotates straight down 90 degrees and then thirty degrees more, but then recovers to a flying attitude, the glider is displaying its stability, its ability to recover from a large displacement from its normal flying attitude.

A glider has good pitch dampening, if for any given disturbance in the air, the glider tends to rotate in pitch more slowly than other gliders. The slower the rotation in pitch for any given disturbance, the higher the pitch dampening.

Pitch dampening is important because hang gliders aren't built to withstand strong torsional loads which come about when the glider is rotated quickly in pitch. Reducing the speed of rotation reduces the torsional loads by the square of the reduction in rotational speeds.

Before the introduction of horizontal tails on rigid wing hang gliders there were a "significant" number of reports of pilots spinning, tucking, and tumbling these hang gliders. Since the tails have been widely adopted (especially on the ATOS and Tsunami gliders), I have received only one report of a rigid wing hang glider tumbling or tucking and none spinning.

I recently reported Ron Gleason tucking (getting his nose underneath him) in his ATOS with a tail, but the ATOS recovered, which is what it is supposed to do if it has a tail, and didn't tumble.

The DHV has certified the ATOS V and VX, both with tails. Last year the DHV published a video on their web site which illustrated how easy it was to spin the ATOS without the tail and how difficult it was with the tail.

The DHV tests provide a pitch curve for each glider. That pitch curve tells us how pitch stable the glider is. Unfortunately, these curves are proprietary and we are not able to compare between the curves for topless flex wings and rigid wings. If we had access to those curves we would have a better chance to test our statements above.

The ATOS C tucks: https://OzReport.com/6.020#1
The data: https://OzReport.com/6.021#3
Gerolf speaks up: https://OzReport.com/6.022#2
Tail plane: https://OzReport.com/6.023#2

Pitch damping effects how rapidly the rate of rotation will increase when a glider is provoked into a tucking situation. The degree of pitch damping is expressed as a coefficient; its value depending mainly on wing sweep. Martin's calculations showed that this coefficient is nearly doubled when a tail plane is fitted.

This above article is very informative.

https://OzReport.com/6.025#6

I did a quick calculation from the data you retrieved and estimate that the righting force that would have been created by a tail plane.

https://OzReport.com/6.026#1

If you are asking me if I think a tail plane would have prevented your tuck then the answer is - almost certainly. The designers can do the math, but you can be sure that a force of this magnitude acting over a long lever arm has a very significant positive influence on the glider's pitching moment coefficient at critical negative angles of attack. (This is particularly true with high aspect ratio/narrow mean chord wings.) Added to which the pitch damping coefficient is also dramatically increased (ref Martin Jursa).

Tentative conclusions: https://OzReport.com/6.027#1
Long discussion: https://OzReport.com/6.030
Links to tucking articles: https://OzReport.com/6.032#1
Felix on tails: https://OzReport.com/6.033#1
Tucks Vs. tumbles: https://OzReport.com/6.034#2

I see tucks as a pitch down situation, where the nose goes to ninety degrees or more. The glider may or may not recover. Tumbles - the glider nose rotates down and continues to rotate over and over. The tuck proceeds the tumble. Others have other definitions for tucks and tumbles.

DHV pitch tests: https://OzReport.com/6.048#0, https://OzReport.com/6.050#0, https://OzReport.com/6.051#4, https://OzReport.com/6.053#3

It is still the case that, during the UK 's fifteen year history of certification testing and detailed accident investigation, those gliders that pass certification tests (and are maintained in that state) do not tuck or tumble. Every tuck or tumble incident that has been reported to us has involved either an uncertified glider or a glider outside of certification specification.

Whip stalls: https://OzReport.com/toc.php?6.95#5

Tumbling with a tail: https://OzReport.com/7.181#5

Tail plane Vs. V-tail: https://OzReport.com/7.184#3, https://OzReport.com/7.185#2, https://OzReport.com/7.187#2

Testing: https://OzReport.com/7.188#5, https://OzReport.com/7.189#3

Tucks with tails: https://OzReport.com/7.191#3

I'll continue with this discussion in the next issue.

Discuss "Tucks, tumbles, and tails (spins, too)" at the Oz Report forum link»

5 topics in this article: Ron Gleason, tuck, tumble, tail, video

The 15^th Annual Pre-Worlds 2004 - day six

Tue, Jan 20 2004, 5:00:00 pm GMT

Results (thanks to Dave Seib) at:

http://www.moyes.com.au/preworlds2004/

Five days ago the forecast was for 30-35 kph northwest winds on this day, and slightly lighter winds tomorrow with the possibility of showers. I've been impressed with the weather modeling services provided to Len Baron who is handling the weather here, much as I do at the US meets.

I'm also impressed with Len's improved ability to forecast the weather. Having the fast internet connection and the fact that we get a local temperature trace and wind speed and direction at altitude when they send a Dragonfly up at 8 AM definitely helps. Len also has a whirling psychromiter to give us the wet and dry bulb temperatures in the tow paddock.

Today Len's thermometer recorded thirty six degrees dry bulb and nineteen wet bulb. The clouds to the east likewise told the news that cloudbase was 11,000'.

The winds were indeed quite strong, 20 to 30 kph out of the northwest in the tow paddock and, given the instability, dust devils would come through every so often and really stir everything up. My Moyes Litespeed S 4.5 was tied to a tree, tensioned and the wings horizontal, so it was easy to set up while the winds blew hard. There were plenty of lulls that provided for very launchable conditions.

Kraig and Jonny worked on my Litespeed S 4.5 last night and got the pulley back in shape. I also got Kraig to show we how to roll up the sail. I just need to start near the front and not at the tip, and that worked great.

A pilot writes:

Re your VG line jumping off the pulley. It has happened to me twice. First time your shaking method allowed marginal movement. Then I set it back on the pulley for next flight. Last summer though, it got totally squeezed inside of one of the pulleys that are deep in the upright.

Ken Brown sent me diagrams of the mechanism right away. I had to take the whole assembly out of the upright but freed it up. Now, when loosening VG I always remember to let it out slowly not with a mindless snap.

The pulley that got out of whack for me was the one on top of the keel by the pilot's hang point. I was conveniently located to allow Kraig to smash it back together. Everything seems to be working fine now.

Very few pilots were setting up and this is always a bad sign. Dave Seib was on the safety committee and all setup and ready to fly. But the other two safety committee members were not set up.

The task committee looked at the strong tail winds and decided to call a 301 kilometer task, to try to break the record set the day before of 242 kilometers (150 miles) as the longest task set and made in a major hang gliding competition. We could fly to Brown Bothers Winery, or to the Mt. Beauty airport, but to get 301 kilometers we needed to throw in a turnpoint and go to Holbrook, the town with the submarine.

The task was called, but the safety committee voted to call the day given the statement from Attila in the Dragonfly that the winds were 35 to 40 kph and the gusts up above were very strong. Attila and Dave will be among a number of pilots who later take off and try to fly 300 kilometers from Hay. I remember when Conrad flew from Hay to the Mt. Beauty airport (225 miles). He was up in the mountains but didn't feel good about flying over them.

Paul Rundell, the meet director, feels that the day was wasted by a bad call by the safety committee to not fly. He says, "This isn't Disneyland." I think he means Disneyworld, in Florida.

You'll notice that Brett Hazlett is in the lead with Oleg, now that he is feeling better, just behind him. On Tuesday, Brett was following Oleg as closely as he could to make sure that Oleg didn't gain more than a second on him. You've got to be good to follow Oleg, and Brett was being smart to follow the guy who has best chance of beating you.

Wednesday is the last day. The forecast is for thunderstorms.

The people and businesses in Hay have been great to us this year with many vouchers for dinners and other services. We are taking the car in for new shocks and an oil change thanks to the local Toyota dealer.

Oliver Barthelmes «oliverbarthelmes» sends this photo of the setup area in Hay for the aerotow guys. Notice that many pilots have staked their gliders into the ground and set them up into the wind. This works very well with gliders that can be tensioned and then the battens inserted:

Discuss "The 15^th Annual Pre-Worlds 2004 - day six" at the Oz Report forum link»

19 topics in this article: aerotow, battens, Brett Hazlett, competition, Dave Seib, Dragonfly, Jon "Jonny" Durand jnr, Ken Brown, Moyes Litespeed, Moyes Litespeed S, Oliver "Olli" Barthelmes, photo, Pre-Worlds 2004, record, safety, tail, tow, variable geometry, weather

The 15^th Annual Pre-Worlds 2004 - day five, task three

Mon, Jan 19 2004, 5:00:00 pm GMT

Pre-Worlds 2004

Results (thanks to Dave Seib) at:

http://www.moyes.com.au/preworlds2004/

Attila says forget about getting dinner if he is on the task committee. With the winds 10-15 kph out of the north-northeast, we call a 150 mile (242 kilometer) task south-southwest to Victoria and the Bendigo gliding club. Everyone seems up for a long straight out task, so why not.

The last time we had a task like this and we made it to goal was at the previous preworlds when Mad Dog was the meet director and he wanted to average 100 mile tasks. The lift got me to 11,000' on that day under a beautiful cloud street, but today we are forecast to get to 7,000' and it will be blue.

Being on the task committee interferes with getting into the launch line but I weasel my way in and am off third. I'm thinking that maybe the earlier start clock is the go at 1:30 (first start clock) or 1:45. I'm rushing everything to get ready and actually input the task coordinates while I'm on the cart.

Grant pulls me into 900 fpm, but the other pilots around me in the start circle seem to have poor lift and nothing is really gelling yet. I launched at 1:15 and see a couple of pilots out by the start circle circumference at 1:30, but that seems like a thin crew to go with. With poor lift in the start circle after my first climb the pilots are bobbling up and down waiting for the next start time. A few more take the 1:45.

A group of pilots heads for the edge of the circle just before the 2 PM start time and they find a thermal that drift us outside the start circle, but not far enough that we can't get back and take the 2 PM start time. Another group of pilots including the fast guys will wait and go back for the 2:15.

I'm a bit low at the start, and with a radio that will not allow me to transmit, so I head south-southeast to get near the highway to Denniliquin, which parallels the course line. There are ten or fifteen pilots in our group so it looks like I might have company. Jonny Durand has gone off my himself further upwind to the east of the highway.

With pilots out in front from the earlier start times and those who were higher at the start gate there are good markers heading down the highway. We're getting to 5,500' AGL and moving along at a good clip leaving the lift whenever it gets a bit weaker.

I'm noticing that I can't easily adjust the Litespeed VG. It has been hard before, but now I have to shake the glider to get the VG off. I also have to pull the cord across my body with my left arm to get the VG to go to a little past half way. I'm wondering what the problem is as I decide to keep the VG on at about half way and try not to mess with it.

At 80 km from the start the highway does a bit of a jog to the south east and I head out on my own over the dirt roads to the southwest paralleling the course. Yesterday I left my buddies to my great regret. On that day I already had 15 minutes on them, and if I had just stayed with Lenny I would have either won the day or come in second. The difference is that on that day I was acting on pride thinking that these guys were too slow for the likes of me. Today, it just seems like the lift is good and I'm moving in the right direction.

I'm crossing the creek six kilometers west of Waganella, and just getting light lift as I glide south-southwest. It's not enough to turn in, but it's great just to be in lift while gliding. Makes me feel good about my decision to go off on my own. Jonny Durand is to my east also on his own. No fast guys to go with him.

As I glide in the lift I hit a strong core and climb to 7,000' in the best thermal of the day so far. After that invigorating climb I'll go on a 20 kilometer glide and start searching seriously for lift at 3,000' AGL. The Edwards River is up ahead and that means trees along the river. I know that I have to find lift before I cross the trees not because I won't be able to make it over the trees, but because I won't be able to concentrate on finding lift if I also have to think about crossing the trees low.

I am searching and searching finding small bits at 1,500' and heading toward some paddocks that extend further south before the tree line hoping to extend my search before coming to the trees. I circle low in broken loft always searching when I'm finally in the last paddock before the trees and I find lift at 700'. Without a working radio, I've got to make it to goal.

I saw some pilots behind me when I first climbed out to 7,000'. Now after my low save I see three of them to my west more on the course line. I come in under them and the lift is decent to almost 7,000'. I've been on the course for over two hours now and am averaging about 55 kph.

Up ahead I can see the trees that mark the Murray River and that is the line that we cross to get from New South Wales into Victoria. The trees are to our right, west, and in some place they must be 5 kilometers across or more. Further south they appear to be thinner, and that's where I'm heading.

I can hear Bo Hagewood and Kevin Carter on the radio 15 to 20 kilometers behind me. Kevin also started at 2, but Bo took the 2:15. Bo is near the fast guys who took the 2:15 clock. It looks like in spite of my low save I'm progressing along well enough.

As I approach the trees from the east, I can see a few other pilots who are also heading south near the tree line heading for the thin spot to get over them. I come in over a red plowed field and climb out to 7,000' again. Nick, from Switzerland, and another pilot will come in a few thousand feet under me and I get high a few kilometers before the trees.

There is a small gaggle a few thousand feet below me as I head out over the trees. It looks like the fast guys are about 10 kilometers behind and I'm high and on my own. I find a good thermal in the brown fields just on the other side of the river so at 75 kilometers out from goal at 5:15 and right on the course line it looks good for getting there.

A couple of pilots come in under me but too far below me as I climb in this thermal to 6,000', so I'm on my own again going to goal. It will remain that way.

I head off to the west a bit to get over some red plowed fields as I get low and have to search again at 1,500'. I see a few little wisps of dust devils over the field, which is a good reason to go to such a field that can display the lift, drive upwind to them and climb out.

I'll have to repeat that little maneuver one more time to stay up. Meanwhile to my east the fast guys will be finding better lift and catching me as I grovel low in search more over the red fields. Bo and Kevin will be flying together and with the fast guys.

It's a slow climb out 24 kilometers from goal to 5,000', but then it looks like I can go on final glide. It's after six o'clock and I'm looking at a 15 kph tail wind, with buoyant late day air over open fields. There is some sink heading for goal, but at 15:1 L/D required to make it, I can float along until I get close and then dive in.

The last two slow climbs cost me the chance to get in early. Jonny Durand flew the whole flight on his own and won the day. Gerolf landed early.

My average L/D over the flight was 17:1, so you know that the tail wind was a big help.

On landing at goal, I had Jonny look at the glider to see what was wrong with the VG. There was a rope that had jumped out of the pulley and was jammed between the pulley and the clamp holding the pulley.

When I was setting up net to Jonny in the morning at the tow paddock. I had mentioned to him how the Climax VG was much more user friendly, easier to pull, less rope. He stated that that was fine, but he had heard that Rohan had had a problem with the rope jumping from the pulley, so there were problems with the Climax VG, implying that there weren't with the Litespeed VG.

I guess God heard him and punished me by having my rope jump off the VG and then having Jonny find it. I spoke with Rohan at goal and he said that it did happen to him once on the Climax in Brazil and that it was on a prototype setup. Kraig and Jonny were very helpful and took that glider to be fixed. Again, I found something that no one had found before. I'm wonder now if this has been my problem with the VG being hard to pull (part of it being user unfriendly) all along.

Task 3:

0in 5.4pt; height:13.2pt"> 1	0in 5.4pt; height:13.2pt"> Durand Jon Jnr.	0in 5.4pt; height:13.2pt"> Moyes Litespeed S4	0in 5.4pt; height:13.2pt"> Aus	0in 5.4pt; height:13.2pt"> 14:00:00	0in 5.4pt; height:13.2pt"> 18:00:48	0in 5.4pt; height:13.2pt"> 4:00:48	0in 5.4pt; height:13.2pt"> 977
0in 5.4pt; height:13.2pt"> 2	0in 5.4pt; height:13.2pt"> Bondarchuk Oleg	0in 5.4pt; height:13.2pt"> Aeros Combat 2 13	0in 5.4pt; height:13.2pt"> Ukr	0in 5.4pt; height:13.2pt"> 14:15:00	0in 5.4pt; height:13.2pt"> 18:15:07	0in 5.4pt; height:13.2pt"> 4:00:07	0in 5.4pt; height:13.2pt"> 961
0in 5.4pt; height:13.2pt"> 3	0in 5.4pt; height:13.2pt"> Hazlett Brett	0in 5.4pt; height:13.2pt"> Moyes Litespeed S4	0in 5.4pt; height:13.2pt"> Can	0in 5.4pt; height:13.2pt"> 14:15:00	0in 5.4pt; height:13.2pt"> 18:15:08	0in 5.4pt; height:13.2pt"> 4:00:08	0in 5.4pt; height:13.2pt"> 955
0in 5.4pt; height:13.2pt"> 4	0in 5.4pt; height:13.2pt"> Coomber Kraig	0in 5.4pt; height:13.2pt"> Moyes Litespeed S	0in 5.4pt; height:13.2pt"> Aus	0in 5.4pt; height:13.2pt"> 14:15:00	0in 5.4pt; height:13.2pt"> 18:15:24	0in 5.4pt; height:13.2pt"> 4:00:24	0in 5.4pt; height:13.2pt"> 945
0in 5.4pt; height:13.2pt"> 5	0in 5.4pt; height:13.2pt"> Bader Lucas	0in 5.4pt; height:13.2pt"> Moyes Litespeed S	0in 5.4pt; height:13.2pt"> Deu	0in 5.4pt; height:13.2pt"> 14:15:00	0in 5.4pt; height:13.2pt"> 18:15:32	0in 5.4pt; height:13.2pt"> 4:00:32	0in 5.4pt; height:13.2pt"> 939
0in 5.4pt; height:13.2pt"> 5	0in 5.4pt; height:13.2pt"> Hagewood Bo	0in 5.4pt; height:13.2pt"> Aeros Combat Ii 150	0in 5.4pt; height:13.2pt"> Usa	0in 5.4pt; height:13.2pt"> 14:15:00	0in 5.4pt; height:13.2pt"> 18:15:32	0in 5.4pt; height:13.2pt"> 4:00:32	0in 5.4pt; height:13.2pt"> 939
0in 5.4pt; height:13.2pt"> 7	0in 5.4pt; height:13.2pt"> Barthelmes Oliver	0in 5.4pt; height:13.2pt"> Moyes Litespeed S4	0in 5.4pt; height:13.2pt"> Deu	0in 5.4pt; height:13.2pt"> 14:15:00	0in 5.4pt; height:13.2pt"> 18:15:39	0in 5.4pt; height:13.2pt"> 4:00:39	0in 5.4pt; height:13.2pt"> 930
0in 5.4pt; height:13.2pt"> 8	0in 5.4pt; height:13.2pt"> Bosman Mart	0in 5.4pt; height:13.2pt"> Moyes Litespeed	0in 5.4pt; height:13.2pt"> Nld	0in 5.4pt; height:13.2pt"> 14:15:00	0in 5.4pt; height:13.2pt"> 18:15:40	0in 5.4pt; height:13.2pt"> 4:00:40	0in 5.4pt; height:13.2pt"> 927
0in 5.4pt; height:13.2pt"> 9	0in 5.4pt; height:13.2pt"> Hideaki Nagamitsu	0in 5.4pt; height:13.2pt"> Moyes Litespeed 4	0in 5.4pt; height:13.2pt"> Jpn	0in 5.4pt; height:13.2pt"> 14:15:00	0in 5.4pt; height:13.2pt"> 18:15:56	0in 5.4pt; height:13.2pt"> 4:00:56	0in 5.4pt; height:13.2pt"> 918
0in 5.4pt; height:13.2pt"> 10	0in 5.4pt; height:13.2pt"> Bares Radek	0in 5.4pt; height:13.2pt"> Aeros Combat	0in 5.4pt; height:13.2pt"> Cze	0in 5.4pt; height:13.2pt"> 14:15:00	0in 5.4pt; height:13.2pt"> 18:16:03	0in 5.4pt; height:13.2pt"> 4:01:03	0in 5.4pt; height:13.2pt"> 912

Totals after three days:

0in 5.4pt; height:13.2pt"> 1	0in 5.4pt; height:13.2pt"> Hazlett Brett	0in 5.4pt; height:13.2pt"> Moyes Litespeed S4	0in 5.4pt; height:13.2pt"> Can	0in 5.4pt; height:13.2pt"> 2804
0in 5.4pt; height:13.2pt"> 2	0in 5.4pt; height:13.2pt"> Bondarchuk Oleg	0in 5.4pt; height:13.2pt"> Aeros Combat 2 13	0in 5.4pt; height:13.2pt"> Ukr	0in 5.4pt; height:13.2pt"> 2745
0in 5.4pt; height:13.2pt"> 3	0in 5.4pt; height:13.2pt"> Durand Jon Jnr.	0in 5.4pt; height:13.2pt"> Moyes Litespeed S4	0in 5.4pt; height:13.2pt"> Aus	0in 5.4pt; height:13.2pt"> 2696
0in 5.4pt; height:13.2pt"> 4	0in 5.4pt; height:13.2pt"> Coomber Kraig	0in 5.4pt; height:13.2pt"> Moyes Litespeed S	0in 5.4pt; height:13.2pt"> Aus	0in 5.4pt; height:13.2pt"> 2665
0in 5.4pt; height:13.2pt"> 5	0in 5.4pt; height:13.2pt"> Holtkamp Rohan	0in 5.4pt; height:13.2pt"> Airborne Climax 13	0in 5.4pt; height:13.2pt"> Aus	0in 5.4pt; height:13.2pt"> 2609
0in 5.4pt; height:13.2pt"> 6	0in 5.4pt; height:13.2pt"> Moyes Steve	0in 5.4pt; height:13.2pt"> Moyes Litespeed S5	0in 5.4pt; height:13.2pt"> Aus	0in 5.4pt; height:13.2pt"> 2535
0in 5.4pt; height:13.2pt"> 7	0in 5.4pt; height:13.2pt"> Barthelmes Oliver	0in 5.4pt; height:13.2pt"> Moyes Litespeed S4	0in 5.4pt; height:13.2pt"> Deu	0in 5.4pt; height:13.2pt"> 2428
0in 5.4pt; height:13.2pt"> 8	0in 5.4pt; height:13.2pt"> Bares Radek	0in 5.4pt; height:13.2pt"> Aeros Combat	0in 5.4pt; height:13.2pt"> Cze	0in 5.4pt; height:13.2pt"> 2332
0in 5.4pt; height:13.2pt"> 9	0in 5.4pt; height:13.2pt"> Durand Jon Snr	0in 5.4pt; height:13.2pt"> Moyes Litespeed S4.5	0in 5.4pt; height:13.2pt"> Aus	0in 5.4pt; height:13.2pt"> 2328
0in 5.4pt; height:13.2pt"> 10	0in 5.4pt; height:13.2pt"> Orgler Andreas	0in 5.4pt; height:13.2pt"> Moyes Litespeed S	0in 5.4pt; height:13.2pt"> Aut	0in 5.4pt; height:13.2pt"> 2238

Oliver Barthelmes «oliverbarthelmes» sends in this shot of a tow in the dust at Hay:

Discuss "The 15^th Annual Pre-Worlds 2004 - day five, task three" at the Oz Report forum link»

1 topic in this article: Pre-Worlds 2004

Tucks, are they inevitable?

Thu, Jul 17 2003, 7:00:03 pm GMT

Richard Lever <RLever@aol.com> writes:

John Vernon's principal argument is being overlooked here.

(editor’s note: Not overlooked, but it is always good to put the spotlight back on it.)

The Atos may have entered an incipient spin due to being flown too slow. I think we all accept that spins are a reality with any high aspect wing and that to fly a rigid you need to watch the speed. But having said that, what happened after the pilot applied correct spin recovery techniques is the real issue.

John mentions that other pilots flying that day referred to conditions as 'similar to a British autumn', if slightly choppy (well even here in Blighty we get the odd rough day, but if you can't fly safely in Britain where can you?). The point is that the glider failed to recover from the ensuing dive - a basic pitch stability issue. It wasn't in a radical/competition environment and it wasn't a non-certified glider.

(editor’s note: We know that conditions in one patch of the sky don’t necessarily correspond to conditions in another patch of the sky. When I tucked in Australia over the flats the air was seen to be just fine by the pilots near me. But one (perhaps very small) patch of it wasn’t.)

Felix is one of hang gliding's pioneers and I hate being one of his detractors. The Atos is one of the sexiest high performance wings ever built and one day I hope to own one. But in the meantime please get the thing sorted!

(editor’s note: I’m thinking that flex wings have also failed to recover from dives. The other day out of Zapata we had Ron Gleason go into a 120° dive when flying an ATOS-C with a tail and he and it recovered. Peter Dall in Australia also tucked an ATOS with a tail and recovered.

I guess I’m unclear as just to which lesson I’m supposed to draw from the fact that the ATOS didn’t recover in one case and did in two others. That flex wings recover in some cases and not in others.

Am I supposed to think that the DHV certification only protects me up to Y limit? Is Y the same for flex wings and rigid wings with tails? If Richard could just enlighten me as to what I’m supposed to think here I would really very much appreciate it.

The only hang glider that I know for sure hasn’t tucked or tumbled in the Wills Wing Falcon. I’m sure that there are others in this class with similar records. Is this due to the design, the pilots, or the conditions in which it is flown in, or all three? If I want to never tuck again should I fly a Falcon only, and only in benign conditions?)

Discuss "Tucks, are they inevitable?" at the Oz Report forum link»

14 topics in this article: Australia, certification, competition, DHV, environment, John Vernon, Peter Dall, Ron Gleason, spin, tail, tuck, Wills Wing, Wills Wing Falcon, Zapata

DHV and BHPA testing

Tue, Jul 15 2003, 6:00:03 pm GMT

Steve Uzochukwu <steveu@which.net> writes:

I have no position in the BHPA. The following is my opinion, and nothing but that. Definitive answers on the BHPA’s Certificate of Airworthiness (C of A) need to come from Mark Dale.

John Vernon:

So, we have a glider that meets the DHV pitching moment standards by at least a factor of two (re Felix's comments and pilot report about flap position for thermalling), fitted with the latest safety device, the V-tail, a pilot that reacted correctly, yet the glider still tumbled.

Steve:

C of A testing provides a benchmark and tests that in "reasonable conditions" the glider is stable. It cannot guarantee against tumbling in all conditions.

John:

Is this "deja vu" of when you tucked and tumbled and the glider met DHV standards.

Davis:

(editor's note: As I recall my ATOS-C didn't quite meet DHV standards given the way it was tuned at the factory. They found this out later when they tested another one tuned as mine was.)

Steve:

Which is why some of us still support C of A testing as a benchmark for people like me who are still ordinary pilots.

John:

Perhaps we should be directing our questions to the standards our gliders are tested to.

Steve:

Looking at BHPA records, the only case involving a C of A'ed glider in which the glider was a factor was a failure of a keel after the glider was ground looped and flown without any strip down or check. All our other major accidents where the glider has been a factor in the accident involved gliders with no C of A.

John:

For instance the BHPA CofA is based around measurements when gliders had aspect ratios about 6. Yet the rigids we fly have AR of 12. As the Cof A test is based on pitching moment coefficient one can show that the pitching moment to meet the standard with our gliders is reduced by approximately 1.414 (the square root of the AR ratio ratios) from that which used to be required unless the standard has been updated recently.

Steve:

The whole point of this is a non dimensionalised constant, so that it is in proportion to the glider size, polar moment of inertia etc. A pitching moment can be fixed, but would be very difficult to achieve for a small glider and easy for a large one. So small gliders get penalised because they have to produce the same pitching moment as a large glider. So we stick with Cm because this is the best way. The pitching moment needs to be in proportion to the size of glider and second polar moment of inertia in the relevant axis.

Also don't forget that the C of A measures pitching moment coefficient, and not damping force/coefficient which is the first derivative, which adds stability in the case of a rapid rate of change of angle of incidence with a glider which has a tail fin.

John:

In respect of the DHV, as I can't find their latest standard on the net, I have to refer to the article published in 1996 or 7 by Martin Pepper and Steve Uzochukwu which states that the pitching moment at negative angles of attack only has to be increasing with increasing negative angle. Does this mean that double the standard means double practically nothing? I am sure not, but is there a minimum value? Perhaps you have access to the data or can find out and can advise here.

Steve:

The DHV standard is available on the net. Minimum pitching moment values at zero lift angles are:

50 Nm at 40 km/h
100 Nm at 60 km/h
150 Nm at 80 km/h
200 Nm at 100 km/h

The details of the pitching moment requirements are given in "Airworthiness Specifications for HG & PG" to be found on the DHV web site.

Basically in addition to dCm/d(alpha) remaining less than zero for all angles below trim angle down to well below zero lift there are some minimum pitching moments to be satisfied. It is these forces that may be satisfied by a margin of two.

John:

The incident took place, I believe, when representatives of both the DHV and the BHPA were present at the ranch who will know the actual measured Cof A test values for this aircraft. I presume that an incident report was raised and some time we will get a statement from these organisations about it and any recommendations they come up with. I do hope it will not just be on the basis the pilot was inexperienced and should not have got into the situation and ignore the tumble part. I am sure many pilots far less qualified than this pilot fly these gliders.

Steve:

Before we go belly aching about the gliders we fly, we need to be sure that:

We are flying gliders which are certified, in the configuration they were certified in.

That we fly them in line with the instructions in the manufacturers manual, which should form part of the C of A and the procedures therein which will have been tested as part of the C of A.

Uncertified glider=hello test pilot *No room for complaint*

Davis:

I continue to be very disappointed with the DHV regarding providing information about gliders to the flying public. No test results. Now, John can't find their standards. Poor show.)

Steve:

Untrue. N'importe quoi. Did they look?

http://www.dhv.de/deutsch/testberichte/index_download.html

Then select:

Bauvorschriften Englisch / Construction Regulations

Links direct to the pdf do not work IME.

DHV test results for ATOS:

http://www.dhv.de/DHVonlineDB/source/technictestreport1.php?lang=EN&templatesetid=-1&fieldvalue=3586

http://www.dhv.de/DHVonlineDB/source/technictestreport1.php?lang=EN&templatesetid=-1&fieldvalue=3921

(editor’s note: I have looked for the technical reports on the DHV site. I will look at these specific URL to see if there is something I have missed. But, what I have seen previously every time I’ve looked for them is very skimpy to say the least. I can’t find any charts or real results in German or English. Just a series of answers to a few questions saying that the thing passed the test.)

Steve:

I have to say that HG pilots seem to have a much less well developed knowledge of testing and certification than PG pilots, which is why they tend to buy all sorts of stuff (and straight off the prototyping drawing board, doing some of the testing for the manufacturer), and why more than 30 years after the start of the sport there are still pitching moment issues with uncertified gliders.

Lastly, I have to state that in any dealings with the DHV in connection with promoting technical understanding of their work *as opposed to political bashing* they have gone out of their way to help with technical information, despite the language barrier. Show me the USHGMA Certification in German? In the words of Chris Rock: "It ain't there!"

The DHV provide a superb resource in English, their second language. Needless to say I'm not holding my breath for *any* of the English speaking Associations (BHPA, USHGA) or the French speaking (FFVL) to do the same in German. Please consider this second language element when bashing away at someone else.

(editor’s note: Please separate my and John’s concerns. I know very little about the DHV beyond its web site. All I’m saying is that as a regular hang glider pilot I can’t find useful information about test results and glider configurations on their web site. Simple as that.)

Very high aspect ratio gliders (HG & sailplanes, ultralight or regular) always have issues with slow flight especially in turns. Respect this corner of their flight envelope.

Later John writes::

It is my belief that it is incumbent on our certification authorities, in the light of these continuing incidents, to thoroughly review the standards that are the basis of the c of a and let us, the pilots, know about their deliberations and recommendations before we find out the hard way that that we should have taken action.

Steve responds:

Martin Jursa did some investigation into this when rigids first came along, looking at pitching moment coefficients and tumbling issues. The DHV were satisfied as far as I know they have revised other things several times since then, but no major changes have been made to the C of A as far as pitching moments go.

When I was involved with Airworthiness for the BHPA I had two tumbling accidents - one was an uncertified glider and the other was beyond Vne. There has been a fair amount of discussion amongst the three certifying bodies for HG in the last 10 years. The pitching moment requirements for the BHPA and HGMA are very similar, based on Cm not going below certain values, concentrating on high pitching moment coefficients at low speeds. The DHV standard places slightly more emphasis on high pitching moments at high speeds.

As it stands the hardest bit to pass in either BHPA or HGMA still seems to be very high pitching moment coefficients required at low speeds and low angles of attack, like when the pilot is going weightless. It is John Vernon's belief that the DHV test is "the most stringent", but in fact, how stringent is dependent on glider size. I don't believe this is the case. Most tumbles happen at low speeds, in mixing air. As I have said, the minimum torque requirement does not have the same effect on a small glider as a large one.

On a different tack - majority of tumbles happen in comps where conditions, adjustments to gliders and risks taken are somewhat extreme compared to ordinary flying. Also looking at this competition crowd the majority of gliders are not certified.

Looks like a good cocktail for a few tumbles.

Discuss "DHV and BHPA testing" at the Oz Report forum link»

18 topics in this article: accident, BHPA, certification, competition, Dale Branham, DHV, HGMA, John Vernon, PG, polar, safety, site, sport, Steve Uzochukwu, tail, tumble, USHGA, Vne

Tails and DHV

Mon, Jul 14 2003, 2:00:05 pm EDT

John Vernon <johnv@emvertec.demon.co.uk> writes:

Got the numbers myself from Mark Dale at the BHPA and also understand an incident report has been recently received. . What the numbers, which I believe also apply to rigids, mean basically, is that the DHV test is more demanding than the others because it specifies a minimum torque which means aspect ratio does come into the reckoning.

So we are left with the conclusion that the glider that tumbled

a) Was tested to the most rigorous standard

b) Met the standard by a factor of two in the set up in which it was being flown

c) Was fitted with a V-tail

d) Was being piloted by someone who reacted correctly to the situation he found himself in (he had seen a video of spin recovery the previous night I understand)

And yet the glider still tumbled. As far as I know this is the second incident like this with a glider fitted with a V-tail (you reported an event in Australia when the glider recovered)

We know of Atos's that tumbled without tails, e.g. Christhoff Kratzner in the middle of a gaggle in Spain in the Algodonales Worlds, your incident, now we are having incidents with tails, thankfully so far without injury.

Lets be clear, not only is an incident like this life threatening to the pilot, but also to other pilots in the same thermal.

It is interesting to note that other British pilots in Spain at the Aerotow camp reported conditions as similar "to a British Autumn" and on the day in question "choppy but not what you'd call rough." Felix himself was observed by pilots flying near in the same thermal, thermalling at speeds which appeared to be below those recommended.

The original pitch stability curves were drawn up based on known glider parameters when glider performance and design was going through major improvements. We are now at a point in the evolution of our aircraft where the aspect ratio has been increased by a factor of nearly two, almost overnight, and surely "first of a kind" thinking must be applied not only to aspects of the glider design which has enabled this progress, but also to the parameters from which they are given their certificates of airworthiness.

(editor’s note: What John seems to keep overlooking here is that flex wings are tucking and tumbling also and they meet the same standards. I assume that the standards mean that unless you meet a particularly mean invisible dragon you will likely not flip.)

Discuss tucks and tumbles at OzReport.com/forum/phpBB2

Discuss "Tails and DHV" at the Oz Report forum link»

14 topics in this article: aerotow, Australia, BHPA, certification, Christof Kratzner, Dale Branham, DHV, gaggle, injury, John Vernon, spin, tail, video, Worlds

Tails

Sun, Jul 13 2003, 6:00:02 pm GMT

John Vernon <johnv@emvertec.demon.co.uk> writes:

Is this "deja vu" of when you tucked and tumbled and the glider met DHV standards.

(editor’s note: As I recall my ATOS-C didn’t quite meet DHV standards given the way it was tuned at the factory. They found this out later when they tested another one tuned as mine was.)

Perhaps we should be directing our questions to the standards our gliders are tested to.

(editor’s note: I think Steve can respond here.)

(editor’s note: The pilot inexperience issue is directed toward only one consideration, the pilot’s air speed while thermaling. He was flying too slow because he was inexperienced – or more experienced flying flex wings where this is possible. Felix has stated repeatedly that you are not supposed to fly the ATOS at minimum sink speed in anything but the gentlest air.

I didn’t speak to David’s qualifications in general, just to the issue of whether he really understood that he shouldn’t have flown so slow on the ATOS. Apparently, for some reason, he wasn’t aware of this. It could happen to anyone who didn’t understand the importance of flying faster on the ATOS.

I agree that there is indeed another issue, the issue of whether the ATOS with a tail is comparable to flex wing hang gliders in its resistance to tucking and tumbling. I sure hope so. It’s my life after all.

Flex wings tuck and tumble under certain circumstances also. Does the ATOS with a tail tuck and tumble under the same circumstances, or under circumstances that are more benign? Is the answer flying the ATOS faster or changing the ATOS configuration?

I continue to be very disappointed with the DHV regarding providing information about gliders to the flying public. No test results. Now, John can’t find their standards. Poor show.)

By the way thanks for giving us a medium where we can air these views, cheque in the post as soon as I can find a pen.

Discuss "Tails" at the Oz Report forum link»

8 topics in this article: BHPA, DHV, John Vernon, safety, Steve Uzochukwu, tail, tuck, tumble

Tail plane Vs. V-tail

Fri, Jul 11 2003, 5:00:02 pm GMT

Felix Ruehle|John Vernon|tail|tuck

Felix Ruehle <felix@a-i-r.de> writes in response to John Vernon’s article:

The V-tail adds damping and pitch up moment.

It's not a question of tail plane or V-tail. A V-tail has other advantages but no disadvantage re protecting against a tuck.

The pitch up moment with deflected flap, for example, has about double of the certified value but that’s not the point. After the rotation has started, at low speed, the double pitch up moment is not enough. However with increased air speed, pitch damping and pitch up moment is higher and the effect of the turbulence is less.

We made further test with tail and I would like to write you more when I'm back. I’m off for five days in Portugal with Ana. At this time flying in Germany is great. Gert Langwald flew 385km and another pilot flew 315. The A-I-R team spent many hours in the air, too.

Adi and I have flown this year recording our g-loads. We flew in very strong conditions, for example, with 50 km/h north wind south of the Alps (don’t try this at home). The g-loading never exceeded 3g’s positive and 1.5 negative. Also at fast final glides of 100km/h or faster the loads were always lower than these figures.

I have heard that some pilots don't like to fly fast because they think that they will overload the glider. There’s no problem with flying at 70 or 75 km/h in very strong lift. The risk of flying slow is much higher. The minimum sink speed for the Atos is about 42km/h and I often fly at this speed, but not when I expect turbulence in strong lift.

Discuss "Tail plane Vs. V-tail" at the Oz Report forum link»

4 topics in this article: Felix Ruehle, John Vernon, tail, tuck

Tail plane Vs. V-tail

Thu, Jul 10 2003, 5:00:03 pm EDT

john vernon <johnv@emvertec.demon.co.uk> writes:

This is my reasoning about the ATOS incident. You may think I have a point to make because I have made tail planes, in fact I have just restarted with the help of "Heli-Ben" Cope who does the main manufacturing now, or you may, like me, believe in the added safety a tail plane can give us :-

I think there are two discussions here 1) is whether the pilot was flying the glider too slowly and 2) is about whether the glider should have recovered.

As I don't fly an Atos and am quite happy thermaling at 23-25mph on the Tsunami I will only deal with 2).

The tail plane can provide us with improvements to our glider's stability by increased pitch damping and adding positive pitching moment at negative angles of attack. From these improvements we derive additional benefits of improved thermaling feel and damping out the effects of turbulence.

Floating, negative angle tail planes provide increased damping and increased positive pitching moment at negative angles of attack and do not change the pitching moment at +ve angles of attack. However they have the disadvantage of increasing bar pressure at speed, which is why I developed the "competition stop" which allows pilots who want to exceed 50-55mph, with a tail plane fitted, to do so. The above is true as long as the glider the tail plane is fitted to is not changed from its certified settings because the tail plane is fitted

Positive angle set tail planes (as I believe are fitted to the ATOS) increase pitch damping and depending on how they are designed and set can provide some increase in pitching moment at negative angles of attack and also can have a negative effect on pitching moment at positive angles of attack. Consequently they do not increase bar pressure at speed.

I assume that, in the case of the ATOS, the tail plane has now become an integral part of the glider's aerodynamics and the aerodynamics have been tuned to meet the certification requirements with it fitted. Consequently it seems to me that there will probably be no additional or only marginal additional positive pitching moment benefit derived from it as compared to the pitching moment safety margins required for the test i.e. the tail plane basically provides added pitch damping but provides no or only marginal extra +ve pitching moment.

When I wrote the article about tail planes in Skywings a couple of years ago (you can read it at www.slipstreamcomposites.com) it became obvious that the combination of increased pitch damping and added positive pitching moment over and above certification standards are necessary to improve our aircraft's tuck and tumble resistance.

Gerard Thevenot wrote in an email recently when questioned about tail planes

"Certifications say that above a line a glider is safe, under the line it is not. It is not a true fact, the more stable the safer the glider will be. A tail plane will improve the safety of a certified glider by a big margin."

In the incident in Spain it strikes me that the aircraft had enough airspeed to recover, it had passed through the first phase of rapid rotation and speed increase where the added damping had done its job, and not apparently gone past vertical, the pilot was still holding the bar and I think had moved his weight forward, at this point the glider should have pulled out and recovered, why didn't it?.

Added pitch up would certainly have been beneficial throughout the recovery and particularly at this point. I personally believe this was an incident where, with a tail plane fitted, the glider should have recovered.

Discuss tail planes and V tails at OzReport.com/forum/phpBB2

Discuss "Tail plane Vs. V-tail" at the Oz Report forum link»

10 topics in this article: aerodynamics, certification, competition, Gerard "Gerry" Farell, job, Laurent Thevenot, safety, tail, tuck, tumble

Flytec/Quest Air WRE – is it all just a dream?

Wed, Jul 9 2003, 5:00:00 pm EDT

At seven this morning I started looking at the day’s forecasts for the weather. Yesterday I received this e-mail message from Gary Osoba via David Glover:

I really like the looks of the long-range weather pattern as things improve this week, into the weekend, and all of next week. Not only will the winds and precipitation picture continue to improve overall, but the moisture they are getting for the second half of our 500 mile path right now will help with cumulus formation as things continue to dry out.

I think we will see both the 500 mile HG record and the 500 km PG record fall later this week, or next week. I am focusing on getting a glider there as soon as possible and as I am done with my other responsibilities to break the Open Free Distance record of 930 miles. Wyoming bound from Zapata!

Yesterday we had some wonderful flying in the morning but by noon it looked decidedly iffy with cloud base rising only to 3,000’ MSL, lots of clouds filling in and vertical development occurring. By the time we packed up and got on the road it was dumping hard to our south. Over development in other areas seemed significant.

A review of the satellite pictures indicated that it might have been possible to avoid the overdevelopment by staying to the west of it along our route, but our pace was quite slow (averaged 30 mph) due to the slow climb rates and low cloud bases, in spite of the 18 mph tail wind. We felt that the chances for a record flight were slim.

As I looked at today’s forecast this morning, I was again struck by the high moisture content of the air to our north. The FSL charts http://maps.fsl.noaa.gov/
rt_plots_40km20km///rh850mb_sc_09.gif showed relative humidity at 5,000’ near us at 40 percent, but at 70 percent up in the hill country and the Edwards plateau at 3 PM.

The satellite photo for the visible spectrum for the morning (http://weather.unisys.com/satellite/sat_vis_sp.html) showed clouds surrounding us to the east, west and north (we were in a little slot).

The enhanced infrared satellite pictures http://weather.unisys.com/satellite/sat_ir_enh_sp.html showed plentiful moisture for the first two hundred miles along our course except for the first bit from Zapata to a bit north of Laredo. This corresponded well with the high relative humidities forecasted for 3 PM.

The national forecast for the day showed a front in north Texas by Amarillo in the evening and continuing through the next day. The winds aloft forecast for the day showed winds clocking around as you went north deflecting off the front and going toward Oklahoma.

Cu’s were already appearing low over Zapata and scooting quickly to the north. There was a bank of cirrus way to the east near the sun. Elsewhere it was blue and as the early morning progressed toward 8:15 we needed to make a decision about whether to set up for a long flight. The cu’s were getting thicker and the streets were beginning to form in the classic Zapata tradition. Sure they were low now, but we knew by 9:30 they would be up about 1,500’ to 2,000’ AGL.

The local forecast was for a 40% chance of thunderstorms today and 30% tomorrow. We felt that the chances of it blowing up along our course line were quite high. We’ve experienced quite a lot of moisture coming up from Mexico throughout the whole time we’ve been here in Zapata. This has suppressed our climb rates in the morning and kept the cloud base low. This has reduced our abilities to go far fast.

Finally at around 8:30 we make the decision to not make the attempt today. At 9 o’clock the cirrus clouds come over and drastically reduce the number and thickness of the cumulus clouds below. The cirrus continues throughout the afternoon (I’m writing this at four o’clock) and there continue to be cu’s under the cirrus all day. Cloudbase has risen to about 4,500’.

Satellite photos of the visible spectrum indicate thicker cirrus to the north over our route. Some cumulus. It is blowing up to the east. There appears to be some streeting to the north of the cirrus, with clouds turning to the northeast. It looks drier than we had thought.

The NOAA marine forecast is:

An onshore flow with moderate seas will continue until the weekend…when a change is possible due to the approach of tropical storm Claudette…now located 200 miles south-southeast of Kingston, Jamaica.

Marine winds are predicted to be moderate southeast through Friday, then turning strong northeast on Sunday as the tropical storm enters the Gulf of Mexico and kills the Bermuda high pressure ridge.

The daily ten day forecast (http://www.intellicast.com/Local/
USLocalStd.asp?loc
=klrd&seg=LocalWeather&prodgrp=
Forecasts&product=Forecast&prodnav=none) indicated much lower temperatures than normal (5 or 10° below normal) and winds no longer out of the south east after Friday (http://weather.unisys.com/mrf/10d/mrf_850_10d.html or https://OzReport.com/txweather.php). The Bermuda ridge doesn’t appear to reconstitute itself in that time frame.

The national forecast for tomorrow morning shows clouds covering Texas ahead of the front. The front will be in mid Texas by 10 AM cutting off any possibility of a long flight. The winds will bend nineties degrees to the east.

During the first two years of the WRE the weather was as spectacular as Gary predicted. Day after day we could attempt long flights in conditions that allowed records to be broken. The last two years of the WRE have been miserable, other than an odd day or two. Moisture has been the big problem for us, but a great boon to the ranchers in this drought prone area.

I came here with the attitude after last year that I would take advantage of the conditions whatever they were. I was completely upbeat and ready to go for it. If the wind wasn’t blowing, well then I’d go for world record triangles and out and returns. Fortunately there have been a couple of days where records of this type were possible.

At the moment we have strong winds, low cloud bases, and wet conditions to the north that seem to preclude any possibility of world records. It is not clear if this pattern is going to change any time soon. The WRE ends in ten days.

Will the epic conditions return next year? I certainly don’t understand the long range prognosis regarding whether we can expect drier conditions next year or not. I know that I’m committed to going 500 miles, but I just don’t know when it will happen.

Discuss the WRE at OzReport.com/forum/phpBB2

Discuss "Flytec/Quest Air WRE – is it all just a dream?" at the Oz Report forum link»

14 topics in this article: cloud, David "Dave" Glover, David Glover, Gary Osoba, maps, PG, photo, picture, Quest Air, record, tail, weather, world record, Zapata

ATOS in Dinosaur

Tue, Jul 8 2003, 10:00:02 pm GMT

Jim Yokum <jim@yocom-mckee.com> writes:

I read with some interest the report of an Atos C with a tail tumbling in Spain. I had an exciting related experience this past weekend while flying from Dinosaur, Colorado.

The Rocky Mountain Hang Gliding and Paragliding Association sponsors the “Barney Fly-in” at Dinosaur. (See the graphic from the t-shirt in Oz Report #171). This year about 30 pilots participated with several flights in the 80 to 130 mile range. I hesitate to write this report as Dinosaur is one of my favorite flying sites and I hate to add to the reputation it has for rough air. I have found most of the rough conditions related to two factors: strong wind and cloud over development. For all but the last day of the weekend, we experienced no over development, but we did have strong winds each day.

Sunday, July 6^th, I launched my Atos C at 1 pm into a nice thermal 100 yards in front of launch. Tim Denton in his Atos B climbed with me to 14,000ft MSL. The thermal drifted almost due east - a good direction for Dinosaur. The forecast afternoon winds were 14mph at 9,000ft (approximately launch level) rising to 35 mph at 18,000ft MSL. On my first glide, I flew between 40 and 45 mph indicated airspeed, with my groundspeed in the 70’s. Later in the flight, as conditions became stronger, I recorded a maximum ground speed of more than 90 mph while flying 50 mph airspeed.

My first glide took me to the foot of Tanks Peak where I found some disorganized lift at about 10,000ft MSL. As I was searching for steady lift and a coherent core, I suddenly hit an area of very strong lift that had my Flytec 4030 Race screaming a tone I have never heard before. I had the flaps set at about half and immediately pulled the basetube in as far as I could.

The nose of the glider was still pointed nearly straight up and there was tremendous wind noise. I soon reached the edge of the thermal where the wind noise just as suddenly stopped. I held the basetube to my stomach as the nose of my glider rotated down and I went weightless. My feet hit the keel and the glider pointed straight down for what seemed like eternity, but soon my airspeed returned and I was able to ease out the basetube and return to normal flight.

I took one more thermal near Cross Mountain to 16,000 ft and glided to Maybell where I decided to land due to numerous areas of virga and lightning. The wind on the ground was gusty and blowing in excess of 25 mph. I was very happy to be on the ground! 55 miles flown in three thermals!

It is impossible to prove whether the AIR V-tail stopped my glider from tumbling, but I was very happy to have it installed! This one incident was by far the worst. I tend to like Dinosaur much better later in August and September. Lighter winds and more manageable thermals.

Discuss "ATOS in Dinosaur" at the Oz Report forum link»

6 topics in this article: altitude, cloud, Flytec 4030, lightning, tail, Tim Denton

The Spanish ATOS “incident”

Mon, Jul 7 2003, 6:00:05 pm GMT

David Cross <d.cross@chello.nl> writes:

I have recently had the unfortunate experience of departing controlled flight in an ATOS rigid wing hang glider. I have written this report to share the experience with my fellow aviators so that any lessons learnt may be shared and the accident assessed by those with a better insight in this field than I.

Description of Flight Conditions

I had launched in the mid afternoon with an aero tow from Aerotow.com's facilities near the town of Avila in central Spain. I was planning to fly some cross country under the tuition of the highly experienced Ron Richardson. It was my second flight of the day. On the previous flight I had found the conditions to be weak with the thermals broken and the climbs poor and I had not been able to stay up for long. The afternoon however improved with the cloud base lifting to about 7000' altitude (average ground elevation of 3000'), with promising cumulus development downwind to the east and no sign of the previous day's overdevelopment.

The second aero tow was bumpy but easy to handle on the ATOS with its excellent control harmony between pitch and roll. I was waved off in some lift over a small ridgeline to the south east of the field. I again found the lift to be broken and the climb weak. Ron was at this stage further to the east overhead the town and was calling a 300'/min climb on the averager. As I was at this stage too low to get over to him I focused on what I had in order to build more altitude. I scratched up to 4800' altitude and then ran for a good looking cumulus on the way to Ron's position.

Loss of Control

Entering the Thermal

I rolled right hand into the lift under the cumulus and worked hard to centre it. The conditions were choppy but not rough and smoothed out somewhat above 5000' altitude to a steady 300 fpm up. The conditions downwind were now looking really good and through each turn I was scanning to pick up Ron's Avian Cheetah on the horizon, and I could hear Darren Blackman heading in towards us on his Swift. Things were at last coming together after a week of poor conditions. I was relaxed, thoroughly enjoying the ATOS and looking forward to the afternoons flying.

Turn Reversal

I had in the last turn noticed a slight increase in lift in the southern sector of my circle. I glanced down to see if there were any birds marking the core and was presented with a magnificent stork circling left hand counter flow to me with slightly intersecting circles. After one more turn I saw that (as always) he was doing a better job than I and so I planned a turn reversal into his circle.

The reversal worked out well. As the stork slid under my nose I experienced a moderate pitch up from the stronger lift and eased the bar in to lower the nose and accelerate while rolling out of the right hand turn into a left hand circle. Due to the fair conditions I had been thermalling at 40-45 km/h (25-28 mph) indicated airspeed (IAS) with 20-25° of bank and had felt very comfortable at this speed.

(editor’s note: Unless the thermal is absolutely light (50-100 fpm) and full with no turbulence, I’m flying at 34-38 mph. The speeds indicated above are much too slow for the conditions described.)

As I had now accelerated into the stronger lift I estimate that the IAS was approximately 48-50 km/h (30 mph) as I started the reversal. The flap was set at 8-10°. The reversal was initiated with moderate spoiler application - I estimate ⅓ to ½ deflection. The altitude was now 6000' (about 2500' AGL due to the ridge below).

Departing Controlled Flight

As the left hand turn was established I felt a light short period aerodynamic buffet on the control frame and almost simultaneously experienced a very rapid nose down pitch rotation through approximately 90° of pitch. I estimate the pitch rotation rate to be 50 -60°/sec. There was also some left hand roll rotation, although this was less than the amount of pitch rotation. I was not aware of any significant yaw.

As the departure started my assessment was that the glider was auto-rotating and that I was in the incipient stage of a spin. I had been thermalling with the bar in the upper chest to lower chin position. As the nose down pitch started I rapidly moved the bar in to the mid chest position in an attempt to reduce the angle of attack, un-stall the wing and stop the autorotation. This appeared to stop the left roll rotation rate but had little effect on the rate of nose down pitch. During the latter part of the initial nose down rotation I estimate that the g loading on my body was 0 - 0.5 g (I felt almost weightless).

The glider then appeared to stabilize very briefly in the vertical nose down position before rotating extremely rapidly in pitch to the inverted position. This second rotation was violent and uncontrollable. As it happened I felt a powerful rearward pull from my hang strap and the control bar was pulled from my grip. I was thrown hard into the undersurface of the glider which was now inverted, next to the A frame. I estimate that this pitch down rate was well in excess of 90°/sec.

The glider now stabilized in the inverted position while descending in what appeared to be a relatively gentle oscillatory spiral. I was somewhat disorientated at this point and so may not be too accurate about the motion of the glider. I do however recall some spiral motion and some oscillation above and below the horizon.

I was lying on the undersurface of the wing to the left of and outside the A frame. I immediately checked the leading edges and tips and observed no apparent structural damage. I assessed that I had sufficient altitude and attempted to right the glider and reached for the A frame to do this. When I grasped the left down tube to attempt to right the glider, the glider entered a very disorientating oscillatory rotation but remained inverted. I assume this was caused by spoiler deflection when I moved the A frame.

After two rapid rotations it did not appear to be recovering. At this stage I was losing situational awareness with respect to the height remaining for recovery. In addition the gliders unstable motion had me concerned about the possibility of being knocked unconscious.

Parachute Deployment

I thus looked for clear air and deployed my emergency parachute hard in the direction of rotation half way between the right hand wingtip and the keel. The parachute deployed immediately and then appeared to semi collapse as the glider was rotated by the parachute deployment into the upright position, swinging me hard to hang to the outside of the A frame. The parachute then reopened immediately.

The system of parachute, glider and pilot now became extremely unstable with the parachute and the glider appearing to work in opposition. The glider appeared to accelerate and pitch nose up, causing the chute to collapse and then re-open before the cycle was repeated by the glider. From my vantage point the parachute was describing a sine curve-like path across the horizon while collapsing partially and re-opening in sequence with the pitch motion of the glider.

The glider and parachute appeared to be rotating rapidly about each other with the centre of this rotation somewhere between the glider and the parachute. At no stage was the parachute positioned above the glider. The centripetal acceleration of this system rapidly became very high. I estimate the g loading to be approximately 3 g and I was swung out helplessly under the wing clear of the A frame unable to control the system at all.

Stabilizing the System

I now broadcast a Mayday call, and informed Ron that I had deployed the parachute and was going down. I described my status and informed him that it did not look promising. At this stage the rate of descent and particularly the angular rotation appeared to me to be very high and I was sure that ground impact in this configuration would have severe consequences.

After several high g rotations I managed to grab the hang strap behind my neck and pull myself toward the A frame and grasp a down tube. Adrenaline is a wonderful thing. I then pulled myself into the A frame. This had an immediate positive effect. The parachute stabilized above the glider, the angular velocity reduced and the g loading reduced. I was now descending through about 500' AGL with a moderate oscillation but no angular rotation at all. I now called Ron to inform him that the situation was under control and proceeded to describe my probable touchdown position to him.

Touchdown

I descended onto the slope of a rocky tree covered ridge. Before impact I positioned myself as high into the A frame as possible as I was not sure what the rate of descent was and I wished to protect myself from any impact on what appeared to be very rocky terrain. I kept my legs bent to absorb as much shock as possible.

I was fortunate to impact into the crown of a moderately sized tree. The A frame took much of the initial impact of the branches. The glider was then swung out of the top of the tree throwing me out of the A frame. As I fell to the ground the glider hooked onto a branch and my fall was arrested with my feet 12cm off the ground. I was completely uninjured. I transmitted to Ron that I was down and safe and that he should cancel any ambulance.

The only apparent damage to the glider was a broken main spar and associated sail damage approximately ⅓ in from the right wingtip. This occurred on ground impact and not in flight. My assessment was that the glider was completely undamaged until ground contact.

Discussion

As with any aviation accident there are several lessons to be learnt. Most accidents are not caused by a single event but by a combination of factors. Often an accident could have been prevented if just one of these factors, however minor it may have seemed at the time, could have been identified and stopped. I will now discuss my background, what I think may have been the contributing factors to this accident and the lessons learnt from it. This is obviously my subjective opinion and I welcome any discussion on these points that may offer a more informed insight.

Flying Experience and Background

I am a USHGA intermediate rated pilot who has been flying for three years. I did my initial training in the French Alps mountain launching and completed my training at Wallaby Ranch where I also obtained an aero tow rating. I did a further foot launching course at Lookout Mountain where I obtained cliff launch, flat slope launch and assisted windy cliff launch ratings. My flying has taken place mostly in Florida and the Alps and has always been under the supervision of more experienced pilots. I currently fly a Moyes Xtralite. One month prior to the accident I had flown under the supervision of Chris Dawes in the UK where I did some winch foot launch training and some aero towing as an early season refresher. Prior to this I had last flown the previous late summer in the Alps.

I am a current airline pilot flying Boeing 747's and a current Air Force reserve pilot on fighter type aircraft. I hold a Glider Pilot's License although I am not at present current on sailplanes. I have some experience flying paragliders although I have not yet completed my license. My total flying experience is 8000 hours.

I have mentioned the military experience as I feel it is relevant with respect to my experience in spinning three axis control aircraft. My air force background has provided me with extensive spin training. I have been fortunate to have had the opportunity of spinning a variety of aircraft, from military trainers and fighters to general aviation aircraft, aerobatic aircraft and sailplanes.

Two weeks prior to this accident I carried out a maintenance test flight on a military trainer that included several multi turn full spins and recoveries. I thus feel that I may be considered current as far as spin identification, entry and recovery on three axis aircraft is concerned. This has relevance as there has been much discussion about the advantages of doing spin training on three axis aircraft before flying rigid wing hang gliders.

ATOS Experience

I had come to Spain specifically for the opportunity of flying the ATOS. At the time of the accident I had flown 11 flights on the ATOS for a total of 5.00 flying hours. All flight had been under the supervision of Felix Ruehle and I had been extensively and professionally briefed by him on all aspects of the glider.

Although this was my first experience on a rigid wing hang glider I had felt comfortable and confident on the ATOS from the first flight. I had on the second flight in smooth evening conditions flown the glider to the stall and found the recovery to be simple. I had confidence thermalling the glider in the moderate conditions I had experienced and at no stage had any reservations about the handling of the glider. I found the control harmony particularly pleasant and aero towing simple.

(editor’s note: An inexperienced hang glider pilot, new to an ATOS, was flying it too slow in a thermal.)

Equipment

The glider was a standard ATOS. I had for most of the week prior to the accident been flying another standard ATOS. The hang point for the accident glider (as on the previous glider) had been adjusted towards the forward centre of gravity (C of G) limit, appropriate to my hook in weight. On the accident glider my hang position was slightly higher than that of the glider I had flown previously in the week and the trim speed was slightly lower. Both the hang position and the trim speed were well within safe limits. The glider was fitted with an A.I.R. horizontal stabilizer.

I was using a Woody Valley Tenax harness with the parachute mounted on the right chest. The harness was fitted with a Metamorfosi Conar 18 Gore parachute, which was just over one year old and had recently been repacked by myself. No swivel was fitted to the bridle. My weight is 72 kg making a hook in weight of 87kg.

Airspeed information was provided by a Brauniger Galileo set to indicated airspeed (IAS) mode and a mechanical pitot system fitted by Felix. I used the mechanical system for airspeed reference as I had not yet calibrated the Galileo and was not sure of the reliability of the airspeed display.

Departure from Controlled Flight

I feel that the departure from controlled flight had two distinct phases, a non divergent autorotation phase, and a divergent pitch instability phase.

Autorotation Phase

The autorotation phase I would describe as a gust induced stall in the turn followed by an autorotation and an incipient spin (the incipient stage of the spin being where the aerodynamic and gyroscopic effects of the spin are still influenced by the initial flight path of the glider - in this case a left hand turn). Although the nose down rotation of this phase was rapid it did not feel to me to be divergent. I thus do not feel that the gust had at this stage placed the wing at an AOA/hang point loading combination that had exceeded any static stability margins.

I was surprised by the limited aerodynamic stall warning and the rate of the initial nose down rotation. For these reasons I think the gust onset was significant and rapid. All my previous spinning experience in aircraft had led me to expect an initial rotation rate in roll and yaw that equaled or exceeded any initial nose down pitch rotation. As the initial nose down rotation started I had reduced the AOA aggressively. This seemed to stop any further roll or yaw rotation but had little effect on the rate of nose down pitch rotation. At no stage did the glider enter a stabilized spin.

I feel that there are several factors that could have contributed to the initial autorotation.

Firstly the glider was trimmed slightly slower than that to which I had been used to on the previous ATOS I had flown. As stated this was well within safe limits but may have caused a tendency towards slightly slower flight if I was distracted.

Secondly, I was using flap to thermal. This would move the bar position slightly back and I would, if focused primarily on bar position, have the tendency to move the bar further forward than required.

Thirdly, I had completed a turn reversal prior to the autorotation and the spoiler deflection would have caused some nose up pitching moment. If not corrected this would cause an obvious reduction in IAS and place the glider closer to the stall.

All the above factors are conducive to slower flight. However I am accustomed to flying aircraft that require accurate speed control and feel that I was very aware of the IAS while thermalling. I was also aware that the spin behavior of rigid wing gliders can be unpredictable and had no desire to explore that environment. My thermalling speed of 42-45 km/h (26 mph) felt comfortable for the conditions I was experiencing. I have since been informed that it was perhaps on the low side but not unsafe.

(editor’s note: Pilot is unaware that he is flying too slow.)

I had thermalled at similar speeds in equivalent conditions for most of the week without ever approaching any stall margins. The accuracy of the airspeed reference must also be considered. As mentioned previously my primary reference was the mechanical pitot system as I felt it was more accurate than my as yet un-calibrated electronic reference.

Some points with respect to the turn reversal technique. I normally unload the wing (thus reducing the AOA) before initiating any reversal in order to improve the roll rate. This obviously also results in an increase in IAS. Whether my technique was sufficient to counter any pitch up due to spoiler deflection may be debated. I did not notice any significant pitch up during this particular reversal. My limited experience on the ATOS could of course preclude this.

In addition I had experienced acceleration on entering the increased lift prior to the reversal. I had countered the nose up pitch that this had caused and so feel that my IAS margins on entry to the turn reversal were probably sufficient for normal conditions. I had as well been briefed on the "rule of thumb" safe range for forward and rearward bar positions and at all times flew within this range.

I thus think there must have been some significant gust effect present. Simply approaching the stall in a turn should not result in the almost immediate and rapid rotation experienced with minimal stall warning. I have described the conditions as moderate. I was experiencing an average climb of 300 fpm with maximum instantaneous readings of 1000 fpm.

However, Ron Richardson reported some strong turbulence while descending through the airspace I had been flying in, shortly after I deployed the parachute. My assessment is that a gust rapidly exceeded the critical AOA of the wing. As I was not yet fully established in a stable turn, there would have been some asymmetric loading on the wing, possibly resulting in the auto-rotation. I feel that this is supported by the fact that my rapid reduction in the AOA had no appreciable effect on the pitch rotation rate.

Pitch Instability Phase

I will now discuss what I consider to be the second phase of the departure. During the initial auto-rotation I had not experienced any reduction in g loading on my body - the hang point still felt loaded. Although the initial nose down rotation was high, I still felt that I had some control input and that the glider would recover. However, as the glider passed through about 60° nose down I experienced a reduction in g loading and felt almost weightless.

From this point I felt I no longer had control of the glider and I was unable to hold the bar in any longer. This is when the rapid rotation to the inverted position occurred and I lost my grip on the control bar. Perhaps the excessive AOA of the wing combined with the unloading of the hang point caused the static stability margins of the wing to be exceeded, causing a divergent rotation in pitch. The first auto-rotation phase initially felt controllable. The second phase of pitch instability was definitely not controllable.

Lessons Learnt

Thermalling at higher speed, steeper bank angles and higher g loadings, while not necessarily providing an increase in stall margin, will improve the damping in pitch and make a departure less likely.

It would be of value to calculate the exact stall speeds for the actual wing loading at various appropriate bank angles. With an accurate IAS reference sufficient margins could be applied to these calculated stall speeds for safer thermalling. An accurate IAS reference is obviously necessary. Of even more value would be a vane type AOA reference (Here's hoping!).

I found the ATOS easy and a pleasure to fly. However, in retrospect I feel that more time spent exploring the performance of the glider in smooth air would have been of benefit. I think in particular, the effect of flap on trim speeds and bar position, spoiler effect on pitch in turn reversals and approaches to the stall in wings level and turning flight should have been more fully explored before flying in more challenging conditions.

I think that my initial reaction to the auto-rotation phase was correct. Moving the bar in reduces the AOA and places the centre of gravity in the best possible position for dive recovery. Should this happen again I will do the same while attempting to hold on tighter. I do however feel that it was impossible to maintain grip on the control bar during the rotation to the inverted position.

Some comments on pilot experience. I was very excited to be offered the opportunity to fly the ATOS by Felix, as I consider myself a low time hang glider pilot. His briefing was comprehensive and gave me confidence in the glider while making me aware of how it differed from other gliders I had flown. I flew the glider conservatively and felt very confident with the general handling.

The afternoon following the accident I flew another standard ATOS in moderate thermic conditions for a 1 ½ hour flight. While understandably nervous at first the pleasant handling of the glider allowed me to settle down and soon regain my confidence. In summary I experienced nothing in the handling of the ATOS that should exceed the abilities of an intermediate pilot. In most respects I found the ATOS easier to fly than an intermediate flex wing hang glider.

Some discussion on three axis spin training for rigid wing pilots. I feel the main benefit of this would be spin entry recognition and reduced disorientation. The spin entry techniques and recovery procedures for a three axis aircraft are different to that of a rigid wing hang glider and themselves can vary dependant on the design of the aircraft. Practicing these procedures would I feel have limited benefit for rigid wing pilots and may even reinforce incorrect techniques. In this accident the main benefit to me of my spin training was recognition of the initial situation and orientation in the unusual attitudes experienced.

Some points on the parachute deployment. It has been suggested, considering the glider was undamaged while inverted, that I could have tried harder to right the glider before deploying the parachute. In retrospect I am glad I did not. I lost a lot of height trying to stabilize the spinning parachute/glider combination. Had I deployed the parachute any later I might have impacted before stabilizing the system. At the time I did not feel that this would have been survivable.

I have discussed this with Angelo Crapanzano from Metamorfosi. He commented that although I was experiencing high g loadings, because the centre of gravity of the pilot/glider/parachute system would have been very close to the pilot/glider combination, my rotational speed would actually have been quite low. In addition he said that my descent rate would perhaps have been even less than when I had stabilized the system. He thus feels that even when the system was not stabilized, it was survivable. The perception from the pilot's point of view remains unpleasant.

In addition it is not certain how the glider may have reacted in the attempt to right it and there is a strong possibility of pilot injury in attempting this. This may then preclude parachute deployment. I thus feel strongly that if one is fortunate to survive a loss of control situation uninjured, the priority is to get the parachute deployed immediately. Considering the instability after parachute deployment, I feel the priority should be to get ones mass as close as possible to the hang point.

Angelo Crapanzano recommends that one gets as close as possible to the nose of the glider, or at least in front of the hang point. This can however be difficult and the A frame is a familiar refuge when under stress and can provide impact protection. It would have helped if I had held onto some part of the A frame before deploying the parachute, as this might have prevented me from being flung away from the A frame as the parachute deployed and righted the glider.

Had I been able to remain closer to the A frame the spiral motion might not have developed. I also feel that some thought should be given to the option of releasing from the glider prior to parachute deployment. All my complications were due to the fact that I was still attached to the glider.

I am very pleased that I had the Conar HG18 parachute. The rate of descent once stabilized was acceptable and the opening time impressively fast. It worked as advertised.

Some discussion on communications and search and rescue procedures. I was able to transmit a Mayday to Ron Richardson seconds after deploying the parachute as I had a transmit button fixed to my thumb. Ron demonstrated professionalism and true airmanship. He acknowledged my call, was overhead my position within minutes, plotted GPS co-ordinates and arranged a rescue. He then landed in a difficult location and was at the accident site within 30 minutes.

Had I been seriously injured Ron's actions would have been potentially life saving. The lessons here are to always fly with someone, be able to communicate effectively with them, even under duress, and always be prepared to assist effectively in an emergency. I had water in my harness but no first aid kit or emergency rations. This has been rectified.

Conclusion

In summary, I suggest that this accident was a result of a gust exceeding the critical angle of attack of the wing by a large margin. This resulted in auto-rotation with a rapid nose down pitch and unloading of the hang point. The static stability margin of the wing was exceeded and the wing experienced a divergent rotation to the inverted position.

Contributory factors were the relatively low indicated airspeed while thermalling, the effect of flap on the control bar position, pilot technique in the turn reversal and the pitch up effect of spoiler deflection.

Flex Ruehle’s Comments

I have attached an email from Felix Ruehle with his comments on the report and the incident.

You report is excellent however I think it's hard to see how quickly or slowly everything happened because my experience is that reports from stress situations follow a different clock.

Since hang gliding was born turbulence can be a problem for safe flying. However different developments improved the safety. One of the latest developments is the fixed V-tail with a lifting airfoil from A-I-R. How does it work? The glider is designed to have the same pitch up moment with tail like the standard ATOS with 0° flap.

With thermal, take off and landing flap setting the pitch up moment is significantly higher with the V-tail. Additionally the V-tail increases pitch damping very significantly with all flap settings. Of course instead of a tail the sweep angle can be increased too to get the same pitch damping effect. However this didn't work out as well for the ATOS, because higher sweep in combination with wing bending would cause dynamic problems.

With the V-tail the glider flies significantly more comfortable. In opposite to the opinion of some pilots, that a positive pitch up moment only protects a glider from tumbling, this is not the case. It is a result of several flight incidents with all types of hang gliders and as well with the hang glider drop test made by the DHV a few years ago that even with a certified hang glider it is possible to tumble.

According to my opinion the main parameters are: Pitch damping which can be increased by higher speed and by the wing area distribution in flight direction. For example a higher sweep angle or a tail, increase pitch damping as well as a forward pilot position. Pitch up moment. This is the moment which must be above a certain value for certification. Small distance from aerodynamic centre to CG.

For example a short A-frame is positive. High airspeed in relation to the turbulence is positive too.

The incident

The air was not very smooth this day and there was over development with rain shortly after the incident at this spot. Ron who landed close to help Dave (thanks Ron) hit some strong turbulence too. However, the day wasn't that rough that pilots usually would stop flying.

According to my opinion the tumbling from Dave was caused due to low airspeed in relation to the turbulence. The thermal speed under this condition was already little slow. The reversal turn reduced the speed probably further. This for example is a very good practice in smooth condition, doing reversal with constant speed. Take care: If you don't pull in during the reversal the speed drops.

I flew to the same spot the next day and felt comfortable with about 55km/h (34 mph) as min. thermal speed. This day looked smoother to me as the previous day.

Does the tail improve the safety? At the online contest (olc) 2002 the ATOS is the glider which has flown the most km before any other wing (including flex wing) and the ATOS flew much more km than other rigids, too. Many pilots have flown sometimes under extremely hard conditions and have reported the good behavior under turbulent condition.

It looks to me like active flying is getting more and more important. With the fast gliders the pilots have the possibility to fly with extra speed or high bank angle without losing too much of performance and it looks too me like the ATOS with the new V-tail is a step to improve pilots safety to a very high level even with the incident of Dave.

Under strong condition the glider gets extra stability with high bank angle and higher speed. While doing a reversal you can easily lose speed and the pilot has no extra g loading. I think this can be an interesting discussion how different pilots handle turbulent air.

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39 topics in this article: accident, aerotow, airline, airspace, altitude, Angelo Crapanzano, bridle, Carlos Avila, certification, cloud, control frame, DHV, environment, equipment, Felix Ruehle, Florida, foot launch, general aviation, GPS, harness, injury, job, landing, military, Moyes Xtralite, parachute, Ron Richardson, safety, site, spin, Swift, tail, technique, tow, towing, tumble, USHGA, Wallaby Ranch, winch

Flytec/Quest Air WRE – thick cu’s real early

Thu, Jun 26 2003, 6:00:00 pm EDT

There were good looking cu’s streaming over the Zapata County airport at 9 AM. These things had real vertical development to them. Not only that, they were blowing out of the south, not southeast, making for a bit of a cross wind over the 120° runway.

I haven’t seen this good a wind direction since I first came here three years ago at the first WRE. We used to have a problem with our static line falling over the fence to the east of the airport. It was so great to see these winds return.

We saw on the forecast that there was a front coming our way from the north about 300 miles out so it didn’t look like a world record day unless the wind calmed down a bit in the afternoon and permitted triangles.

Ron Gleason in an ATOS, Pete Lehmann in the Attack Falcon, and Gary Osoba got off around 10:30, knowing that the day would be cut short to the far north. Ron went 100 miles and never crossed interstate 35 which runs northeast out of Laredo. His heading was 306° which has never been accomplished here, quite far east of any track we’ve seen before.

Pete tried to chase Gary and felt foolish for it landing a short ways from the airport. Gary, in the Sparrowhawk knowing about the front stayed around helping Ron for the first few miles.

Junko took off at noon in the Swift Light for a couple of local flights while Bo had three tandem passengers, the first, an 85 year old lady who came out on her own and couldn’t wait to tell all her friends tonight at Bingo. He said she never tells her family about dangerous things she’s going to do, until she’s done them.

Later Ron told the story that after breezing through the first 55 miles in 70 minutes, he ran into rough air in front of the front. He went half inverted at one point. Thank goodness for the tail. We’ve never experienced a front down here and usually the air is very pleasant.

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11 topics in this article: Gary Osoba, landing, Lawrence "Pete" Lehmann, Quest Air, record, Ron Gleason, Swift, tail, tandem, world record, Zapata

Shake your tail feathers, baby

Tue, Jun 24 2003, 6:03:05 pm GMT

tail|Zapata

I mentioned noting that the AIR ATOS tail was shaking when I flew slow in Wisconsin (bar trim). I thought I would notice that here in Zapata also in the light conditions of the early morning flying. But, I haven’t felt any shaking at all, and I wonder if the temperature makes a difference?

It is very important to pull on your flaps when thermalling at ATOS-C. On the ATOS I hardly ever bothered, but with the ATOS-C I use the flaps a lot to slow down in the thermal and get a better climb rate as well as more control. If you’re not doing it, check it out because the difference is dramatic.

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2 topics in this article: tail, Zapata

Shake your tail feathers, baby

Mon, Jun 23 2003, 2:03:04 pm EDT

tail

I noticed that the ATOS was shaking a bit at low speeds when I was flying in the extremely light conditions in Wisconsin. I had to fly at about minimum sink speed to experience this effect.

I wrote to Felix to see if he had experienced the issue. Felix wrote back:

I think some tail shaking comes from the slack from the tube connection. I think that you feel some vortex from the slot of the flap hitting the tail at higher angle of attack. The minimum sink should be at 26mph and I think it's not so bad that you feel this point.

You can put a layer of tape to the connection.

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1 topic in this article: tail

Metal windsocks

Sun, Jun 22 2003, 2:03:06 pm EDT

cost|magazine|tail|William Wixon

William Wixon <wixon@warwick.net> writes:

The May 2003 issue of Experimenter magazine, "Metal Windsocks!" http://www.home.earthlink.net/~gigax7/

Very durable. He sells plans for $30. It says materials can cost less than $75.

You can see in the photos it's got a little tail fin. Rigid pilots will like that feature. Hey, a rigid windsock for rigid pilots.

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4 topics in this article: cost, magazine, tail, William Wixon

Yet another final glide discussion

Sat, Jun 21 2003, 2:03:01 pm EDT

I hope that interested readers will closely follow the arguments presented here as well as in the previous articles that address this issue.

Chris Arai, Arai Design <chris@araidesign.com> writes:

Thought I would chime in on the perennial topic of final glides and whether or not jumpy numbers matter. I have to admit that I don't know to what degree the numbers jump on a Brauniger deck, but I seem to recall that people say plus or minus more than 1000' in certain conditions. Correct me if I'm wrong, but I'll use that figure for a point of reference. I'll also discuss (again) the why I believe that automated wind calculations for final glide actually reduce the usefulness of the final glide numbers.

(editor’s note: I wouldn’t characterize it as jumping around quite that much, but I’m sure at some points I have seen that level of jumpiness. It appears to be less now with the longer time constants.)

Jumpiness. Why does it matter? If the numbers are jumping up and down +/- 1000 feet, the safe thing to do is pick the most conservative number and climb to that level. Making the assumption that the mid point was the correct number, the safe pilot must climb an extra 1000'. At a nice climb rate of 500fpm that is two extra minutes. Two minutes might seem like nothing to the novice who is grateful to make goal, but anyone who as placed in the top 40 (50? 60?) of a major meet will tell you that 2 minutes is huge. Well 2 minutes becomes 3+ minutes if the climb rate is 300fpm, 5 minutes at 200fpm, and so forth and so on.

I believe Peter was saying that steady numbers are some how masking changes or are stale. Take this example. You’re gliding on final right on the path and suddenly the sink increases by 200fpm. Now assume that you had a 1000' margin built in for safety. It would take 5 minutes before that margin was completely eroded. That is a long time.

Tangent pilots know that by comparing the Altitude Required field with the Altitude field one can easily see if he or she is eroding the margin. Yes, time is required to do a calculation known amongst mathematicians as subtraction. (Most pilots are capable of this although sometimes I wonder when you see how short the collection of money can be when it's time to pay for dinner.)

Now consider using an instrument that the final glide info is jumping around by +/-500 feet (I'm being more lenient than the +/-1000' I said I was going to use.) How do you determine how your final glide is proceeding? One minute you are on the path, the next you have used up all of your 1000' margin. Your choice is to pick a number in the middle of the jumpy numbers or average them. I think either calculation uses far more of the pilot’s minimal bandwidth than subtraction.

Peter Brauniger said that "the quality of a final glide calculation can be measured by the stability of the displayed result is clearly a misconception." As a riposte to Peter I would suggest that what I am hearing from pilots (and from a little personal experience) is that stability seems to be more useful and causes less anxiety, even if it is of lower quality ;-) .

So why are the Brauniger instrument final glide numbers so jumpy? Peter Brauniger correctly points out the variables used in a final glide calc:

Variables: Pilot distance from goal, Pilot height above goal, Speed of wind (component in direction of flight), Airspeed of glider

Two of those variables, distance and altitude from goal are relatively slowly changing variables, perhaps only a few percent per minute.

Airspeed can and does change radically, as much as a factor of 3 (20 - 60mph).

Wind doesn't change quickly unless one of two things happen: first, a strong wind shear, which is rare in my experience. Second, the calculated wind changes due to calculation errors.

The airspeed and wind speed are the key. I'm not sure which has the greater contribution, but my guess is that it is airspeed. As Peter describes in Vol6, N38 of the Oz Report, his arrival height calculation is based upon wind, current altitude, distance, and current L/D. Current L/D is calculated from the polar and current airspeed. The problem with this method is that one’s airspeed will (and should) vary. True, the glide does change with airspeed, but we don't care about where the slope is pointing at any given instant, we only care about where the glide slope points in the long run.

So what airspeed do you use to calculate this L/D? I suspect that the Brauniger decks average the airspeed and that the jumpiness has calmed down as the time constant of that averager gets longer with each software revision. The problem I see with averaging the airspeed is that it may give you information that is too optimistic or pessimistic.

Let’s say you average the airspeed for 1 minute (probably longer than is done on the Braunigers.) After gliding through heavy sink for a minute your final glide calc is now saying that you will now arrive 1000' below goal. Yeah, Yeah, I know it doesn't use sink for the calculation, but it is a speed-to-fly (S2F) instrument right? And more sink means that it has told you to speed up and thus your L/D has been reduced.

That pessimistic estimate will slowly return to normal as you fly in less sinky or lifty air, but you have to chew your nails that whole time, when in reality you may have only lost a couple hundred feet of your margin. The real peril here is that it will tempt you to slow down to improve your glide. We all know that slowing down in sink is a cardinal sin in S2F theory. The optimistic scenario is exactly the reverse. Shortening the airspeed averaging time will add to the jumpiness of the arrival height numbers.

So although lift and sink are not used ("We never take into account a current or an average sink rate.") in the Brauniger decks, sink rate does have a direct effect on the arrival height numbers as shown in the above paragraph.

How does the Tangent avoid this morass? It doesn't use current airspeed at all to calculate the L/D. Instead, it uses the optimum airspeed based on the Speed Ring setting and Wind setting.

Since we all assume that the net airmass sink will be zero, why not calculate your gliding speed in zero airmass sink for a given speed ring and wind setting? Since the vario is telling you to fly the correct speed for those two parameters for any airmass movement, I make the assumption that the pilot will actually try to follow that speed. (Smart people shell out big bucks in the hopes that they can believe what the "instrument" is telling them. The rest are happy if it looks good.) If the airmass is zero in the long run as we assume, then the average speed will be close to that of the one calculated.

It may seem to those who have never used a Tangent that this method denies the pilot of critical information. It doesn't. If the Altitude Required is not tracking Altitude, then something is wrong: More lift or sink than "zero" or the wind estimate is not correct. If the wind speed seems different than the estimate, then change the estimate. If not, then there is too much lift or too much sink. If it's too much lift, then hooray, bump up the speed ring (if you believe the corresponding sink is not ahead.) If it's too much sink, it's time to alter your glide path to get out of the sink.

This brings us to the topic of automated wind vs manual wind in final glide calcs. I have discussed this before (see links below) so I'll just summarize (this is long winded enough, don't you think?) The problems with automated wind input are in two categories.

1. Errors in GPS wind measurement.

2. No ability to compensate for different winds at lower altitudes.

Item 1 can probably be reduced, but will always be a problem to some degree. If the wind measurements are noisy then the final glide calcs will reflect that noise.

Item 2 is important, and can only be done by a human. Although the automated wind will be correct (apart from item 1) at all altitudes, it may give false final glide calcs at the high altitude where final glide begins. If you calculate final glide based on a 20mph tail wind at 10,000' but it doesn't stay 20mph to the ground, you come up short.

More info on the final glide and the GPS wind problem can be found in the Tangent online manual. Go to http://www.araidesign.com and click on the "Manual" button. Then read these sections:

Why Doesn't the Tangent Automatically Use the GPS Wind in the Speed-to- Fly? The Final Glide Calculator Final Glide Techniques

Also see the previous Oz Report discussion on final glides at https://OzReport.com/toc.php?6.038 https://OzReport.com/toc.php?6.044

Steve Pearson at Wills Wing <Steve@willswing.com> writes:

We cleared that up a long time ago, and it's even addressed in Peter's last email. Peter absolutely positively does not use the algorithm Chris speculates about. I think it's grossly unfair to Brauniger to propagate a myth that the display alternately displays goal arrival +/- 1000'.

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11 topics in this article: altitude, Chris Arai, GPS, Oz Report, polar, safety, software, Steven "Steve" Pearson, tail, tracking, Wills Wing

Midwest Regionals – cu nimbs and guys at goal

Sat, Jun 14 2003, 6:03:00 pm GMT

http://www.flytec.com/mwregionals

Check out the animated track logs (click “Top Tracks” - you have to wait for a few minutes for them to begin animating).

Check out the photo gallery (http://flytec.com/mwregionals/gallery.html)

The FSL forecast shows that there is the possibility of over development, but while I inform the task committee of this possibility I forget to mention it to the pilots. There is large patches of cirrus both north and south in the late morning, and the cu’s are forming slowly and they look soft and weak.

The wind dummies are up and staying up, so it’s a good sign. We’ve got the option of launching at 12:30 PM with a 2 PM start window (way more time than we need to get everyone in the air with four Dragonflies waiting to pull us up).

I notice that Jim Lamb is suiting up early and he’s thinking that its time to go soon after the launch window opens. The task is a 46 mile dog leg to the east south east, away from Class D airspace at Janesville and over to an airport at Monroe where hang gliding pilots use to truck tow.

The five rigid wing pilots all notice that Jim and Dave are getting ready so we all get ready and we are all in line together by ourselves as the flex wing pilots look on. No body wants to be left behind.

We’re up in a few minutes and it is a quick climb to cloud base at 4,400’. The flex wing guys get in line right behind us and everyone other than Paris who has been sitting around in a lawn chair is off before 1 PM. No waiting around today.

The cu’s get thicker and thicker and it looks like we won’t be waiting until the 2 PM start time. Dave Brandt heads out to the south and the rest of us rigid wing pilots up high follow him and Russell out toward the start circle. But Dave doesn’t get up and everyone but Russell turns back to get back up again with the flex wings.

Dave gets lower and lower out on his own, as he’s not willing to come back and join us low, and I’m wondering what the point is. This meet has taught us to work with our friends above all else, and I can’t figure out why Russell and Dave have gone out on their own, way early.

The rest of us are back working lift and getting back up to cloud base. We drift down wind under the clouds and get right up to cloud base and near the start circle circumference. I watch as Ron Gleason and Jim Lamb head out on course as I hold back. Three flex wings cross the line also. I wait and let them check out the lift out in front while I get to start my start time later than them.

Finally I head out and head right for the rigid wings who are five miles out. I get there with their altitude and I’m feeling great. We’ve got six guys together and it looks like we’ll have plenty of helpers.

Eleven miles out we encounter a large cu nimb just to our south. We are working on the northern edge of the cu nimb. The ground is completely shaded. The cu-nimb stretches to the west for another fifteen miles. Thank goodness we are just on the northern side of the cu-nimb and the winds are out of the northeast.

Brad sends over this graphic that shows the raining part of the cu-nimb.

We climb up slowly at first with everyone looking around. Jim and Ron are just above me climbing a little bit better. I have no idea where Russell is.

I’m looking back and seeing Rik Boumeester flashing his wings in a high bank. Ron and Jim who were just above me have gone further along the course line and don’t see Rik a few hundred feet behind us. I go over to him and soon Krzysztof Grzyb and I are two thousand feet over the five guys who’ve gone ahead.

The cu-nimb is right next to us as we head west quickly trying to run past it. Everything is as dark as can be, both the sky and the ground. We continue to find bits of lift on the edge of the cu-nimb and we can see the rain coming down five or ten miles to the south.

As we are circling up I see a lightening strike to the south about five miles away. I’m wondering if the cell is going to come our way. I can see that if we go another ten miles to the west we should be able to get around the storm. I’m hoping that there aren’t any gust fronts or more lightening.

I’m nervous about the storm so I’m leaving lift earlier than usual. I’m leaving everyone behind and I got out fast on my own hoping to get away from the storm. Whoa, I’ve caught up with Russell. I come in under a few hundred feet below him. It is great to be able to cover Russell.

We’re almost to the Albany turnpoint and I climb back to cloud base as Russell heads out. I can see a few of the guys I was with behind me getting up from below. I’ve got to hang with Russell now.

Things are happening fast as it is only an eleven mile leg to goal. I’m at 4,000’ AGL 14 miles out, three miles before the turnpoint. I’m hoping that this is enough with a good tail wind to make it to goal.

Nine miles out I see Russell come in a few hundred feet over my head. We work a bit of lift gaining two hundred feet. I can see the guys behind me at the turnpoint climbing high. Given how low they were when I left them, they must have found much stronger lift than I did.

Four miles out from goal I’m at 1,250’ AGL. That’s a 17:1 glide to goal, so I decide to take the weak lift I’m in and climb 500 feet. Russell continues on to goal to get there first. A few of the pilots behind me catch up and keep going just over my head.

I will have the extra 500’ when I get to goal with 500’ to spare.

Paris started late at 1:45 PM and wins the day getting to goal as the first flex wings. Ron gets across the goal line a few minutes before me. Bubba, Chris and later Dennis comes in.

All the times get moved to 2 PM as everyone started before the 2 PM start clock. The finish times just represent there total time to goal.

Flex wings today:

Place	Name	Glider	Finish	Total
1	WILLIAMS Paris	Aeros Combat	15:20:06	932
2	PAGEN Dennis	Moyes Litespeed	15:34:24	776
3	GOODMAN Bubba	Moyes Litespeed 4	15:35:28	756
4	GRZYB Krzysztof	Icaro MRX700	15:36:56	742
5	MORRIS Dan	Wills Wing Talon		464
6	BURICK Carl	Airborne Climax		452
7	OLSSON Andreas	Moyes Litespeed 4		420
8	PRESLEY Terry	Moyes Litespeed 4		357
9	SAYER Wayne	Moyes Litespeed 3		351
10	HAGEWOOD Robert	Aeros Combat 2		327
11	CIZAUSKAS Rich	Wills Wing FusionSP		258
12	DUGGAN Dan	Icaro MR700WRE		68
13	BOUMEESTER Rik	Aeros Stealth		59
14	GILLETTE Rhanor	Wills Wing Ultra Sport		0

Flex wing totals:

Place	Name	Glider	Total
1	WILLIAMS Paris	Aeros Combat	3556
2	PAGEN Dennis	Moyes Litespeed	2997
3	OLSSON Andreas	Moyes Litespeed 4	2987
4	PRESLEY Terry	Moyes Litespeed 4	2899
5	GOODMAN Bubba	Moyes Litespeed 4	2461
6	GRZYB Krzysztof	Icaro MRX700	2209
7	SAYER Wayne	Moyes Litespeed 3	1679
8	HAGEWOOD Robert	Aeros Combat 2	1669
9	MORRIS Dan	Wills Wing Talon	1416
10	BURICK Carl	Airborne Climax	1378
11	CIZAUSKAS Rich	Wills Wing FusionSP	1035
12	BOUMEESTER Rik	Aeros Stealth	971
13	DUGGAN Dan	Icaro MR700WRE	631
14	GILLETTE Rhanor	Wills Wing Ultra Sport	409

Rigids today:

Place	Name	Glider	Finish	Total
1	GLEASON Ron	AIR Atos C	15:35:27	986
2	STRAUB Davis	AIR Atos C	15:36:03	930
3	BROWN Russ	Flight Designs GhostBuster	15:45:16	793
4	LAMB James	AIR Atos C	15:53:01	718
5	BRANDT Dave	AIR Atos		274

Rigids total:

Place	Name	Glider	Total
1	STRAUB Davis	AIR Atos C	4076
2	BROWN Russ	Flight Designs GhostBuster	3716
3	GLEASON Ron	AIR Atos C	2815
4	BRANDT Dave	AIR Atos	2262
5	LAMB James	AIR Atos C	2210
6	BOWEN Campbell	Flight Designs Axxess +	2026

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23 topics in this article: Aeros Combat, Aeros Combat 2, Airborne Climax, airspace, altitude, Bubba Goodman, Carl Wallbank, cloud, competition, Dave Brandt, James "Jim" Lamb, Jim Lamb, Krzysztof "Krys/Kris" Grzyb, Moyes Litespeed, Paris Williams, photo, Rik Bouwmeester, Ron Gleason, sport, tail, tow, Wills Wing, Wills Wing Talon

Midwest Regionals – sunshine, cu’s, goal finishers

Fri, Jun 13 2003, 6:03:00 pm GMT

http://www.flytec.com/mwregionals

Check out the animated track logs (click “Top Tracks” - you have to wait for a few minutes for them to begin animating).

Check out the photo gallery (http://flytec.com/mwregionals/gallery.html)

While it has been great fun flying in overcast conditions here in Whitewater, Wisconsin (half way between Milwaukee and Madison in southern Wisconsin) today we were actually blessed with sunshine. While it has been a while since we’ve seen that luminescent orb during the flying part of the day, we quickly adjusted ourselves to the prospect of calling a task and having pilots actually make it back to goal.

There was a low pressure centered off to our southwest with an east/west front in Illinois. We could see the upper level clouds from the front overhead as the task committee met. The one o’clock BLIPMAP showed weak lift, and very low cloud bases but the 3 PM FSL chart showed good lift and high bases (4,000’ MSL). At least they both agreed that the winds would be light.

Given that we are conflicting forecasts for lift and heights we called two triangle tasks to the south (hoping for the flatter, hotter bare field to the south), one fifty miles and one thirty. A short time later Jim Lamb who had suggested we go south, thought better of his suggestion given that the southern sky had the high clouds and the weaker looking cu’s underneath. I came up with a 50 mile triangle task to the north and east.

As one o’clock rolled around the high clouds had disappeared as the front headed off to the south and east. There were cu’s ever where and it looked like it might be possible to go 50 miles, and not settle for a 32 mile out and return, which was now our secondary option.

I got towed up after Bo and immediately climbed out to 4,000’ MSL and cloud base. We were repeatedly able to touch the bottoms of the clouds today without any fear of being sucked up given the light lift.

The cu’s got big, and the ground got dark. In spite of all the sunshine it would have been good to use the yellow lens, but I had my orange ones.

Everyone was getting up under the dark cu’s and shaded ground and we all gathered up to take the first clock at 2 PM. Might as well if everyone else will go with you.

There is a northeast wind going to the first turnpoint, and we don’t get out very far as we find the first lift, after leaving the three mile radius start circle at cloud base. At 3:11 (four minutes before the next start window), we have drifted back right next to the start circle. Still no one goes back to take a new start time. Paris and a few others have been holding back and will take the 2:15 PM start time.

Half the field is with us as we head out after climbing almost back to cloud base. The ground is shaded ahead and there are dark cu’s everywhere. It is hard to find any sunlight. But, then, this is what it has been like the past few days, so it is not a great worry. We are already getting 1,400’ higher than we were over the last two days, so a little (or a lot) of shading doesn’t hold that much terror for us.

While a couple have dropped out, we climb back to cloud base at 4,300’ MSL and look out to more shading, but now under clouds that are flat and gray, not puffy and back. It looks like a dead zone in front of us, and we are slowly progressing into the wind toward the first turnpoint nineteen miles to the northeast.

A few flex wings are out in front and Bubba finds very light lift at 800’ AGL under the a gray sky with the tiniest bit of light on the ground. Soon there are eight of us in the gaggle. Luckily I’m on top, because the middle six are all on the same level with Terry Presley on the bottom. Six pilots have to learn to get along on their marry-go-round and I merrily float above them as though I had hollow bones or an extra hit of helium.

It takes 17 minutes to climb 1,000’. The clouds disappear and there is sun every where and we get over a hot spot to the north and we get up to 4,500’. Now the dark clouds are much further apart. There is sun on the ground and things are looking better.

I’m with Ron Gleason and Russell Brown on rigids and Terry Presley on a flex. As we approach the first turnpoint I can see four flex wings to the south high, obviously a mix of later starters and some of the flex wings from our previous gaggle. Ron heads out first toward the turnpoint as Russell and I hold back. Ron gets ahead by finding a good thermal on his own just before the turnpoint.

The flex wings from the south, Russell and I come in under Ron, get high fast and I make the turnpoint as Russell has already taken it.

Now it is a chase as Russell, Dave Brandt in an ATOS, and I push to catch up with Paris Terry, Dennis and Ron. We are just behind and below them in the next thermal and Paris, Ron and Russell get away from the four of us five miles before the second turnpoint. We can see them getting high two miles before the turnpoint as we work a thermal also getting high two miles back.

Terry, Dennis and I get to the cloud that Paris, Ron and Russell left five minutes previously and we climb to almost 5,000’ two miles before the second turnpoint. I head out as we hit cloud base on a mission to catch up with Russell so that he doesn’t gain too many points on me.

I find Dave Brandt south of the turnpoint as he didn’t go to the good cloud with us. We’ve got a sixteen mile leg back to Twin Oaks, due south with an east wind (just as forecast). I spot Paris way high above and out in front of me climbing under very small clouds. He’s right on the course line so I go for him and start climbing in lift that averages 200 fpm. Good for the day that averages 130 fpm.

I’m down to 2,400’ AGL when I enter the thermal and 13 miles out. I climb to 3,500’ AGL before it gets weak. It’s 19.6 to 1 to get to goal. My IQ-Compeo says I’m 350’ above the best glide line. It must think I’ve got a tail wind. My polar is about 17 to 1 at best L/D speed of about 32 mph.

I go on glide as I can see good clouds ahead of me if I need any lift. I’m watching the final glide calculator. I’m aware that the goal is a quarter mile cylinder so I have a little extra margin of safety.

At eleven miles out I come in under the clouds Dennis and Terry are way back below me and Dave has gone way off to the east to get under some clouds. I get 500 fpm as I glide straight. The vario says I have the goal so I just push out and don’t turn. I climb 400’ and am at 3,500’ AGL 10.5 miles out. It’s a 15.8 glide to goal. The IQ-Compeo is saying I’m 1250 feet over the best glide line and that I’ve got goal by 1,250’.

I keep flying straight given the IQ-Compeo reading and my feeling that I’m going to make it. Also I really want to catch up with Ron and Russell and I know they aren’t at goal yet, but I haven’t seen them.

As I keep gliding suddenly I see Ron and Russell 700 feet above me a mile to my right more on the course line. They are just a little in front of me and now I’m sure that I have to keep gliding so that they don’t get into goal too far in front of me.

I glide for 10.5 miles in sixteen minutes averaging 39 mph over the ground. I tried to fly at the indicated best L/D speed over the ground. My average rate of sink over the last 10.5 miles was 220 fpm.

I came into Twin Oaks at 100 feet over the quarter mile cylinder and would have made the goal with zero altitude to spare. I didn’t speed up at the last minute I’ll tell you that.

I wonder what happened to the 1,250 feet of extra room over the best glide line. Was I just going too fast? Perhaps I should just have made sure that my air speed was 32 mph.

Ron and Russell are first and second into goal. I’m two minutes behind Ron. Paris uncharacteristically came in high behind me, but won the day as he started at 2:15 PM.

Terry and Dennis were able to get to goal also along with Dave Brandt. Campbell Bowen left to go to a wedding so he wasn’t here to fly the last three days of the meet. We will fly through Sunday.

Paris moved from third to first and Andreas moved from first to third. Terry Presley stayed in second.

Flex wings today:

Place	Name	Glider	Finish	Total
1	WILLIAMS Paris	Aeros Combat	17:03:10	906
2	PRESLEY Terry	Moyes Litespeed 4	17:22:04	749
3	PAGEN Dennis	Moyes Litespeed	17:22:36	737
4	OLSSON Andreas	Moyes Litespeed 4		474
5	GRZYB Krzysztof	Icaro MRX700		333
6	GOODMAN Bubba	Moyes Litespeed 4		328
7	SAYER Wayne	Moyes Litespeed 3		238
8	CIZAUSKAS Rich	Wills Wing FusionSP		182
9	HAGEWOOD Robert	Aeros Combat 2		163
9	GILLETTE Rhanor	Wills Wing Ultra Sport		163
9	MORRIS Dan	Wills Wing Talon		163
9	DUGGAN Dan	Icaro MR700WRE		163
13	BURICK Carl	Airborne Climax		0
13	BOUMEESTER Rik	Aeros Stealth		0

Flex wing total:

Place	Name	Glider	Total
1	WILLIAMS Paris	Aeros Combat	2766
2	PRESLEY Terry	Moyes Litespeed 4	2656
3	OLSSON Andreas	Moyes Litespeed 4	2637
4	PAGEN Dennis	Moyes Litespeed	2338
5	GOODMAN Bubba	Moyes Litespeed 4	1747
6	GRZYB Krzysztof	Icaro MRX700	1497
7	HAGEWOOD Robert	Aeros Combat 2	1352
8	SAYER Wayne	Moyes Litespeed 3	1336
9	MORRIS Dan	Wills Wing Talon	954
10	CIZAUSKAS Rich	Wills Wing FusionSP	783
11	BURICK Carl	Airborne Climax	765
12	BOUMEESTER Rik	Aeros Stealth	750
13	DUGGAN Dan	Icaro MR700WRE	569
14	GILLETTE Rhanor	Wills Wing Ultra Sport	163

Rigids today:

Place	Name	Glider	Time	mph	Total
1	GLEASON Ron	AIR Atos C	2:59:52	17.03	1000
2	BROWN Russ	Flight Designs GhostBuster	3:00:32	16.97	946
3	STRAUB Davis	AIR Atos C	3:01:48	16.85	908
4	BRANDT Dave	AIR Atos	3:22:08	15.16	739
5	LAMB James	AIR Atos C			209
6	BOWEN Campbell	Flight Designs Axxess +	ABS		0

Rigids total:

Place	Name	Glider	Total
1	STRAUB Davis	AIR Atos C	3146
2	BROWN Russ	Flight Designs GhostBuster	2923
3	BOWEN Campbell	Flight Designs Axxess +	2026
4	BRANDT Dave	AIR Atos	1988
5	GLEASON Ron	AIR Atos	1829
6	LAMB James	AIR Atos C	1492

Discuss "Midwest Regionals – sunshine, cu’s, goal finishers" at the Oz Report forum link»

28 topics in this article: Aeros Combat, Aeros Combat 2, Airborne Climax, altitude, Bubba Goodman, Campbell Bowen, Carl Wallbank, cloud, competition, Dave Brandt, gaggle, James "Jim" Lamb, Jim Lamb, Krzysztof "Krys/Kris" Grzyb, Moyes Litespeed, Paris Williams, photo, polar, Rik Bouwmeester, Ron Gleason, Russell "Russ" Brown, safety, sport, tail, Terry Presley, triangle, Wills Wing, Wills Wing Talon

Midwest Regionals

Mon, Jun 9 2003, 6:03:00 pm GMT

http://www.flytec.com/mwregionals

Check out the photo gallery (http://flytec.com/mwregionals/gallery.html) and the animated track logs (Top Tracks button - you have to wait for a few minutes for them to begin animating).

With a strong west wind we initially call a 75 mile out and return due south (east takes us into Milwaukee). But as we get ready to launch this task looks less and less like a good idea given the winds. We quickly switch to a crossing tail wind 35 mile leg to the northeast, and then a final 50 mile leg north-northeast along the coast of Lake Superior. We’re hoping for a little bit of convergence from an on shore flow going against the strong west wind. Maybe just enough to cut down on wind speed.

The BLIPMAP forecasts 500-600 fpm lift (not climb rates) and 7,000’ cloud bases at 1 PM. It sure is looking a lot lower than that at noon, about 4,000’ MSL, and it’s not clear that it is going to get warm enough on the ground to get us that high.

Bo is off first at 12:20 and I’m right behind him. We’ve got 1 to 1:30 PM start window times with 15 minutes intervals. I climb out to cloud base at 4,400’ MSL and immediate head to the north to get at the top of the five mile start circle, so that I can be upwind of the northeast leg with the west, northwest wind.

I hang out there for almost an hour until finally Campbell Bowen, Terry Presley, Andreas Olsson, Wayne Sayer, and Dennis Pagen join me just before the 1:30 and last start time. Bo has already taken an earlier start time thinking that I went on course, when in fact I went five miles to the north. He’ll find himself out there alone.

Given the strong winds (measuring 16 mph), I am absolutely not going to get caught down wind of the first turnpoint and keep pushing north, assuming that I’ll drift to the east when ever I’m thermaling. The rest of the pilots started the task along the course line or down wind of it so we don’t ever see them.

Given my paranoia about not getting caught down wind, I’m soon on my own as the rest of the gaggle moves along the course line to the northeast, except for Campbell whose just south of me. Ten miles out I find myself down to 240’ AGL, but I’m in zero sink. The wind is blowing fiercely and this is usually a bad combination – light lift, strong winds, down low. But this time it works out as with a help of a couple of hawks I slowly climb out to 2,000’ AGL.

There are cu’s every where and the forecast was for strong lift, but other than right over Twin Oaks airport and Raven Sky Sports, the lift has been very light. I’d already warned myself that I had to be especially careful, now I had just been given another warning and a reprieve. Fifteen minutes later I was back down to 450’ AGL.

Two warning and now I was going to make sure that I started working weak lift a lot earlier and not wait until I got too low. The average rate of climb during the task for me was 150 fpm, which is pretty darn low. So much for the forecasted lift. I should have paid more heed to the FSL chart which showed that the lift wouldn’t be as strong as forecast by the BLIPMAP.

With more patience I spend more time in the weak lift (rarely finding any better) and start getting a lot higher. Still it takes a little over two hours to cover thirty five miles. Getting low really slows you down. Weak lift doesn’t help either.

I find the best thermal of the day right at the turnpoint northwest of Milwaukee, and climb to a little over 5,000’ MSL. Campbell Bowen joins me for the ride up, the first pilot I’ve seen in a while and when we head out we almost immediately catch up with Terry Presley and Andreas Olsson.

It’s great to have three more pilots to help out finding the lift and we worth together heading north-northwest trying to stay upwind of the course line. Campbell gets low about eight miles out from the turnpoint as the three of us head northwest to get on the front side of some clouds and avoid the blue hole to our north. This turns out to be a mistake and looking back on it we should have gone northeast to the clouds more on course line. We’re still trying to make our way upwind, when the winds have actually died down some.

It’s a long glide and Terry Presley gets a bit lower and lands. Andreas finds the light lift a mile behind me at 500’ and I go back to join him. The lift is extremely light and we spend the next twenty minutes gaining 2,000’. Andreas is about 500’ over my head having reached the lift first.

It’s now 6 PM and the day is dying. We are still more than 30 miles out. Terry Presley on the ground calls Belinda up and tells here how impressed he was with our low save and that Campbell is high to our east, more on the course line.

Andreas and I work out way slowly to the north working very light lift under any clouds we can get to, but they are drying up, there is cirrus overhead to the north, the sun is filtered and at about 25 miles out the cu’s give out. We land about two miles apart. Campbell is able to eek out another mile and a half not having to make the save that we did.

Flex wing round two:

Place	Name	Glider	miles	Total
1	OLSSON Andreas	Moyes Litespeed 4	62	900
2	PRESLEY Terry	Moyes Litespeed 4	53.1	813
3	WILLIAMS Paris	Aeros Combat	42.9	697
4	PAGEN Dennis	Moyes Litespeed 4	41.1	675
5	GRZYB Krzysztof	Icaro MRX700	30.9	540
6	SAYER Wayne	Moyes Litespeed 3	22	430
6	HAGEWOOD Robert	Aeros Combat 2	21.9	430
8	GOODMAN Bubba	Moyes Litespeed 4	19.9	400
9	MORRIS Dan		17.8	363
10	BURICK Carl		16.2	331
11	BOUMEESTER Rik		15.5	316
12	CIZAUSKAS Rick		7.3	131
13	DUGGAN Dan		0	0

Cumulative:

Place	Name	Glider	Total
1	OLSSON Andreas	Moyes Litespeed 4	1556
2	PRESLEY Terry	Moyes Litespeed 4	1301
3	WILLIAMS Paris	Aeros Combat	1287
4	PAGEN Dennis	Moyes Litespeed 4	1059
5	GRZYB Krzysztof	Icaro MRX700	841
6	SAYER Wayne	Moyes Litespeed 3	831
7	GOODMAN Bubba	Moyes Litespeed 4	753
8	HAGEWOOD Robert	Aeros Combat 2	752
9	MORRIS Dan		524
10	BURICK Carl		498
11	BOUMEESTER Rik		483
12	CIZAUSKAS Rick		334
13	DUGGAN Dan		139

Rigid wings, round two:

Place	Name	Glider	miles	Total
1	BOWEN Campbell	Flight Designs Axxess +	63.4	900
2	STRAUB Davis	AIR Atos C	60.3	868
3	BROWN Russ	Flight Designs Ghostbuster	32.2	501
4	BRANDT Dave	AIR Atos	22	385
5	GLEASON Ron	AIR Atos-C	19.9	358
6	LAMB James	AIR Atos C	12.6	239

Cumulative:

Place	Name	Glider	Total
1	BOWEN Campbell	Flight Designs Axxess +	1800
2	STRAUB Davis	AIR Atos C	1768
3	BROWN Russ	Flight Designs Ghostbuster	1400
4	BRANDT Dave	AIR Atos	877
5	LAMB James	AIR Atos C	731
6	GLEASON Ron	AIR Atos-C	565

Discuss "Midwest Regionals" at the Oz Report forum link»

21 topics in this article: Aeros Combat, Aeros Combat 2, Andreas Olsson, Belinda Boulter, Bubba Goodman, Campbell Bowen, Carl Wallbank, cloud, competition, Dennis Pagen, gaggle, Ghostbuster, Krzysztof "Krys/Kris" Grzyb, Moyes Litespeed, Paris Williams, photo, Raven Sky Sports, Rik Bouwmeester, tail, Terry Presley, Wayne Sayer

Aerotow paragliders

Sun, Jun 1 2003, 2:03:03 pm EDT

Mark Stucky <stucky_mark@hotmail.com> writes:

I just noticed the discussion on the bigair paragliding forum regarding the recent paraglider aerotowing shown on the Oz Report. For several years I've occasionally put thought into the conceptual design for aerotowing a paraglider. I really think the future is in aerotow and discussed the issues some with David Glover (who is also very interested in it for big meets) last September at the Tehachapi sailplane fly-in. I wish we could have talked more but most of my attention at the time was dedicated to the Lighthawk flying debut.

The obvious issues with aerotowing are the slow flying speed of a paraglider and the relatively small amount of pitch and airspeed control available. Some comments on the web about concerns with the vertical distance of the canopy from the tow point are not that big of a deal due to the low thrust and drag forces involved. After all, if a paraglider couldn't handle 80 lbs of thrust near the CG of the pilot then powered paragliders would not work either!

I see three methods for aerotowing a paraglider.

Method 1: The obvious solution is a tug that tows at a compatible speed and climb rate. This method would involve conventional "follow the tug" procedures and a fixed length of towline. While having a PPG or powered PG trike arrangement has some appeal due to their slow flying speeds, I think they will cause more problems than they solve. I think a better tug would be a fancily flapped ultralight or a very large yet lightweight hang glider trike. Until such an exotic tug is designed we will have to make due with exotic procedures.

Method 2: Perhaps the best solution for paraglider aerotowing is to make a lightweight payout winch that can handle 2500 feet of spectra. Until we can get the tow airspeed slow enough to match the speed the paraglider pilot would like we will need to figure out how to handle a speed differential. With a payout winch you could use existing tug aircraft with procedures similar to a ground payout winch tow, the paraglider could simply climb up behind the tug without regard to maintaining the same relative altitude as the tug.

Let's assume we can get a tug that can tow at 45 feet/sec (30 mph) and have a paraglider that wants to fly at 30 fps (20 mph) for a differential speed of 15fps. I think a comfortable climb rate for a paraglider from a ground tows is 500 fpm. If the tug was also climbing at 500 fpm then the total climb rate of the paraglider would be 1000 fpm so a two minute tow to 2000 feet AGL would require 1800 feet of tow line (plus whatever amount you initially laid out). The benefit of an aerotow winch would be that you could use a small field and any wind direction instead of being tied to a long road.

Additionally, the tug could tow you to a thermal although once the line pays out beyond a few hundred feet the tug will be limited to shallow banks or short, quick turns (similar to ground circuit towing). The winch would have to have some kind of rewind capability and a small drogue to ensure it couldn't recoil into the tug's propeller.

Method 3 is obviously not for the faint of heart and requires advanced skills at both ends of the towrope. It is designed to make due with existing tow aircraft and uses a small fishing reel as a short duration payout winch. One way to manage a small speed differential is by using differential bank angles to fly concentric arcs with the paraglider flying a slower speed on the inside of the turn.

Stu Caruk's comments about delivering a bag of goods from a Cessna by hanging it out a window and flying circles around it has some merit. I was once involved in a government program that built upon that technique in an attempt to hover a small spy package several feet off the ground. The package contained sensors and fed position and altitude information back to the aircraft that was equipped with an exotic hydraulic winch which would make the fine high speed in/out corrections to the tow line while the pilot make the rough corrections by following guidance to fly an exact arc thousands of feet overhead. The program got cancelled and I sure wish I could have figured out a way to get my hands on the winch and the 10,000 feet of spectra!

To tow successfully without a high capacity payout winch, we need to manage not just the airspeed but also the climb rate, turn rate, and rope length. To manage the rope you need to first start with the proper length of towline. Too short of a rope and the workload is too high, the allowable lateral/vertical errors too small, and the probability of a lockout is too high. If the rope is too long then the turn circles are no longer concentric and havoc will quickly result.

We need to fly the proper arcs at an angle of bank that does not require extraordinary piloting skills or decrease the climb rate excessively. This means we need shallow bank angles so we can increase or decrease them as required without generating excessive turn rates that would be impossible to manage in a tethered relationship.

Successfully aerotowing a paraglider with this method requires a change to the traditional paradigm of towed flight in which the glider must dutifully follow the tug. Both the paraglider pilot and the tug pilot will have to abide by a pre-coordinated plan for dealing with the continuous corrections that will be required. In the absence of such an advanced plan, the aerotow will be short-lived.

If our 45fps tug flew at 13° bank then his radius of turn would be 275ft at a leisurely turn rate of 10° per second. To achieve the same turn rate with the 30 fps paraglider, it would use 9° of bank for a radius of turn of 178ft. At these conditions I computed a 160 ft towrope as optimal. Under these conditions the paraglider is approximately 45° off axis from the tug (i.e. with both aircraft in a left handed turn, if the paraglider is pointed north, the tug would be pointed northwest).

While this would normally be disconcerting to a tug pilot used to conventional aerotows, it is possible to tow with the line leaving the tug at a 45 degee angle (and only 70% of the tow tension providing thrust to the paraglider). As always, though, the paraglider pilot should strive to keep the towline square to the harness and canopy. Note that if the towrope was routed to the tug's tail then the drag of the paraglider would always be trying to pull the tail inline with the glider and the tug would have to have sufficient rudder power to counter the torque of the off-axis tow or else have some sort of CG/bridle hook up.

If both aircraft are climbing out at the same rate then everything is perfect but chances are there will be some errors. Here is where the pre-planning is required. If the tug is climbing faster than the paraglider, then the paraglider should decrease its bank slightly to increase its speed and climb rate. If the paraglider is climbing above the tug (more likely) he should increase his angle of bank to cut to the inside. Here is where a smart tug pilot will make or break the tow.

He needs to evaluate if the paraglider pilot has been doing a good job and if it has room to make the required correction. If the paraglider is slightly out of position but correcting back then the tug may just observe. If the paraglider pilot is already in the planned position (about 45° inside the turn) then there isn't much more he can do and the tug pilot should either throttle back or increase his bank angle to decrease the climb rate. His course of action should be based upon his interpretation of the paraglider's 3-D position and heading (if the paraglider has dug far inside the turn and the tug turns harder then the paraglider will have to deal with a huge change in heading and possibly even slack line).

If the plan is properly coordinated and well flown by both pilots then a small payout winch could be mounted on the tug. The purpose of the winch would be to handle short periods of excess tow pressure. The winch could simply be a large fishing reel with some pretty small towline (or large fishing line - depending upon your point of view). I'm not a fisherman but I think you could get a commercial product with 500 feet of line that only weighs a few pounds.

You would set the drag for say 20% more than the planned tow force and it could handle short periods of time while the aircraft are transitioning back to the proper positions to reset the planned steady-state conditions. A small electric motor could wind the line back in at the completion of the tow. The reel should be mounted in the field of view of the tug pilot and the line could be routed through guides or pulleys to route it clear of the propeller.

(editor’s note: I believe that all of these methods are being looked at and attempted in some cases at Quest Air.)

Discuss aerotow paragliders at OzReport.com/forum/phpBB2

Discuss "Aerotow paragliders" at the Oz Report forum link»

30 topics in this article: aerotow, altitude, bridle, David "Dave" Glover, David Glover, drogue, electric, government, harness, job, Lighthawk, Mark "Forger" Stucky, Oz Report, payout winch, PG, power, powered, powered PG, PPG, Quest Air, sailplane, Stuart Caruk, Stu Smith, tail, technique, tow, towing, trike, tug, winch

Superflytec PG Championships

Thu, May 29 2003, 6:03:00 pm GMT

Apparently the weather this last month or so in the mid Atlantic states has been miserable with clouds and rain almost every day and nary a peek of the sun. There seems to be a persistent low pressure over the mid Atlantic states that is responsible for this sorry state of affairs.

Thursday’s conditions.

Down here in Florida the spring has been dominated by west winds, and that has been no different this week, even though the summer wet season conditions have gone away, thankfully. The west winds were stronger than predicted today, so it was quite a good idea that we headed north again to tow paragliders from an open field three miles south of the turnpike.

We called a 44 mile task, the longest of the meet, in light of the predicted high cloud base, moderate lift, and good tail winds. Unfortunately, in order to keep the paragliders out of the Orlando airspace, we needed to give them a somewhat cross wind leg.

We sent them down wind at 80° 21 miles then made them turn to a heading of 30° for 15 miles, before an 8 mile leg at 60° going into goal. It was on this second leg that a number of pilots would go down unable to keep from being blown down wind of the turnpoint.

The red area is the Orlando airspace with a 6,000’ MSL floor.

The winds were predicted to be 5 mph rising to 10 mph at the start of the inversion at 4,500’ out of the west-northwest. Above the start of the inversion they would be stronger up to 25 mph out of the west-southwest. With mixing the winds all the way down were supposed to switch to west-southwest by 3 PM. Apparently they stayed west-northwest all day, making the second leg that much harder.

Most pilots experienced good lift at the tow paddock as soon as they found a thermal, which often meant finding one from down low. In one case low and just in front of the high tension power lines down wind of launch. Some pilots reported 500 fpm as they climbed out to over 5,000’.

Out on the course they were able to get into a convergence zone before the first turnpoint and find 1,100 fpm to 1,400 fpm to almost 6,000’. But it was at the first turnpoint where the helpful winds turned into a hindrance. Pilots were down to 3,000’ at the turnpoint and didn’t have enough altitude to make it cross wind to the next turnpoint.

Pilots who just took the western edge of the turnpoint and immediately turned north were the only ones with an opportunity to make the fifteen miles to the second turnpoint. Others found themselves in the unfortunate position of fighting a 20 mph head wind as they tried to get back on the course line. Many landed nearby the turnpoint.

Three pilots mention that they’ve never seen faster ground speeds on their GPSes. One pilot says that after he landed winds of about 30 mph came through for 20 minutes.

Two pilots made goal. Day Five:

Place	Name	mph	miles	Total
1	COHN Josh	29.19	44.6	933
2	HOISINGTON Zach	22.81	44.6	763
3	HUEY Jeff		34.7	553
4	SWAIN Gavin		33.5	542
5	PRENTICE Dave		33.1	537
6	HOFFMAN Doug		28.3	463
7	SPORER Rob		28.2	461
8	BROCK Gary		28.1	459
9	FARRELL Jeff		26.4	418
10	SZAFARYN Len		14.5	158
11	MOOK Tom		3.8	50
12	KEARNEY Bill		2.1	28

After five days:

Place	Name	Total
1	COHN Josh	3062
2	HUEY Jeff	2448
3	FARRELL Jeff	2224
4	BROCK Gary	2066
5	HOISINGTON Zach	2007
6	PRENTICE Dave	1963
7	SWAIN Gavin	1596
8	SPORER Rob	1163
9	MOOK Tom	1149
10	HOFFMAN Doug	1097
11	SZAFARYN Len	1045
12	KEARNEY Bill	404

Discuss competition at OzReport.com/forum/phpBB2

Discuss "Superflytec PG Championships" at the Oz Report forum link»

11 topics in this article: airspace, altitude, cloud, competition, Florida, Orlando Stephenson, PG, power, tail, tow, weather

Flytec 4030 Race testimonial

Wed, May 28 2003, 6:03:02 pm GMT

As I heard from various pilots at the Flytec Championship that they liked the new final glide functions of the Race version of this vario, I asked Steve Kroop to make sure that they sent me their reports on how this new unit was working for them.

Kraig Coomber <kraigc76@hotmail.com> writes:

I started flying with the Flytec 4030 Race towards the end of the Australian competition season this year. The transition to the new model was straightforward and I was able to take advantage of its features on my first flight.

The most significant improvement for me is the final glide mode. It increased my confidence dramatically by offering more information both on the approach to final glide altitude and the final glide itself. It does this by giving you your altitude below your required height well before you have reached it, allowing you to monitor how well you are doing relative to the required height whilst on glide to the final climb.

Once you are on final you always have a reference to your optimum final glide slope. The advantage of using this as the reference is that the numbers do not jump around but stay relatively consistent providing you with usable feedback throughout the duration of your final.

Adjusting the head/tail wind component is done by simply pushing the up/down arrow on the key pad. The benefit from being able to enter this in manually is that you can take into account a possible variance in wind strength at lower altitudes.

Using the 4030 Race has resulted in shaving minutes off my overall times. It is so simple to use that anyone can take advantage of what it has to offer without any added concern or complications. I'd like to thank Flytec USA for hooking me up with what I feel is the best all round instrument presently available.

Discuss "Flytec 4030 Race testimonial" at the Oz Report forum link»

8 topics in this article: altitude, competition, Flytec 4030, Flytec Championships 2003, Flytec USA, Kraig Coomber, Steve Kroop, tail

Aerotowing PGer’s

Fri, May 16 2003, 12:00:05 pm EDT

Hans Bausenwein <Hans@aerosport.de> writes:

Great attempt by Dave Prentice! I think the solution would be to fix a small payout winch to a Dragonfly, run the rope through a steel tube to the end of the tail and off you go. I have such a unit made by Christoph Schuhwerk an engineer and hang glider pilot from Germany.

This little payout winch only weighs 20kg, has a Kevlar drum and an exact means of setting the thrust to anywhere up to 100 kg (ideally you set it to the pilots body weight). The unit has a small bicycle bell on it that rings with every revolution. So you hear how fast you are paying out rope and can speed up or slow down accordingly.

It is usually used on a car and is ready to mount on a 50mm ball head of a tow bar. It even has a guillotine to cut the rope in an emergency. The release rope of the guillotine is run to the driver’s seat. We use a large mirror (like a traffic mirror) mounted on the bonnet of the car with big suction cups to see the pilot all the time.

The drum has 600m of 3mm spectra rope and can hold more than 1000m. I will be coming to southern Texas end of June and could bring it if anybody wants to try to fix it to a Dragonfly. Contact me if you are intersted <hans@aerosport.de>. The unit even has a DHV Gütesiegel. It is several years old, but I only have used it a little bit (less than 50 tows). Cost was around 3000 US $. I do not know how much it will cost today.

Gin Gliders have bought two of these Schuhwerk payout winches just recently to use them on an expedition to Mongolia. The expedition is not happening now and Gin wants to sell them again. Contact <gin@gingliders.com> if you are interested. Gin Seok Song also had the intention to come to South-Texas for long distance flying, but wasn't sure if he will find the time.

Mike Dillon <mikedillon@flightconn.com> writes:

It was good to hear that someone has finally aerotowed an paraglider. I've been daydreaming about this for years. The way Dave and Bobby accomplished this sounds fun, but I don't know if it would catch on, it sounds way too complicated.

I think a more practical way to aerotow would be behind a powered parachute (not a paraglider, but one of those large, low performing square chutes powered by a trike). I think they have a top speed of about 28 mph and a bottom speed of about 24 mph (maybe even slower). I've thought for a long time that this would be the ideal tug for a paraglider. I don't have the balls to try it, but it sounds like David Prentice just might - anyone?

Gordon Rigg writes:

Gerard Thevenot did some experiments aerotowing paragliders in 1996 or before using a trike. Given up as too unsafe.

Discuss aerotowing PG’ers at OzReport.com/forum/phpBB2

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20 topics in this article: aerotow, bicycle, cost, David Prentice, DHV, Dragonfly, Gerard "Gerry" Farell, Gordon Rigg, Hans Bausenwein, Laurent Thevenot, parachute, payout winch, PG, powered, release, tail, tow, trike, tug, winch

Wills Wing UltraSport - $1500

Tue, May 13 2003, 3:00:06 pm EDT

flight park|Quest Air|tail|wheels|Wills Wing

OBO. WW US 135 for the smaller pilot. 50 hours. Very good shape. Comes with pneumatic wheels and tail.

Click the above photos to see a bigger version. $1500 FOB at Quest Air Flight Park. Contact <davis@davisstraub.com>.

Discuss "Wills Wing UltraSport - $1500" at the Oz Report forum link»

5 topics in this article: flight park, Quest Air, tail, wheels, Wills Wing

Home made tails

Sat, May 10 2003, 5:00:04 pm EDT

tail|technology|Valerio Canestrelli

Valerio "Air Blade "Canestrelli

The Tail…Blade is born !! After months of work the tail from Air Blade is ready to fly. No new concep , but simply the best " all round " project( symmetrical airfoil pivoted at nose), the super tested airfoil ( NACA 0007), and the best building technology (vacuum sandwich painted in the mould).

The materials and technology are the same of the AIR V-Tail , a glass- 2 mm. thermant-glass sandwich, with some carbon belts and spar to build two shells glued together. As for the others Air Blade creatures I plan and build mainly for myself, but I'll build a very limited series of tail blades for others.

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3 topics in this article: tail, technology, Valerio Canestrelli

AIR ATOS’s tail as stall alarm

Wed, May 7 2003, 7:00:06 pm GMT

Christof Kratzner|Florida|Ron Gleason|tail

Ron Gleason reports that his new AIR ATOS v-tail makes an excellent incipient stall alarm with quite a bit of shuddering when it first starts to stall (before the main wing does).

Felix also recommends that pilots be sure to put on a significant amount of flaps while thermaling to slow down the ATOS. He recommends this especially with the tail. We’ve found that it is quite important to put the flaps on in thermals to slow down the ATOS and get a better climb.

Thanks again to Felix for sending out a great ATOS-C for me to fly (not that well, I’m afraid) and to Christof from the AIR factory for coming to Florida and updating lots of ATOSes and making sure that they were tuned correctly.

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4 topics in this article: Christof Kratzner, Florida, Ron Gleason, tail

AIR ATOS newbie

Fri, May 2 2003, 4:00:04 pm GMT

Peter Gray <peter@graynet.net> writes:

I hadn't flown a rigid wing since the early '80s, with the Fledgeling 2, a much higher-drag glider with hand-operated rudder controls. Last Sunday, we set up Johann's ATOS-C, 2003 competition version, with plans to take a morning sled ride, then later soar it in the afternoon.

The first thing we discovered was that there was no practical way to make my Wills pod work in the ATOS control frame, so I used Johann's Rotor harness. Since it was only going to be a sled ride, I brought minimal equipment: a vario, helmet, and T-shirt. No GPS, no gloves, no airspeed indicator.

Johann had advised me that the ATOS would lift its tail early in the ground roll, and would quickly support its own weight, but that I should stay on the cart a little longer than with a flex wing, until I lifted the wheels off the ground. Johann also told me about roll lag and responsiveness (or lack of), and the potential for roll-yaw PIO.

The tail-up effect didn't feel much different from a flex wing, and the take-off roll was about the same. If anything, the ATOS-C felt easier than a flex wing to keep at the correct elevation relative to the tug.

For the first 100 or so feet of climb, I found myself moving back and forth laterally more than necessary, but that gave me a quick feel for how the spoilers work, and it didn't lead to any PIO. It felt somewhat more sluggish in response, but considerably less likely to yaw or roll off the tow line, than what I've been used to. Also, the more efficient wing seemed to make the rigid quicker to climb to tug level if I got low.

I had been flying with half flaps on tow, and a little more for scratching under the clouds, and now I let the flaps up to zero. Wow! Pitch pressure dropped to nothing while the wing rapidly accelerated to 30-35 mph. It trimmed there, with light nose-down bar pressure and fairly heavy nose-up pressure.

It was immediately obvious that the ATOS has long legs. A moderate headwind felt like nothing. I had flown a late-model full-race Laminar MR13 a few days earlier; the ATOS-C has a much flatter glide and its advantage in glide retention at high speed felt even more dramatic.

By the time I found a workable thermal, I was down to 600 feet AGL, over the woods in gliding range of Wallaby. At first I flew in the kind of low-bank, stately circles that I've seen most rigid pilots use, and soon found that it worked better to fly a route through several nearby cores, than to try to stay in one small core.

My first instinct in roll, carried over from flexwings, was to "weight shift" excessively. Feedback from the spoilers is fairly light and subtle, and it wasn't immediately obvious when a spoiler hit the stops. Although I knew intellectually that going beyond the stops would have absolutely no effect on roll rate, it took some repetitions to train myself to be patient and not waste effort.

My main goal for a first flight was to tow safely and land gently, so I hadn't paid as much attention to what Johann told me about flap settings, and I probably thermaled with too much flap most of the time. One thing that became immediately clear was that the ATOS did not want to thermal with zero flaps. Or at least that's how it felt to me. I tried a few thermaling turns without flaps, but I wasn't inclined to find out whether it would stall at higher speed with flaps off than with a climb setting.

It was fun to just look out at such a different kind of wing while circling. The glider felt quite solid and predictable at a wide range of bank angles and speeds. With some patience, I climbed to a comfortable 3,000 feet, and later to 4,500 or so. That allowed me to range much farther from home than I could have in a comp flex wing, and quite a bit faster.

Although I had could make sensory estimates of speed, it would have been nice to have air and ground speed indicators, as well as net climb (although I didn't have an ATOS polar in my Brauniger IQ Comp anyway). To test energy retention, I flew several times in smooth air at what seemed like a fast glide (trim with flaps off), then pushed out enough to get the vario beeping, and rolled into a shallow turn. The glider could do almost a full, large, 360, climbing at 50-100 fpm, before slowing to near a stall.

Since the air was mostly smooth and balmy, I was tempted to put the wing through some high-banked turns, and practice a spin onset and recovery, but I remembered the warnings against spinning the ATOS, and decided to err on the side of caution.

I don't consider three and a half hours nearly enough to tune in to a really different type of wing, so more experience could change my mind, but the glider felt less versatile and capable than a flex wing for scratching in weak or inconsistent lift. I am used to being able to slip, skid, and continually adjust my turn to try for the best climb rate, and it felt odd at first not to be able to do that.

Now I'm beginning to understand why rigids usually thermal in such a stately manner. They don't have a very high roll rate, and whenever a spoiler is deployed, there is some loss to drag. However, the ability to glide to another source of lift with little altitude loss, combined with a lower sink rate, probably makes up for reduced maneuverability, in most conditions.

Back at the Ranch, I pulled on full flaps and followed Johann's advice to make a wide, gentle approach. In almost zero wind, I flared and landed normally with a couple of steps. It didn't seem noticeably more difficult to land than a high-performance flexwing, but I imagine it would be in rougher air. The main difference was that the wing stalled and dropped onto my shoulders a little more suddenly and heavily.

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16 topics in this article: altitude, cart, competition, control frame, equipment, gloves, GPS, harness, helmet, Peter Gray, polar, spin, tail, tow, tug, wheels

The 2003 Wallaby Open

Tue, Apr 22 2003, 4:00:01 pm EDT

http://www.wallaby.com/wallabyopen/2003/

It’s another beautiful day at the Wallaby Ranch in central Florida. The forecast is for winds 10 mph on the ground out of the west rising to 17 mph up near cloud base. The BLIPMAP shows better lift and higher cloud bases to the south east of us along the east coast. We do have a couple of goals over in that direction (River Ranch and Hibiscus), but I can’t get the task committee to go along with me.

The FSL MAP model is showing the possibility of towering cu’s, although thunderstorms are not in the forecast. There is a cold front to the north and it is forecast to come through sometime later in the evening. So far (at 7 PM) the surface maps still show it far to the north. Perhaps it is stalled.

We wrangled around in the task committee (with so many people involved many things can happen). Finally two tasks toward the south, southeast were proposed but later we have to add Bok Tower as there is still a sky diving contest at Lake Wales, and the course line would put us too near them.

The GPS will go out just north of Bok Tower so it’s hard to say just how they will handle this when they score the meet. Do we get the waypoint if it looks like we came close? I think so.

Just before we launch we do agree on a short task to Avon Park airport with a control point at the Bok Tower:

With a stuff breeze in the take off area it is a bumpy ride over the trees. Belinda said that there were a lot of reflights today from pilots that didn’t stick the first time. I find something at 1,100’ over the northwest corner of the Ranch and work up 220 fpm to 3,700’ cloud base.

All of us who get to cloud base work our way upwind to try to get on the west side of the ranch but to the south of Interstate 4, near the edge of the start circle. The gaggles are very small given all the wind at cloud base, and I’m hanging with three flex wings.

On the ground there’s lots of action. Jim Lee has chosen a cart that puts his nose at too high of a nose angle. There are plenty of carts with high tail holders here at Wallaby, and they are to be used by pilots whose gliders have long down tubes. They are painted a different color so you know to use them if you have a Wills Wing Talon, for example.

Jim didn’t use one of these carts.

Apparently Jim was in line with the wrong cart and when he asked for a different cart, he was told he needed to go to the end of the launch line and get a new cart. He chose to continue. Belinda and others witnessed what happened next.

Just like last year it was an immediate lock out with one wing high and a 180° turn. He took out one down tube. He quickly fixed that and was soon launched again (I assume with the correct cart).

Another pilot did something similar again with too high a nose angle. Pilots have got to recognize which cart works for them. Long down tubes equal painted cart.

Meanwhile it is getting toward 2 PM, which it seems will turn out to be the real start (Race) time. We didn’t start launching until 12:30, so 2 PM is really the first time that other than the first early launchers would want to get going.

I’ve pushed west on my own and I hook up with Oleg and Johnny Durand, Jr. and Kurt Warren. There is not another rigid wing in site. There are many gliders miles downwind to the east. We are the pilots furthest to the west.

We race south until Kurt and I find 500 fpm just east of Winter Haven to 4,200’ and cloud base. We then go on a long glide that takes us through the blue toward Bok Tower. At this point we should have gone downwind to the clouds, as that’s where the lift is, but having worked so hard to get upwind we are reluctant to do so.

We get low coming into Bok Tower and Curt turns back and lands. Looks like I’ve led him astray. I head over the tower as I see some pilots turning high, but I don’t catch anything until I’m down to 700’ AGL over the back of the tower amongst the orange groves.

Yesterday it was pleasant at 340’ AGL. Today with the wind it is quite rough near the ground and I’m holding on tighter than normal. Its a few thermals before I get back to 3,500’ and drifting 6 miles east of highway 27. I’ll miss the next thermal and land twelve miles from goal.

Other pilots will be able to keep themselves high and to the west of highway 27 after they get the Tower waypoint and drift slowly to the southeast in the winds that get up to 20 mph at cloud base.

The preliminary results are very preliminary. Oleg Bondarchuck wins the flex wing task today as Manfred goes down way early, even before Bok Tower. Christian Ciech goes down before the goal also, so the two leaders don’t make goal. Alex Ploner wins the day for rigid wings.

The preliminary results aren’t out yet (printed preliminary results for Class 1 with the incorrect distance was out at 8:30 PM), so hopefully there will be something up by the time you read this. You might also try: http://www.elltel.net/peterandlinda/Wallaby_Open_2003/2003_Wallaby_Main.htm

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17 topics in this article: Alessandro "Alex" Ploner, Alex Ploner, Belinda Boulter, cart, Christian Ciech, cloud, Florida, GPS, Jim Lee, maps, Oleg Bondarchuck, site, tail, Wallaby Open 2003, Wallaby Ranch, Wills Wing, Wills Wing Talon

About the caterpillar

Thu, Apr 17 2003, 3:00:06 pm EDT

Paul Dees|photo|Sue Bunner|tail

Paul Dees <av8rpaul@attbi.com> writes:

My sister Sue saw the caterpillar photo in v7#102 and she says it is a Spicebush Swallowtail caterpillar just getting ready to pupate, so its color changed from green to orange. It wanders looking for a place to form a pupa, when it changes into a swallowtail butterfly, the ones that have an extra tail- like part to their hind wings.

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4 topics in this article: Paul Dees, photo, Sue Bunner, tail

The Dragonfly accident

Fri, Apr 11 2003, 12:00:05 pm EDT

accident|Dragonfly|parachute|picture|tail

The accident occurred a little after 9 AM this morning. Chad was flying the Dragonfly with the heavier 4-stroke engine at about 800 feet. There was a strong west wind and in a turn one of the wings folded up. The cause of this fold up was the fact that the bottom strut for that wing was not bolted to the box at the main bulkhead.

During assembly the strut was inserted incorrectly into the box. The bolt marked below with the red arrow was inserted but the strut was inserted into the box above the bolt hole so that the bolt wasn’t attached to the strut. The bolt was tightened down squeezing the box and holding the strut in by friction. Again, the bolt was not inserted in its correct spot through the strut.

The friction held the strut in place until the flight regime increased the forces on the strut to exceed friction’s hold on the strut and it came out and the wing folded up.

Chad pulled the BRS handle immediately and the rocket took off with a loud bang which caused me to go outside and I watched the Dragonfly diving toward the ground.

Apparently the BRS rocket pulled the chute from the canister correctly but the parachute shrouds tangled in the wires on the tail going to the wheel as per this picture: The parachute therefore didn’t inflate.

On this Dragonfly and the other ones with the 4 stroke engines have the BRS canister mounted just in front of the pilot on the pilot cage, and not at the apex above the wings on the leading edge (more pictures on this tomorrow). The canister is mounted in this location when the Dragonfly has this engine to offset some of the weight of the engine.

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5 topics in this article: accident, Dragonfly, parachute, picture, tail

The AIR ATOS-C’s show up and we fly ‘em

Fri, Apr 4 2003, 5:00:03 pm EST

Johann Posch showed up and we put our newly revised ATOS-C’s, that we last flew in Australia, together. Jim Lamb, Heiner Beisel, and Alex Ploner also have ATOS-C’s here at Quest Air. No shipping damage!

Sure I flew David Glover’s ATOS-C a few weeks ago but I’ve been hoping on one flex wing after another for days on end here, trying to meet the demands of the Oz Report readers, so it came as quite a shock when I got back on my ATOS-C.

No bar pressure, that’s what it felt like as I towed up, after towing up the Aeros Target earlier in the day. Jeez this is a bit scary. And not only that, but the bar is way back and there is no bar pressure. Feels like it could just keep right on going back.

Of course, there is bar pressure, but I’ve just had a reasonably long flight on the Target and my muscles are remembering that. My mind is having a hard time taking in the messages that say this glider is going over as everything is so light.

The tow is after 4 PM and I’m under a big cloud that is forming late in the day in mellow lift. I’m climbing and trying to reprogram myself. The glider turns without the slightest effort. The bar goes to my chest with no effort. I’m freaking, but trying to calm myself. This is so strange.

It takes a half hour to calm down and realize that no there is in fact some bar pressure. That I can indeed pull in to my waste and the bar pushes back.

I fly around in very delightful air as I wait for Johann to get up. Boy, this thing feels like a sailplane after all those flex wing gliders, especially the single surface ones. It feels like I have double the glide ratio or more.

Johann and I do a long glide together and we are dead even. I’d love to try this with Christian Ciech, Alex Ploner or David Chaumet. My ATOS’s sweep is set at 2300 mm. The new standard for all ATOSes.

At the end of the flight I’m going this is great! What a glider.

I can see how it would be nice if the bar was normally further out, just a psychological kind of thing. It feels like it is so far back normally, that it has only a little ways to go before it slips out of your hands, especially as it seems like there is no bar pressure.

But this is all a jumble. Of course, Felix puts the control bar where he does because he wants you to have the ability to pull back hard if the nose gets popped in a big thermal. It’s just that all these little considerations go into a glider design and it is amazing that it all comes out at all.

Did I say that all the gliders came with tails? Sure seems to calm the glider down compared to David’s without a tail.

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9 topics in this article: Aeros Target, Alessandro "Alex" Ploner, Christian Ciech, David "Dave" Glover, David Chaumet, glide ratio, James "Jim" Lamb, Johann Posch, tail

ATOS wing sweep check

Mon, Mar 24 2003, 8:00:03 pm GMT

tail|Vincent "Vince" Endter

http://vincenancy.com/atos/wing_sweep_check.html

https://OzReport.com/Ozv7n17.shtml

https://OzReport.com/Ozv7n18.shtml

Vince Endter <vince@vincenancy.com> writes;

The original Atos has a sweep set between 2285 mm and 2330mm. When he came out with the Atos-C he increased the sweep to between 2330 mm and 2330mm. This decreased nose angle is used for all Atoses now, not just the C and with or without a tail.

Felix increased Davis' nose angle on his C from 2330 mm to 2300 mm. Felix said you don't get more performance increasing the nose angle, just less pitch dampening. I have pictures of how to check the nose angle at: http://vincenancy.com/atos

Felix is working on different nose angles in conjunction with different rib angles and different hang point location. He is doing this on prototype gliders. I had not thought much about the hang point location other than to more it forward to trim faster and back for slower, but on the prototypes the hang point it also used to balance the other changes he makes. He again said he will publish his results when he decides which prototype fly's the best and safest. He said for pilots to keep their sweep setting between 2300 mm and 2330 mm with or without a tail.

The original Atoses were shipped with the sweep between 2285 mm and 2300 mm. All new Atoses, and Atos-C’s as well as any Atos that come in for their {German) mandatory two year check are set between 2300 mm and 2330 mm.

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2 topics in this article: tail, Vincent "Vince" Endter

Platz Glider

Sun, Mar 23 2003, 8:00:11 pm GMT

Brett Snellgrove <Snelly14@cs.com> writes:

It was with total amazement that I saw Dan Gravange's posting regarding the Platz wing one issue before mine. Although it appeared otherwise, my posting was not in response to his and quite an amazing coincidence that shows the ongoing interest in this design.

Although I must bow to Bill Berle's experience with models (vastly superior to any hypothetical musing) my attachment to this design makes me reluctant to give up on it so easily.

Firstly, I see an inconsistency regarding Bill's comments on roll control. From the photos I sent you (not the ones posted thus far) it is quite clear Platz is freely and easily soaring a long dune ridge -- this would be difficult without adequate roll control and impossible with none at all as Bill noted. Secondly, Bart had found documentation describing excellent roll control up to and through stall in both models and the final design and clear documentation that the rudder Bill considers necessary was not needed. Something's amiss somewhere.

Bill surmised that the absence of roll control in his model was due to drag created in closing of the slot on the down going canard. In the photos it appears the canard was well forward and up of the main wing -- too far in my view to form an effective slot. If this was indeed the case I see 2 solutions.

One would simply to be to use upward motion only on one canard, no downward on the other. If indeed the down going canard did cause excessive drag then perhaps downgoing motion only, similar to a paraglider brake would be effective?

Bill also described difficulties with trimming the model. If as I, suspect he copied earlier designs shown in the photos, and the canards were hinged at the LE, this would be expected. Hinging at the ⅓ rd chordline as Platz later did might solve the problems Bill encountered. I suspect Bill rigged his model hinged from the canard LE and with equal action via RC servos. In reality the Platz glider was flown with the hands, hinged at the ⅓^rd chord and a good degree of differential action allowed such that the pilot could manipulate the controls independently to effect roll.

Bart also notes sailplane clubs were considering usng Platz's wing as a trainer. I find it difficult to believe they would do this if the problems Bill notes in his models weren't somehow solved (without a rudder).

Bill Berle <auster5@earthlink.net> writes

I took a few photos of my Platz glider model.

The model was built of curved laminated balsa keel and mainspar, covered with Japanese tissue held to the frame by glue stick. Thread formed the trailing edges of main wing and canard/jib surfaces.

An electric motor platform was added at the front of the keel. I used a rubber block with the canard strut wires held in place by friction, so I could easily adjust the decalage and control inputs.

As I mentioned before, I could not get the model to turn in a reasonable circle with the canard jibs alone, either in a glide or under electric power. I added a vertical fin, and was all set to put on a rudder (which I was and am confident would have added proper control authority). But the model was not able to sustain level flight with the electric motor weight, and the repairs were already too numerous, and I simply retired the model.

I had gotten the information I needed, which was that some form of yaw control was needed. As an alternative to the fin and rudder, drag spoilers on the wingtips that "pulled" one wing back would more than likely provide plenty of yaw control without changing the basic shape of the Platz design. The moment from the CG to the rudder would have been even less than the moment arm from the CG to the tip drag spoiler, so yaw control would have been very effective.

Brett Snellgrove writes:

I built a model of the Platz glider today and believe I solved the riddle of how Platz achieved sufficient roll control to soar dunes. Firstly, the glider flies very nicely and is remarkably stable considering how close to the mainwing the canards are -- yet it seems to fly with the stability of a tailed design without a long tail lever. This alone makes it an attractive option.

The glider is quite responsive in pitch to uniform motion of the canards. I noted that same thing Bill did in that aileron type deflection produces little change in direction. I suspect the drag of the downgoing canard produces significant adverse yaw. I then tried unilateral canard deflections and as expected, one canard deflected downward produces a diving spiral to that side.

However a unilateral deflection upward produces a nice rapid flat turn to the same side!! This may be due to the closing of the slot as Bill notes but I think it is simply due to the extensive drag associated with a large upgoing surface deflection associated with mainwing dihedral. There appears to be no roll away from the upward deflection and significant, now proverse, yaw associated with the turn. I suspect the dihedral of the mainwing cancels what would now be adverse roll? There does not appear to be a significant pitch up associated with the turn. Possibly the loss of lift on one side compensates for any upward pitching motion.

Platz would have most certainly experimented with rolling the glider during the extensive tethering tests and not attempted free flight without effective roll control. Given Bill's and my experience with models this seems the most likely solution. So it conceivable Platz discovered paraglider type control years before MacCready did the same thing with the Gossamer Condor. In fact the wing would be flown exactly like a paraglider for pitch and turning and should make for a very simple transition.

Bill Berle writes:

Brett, I think either you or I have something backwards. When you describe a unilaterally upward or downward "aileron' deflection I think we have it opposite.

On the fixed wing aircraft designs that I am familiar with, an "upward" motion means that the trailing edge of the control surface moves up. In the case of the Platz, I would expect an "upward" motion to mean that the control handle at the rear of the canard boom was raised up above the pilot's head. In this case "upward" motion of the canards would be making the glider dive, the same way as upward movement on the canards of a Vari-Eze canard power plane makes it dive.

A downward motion would mean that the trailing edge of the canard moves down, making that canard produce more lift in theory.

What do you mean by a "unilateral" upward motion? Do you mean that the pilot would raise or lower the handle? Do you mean that he would move it all the way full travel up or down?

I think I understand your results after reading it a few times, but I still cannot get how using full "up-elevator" control on one side (to cause a drag-related turn) would not ALSO act like an elevator and raise the nose at the same time.

Although you may be able to trim the glider into a level flight turn using the method you discovered today, I still strongly suspect that using the canards as a drag device would have some negative effect on pitch control especially if you needed it at the same time.

Brett, please leave room in your model to try the tip spoilers I suggested. I think that little tip spoilers or drag plates would allow you instant, smooth turning control that more importantly did not interfere or affect the use of the canards together for pitch. I would bet that at the end of the day, this is the control setup that would allow a safe man-carrying version to be built.

When the time came for it to be flown in "big air" as the HG pilots say, I would bet what's left of my balls that a fixed or movable vertical fin would be the only thing that would make it safe to fly. Dihedral is not a substitute for yaw stability dihedral only rolls the airplane the right way for any given yaw. So when a gust blows you 45° off course into a hillside, at least your yaw string will be in the center on impact.

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9 topics in this article: Bill Berle, Brett Snellgrove, Daniel "Dan" Gravage, electric, Platz, power, sailplane, tail, travel

Peter’s wild ride

Fri, Mar 21 2003, 6:00:03 pm GMT

Peter Dall <Peter.Dall@casa.gov.au> responds (finally) to my request for his story:

It is always interesting to read how outsiders perceive stressful situations we find ourselves in. My impressions of going upside down at Hay are a little different to what Grant reported (https://OzReport.com/Ozv7n24.shtml)

I had finally gotten around to trying the tail Felix sent me for my ATOS (early model). I wound the nose catch in 2 turns to compensate. Not sure why I did this – probably something I read in the Oz Report ☺ - or maybe something Tony or Johann had told me.

At first I didn’t like the way the glider felt with the tail on.

I found the yaw characteristics of the glider were changed, and I couldn’t do yawing turns like I used to when tightening up in a thermal.

I also found stall buffet to be annoying, in thermalling, and also when pushing the bar out on car tow. This problem was diminished when I moved my hang point forward, or maybe I just got used to flying faster. I guess I was in the habit of flying a bit slow. But I had gotten used to recognising the onset of stall and wing drop, and this was always benign and felt comfortable. Of course I made sure I had plenty of height before slowing right down.

On the second last day of the comp I took the tail off again, and put the nose catch back to how it was before. But now I didn’t like this either! The tail certainly does damp out the pitch twitchiness.

So on the last day I put the tail back on, readjusting the nose catch as before. I was feeling glad that I’d done this, as it was a big day, with huge dust devils. Easily the biggest diameter dusties I’ve ever seen, with dust towing to well over 1000’.

At 1100ft on tow, I flew abreast of one of these monsters, so pinged off, and headed into it. Being big, it didn’t look as violent as some of the small tornadoes. It was rough, but not too scary.

My harness zip kept catching on my pants, so this distracted me, and I was having trouble finding a nice core, but I’d climbed up to around 3000’ in turbulent lift. My team mate called up and said I should come over because he had 1600fpm of very smooth lift. Sounded good, so I opened up my circle downwind and headed over.

The next thing I know, I pitched up, then down over the falls, pointing at the ground with one wing low, but not quite under me. A few seconds later I’m upside down, looking at the sky. I’d always wondered if you could fly a hang glider inverted, and here I was doing it. Nothing seemed to be broken, but perhaps it was time to deploy the chute. I must admit that I found it a bit hard to reach for the chute while hanging on for grim death.

I had only a short time to ponder this problem, when the glider took another wild pitch and did a nice half loop. I came out flying pretty much straight and level. At no time did I lose my grip on the base bar, so when I was upside down I probably only experienced a small negative load. I don’t recall hitting the sail or the A-frame, but I guess the harness back plate supported me wedged in the A-frame.

I don’t know how fast I got up to when pointing at the ground, but I didn’t have the feeling that I might have over-speeded. I wasn’t going particularly slowly when it started. I’m guessing 50-55kph. Certainly comfortably above stall, and basically straight and level. (less than 15º)

I guess I wasn’t too shaken, since I flew back into the dust devil, climbed out to 10,000’, then flew 200km to goal.

I was expecting that this wouldn’t happen when the tail was on. I can only think that my rotation speed would have been a lot faster without it, and perhaps I wouldn’t have been able to keep my hold on the base bar.

I’ve since spent a lot of time retuning the glider. Despite flying back into the dustie, I’m finding that my confidence has been shaken.

It seems logical that the tail should add some extra static stability margin as well as improving the dynamic stability, therefore allowing a bit less washout or a bit less sweep. But I have since been told that I shouldn’t have changed the wing sweep.

(editor’s note: Not necessarily true. See Oz Report interviews with Felix Ruehle published on the first day of the Australian Nationals https://OzReport.com/Ozv7n17.shtml and https://OzReport.com/Ozv7n18.shtml before Peter had his flight.)

I checked my rib angles and adjusted a couple of outboard rib to give more washout. They weren’t perfect, but overall not too bad. One #8 rib was 0.5º low, and one #9 rib was 2º low. I’m still not sure whether to measure these with the sail on or off, or what difference this makes. To put this into perspective, 1º equates to about 1cm at the trailing edge.

My next flight back in Canberra was on a really twitchy day. Looked good with moderate winds, but there was some real awful soup up there at a shear layer that we just couldn’t get out of. I think the storm cells were dropping a cold stream that was hitting the shear layer, and spreading out in all directions. You would be flying along, at cruise, do nothing, and suddenly the glider would stall because of tail gusting. The glider was really spooking me, making me think it was going to go over any second, so I landed after 25 minutes. I was relieved to find that my two buddies also landed soon afterwards because they also found the air unpleasant, and reported similar stalling.

Nonetheless, I still kept thinking that even in shitty air, the glider should make me feel more secure than it did. Back to the drawing board.

My glider is the first one built, so the sail has a few years on it. I have noticed that the outermost seam no longer sits over the #9 rib. I figured the sail has shrunk. Maybe this would also explain why I had suddenly started breaking tip wands, after not having broken one since the glider was built. Also I could never seem to get the trailing edge Velcros to line up, especially over the flap. The top Velcro overshot the lower, almost to the point where they made no contact. I addressed the first problem by sewing an extra piece of Velcro onto each side of the centre zips, effectively moving each sail 2 or 3 cm outboard. Suddenly everything fit perfectly (well after a lot of adjusting), including the trailing edge Velcro (not sure why this would change, but it did).

Subsequent flight testing is encouraging, with the glider now flying very sweetly. Still remains to be seen how I shape up to the big air again next season. One thing I noticed is that the sail strap and rib tension seems to make a lot of difference. Probably more than playing with sweep and washout. Tight is good.

Discuss "Peter’s wild ride" at the Oz Report forum link»

8 topics in this article: dust devil, Felix Ruehle, harness, Peter Dall, tail, tip wands, tow, towing

It’s on at ⁢Stanwell Park »

Fri, Dec 13 2002, 11:00:02 am EST

landing|tail|Tascha "Tish the Flying Fish" McLellan

Turned on late on Thursday night, and this afternoon on Friday. The Moyes factory guys came down and test flew three Litespeeds a piece. Kurt flew his new Litespeed then did two tandems. Bo and Paris flew and then were whisked away to Manila by Tish.

I flew the ATOS with the tail. Flew great. The air was baby butt smooth and you could get 1000’ over in one pass. Flew straight to Bulli and back with one turn at each end.

Paris was playing in the air over a knob 150’ over the beach. Wing over after wing over and never went down.

All the landings were great at the park with the wind coming straight in and no rotor off the bushes to the right.

I can see why some locals are upset with the hang gliders. The new rules look like they scare off the people trying to walk to the beach. The hang gliding schools have to put up a series of cones that say – No Entry. Should say – Enter at your own risk – hang gliding landing area.

The shire made up the cones. Really an over reaction and it sends a bad message. There are a lot of other signs warning about hang gliding also. Can’t we all just get along?

The ATOS was flying great with the tail. It was very slightly twitchy compared to the AirBorne Climax. I need to get myself a little lower.

Discuss "It’s on at ⁢Stanwell Park" at the Oz Report forum link»

3 topics in this article: landing, tail, Tascha "Tish the Flying Fish" McLellan

Flying naked – no V-tail

Fri, Aug 2 2002, 6:00:05 pm EDT

I made a very big mistake and gave my tail to Tom Pierce in Chelan right after the Worlds, based on a promise from Felix that I would have a new tail in time for the US Open. I wanted to help out Tom, Felix asked me to give Tom the V-tail, but I loved my wonderful AIR V-tail. I knew it was a big gamble, and I really really needed the tail in Texas.

Well, on Thursday I got an e-mail message from Emily at AIR that the tails had been sent out that morning and would arrive in about 5 days. 5 business days? Really, in 5 days? That meant that my tail wouldn’t arrive until after or maybe even well after the start of the US Open. Was I happy about that? Did I think I had been screwed? Did I feel stupid for giving away my V-tail?

I tried for half a day to get Tom on his cell phone so that he could ship me the V-tail overnight. Turns out he was out of town at a funeral, and I couldn’t reach him. I couldn’t get any response from Emily when I asked her to ship me a V-tail overnight, Saturday delivery. I sure was hoping that the promise would be kept.

I would have to go bare for the first time since I gained the KNOWLEDGE. No longer would the gyrations of the control bar be dampened. No longer could I forget about the inside wing dipping down to make me think it was going over. Soon all my fears would return and hang gliding would become distinctly unpleasant once again, in an especially big air environment.

Yes, I use to fly without a tail, but now it is too late. I have tucked and I have flown with a tail, and that is just part of my life story which my mind can’t erase.

Mike Degtoff is here and can’t imagine what the tail is for. Then he flew in the big air of Big Springand got kicked around (George said that today was by far the smoothest day so far here). He didn’t see how a tail would have helped. But Mike Degtoff doesn’t have the KNOWLEDGE.

My only hope is that in the middle of a competition that my mind will be drawn to the competition and away from my fears. This worked in Florida, but this isn’t Florida.

Yes, I’m just a super sensitive kind of guy, and most of you out there don’t have to worry about this level of sensitivity, but I notice around me that there are a few rigid wing pilots who are hoping and praying that their V-tail will come soon. I couldn’t talk Campbellout of his John Vernon’s non T-tail. Campbellis the only one flying here with a tail – unlike the Worlds.

Flew with football receiver gloves today. Didn’t have to put my wrist straps on as they provided a level of grip that I use to be able to get from the grippies. Loved ‘em.

Discuss "Flying naked – no V-tail" at the Oz Report forum link»

6 topics in this article: Florida, tail, John Vernon, Mike Degtoff, Tom Pierce, Worlds

Flytec Championship – 70 mile fish bowl »

Sat, Apr 27 2002, 9:00:00 pm GMT

David Glover was very smart and every day as the meet went on he would drag up folks to thank them for their help at the Flytec Championship. During the week he thanked the tug pilots, the volunteers, the ground crew, the Quest Air crew, the people who put the dinners together, Frank and Steve Kroop, the registration crew, etc. Because it happened every day everyone got more applause and more attention than if he had put it off until the last night, when everyone gets crammed together.

David and Steve did something also very clever, they had GW create a video taking footage and shots during the week. On Saturday night, the last night of the Flytec Championship, the video was ready to go and we got to see the whole video with the sound track. It was amazing that it had been done so quickly, all the while GW just looked like he was hanging out taking pictures and having fun.

But, not only did we get to see the video, all the pilots and tug pilots got a copy of the video last night. It really showed off what we do at a Floridaaerotow competition and we’ll be able to take it around and show it to our friends (if we have any outside of hang gliding).

Dave was a kick all week making announcements, telling jokes, getting pilots to come to the pilot meetings because they were so much fun. Belinda commented that we hadn’t seen Dave in his element in quite a while. While there were many many people who played keys roles in making the Flytec Championship such a great meet, I’ve got to feel that it was Dave Glover that really put it over the top and made it so much fun.

One of the key elements to its success (I feel), is that he was able to delegate responsibility to others, and in this case I’m referring to the task committee. I had written to him early on stating how giving the task committee the complete responsibility for calling the task was one of the keys to Tove’s great meets in Australia. David, like Tove, had the personality that allowed him to delegate responsibility and not get tied up into knots about it.

Chris Arai, Revo, and I had complete authority to choose the task each day, we took lots of pilot input and we did our best for the pilots to make the meet fair and fun. I can tell you that there was no barbeque task on the last day (although we did come back to Quest Air) as there has been in the past.

Having a task committee made up exclusively of pilots who without prodding from the meet director or organizer (well, we kept Dave away almost all of the time), is a key to having a meet (there are other ways to do it, but there are very very few individuals who can pull it off, and I can think of only one, Mad Dog, in Australia) that satisfies the pilots. This will continue to be a difficult issue and I hope that there will be a way to work this out at the upcoming worlds in Chelan.

Oh, yes, we did have a task on day seven. First, we heard from Gary Osoba:

Looks like a 7 day meet, thanks to the task planners, meet administrators, and reasonably good weather. Congratulations!

For a change, the entire soaring window today should provide for relatively consistent wind directions and strengths. Should make the planning a little bit easier. Here's how it stacks up:

11am Weak lift. Probably a bit early for clouds to be forming yet. When then do (likely closer tonoon), they should be around 2500'. Surface winds sse around 6. Winds aloft a little bit more southerly at 10-12.

2pm Good lift, strong in spots. Cb 5000' to 5300'. Surface winds sse 5-8, aloft sse 12-14.

5pm Moderate lift, good in spots. Cb could go to around 6000". Surface winds sse 8-10, aloft sse about 12.

"Only a fool would try to predict the weather"!

So we’ve got strong winds aloft out of the south, but good lift also. With the good lift we can come back against the strong winds, and that is exactly what we plan to do. We have really been counting on Gary’s forecasts, and he has done a great job for us. We really pick the tasks based on his weather predictions.

We call a 70 mile task (no barbeque task this one) that will first take us downwind 17 miles to the west, northwest to Bushnell, back against the head wind to Quest, south into the head wind to the intersection of highways 33 and 474, then north, downwind past Quest to Gator field, then 7 miles upwind for the final glide to goal.

The task keeps us near Quest, while at the same time making it difficult to complete. We come back over Quest to get everyone on the ground excited and it keeps us out of the swamp.

There are plenty of clouds when we start taking off, and it looks like maybe there are too many, maybe it will over develop after all. The wind seems awfully strong also, but it’s too late now to come up with an other task.

We hang around until the middle start time at 1:15although everyone is in the air in half an hour. We just stay at cloud base for an extra 15 minutes. GAP gives one very little reason to go out in front and leave the gaggle behind. Johann and I have already made up our minds that we will take the middle start time, and maybe everyone else felt that way also, or, when two pilots left, they all decided to go with us.

We can see all the darkness out to our northwest and it looks like we are jumping into a black hole. There are high cirrus clouds that dull the areas on the ground where the cu’s don’t block out the sun.

We spot the guys who took the 1 PMstart time and that makes it easier to make our way to the turnpoint through all this very gloomy looking area. Still we’re down below 1,400’ before we connect with the big lift that gets us to the turnpoint and back out again.

Well, that was a downwind task, but we averaged only 27 mph getting there, so the south wind didn’t help that much. Coming back will prove to be much more difficult (and most if not all of the pilots who don’t make it will drop out here), as the average speed will go down to 15 mph.

I’ll charge across some blue areas to get under what seems to be a cloud street, find nothing then push up wind to get under some pilots turning at 8 miles out from Quest, only to find myself at 450’ and working lift that averages 140 fpm, starting out at a much lower value. It turns out that every one will have difficulty making it back to Quest and will get low on this leg.

Christian Ciech and Alex Ploner are doing much better in this meet than the rest of us, and they have zoomed out ahead. They were half a mile ahead at the turnpoint, and I lost them coming back as I went more easterly, but they will also get quite low. They are flying together.

I’m flying with Johann, but I’ve lost him also. Given how weak the conditions are we are all struggling and it looks like a long day if we can stay up. I’ve got quite a few other gliders here with me, so we hang on and the lift improves, as we drift north away from Quest, but with stronger lift it is no problem. Twenty minutes after coming in low, I’m up to 4,000’ and on my way to Quest with Curt, Paris, Ron Gleason, and some other ATOSes.

We are styling now, hitting good lift and staying high as we come into Quest. We can see a gaggle forming to our south that includes the Swifts, so they must have struggled also. I can see Alex and Christian in the gaggle also.

Johann will lose it here and head off to the west to get under better looking clouds, while I’ll continue to the south to join up with the gaggle. Johann, who is in second place, will almost land at Quest.

I catch up with the lead gaggle, which is putzing along. I guess they don’t see any need to probe out into the blue to the south. All the clouds that we had by Bushnell have not come down here in the late afternoon, and there are mere wisps to our south.

With a bunch of rigid wings, Curt Warren, and above us all the two Italian rigid wing pilots, we start punching our way south only to find good lift, light sink in between, and long patches of buoyant air. We stay high and work light lift to get to 5,000’.

We are still running into the wind, so it takes a while, but we have no problems getting down to the south to get the turnpoint with Alex and Christian leading the way. The Swifts start to get ahead of us now, with Manfred taking the third turnpoint and coming back to greet us when we are 2 miles out from it.

As soon as we get the turnpoint, we can drift back north along 33 in strong tail winds and buoyant air. With the lift averaging less than 200 fpm in the cores, we are just taking a little bit here and there. After the long up wind grind it is a joy to drift toward the Gator turnpoint.

Now there are only rigid wings in the lead as we come into the Gator turnpoint and turn to get back to Quest. It’s been a long glide into Gator before our upwind final glide. My IQ/Comp has been acting up and not reporting any final glide info, so I’m just hanging with the four other rigid pilots. Heiner goes on glide and we all just speed up as it becomes clear that no matter that fact that we are going into a strong head wind, we will make it back to Quest without a problem.

Mike Barber who bombed out on the previous day (after passing up lots of lift trying to go faster) goes all out and will win in Class 1 as the flex wings will come in about 20 minutes behind Alex Ploner who takes first in the rigid wings. Then again he'll start fifteen minutes behind us, so you can see how much Alex and Christian were holding back, just tracking the rigids below them.

Class 5 on the last day:

1	Ploner, Alex, 65	Air Atos C	Ita	13:15:00	16:20:00	03:05:00	953
2	Ciech, Christian, 47	Icaro Stratos	Ita	13:15:00	16:20:11	03:05:11	935
3	Biesel, Heiner, 101	Air Atos	Usa	13:15:00	16:28:30	03:13:30	848
4	Gleason, Ron, 300	Air Atos	Usa	13:15:00	16:28:35	03:13:35	839
5	Endter, Vincent, 43	Air Atos	Usa	13:15:00	16:28:36	03:13:36	832
6	Straub, Davis, 50	Air Atos C	Usa	13:15:00	16:28:55	03:13:55	825
7	Zeiset, Jim, 66	Air Atos	Usa	13:15:00	16:38:43	03:23:43	762
8	Barmakian, Bruce, 17	Air Atos	Usa	13:00:00	16:34:50	03:34:50	741
9	Brandt, Dave, 60	Air Atos	Usa	13:15:00	16:48:51	03:33:51	713
10	Posch, Johann, 112	Air Atos	Aut	13:15:00	16:54:20	03:39:20	689
11	Campanella, Mario, 186	Flight Designs Ghostbuster	Bra	13:15:00	16:54:52	03:39:52	685
12	Almond, Neville, 116	Flight Designs Ghostbuster	Gbr	13:00:00	17:45:14	04:45:14	469

Class 5 finals:

1	Ciech, Christian, 47	Icaro Stratos	Ita	5804
2	Posch, Johann, 112	Air Atos	Aut	5354
3	Ploner, Alex, 65	Air Atos C	Ita	5272
4	Straub, Davis, 50	Air Atos C	Usa	4994
5	Gleason, Ron, 300	Air Atos	Usa	4983

Class 1 last day:

1	Barber, Mike, 2	Moyes Litespeed	Usa	13:30:00	16:41:15	03:11:15	915
2	Wirdnam, Gary , 39	Aeros Combat 2	Gbr	13:30:00	16:41:37	03:11:37	902
3	Bessa, Carlos, 155	Moyes Litespeed	Bra	13:30:00	16:42:09	03:12:09	891
4	Warren, Curt, 73	Moyes Litespeed	Usa	13:15:00	16:40:29	03:25:29	843
5	Zweckmayr, Josef, 18	Icaro Laminar	Aut	13:00:00	16:33:16	03:33:16	841
6	Bondarchuk, Oleg, 107	Aeros Combat 2 13	Ukr	13:30:00	16:55:38	03:25:38	800
6	Agulhon, Dorival, 94	Icaro Mrx	Bra	13:15:00	16:45:15	03:30:15	800
8	Harri, Martin, 31	Moyes Litespeed	Che	13:30:00	16:55:41	03:25:41	797
9	Williams, Paris , 1	Icaro MR700WRE	Usa	13:30:00	16:56:04	03:26:04	793
10	Bertok, Attila, 64	Moyes Litespeed	Hun	13:30:00	16:56:08	03:26:08	790

Finals Class 1:

1	Bondarchuk, Oleg, 107	Aeros Combat 2 13	Ukr	5841
2	Williams, Paris , 1	Icaro MR700WRE	Usa	5644
3	Volk, Glen, 5	Moyes Litespeed	Usa	5584
4	Hamilton, Robin, 30	Icaro MR700WRE	Gbr	5515
5	Warren, Curt, 73	Moyes Litespeed	Usa	5440
6	Hazlett, Brett, 90	Moyes Litespeed	Can	5437
7	Wirdnam, Gary , 39	Aeros Combat 2	Gbr	5434
8	Wolf, Andre, 117	Moyes Litespeed	Bra	5389
9	Olsson, Andreas, 27	Moyes Litespeed	Swe	5369
10	Rotor, Nene, 77	Wills Wing Talon	Bra	5348

Preliminary results are up on the www.flytec.com web site.

Discuss "Flytec Championship – 70 mile fish bowl" at the Oz Report forum link»

30 topics in this article: A.I.R. ATOS, Aeros Combat, Aeros Combat 2, Aeros Ltd, Alex Ploner, Chris Arai, Christian Ciech, cloud, competition, Curt Warren, David "Dave" Glover, Flytec Championships 2002, Flytec Championships 2005, gaggle, GAP, Gary Osoba, Ghostbuster, job, Mike Barber, Moyes Delta Gliders, Moyes Litespeed, Quest Air, Ron Gleason, Steve Kroop, tail, tracker, tug, video, weather, Wills Wing Talon

Flytec Championship – the sea breeze »

Mon, Apr 22 2002, 8:00:00 pm GMT

Flytec Championship – the sea breeze

The weather forecast calls for west winds at 10 mph, no cu’s, moderate lift. The task committee wrangles over a 66 mile task down to the south to the Winter Havenairport and back Vs. a 50 mile task to the Fantasy of Flight, also down 33, and back. I’m pushing for the shorter task, given the winds, and lack of cu’s. With a seven mile start circle for the flexies (4 for the rigids) it seems a bit short to the other task committee members, so we go for the longer task.

This will put us in an area of weak lift at the Winter Havenairport which is surrounded by lakes. It could prove to be a tough task. A major concern is the likelihood of a sea breeze from the west setting up in the afternoon. This would kill the lift.

We push back the start times given the prognosis of weak lift and no cu’s early assuming that pilots will not be eager to launch while things look weak. Then at 11:30 AMthe first cu’s start popping a little off to our east and we are taken by surprise.

The cu’s build and spread and within an hour there are cu’s every where. They aren’t getting high, but they are definitely there. This is plenty of encouragement and pilots are talking about starting at the first start time, 1:45 PM.

Mike Barber calls Patty on the west coast and finds out that the sea breeze hasn’t started by noon, and the report is 5 mph out of the north. Maybe we won’t get the sea breeze after all.

Pilots are eager to go and we get a lot of pilots in the air quickly. With the strong winds out of the west, its pretty easy to get under a cloud on the west side and climb up. The lift is light to the west of Quest and strong downwind to the east.

A couple of flex wing pilots head almost straight upwind toward the GreenSwampand I join them. We work our way forward against the wind and toward the western edge of the start circle (smaller for me) climbing in lift that averages less than 200 fpm. With cloud base at 4,000’ it isn’t hard to stay high enough to stay near cloud base.

We’re thinking about the earliest start time (1:45) but I’m only at 3,500’ at the start time, so I continue to head west until I’m almost 6 miles out and work the light lift. I’m figuring that I’ll get under a cloud, hang with it and drift back into the start circle just as the next start time rolls around. Fortunately I’m just able to do this, see the graphics:

The track log shows me circling and drifting to the east to get into the 4 mile radius start circle just in time.

The altitude graph shows me topping out at 14:00(2 PM) right at the edge of the start circle just as the start time begins on the fifteen minute interval. Couldn’t have worked out better.

Alex Ploner, Johann Posch, Christian Ciech and I take the 2 PMstart time. Some flexie and rigid wing pilots have already taken the 1:45start time and are out in front of us. There are also flex wing pilots taking the 2 PMstart time starting 3 miles further south of us, so there is plenty of activity in the air.

Christian comes in under me at the intersection of 474 and 33 as I enter a gaggle with the earlier rigid wings and 2 PMflexies. I’ve taken the tail off to check out whether the T-tail with the wrong pitch angle is the source of all my extra drag from the Wallaby Open and the first day of the Flytec Championship.

Christian and I climb at 200 fpm to 3,800’ and go on glide. Hmmm! Unlike the previous day, now I’m gliding right with him. It sure looks like my misaligned tail was causing the problems. I will go on two more four mile glides with him, and I find myself now able to glide with him.

John Vernon will be sending a new fin for the T-tail that will allow the tail to make a -1° angle with the mean chord line, instead of -6. Should be here on Wednesday. We’ll try the tail again then.

Christian gets me on the fourth climb and gets a few hundred feet over my head. We have completely caught up with all the pilots in front of us. The run south down highway 33 has been consistently good with climb rates at about 400 fpm, and our top out heights rising.

We climb out south of I-4, 5 miles out from the turnpoint at Winter Haven to 4,400’ and go on glide due south hoping to come up on the airport from the west. There are about a dozen gliders in this first gaggle. Christian is on top heading more toward the turnpoint. A number of rigids are heading with me and the flexies to the south.

We are surrounded by lakes, so we are looking for areas of dry land that are continuous to the west, hoping that the cloud streets are setting up over the land.

It doesn’t happen and by the time we are all at the airport turnpoint we are down to 2,300’. This is in an area of weak lift so things look bad. It is at this point that I make a crucial error, but the gaggle doesn’t.

I head back to the northwest to get on the west side of a small lake. The gaggle heads straight north downwind of me. The error – don’t try to go upwind when you are relatively low, find lift first. I choose to ignore the gaggle, also not a good idea when you are relatively low, and then ignore them again when I see them start turning, thinking I can find my own lift. I don’t and soon land.

The gaggle continues north toward I 4 and back toward 33. Meanwhile back at Quest Air, the sea breeze has kicked in and the wind has increased to 15 mph on the ground. All the clouds are wiped away in the area near the flight park. We don’t see this yet further to the south.

As the pilots move north, it becomes clear that the clouds that they are flying under are ending to their north. Some pilots drift east toward Wallaby Ranch to stay under the clouds. Others venture out in the blue to find weak lift.

We made the turnpoint at about 3:10. Christian is able to make it back to Quest first (after the Swift’s) in a total time of 2:30 hours, so it only takes him 10 minutes longer (with four additional miles) to get back to Quest.

Other pilots will dribble into Quest working their way slowly through the blue.

The rigid results so far:

Today – Ciech, Mario, Ron, Heiner (make goal). We will see Johann land about one mile due east of goal.

Cumulative - Christian, Mario, Ron, Alex

The flex results so far:

Today – Hamilton, Paris, Oleg, Wirdham, Reisinger, Bolt, Arai, Olsson, Hazlett, Wolf (first ten into goal) Zwecky will land 2400 feet away from goal in a small yard. Barber lands 150 feet short.

Cumulative – Oleg, Paris, Hazlett, Hamilton, Wirdham, Wolf, Warren, Reisinger, Olsson

Not quite 25 percent into goal.

David Glover is remiss in not putting up preliminary results on the www.flytec.com web site. They should be up some time tomorrow.

Day one finish position by Class:

Flex, Rigid, Swift

Warren, Ciech, Porter
Gerolf, Ploner, Ruhmer
Oleg, Posch
Hazlett, Straub
Wolfe, Gunter
Harri,Campenalla
Jerz, Gleason
Rotor, Hollidge
Walbec, Dinauer
Paris, Barmakian
Dorval, Ferris
Zwecy, Trimmel
Attila
Bessa
Castle
Ollson
Wirdnam
Richardson
Hamilton
Shipley
Reisinger
Holtcamp
Volk
Sugarman
Barber
Pagen D.
Presley

18 topics in this article: Alex Ploner, altitude, Christian Ciech, cloud, David Glover, Fantasy of Flight, flight park, Flytec Championships 2002, Flytec Championships 2005, gaggle, Johann Posch, John Vernon, Mike Barber, Quest Air, Swift, tail, track log, weather

T-tail on ATOS

Thu, Apr 11 2002, 3:00:06 am GMT

Andrew "Andy" Hollidge|John Vernon|Steve Elkins|tail

John Vernon <johnv@emvertec.demon.co.uk> writes:

Atos C with Teetail at Mam Tor in the Derbyshire peak district last Friday prior to take off, Steve Elkins is the pilot. Andy Hollidge has a demo unit with him at Wallaby/Quest (arrives 09/04) which fits the Atos and Litespeed for anyone who wants to try it out.

To get an idea of the down force created, mount the unit on the keel stinger removed from the glider and feel the force created as you angle it to the wind.

Discuss "T-tail on ATOS" at the Oz Report forum link»

4 topics in this article: Andrew "Andy" Hollidge, John Vernon, Steve Elkins, tail

Breaking new world records in Florida »

Sun, May 20 2001, 7:00:00 pm GMT

I'm up at 7 to check the weather. It had been cool in the night and without much of a blanket I had awoken earlier in the dark thinking about the day to come. I had checked the forecasts the night before and it sure looked like we were in for yet another killer day, over 90°, strong lift, high cloud base, light winds.

There is a cold front stretching from west to east way to the north of us in northern Georgia, but it is supposed to spawn clouds into northern Florida, and just to the north of us. The wind cast predicted winds out of the southwest at 5 to 10 knots at 2 PM

And

5 knots out of the south at 8 PM, with a general area of convergence over the middle of the state.

At 7:30 the modeled sounding for Kissimmee for 2 PM predicted cloud base at over 6000, strong lift, and light winds out of the southwest.

At 9 AM I can get the data from the 8 AM weather balloon sounding at Tampa Bay. It shows that the height of the minus three is over 6500 with an 85° trigger temperature for that altitude. With predicted highs around 91°, there should be plenty of lift.

=== Interpolations (temps in °F, altitudes in feet MSL) ===

MSL	TI	Wdir	kts	trig		VirT	3.2 degrees/division ("`": Dry Adiabatic)
----	-----	---	---	----	-	----	-----------------------------------------
8000	-0.2	250	9	91	:	52.0	:
7500	-0.7			91	:	53.7	:	`
7000	-2.2	230	14	88	:	53.8	:	`
6500	-3.6			85	:	53.9	:	`
6000	-4.8	215	15	83	:	54.4	:	`
5500	-5.2			83	:	56.4	:	`
5000	-5.6	200	15	82	:	58.4	:	`
4500	-5.8			81	:	60.6	:	`
4000	-6.1	185	12	81	:	62.7	:	`
3500	-6.4			80	:	64.9	:	`
3000	-6.5	195	10	80	:	67.3	:	`
2500	-7.0			79	:	69.2	:	`
2000	-7.9	230	6	78	:	70.2	:	`
1500	-9.4			75	:	70.2	:	`
1000	-11.6	260	6	71	:	69.0	:	`
500	-13.9	285	5	67	:	67.4	:	`

What aren't in the forecast are the high clouds from the front that appear early in the morning and continue to thicken and fill in during the day. By 1:30 it is completely dark for miles around Wallaby Ranch. The sun is hidden behind all manner of high clouds.

Still pilots who have launched around 11 are still up and still plenty high. The sun may not be hitting the ground, but it is plenty warm down here and the lapse rate is working. We are seeing a few cu's under the high clouds.

I launch at 2:05 and find lift on tow at 1200. I had just said that I wasn't going to pin off early given all the shading, but I'm just too embarrassed to stay on tow when I'm in lift. It's a struggle at first but then I run and get under the next pilot who has pinned off at 1000'. We climb out in lift that starts at 300 fpm and ends at 700 fpm to over 6600'.

I've drifted to the east in the southwest winds and come back to take the start gate at Wallaby for the 25-kilometer triangle at 6000'.

The high clouds completely cover the sky for miles in every direction. I can't imagine how I will be able to complete the task as there are no cumulus clouds on the course line. I'm just going to try it and see.

As I race toward the first turnpoint the high clouds quickly begin to dissipate leaving neither high clouds nor cumulus clouds in front of me. I've got a bit of a tail wind and my ground speed is 45 mph, while my air speed at speed to fly is 35 mph. My speed ring is set at 300 fpm.

Once I round the first turnpoint, my ground speed decreases by 20 mph as I head into a 10-mph southwest head wind. I haven't found any lift yet and don't find any until I'm within two miles of the second turnpoint and down to 1600'. There is a small cu forming just downwind of the second turnpoint and as I'm below 2000' I'm in survival mode and no longer in race mode.

The lift is broken and I can't climb well in it. I decide given the strong head wind that I'm not going to be able to make the second turnpoint in the required time and I work myself up and back toward the Ranch.

I'm able to find 400 to 500 fpm in various thermals and work my way back up to just under 6000' east of the Ranch. I'm ready to try for speed around a 25-kilometer triangle once again.

My record speed on Thursday was 45.60 km/h. I was now trying to beat that speed and Tomas's flex wing speed of 50.84 km/h. The conditions appeared to be much worse that they were on the day that I first set the record.

The upper clouds have dissipated, but the cu's that were now forming were quite small and quickly dissipating. There was a 10-mph wind out of the southwest. It looked like I would be doing this task just for the practice.

I flew back to the start point at Wallaby Ranch making it at 3:20:28 PM at 5270'. I knew that I had to come back with an altitude of 3700' for the flight to count for the record. This seemed to be a reasonable altitude.

I could see a line of clouds forming just to the left of the course line as I raced to the first turnpoint. Unfortunately I wasn't under the clouds and I was soon going down quickly. I turned and flew toward the west to get under the clouds. I found between 400 and 700 fpm lift as more clouds formed to the north of me toward the turnpoint. I climbed out from 3000' to 5400'. I found lift all the way to the first turnpoint and was able to round it at 5400'.

It was all blue all the way to the second turnpoint so I didn't expect much in the way of help. The wind was still 10 mph out of the southwest so I was cruising along at 25 mph, instead of 45 mph like the first leg. But, unlike the first attempt at this leg on this day, I was quite high. Fortunately I did find quite a few spots of lift along the way, but didn't have time to turn. I just wanted to get this upwind leg over with as quickly as possible.

I got to the second turnpoint at 4200' and then found the sink heading toward the goal at the Ranch at 50 mph. But I knew that there was most likely strong lift up ahead as there were clouds forming.

3 miles out from the Ranch I found 900+ fpm and took it high enough to make the goal with enough altitude to make the triangle speed attempt valid arriving at goal at 3:50:13 at 4420'. I completed the 25.1 kilometer triangle in 29 minutes and 45 seconds for a speed of 50.62 km/h (31.45 mph). It was a new world record for Class II, but just slightly less than Tomas's 50.84 km/h flex wing record for the 25-kilometer triangle.

Central Florida continues to please everyone who shows up for the day or the week. We just had a few visitors from the northwest and they went home very happy but sad to leave.

A pilot from France that I met a few years ago while flying the Canadian Nationals dropped in for the day. The place blew him away. I've encouraged him to write up a little something.

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16 topics in this article: altitude, balloon, blog, cloud, clouds, Florida, record, records, survival, tail, Thursday, tow, triangle, Wallaby Ranch, weather, world record

Oz Report

topic: tail (45 articles)

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AIR ATOS newbie

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About the caterpillar

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ATOS wing sweep check

Platz Glider

Peter’s wild ride

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T-tail on ATOS

Breaking new world records in Florida »

The 15^th Annual Pre-Worlds 2004 - day six

The 15^th Annual Pre-Worlds 2004 - day five, task three