Wills Wing
Flytec

Oz Report

Volume 3, Number 135
Monday, December 20 1999

https://OzReport.com
"Toto, I have a feeling we're not in Kansas anymore."
Sun, Dec 19 1999, 6:00:00 pm EST

to Table of Contentsto next topic Back in Manilla

Manilla|PG|sailplane

Today the cues started forming over Mt Borah somewhere between seven and eight AM. We just weren't ready to get up there that early, but we did make it up a bit later and it was ridge soarable on the west side facing Lake KeepIt (about twenty miles away). You hung out and waited for the thermals to come through.

It was a bit too west today but with a good 15 mph wind (I'd hope for 30 knots). It was hard to make really fast times going north along the paved highway.  The punters headed northeast into the woods, but landed before the landing areas gave out.

Godfrey in his tandem paraglider felt the ATOS would have screamed across the woods and made to the New England Highway on the other side.  Oh, well, I went the wrong direction.  I decided to land at the first town to the north of Manilla, Barraba, at their little grass strip airport.  Looks like it might swing to the south by tomorrow and open things up for the big one.

Flew at Willi Ewig's new Sky Ranch at Lake KeepIt yesterday (see https://OzReport.com/3.123). Willi has a new Air Borne trike, which he really likes, and lots of experience towing pilots in Germany.  He's right near the Lake KeepIt soaring airport, so they keep in touch when Willi is towing.

BTW, Willi said that there was a problem with kangaroos at the airport.  We saw a herd of about ten as we came back to Willi's yesterday.  It appears that they love the grass at the airport and if you are coming back low, late (say 7 PM) you might just put your sailplane through a couple of them.

It's very cheap to tow at Willi's, just $15 AUS per tow.  The trike has a small wing and you go up very fast.  Get high enough so that you can feel comfortable thermaling up over the lake.

Willi and his wife Tina, have moved from Germany to Australia, purchased 850 acres for the Sky Ranch, put in a large steel hanger (one week to erect). They have water, a phone, a couple small trailers, and the office is getting put together now.  The runways are in, and the place is operating.

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to Table of Contentsto next topic All we are, are dents in the wind

Sun, Dec 19 1999, 11:00:01 pm GMT

Dave Sharp|Felix Ruehle|sailplane|Terry Reynolds

Dave Sharp|Felix Ruehle|Oleg Bondarchuk|sailplane|Terry Reynolds

Dave Sharp|Felix Ruehle|Oleg Bondarchuk|sailplane|Terry Reynolds

Last Oz Report, I wrote about the dents I now have in my ATOS from carrying it around on racks without sufficient padding.  This generated a bit of e-mail as follows:

Terry Reynolds, «TRGLIDERS», writes:

My sailplane repair manual suggests, for dents like you describe, heating the area to 150F with a hot air gun.  The dents are supposed to just pop out.  The skin on the sailplane wings sounds similar, i.e., carbon over foam, so it may work for you.  Be careful, or better yet ask the engineer/designer.

I've asked Berndt Weber, «info», and Felix Ruehle, «info», at AIR about this, but no answer yet.  Perhaps Mathias, «flightdesign», at Flight Design has some comments?

G.W. Meadows, never a shrinking violet when it comes to seizing a marketing opportunity (but always nervous about what's written about him and AEROS in the Oz Report), writes:

In last Oz Report, you wrote about fragility of the ATOS D-spars during transportation on your car rack.  Aeros thinks it is time to give you some information about their D spar construction and the fact that they had already realized that this was a problem.

Aeros researched and discovered a special D-spar construction which increases the D-spar surface strength to at least twice as much as what the ATOS has.  Oleg Skirko (chief rigid wing designer at Aeros) tells me this: "The problem with the fragility of the skin is very well known in sailplane production.  For getting smooth surface we need to use the foam and for protecting the skin from damage during transportation we also need to make the skin heavier.  But for sailplanes, it is not as important to get lighter weight as it is for us."

"We did a lot of research and tests - applying different material and different construction and now we have found a very good carbon fabric with light weight plus very good foam and applied the special skin construction that improves the surface strength.  We exerted test forces to the skin surface and checked for depression depth and characteristics.  The force was twice as much as we exerted to the skin with traditional construction and it did not make any depression."

"At first we had the questions about the torsion strength but now we have already made the D-spar load tests and gotten very good results for bending with torsion on our first attempt.  The weight of just one D-spar is 2kg (or 4.4 pounds) less than Aeros' first D-spar.  (That's an almost 9 pounds savings)."

Then, Dave Sharp, who represents Altair, the US distributor of ATOS, chimed in with his rack design (as he carries the ATOS all over the country):

I wanted to offer a couple of solutions I've invented to provide the extra needed care of rigid wings.

I made my rack by taking four bike type racks.  Take a 1/2 inch piece of plywood cut to the length and width of two racks put together Put 4 inch thick open cell foam on top and cover the board and foam with vinyl, use a staple gun to fasten the vinyl to the bottom of the wood.  Next mount the wood to the racks.  You need four racks to make two supports.  For a truck or car you would use the two support mentioned with a conventional rack in front.  Place the heavy end of the rigid on back where the extra weight will appreciate the soft, thick and wide padding.

I had Betty at High Energy Sports make a special X-C cover bag , it has two hollow tubes the length of the glider at the bottom of the bag.  The tubes are stuffed with 1inch pipe foam, close cell.  The tubes are approximately 5 inches apart.  For flying I just stuff half the bag down one D-tube and the other half of the bag down the other side of the D-tube as the foam won't allow you to fold it up and put it in you harness.  The advantage of this bag is that you hear a "gush" not a whack when you set it on the ground.  Or if you have to put your wing on a tram, or a car with poor pads you have that extra security.

You can reach Betty at «bettp» ask her for the Sharp Bag.

Discuss "All we are, are dents in the wind" at the Oz Report forum   link»

Sun, Dec 19 1999, 6:00:02 pm EST

to Table of Contentsto next topic Raptor 2 Update

carbon fiber|Matt Kolmann|weather

carbon fiber|John "Ole" Olson|Matt Kolmann|weather

(?-i)John "Ole" Olson|carbon fiber|Matt Kolmann|weather

carbon fiber|John "Ole" Olson|Matt Kolmann|weather

Matt Kolmann, «kollmancomp», writes:

I did manage to get several good soaring flights on the R2 before winter kicked in. The good news is the R2 is flying exceptionally well.  I greatly enjoyed all my flights.  It feels more like a weight shift glider than the weight shift gliders I remember flying.

All flights to date have been towing by either truck or trike.  Cross wind launches from the tow dolly are uneventful.  The glider self levels as it picks up speed and the rudders become effective.  It almost sets the crab angle automatically once becoming airborne.  I've heard the other rigid wings are the same.  This is clearly a real advantage in a shifting control bar control system.

Roll control is crisp and responsive with excellent coordination.  Roll rate from a 45 to 45 deg bank are in the 3 to 4 second range using the internal chronometer.(one Mississippi, two Mississippi, etc..) I've had the R2 in 800 ft/min thermals and blasted through 1600ft/min sink at 55 mph in some of the roughest air Ohio has to offer.

The bar pressure on the R2 is very light however it is positive and stable up to 65 mph.  I haven't flown it any faster than that.  There is a noticeable improvement in glide performance over the previous Raptors.  It is most noticeable at higher speed.

The spoiler system still needs some work.  The spoilers are very effective but at their first location deploying them causes a 15 mph increase in trim speed.  I have resewn the spoilers at a new location that should be better.  When the spoilers are at the right spot there won't be any change in trim speed when deployed.  Finding that exact spot does involve some trial and error.  I haven't been able to test the new location due to the weather.  I doubt if it will be perfect this time but with the additional information it will make the third try a more educated decision.

I did let one of the local pilots fly the R2. He seemed very impressed with the handling and performance.  Look for him to be writing you about his impressions of the R2. I'm sending you some pictures to illustrate some of the differences between the R2 and the rest of the rigid wings.  These were taken during the construction of the R2. The model is a 1/4 scale built to evaluate different methods of glide path control.  This one had coupled flaps and rudders.

 

The R2 is a completely different concept both in wing planform, construction and control.  To begin with the R2 has much less sweep and twist than the other rigid wings.  One of the problems with sweep is it diverts more airflow toward the tips.  The result is the center section isn't as efficient.  (I believe the Hortens referred to this as middle effect) That is also why you see flaps on these wings.  They are there to increase the poor lift coefficient from the center section.  The R2 decreases this problem by minimizing the sweep.

There is also a true 2 to1 taper ratio.  This puts a much thicker longer airfoil in the center to maximize its performance.  The result is a more efficient wing.  The more efficient a wing the higher the performance.

Pitch stability on the R2 comes mostly from the pitch stable airfoil.  The first Raptors used Jim Marske's original airfoils and proved to be excessively pitch stable.  The R2 now flying uses the same airfoil but with a reduction in the reflex.  I personally like this configuration but don't know if it is acceptable for a production glider.  I wouldn't want an inexperienced pilot flying a glider set up like this.  The problem is with this low bar pressure it would be effortless to exceed Vne.

The plan is to build a couple different rib sets with various reflex.  This will make it possible to make the R2 available in two different formats.  One has more bar pressure and sacrifices some high-speed glide like the earlier Raptors.  By changing out the ribs it is possible to reduce the bar pressure and maximize the high-speed glide.

The structure of the R2 is completely different from other rigid wings.  The d-tubes shell use solid kevlar ribs inside the d-tube - no core material in the shell.

I did several hundred test pieces on every core material/composite combo I found one basic flaw.  To get the necessary weight a thin layer of composite material was needed over a lightweight core.  This has one drawback.  It offers very poor puncture and crush resistance.  A sharp edge could penetrate the structure.  A blunt edge would dent it. This means if the D-tube was laid down on a rocky surface or even a poorly padded rack it would dent and possibly fail a small area on the d-tube.  This wouldn't significantly weaken the d-tube but over time this damage would add up.

See "All we are, are dents in the wind."

The Kevlar offers nearly the same weight as the carbon fiber and is significantly tougher.  Without the core material the thicker material is also able to flex and absorb impact without denting or failing.  The center section is completely different than any other rigid wing.  I designed this junction with guidance from Jim Marske.

One thing I learned long ago is that the two d-tubes folded against each other make for a big package.  Separating the two seemed the logical choice.  Also the mechanics that allowed the d-tubes to hinge added a lot of weight.  Why is it necessary to hinge the D-tubes if you are going to disconnect them from each other?

The obvious solution was to extend the spars past the end of the D-tube and plug them into each other.  So on the R2 the spars begin a gently curve 3' from the center section.  This curve allows the spars to meet and plug straight into each other.  Two steel pins go through this junction.  The upper and lower keel mounts directly on these pins.

To set the R2 up you unzip the bags to expose the center section on the d-tubes.  The d-tubes are laid out and plugged into each other.  The whack tube has a steel tube mounted in the end.  It plugs into the lower hole through the spars.  The nose catch bolts are then installed.  The keel plugs onto the steel tube sticking through the center section.  One wing tip is lifted until the proper dihedral is reached and the spar hits the stop block.

I usually stick the rudders under the tip to hold it in place until the upper pin is installed.  This upper pin also plugs into the upper keel.

Now stand it up on its control bar.  The nice thing is the center is locked in place and solid and the wing halves are still in the bags with only the centers opened.  From here you unzip and remove the bags and fold out the ribs and tension the sail.

Another major difference on the Raptor is the rudder control.  The Fledge demonstrated that tip rudders could meet the HGMA roll requirement.  I don't see the logic of constantly deploying a large spoiler in a soaring craft.  The last thing I would want to do when flying into a big thermal is open a spoiler.  From what I am hearing some of the "second generation" rigid wings require high siding in turns.  Which means one of the spoilers would be held open when thermaling.  That can't be good for the climb rate.

The rudders also provide an effective yaw dampening system.  The rudders hinge out only.  If the glider yaws to one side the upwind rudder is held against the stop.  The downwind rudder is allowed to pivot into the wind.  This results in the upwind rudder creating more drag to correct the yaw.

The original plan was to certify the R2 before beginning deliveries.  I have received info from the HGMA and been able to review it. I am having doubts if I will certify this design.  The truck testing is a valuable tool for verifying glider strength and stability.  I will truck test the R2 to the level required by the HGMA Airworthiness standards before delivering any gliders.

However to receive HGMA certification I will be required to submit detailed engineering drawings along with the layup schedules including a detailed description of the production process.  So in essence I have to not only hand over detailed construction information.  I have to also describe exactly how to build one.  This information is then shared with the HGMA members.  The HGMA is composed of members from several different hang gliding manufacturers.  So basically I will be giving all this information to my competition.

I wonder if this is why most of the rigid wings currently certified seem to be clones of each other?  The HGMA in my opinion isn't really set up to deal with a composite airframe.  The HGMA standards refer to a sail covered tubing airframe glider.  Mostly wanting to know tubing size, wall thickness, location of bolt holes, etc.  There is no reference to composite material anywhere in the documentation.

I have two big concerns about certification.  First is of course someone will use this information to clone the R2. This is a relatively simple glider to manufacture once you know a few secrets.  The other problem is the composite structure is a different type of structure than the HGMA is formatted to consider.  I'm therefore concerned that it could become a quagmire of red tape that could drag on endlessly.

Raptor hardwing kits are now available.  I am also taking deposits for ready to fly Raptor 2. Truck testing of the R2 will be in early spring.  Deliveries of ready to fly Raptors are projected to begin in April.  The price of the Raptor and Raptor kit is going up $500 effective January 1 in the year 00.

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Sun, Dec 19 1999, 6:00:03 pm EST

to Table of Contentsto next topic More powered fun

Ghostbuster|John Reynoldson|PG|Phil Seeley|video

Karl Stice sent me the address for the site for the Explorer harness in Australia (clone of the Mosquito): http://www.ffa.com.au/airtime/index3.htm.

Oliver Moffatt, «Oliver», writes:

Very interesting to read about Project Thistledown.  You may be interested to know that there were four powered hang gliding harnesses on show at the recent airsports exhibition in England.  The Mosquito, of course, and the Hornet - a virtual Mosquito clone which has a better flat-top made-to-measure harness and a few other variations on the theme.

Two UK manufacturers are taking different approaches.  Solar Wings' designer Billy Brookes has produced a design, which is effectively like a Mosquito, but straps onto the back of "any existing flat-top harness". The idea is that you just attach the engine as and when required.  The only permanent modification to the harness is a couple of mounting lugs, which are bolted through the cloth on either side of the pilot's ribcage.  Attaching the engine (which is mounted on a fibreglass moulding that looks a bit like a beetle's wing cases on the back of the harness) takes "a few seconds". The unit has a self-folding propeller, for reduced drag engine-off.  Attach the fuel tank to the top of the control frame, remove the glider's stinger and you're ready to go. Very neat indeed.  They were showing videos of it in action.  Email «pegasus».

Ben Ashman, of Flylight, produces the Doodlebug.  This is similar to the Thistledown but without the wheels.  The pilot is supine, legs above the control bar on a stirrup.  The pilot takes off on foot then rotates backwards into the seat.  The action of bringing the stirrup down from above the pilot's head after takeoff neatly stows the landing legs in their inflight position.  Behind the seated pilot is a faired pod containing the fuel tank and the pilot's sandwiches; putting the fuel here means the unit is self-contained.  There are some clever touches, and as you would expect from Ben, everything is beautifully finished.  It was shown attached to a Ghostbuster, I think, but I don't know whether they've flown together.  Email «flylight».

Ed Cleasby, who runs an annual powered hang-glider and powered paraglider meet in the Lake District, says there is little to choose between the units under power, (I believe they all use similar, if not identical, engines) but engine-off the Doodlebug suffers slightly from increased drag due to the supine pilot.  On the other hand he's probably much more comfortable than the others, except for his cold feet!  (Which reminds me that a small forward fairing is an option on the Doodlebug.)

Phil Seeley, «Phil_Seeley», writes:

You may be aware that for the last few years foot launched hang gliding (and paragliding) has been deregulated in the UK and this has spawned a number of different approaches, the most recent and (on the face of it) appealing being the Doodlebug.

At a recent trade fair there was even a Doodlebug fitted with a small (and ultra light) jet engine !!! although I don't believe this has been flown (yet !!).

The Doodlebug has been flown on an Extaccy, with a 45mph cruise at 1/2 throttle, 38mph cruise at 1/3 throttle.

See http://www.woodleydowns.demon.co.uk/Manufacturers.htm for a quick roundup of what's currently available.  Info is also available at http://www.lejair.co.uk/powered/powered.html with the interesting addition of the Nargfly, the only "Pulling" prop FLHG I've seen.

John Reynoldson, «microsoar», responds:

Here in Oz, we don't have to footlaunch below 70kg, so it makes for a bit more flexibility, and, as I mentioned, I'm not comfortable with having to foot-launch/land all the time with the power pack.  We've had far too many broken props on Mosquitos here.  It doesn't seem to be a matter of *if*, but a matter of *when*.

The Thistledown is a flying test bed - but fun is priority-one.  I've been looking at ways of rebuilding it as a suprone machine similar to the Doodlebug, but as this is not a commercial endeavour and funds are limited, this may take some time.  The eventual machine would end up with fixed bar wheels and a pair of steerable splayed wheels arranged like the Mosquito/doodlebug skids at the rear.  Pilot foot pressure on the foot stirrup would steer the rear wheels.  The machine could be foot or wheel launched/landed.

I'd also like a folding prop, but this is really getting expensive!  (Arplast make one for the Solo combination).

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Sun, Dec 19 1999, 6:00:04 pm EST

to Table of Contentsto next topic Cleaning up e-mail text

Sun, Dec 19 1999, 6:00:04 pm EST

Seems like folks liked my little article on Mail Magic Monitor, so I thought I would tell you about Text Cleaner.  I copy a lot of text out of e-mail and paste it into Microsoft Word.  I need to get rid of the manual line breaks at the end of each line (e-mail clients put these in), change double spaces to single spaces, get rid of the ">" marks, put paragraph marks between paragraphs.  I use to do this manually in Word (you could set up a Word Macro to help do it also).

Now I'm using Text Cleaner (shareware at $19), which does this little piece of work for me. It cleans the text in the clipboard automatically when it is running.  You'll find it at www.comp4learn.com/cleaner.

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Sun, Dec 19 1999, 6:00:05 pm EST

to Table of Contentsto next topic Coming soon:

Mark Stucky|Quest Air

Mark Stucky's article on weak link testing.
Pictures from Manilla - Gowana up a tree.

Also, Atlantic Coast Championships at Quest Air – April 24th – 29th (six days). One rest day between it and the Wallaby Open – April 16th – 22nd.

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The Oz Report, a near-daily, world wide hang gliding news ezine, with reports on competitions, pilot rankings, political issues, fly-ins, the latest technology, ultralight sailplanes, reader feedback and anything else from within the global HG community worthy of coverage. Hang gliding, paragliding, hang gliders, paragliders, aerotowing, hang glide, paraglide, platform towing, competitions, fly-ins. Hang gliding and paragliding news from around the world, by Davis Straub.

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