Oz Report

January 29, 2012, 11:09:53 PST

Only one reserve thrown on day four

Nick Greece with help from friends flies well

(Valle de Bravo, Mexico)

parachute|PG|video

http://www.youtube.com/user/herminiocordido

http://www.paraglidingworldcup.org/sites/default/files/T4_0.kmz

http://andre-comps.blogspot.com

http://www.xcmag.com/2012/01/paragliding-world-cup-superfinal-2011-luc-armant-first-in-goal-again-on-task-4/

http://www.paraglidingworldcup.org/node/10704

http://www.paraglidingworldcup.org/node/2005

January 28, 2012, 10:05:07 PST

Only four reserves thrown on day three

Nick goes into the trees

(Valle de Bravo, Mexico)

CIVL|parachute|PG|video

http://andre-comps.blogspot.com/2012/01/valle-super-final-day-3-task-3-update.html

A chaotic day now that all reports are in! Four reserve rides including Nick Greece, who flayed his glider through the trees and punctured himself in the process. Nothing too serious I believe (just a small thing really).

http://www.paraglidingworldcup.org/node/2005/reports

http://www.xcmag.com/2012/01/paragliding-world-cup-superfinal-2011-luc-and-luca-joint-first-on-day-three/

http://www.youtube.com/watch?v=_RjOW0SzZ_Q

Analysis: http://www.paraglidingforum.com/download.php?id=38500

http://www.paraglidingforum.com/viewtopic.php?t=44790&postdays=0&postorder=asc&start=143

Already there have been more reserve rides in this event than in all the previous superfinals. Is Valle really that rough? It seems unlikely given conditions in Turkey and even Italy (Norma anyone?).

I wonder whether the CIVL bureaucrats are watching and have noticed the adverse effect their decision to ban Open Class has had on safety for these absolute top level pilots. How much worse is it going to be when normal pilots are flying these serial class 2-liners.

January 27, 2012, 9:56:47 PST

Only three reserves thrown on day two

USA team doing well

(Valle de Bravo, Mexico)

parachute|PG|video

http://www.paraglidingworldcup.org/

http://www.xcmag.com/2012/01/paragliding-world-cup-superfinal-2011-juan-becerra-sneaks-ahead/

http://www.youtube.com/watch?v=TxrpJKWqKGA

September 25, 2007, 8:04:40 PDT

Trikes

More power than brains

crash|Dave Connors|parachute|trike

http://ozreport.com/forum/viewtopic.php?t=9596 Thanks to Dave Connors and Alan.

Fri, Feb 23 2007, 5:42:09 pm PST

Harnesses

Similar problem - strap looped to another strap without carabineer in between

(Vionnaz, Switzerland)

Andreas Orgler|fatality|parachute|Reto Schaerli

https://OzReport.com/forum/viewtopic.php?t=6622

Mathieu for the Delta-club Valais «secretariat» writes:

One of our friends died a few days ago after throwing his parachute. His harness has a strap which cut the bridle when the parachute deployed. Reto was flying at about 400 meters AGL. He sped up and immediately started tumbling. The glider broke immediately. Reto threw his parachute but the seam of the bridle from the parachute had been cut by another strap from the harness.

After this accident occurred, a failure was noticed on a hang gliding harness from the French manufacturer Ellipse. This model has been manufactured since 2001. A strap in the harness will cut open the seam of the parachute bridle when it comes under sudden tension due to the opening shock of the parachute. Pilots using such harnesses should contact the general dealer in Switzerland or the French manufacturer to have their harnesses modified.

Click on the above for a higher resolution photo.

Strap 1 seems to be the parachute bridle. The problem is that it is looped around strap 2 without a carabineer in between the straps. Also, it is free to slide around on strap two, which then cuts it. This is exactly what happened to Andreas Orgler, when he threw his chute. You are not supposed to connect strap to strap because one will cut the other.

More here: https://OzReport.com/forum/viewtopic.php?t=6669

General dealership Switzerland:

Aérocentre
CP 21
1964 Conthey
+41 79 449 33 11

Manufacturer in France:

Ellipse
Rte de Bonnevent
70150 Etuz / France
+33 381 57 60 22

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Mon, Jul 11 2005, 9:00:01 pm GMT

Chelan XC Classic 2005|Douglas Pohl|parachute|PG|US Nationals 2005

CXCC

From the 9^th of July

Here

Douglas Pohl «dpohl» sends the URL for his pictures and writes:

Yes indeed - many paraglider pilots were at the Butt this weekend in preparation for the U.S. Nationals - with one successful reserved deployment at 11:30AM during the Classic Pilot Meeting.

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Fri, Oct 24 2003, 8:00:02 am GMT

accident|bridle|George Lutkowski|Glen Volk|Kathleen Rigg|Mike Barber|Moyes|parachute|Peter Birren|Rodger Hoyt|wires

Peter Birren «peterb» writes:

In 1991 (12 years ago), George Lutkowski did just what was described (Some day there will be a chute deployment by a pilot in a glider that has stripped wires and the parachute bridle will be cut in half) and his chute bridle was severed, leaving material embedded in 54 inches of bare flying wire. George will never fly again and has lost 90% of the use of one hand due to nerve damage, all in the name of better(?) performance.

Who wants to be next? From severed noses to bridles to bystander injuries, stripped wires are a hazard to everyone.

Rodger Hoyt «rodger» writes:

The potential cutting of a parachute bridle is avoidable.

When removing a worn parachute bridle several years ago, I discovered to my shock, how easily Type 18 bridles are severed with minimal heat and friction! The thought of this type of material sliding along a flying wire, stripped or not, under the tension of deployment, made me afraid to ever use it again. That's when I switched to Kevlar. Even a well worn Kevlar bridle was impervious to my hot knife, and required a concerted effort to cut at all. Kevlar has the additional advantage of being much thinner and therefore bundles smaller in your 'chute container.

Unquestionably, most aspects of parachute design and construction are compromises, each having its pros and cons; Kevlar is no exception. Kevlar fell into disfavor some years back when leading parachute manufacturer Rich Pfeiffer denounced it for lacking the elasticity necessary to absorb the shock of a terminal velocity deployment without destroying the parachute itself. But Rich's perspective was that of a former skydiver; few hang glider deployments are at terminal velocity.

Another drawback of Kevlar is, if the occasion ever arises where a hook knife is needed, it would be useless on Kevlar - plan on cutting your harness mains instead. It's also rumored that Kevlar is less tolerant of UV; I keep my bridle sheathed.

Each pilot must decide what characteristics are most important to him. I'm confident with Kevlar.

Also, if cut bridles are a concern, one should consider the airframe material. 6061 responds to impact by bending; 7075 (the current material of choice) shatters, leaving sharp edges (don't ask how I know this!).

Kathleen Rigg «Kathleen.Rigg» writes:

I'd just like to point out that I do not believe my accident was actually caused by the wires (which I did not strip but are delivered by Moyes with no plastic coating). In fact after inspecting the glider and assessing the angles and evidence of blood on the glider my injury appears much more likely to be from violently forcing my nose up between the swages at the very nose of the glider rather than from the actual wires.

There is also some doubt as to whether the wires caused Mike Barber's accident as well - in fact it is more likely to have been caused by the back edge of the carbon base bar (which is very similar to an accident Seppi had shortly before Mike).

I'm not saying that stripped wires are necessarily a good thing, but I don’t believe either of the two accidents that Glen Volk mentions can be accredited to stripped wires!

Discuss stripped wires at OzReport.com/forum/phpBB2

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Mon, Aug 25 2003, 6:00:03 pm GMT

Mino Bricoli

Angelo Crapanzano|Conar HG20|fatality|LaMouette Tsunami|Mino Bricoli|parachute|Pre-Europeans 2003|sailplane|tuck

Angelo Crapanzano «angelo» writes:

I'm so sad to inform all of you that Mino Bricoli, four times Italian champion and several times member of the Italian team since 1978, had a fatal accident last Sunday.

Mino was flying a LaMouette Tsunami from Monte Caio (his home flight near Parma, Italy) and during the landing approach at approximately 60 meters high, was seen pulling speed with the flaps down (40 cm of rope out), pitching down in an almost vertical dive and then tuck in.

The glider broke while inverted and Mino immediately threw his chute (Conar HG20) which came out of the deployment bag but could not inflate in time.

At 57 years old Mino was very happy to be back to hang gliding competitions after a bad sailplane accident which took a few years to recover from despite his strong will. Recently he proved to be still better than most younger pilots and placed 14^th at the Pre Europeans in Millau.

Mino leaves lots of friends, his wife Paola and his twin brother Stefano. Mino and Stefano were even more than twins, if possible. A few years ago Mino told he was not worried about dieing, but he was rather worried about surviving his brother. Now it is Stefano's duty to live for Mino too.

Discuss "Mino" at the Oz Report forum   link»  

Fri, Aug 1 2003, 4:00:03 pm EDT

DHV|Icaro 2000|Icaro 2000 Laminar|Koos de Keijzer|parachute|safety|tuck

Koos de Keijzer <koos@hetbadhuis.nl> writes:

On the third day of the Slovenian-Dutch Open at Vipava (Slovenie) I had to use my parachute. I fly a Icaro 2000 Laminar 2003 with DHV sprog settings. I was chasing another glider a little bit in front of me and a little lower with a little over ¾ VG.

We were flying around 100 km/h groundspeed with slight headwind along the ridge. I was flying faster than I usually do because the other pilot did. I thought I would see him hitting turbulence first and I would have time to react. I hit a strong thermal in the middle and with my arms stretched at the bar I was going vertically up.

Maybe I should have made a wingover or loop. I had enough speed for that, but it didn't cross my mind. After losing all my speed things happened quickly. The bar was flung out of my hand and I found myself behind the back wires. Tucked or tumbled I don't know, it happened too fast.

After the second or third tuck I realized the glider was damaged and I threw one of my safety-chutes. I landed very softly on my glider in low bushes. The glider had one leading edge broken and all the four steel sprog wires were broken.

My lessons are: stick to my own speed limits. If you are going vertically upward G-forces will be quickly gone and with them your weight shift control. In my situation a wingover or loop was possible but I had to decide very quickly. If you fly with two safety chutes you better fly with two good sized ones. One of mine was my girlfriends old one. I thought of using this one only in case the main one would fail or wrap up. I ended up throwing the old one. It came out fine, but…

Discuss tucking at OzReport.com/forum/phpBB2

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

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

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.

Discuss "The Spanish ATOS “incident”" at the Oz Report forum   link»

Sat, Jun 21 2003, 2:03:06 pm EDT

competition|Florida|parachute|release|video

Mark Windsheimer <AirtimeHG@aol.com> writes:

In May of this year I ran a small parachute clinic for some pilots that had attended the Comps in Florida. This Clinic was held in Golden Colorado.

In the Clinic we had a couple of Metamorfosi chutes and many others. One of the Metamorfosi had a factory pack on it. When the pilot tried to deploy it he ended up with the lines and Diaper tied in a knot about 3 feet from the skirt of the canopy. This clearly happens as the pilot is about to release the diaper into the air, from a spinning situation. Since we were filming each throw we could look back and clearly see what happened. The canopy size would have been seriously compromised by this knot.

(editor’s note: Perhaps you can share this video with Angelo as he has been so nice to share his with us. By the way, Angelo is off at a competition and won’t be answering e-mail for another week.)

The other Metamorfosi opened cleanly as the staged diaper should have. All of the bag systems (even those with the handle on the bottom of the bag) had no problems. I attribute this to the pilots getting their chutes repacked at least once a year, with fresh rubber bands, or stows.

I have been working with parachutes in Colorado since they first arrived on the Hang Gliding scene. I owned the first reserve for Hang Gliders in Colorado. I have seen both diaper and bag failures. But in most cases from what I have experienced, the bag system seems to give the pilot a better chance to get the chute into clean air in violent situations.

One of the keys to a proper working system is proper maintenance. The Metamorfosi that failed was only a year old. But the Canopy decided to come out before the lines were fully staged. The Diaper defiantly allowed this to happen easier.

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Fri, Jun 20 2003, 6:03:06 pm GMT

Angelo Crapanzano|bridle|DHV|Europe|harness|Juan Lara|parachute|power|video

Gary Douris <gary77douris@yahoo.com> writes:

We have tested the swivels both from an aircraft and from relatively slow hang gliders. Angelo is correct in assuming that the swivel can cause the bridle to drop below the bag when the glider is traveling more or less straight down.

Our rationale is that very few cases have the glider traveling in a straight vertical down attitude. On all but one of the several broken gliders I have seen they have had some horizontal track. In this case the bag with canopy has a relative wind to help move it away from the glider and deploy.

Remember, parachutes do not work every time. There are too many variables with gliders in different configurations to guarantee a successful deployment in all cases. We can only do our best.

As far as your canopies or anyone else’s, if the canopy does not clear the end of the wing and the bridle catches on something a swivel can make all the difference.

One of ours was caught on the wing tip a few years ago and wound up with 97 twists in the lines and bridle. The canopy was completely collapsed because the glider was spinning so violently. The pilot survived since he landed in some bushes and we soon after started using swivels.

No canopy design is sure of not having a problem with the bridle snagged. If the glider spins badly enough the canopy with collapse no matter the design. The reason we put the swivel where it is is to get it as far from the glider as possible so if the bridle does snag the swivel still has a chance to work. It also adds weight to the bag which helps extend the bridle faster.

If I can find it I will send you a video of a test we did a few years ago with a spinning canopy. It opened my eyes and made a believer out of me.

The L.A.R.A. comes with the swivel optional.

Angelo Crapanzano <angelo@metamorfosi.com> writes:

I agree with you again: it's just a matter of compromise and different experiences.

I've seen most broken gliders falling straight down and out of 276 real openings that I know with my parachutes only one may have needed the swivel (the parachute didn't fully collapse and the pilot was uninjured). I'll be very interested in looking at the video: there is always something to learn.

Our experience brought us to different solutions of the same problem and I'm actually sorry to have involuntary started this debate on swivel: the number of saves proof both systems are safe enough.

Angelo continues:

As I wrote in a mail last year on OzReport (https://OzReport.com/toc.php?Ozv6n27.shtml) personally I don't like swivels (mainly because I feel they are not necessary for my parachutes) but I agree they could be useful in other parachute design. In that article I already explained, in a fast way, why I don't like the swivel near the junction bridle-parachute, but I was not exhaustive. Actually I thought nobody was using the swivel in that position until, a few weeks ago, I've seen a parachute like that (as you know, in Europe the swivel is not common and, in Italy, almost unknown).

Sorry but, to be clear, I've got to start from the way tests are normally done. I you want to understand what I mean, please have a look to the videos which are better than a thousand words.

When making tests with forced opening from an airplane or skydiving it is the parachute strength, stability and sink-rate that is tested but not the deployment sequence in a real hang gliding emergency situation:

- If the deployment is forced with a static line the deployment bag design makes almost no difference because it's the dummy weight which pulls the parachute put of the pod.

- If the parachute is tested while skydiving, everything happens at very high speed: very little in common with a "normal" emergency situation.

The DHV, to test the opening time and sequence, lets fall at the same time from zero speed, a dummy and the parachute still closed in his deployment bag: the parachute have to fully open within 60 meters. In this test the torso dummy is obviously falling faster than the pod thus it is the force due to the different velocities which extracts the parachute from the pod. (Kok7 video) (There is quite a lot to say about this test too but, again, it's another long story…)

For your knowledge, the terminal speed of the dummy is probably close to 100 m/s (360 km/h or 225 mph) while the terminal speed of a parachute still closed in his pod is around 12 m/s (43 km/h or 27 mph). As a comparison the terminal speed of a parachutist (quite variable because depends on his position) is normally considered as 50 m/s (180 km/h or 112 mph). To make it clear for everybody, the terminal speed is the maximum speed achieved by a body falling in the air. It is the speed at which the drag force equals the weight force thus the body would not accelerate and keeps constant speed. Of course, depends on the weight and the shape of the body. Things would be much easier to calculate without air because everything would fall at the same speed, but we could not fly either :-)

Lets go back to reality and imagine the pilot lets the parachute fall (something which happens very often) instead of throwing it forcefully. Just a quick note: to throw the pod forcefully and in the right direction helps a lot the deployment sequence but, try hanging in your harness close to the ground, it's almost impossible to fully stretch bridle, line and canopy horizontally just with your force. Moreover you would never be able to throw it upward more than a couple of meters: in my opinion the parachute needs to be able to open on his own, even if it's not thrown forcefully.

As everybody knows, in many real emergency situations, if the glider is not much broken the pilot is falling relatively slowly and, quite often, slower than the parachute still closed in his deployment bag. In this situation it is the deployment bag which falls down compared to the broken glider. Again it's the difference in speed between broken glider and closed deployment bag which extracts the parachute (but this time the other way round compared to the DHV test). In this situation, once the canopy is out of the deployment bag, the parachute is pointing down then it "flies" up (still not inflated) and can open only once above the pilot, with the lines stretched. (Kok4 video)

If the glider is badly broken the pilot will fall down very fast. The situation gets similar to the DHV test: the deployment bag goes up compared to the glider and the parachute comes out of the pod because of the different velocities: once the parachute gets out of the pod it is already above the pilot, with the lines stretched, and opens. (Kok6 video)

But what will happen if broken glider and pod are falling, more or less, at the same speed? In this case there is very little difference in velocity to open the pod. What actually opens the pod is the drag on bridle and lines which makes an arc between pilot and pod and extracts the parachute. It is evident that in this case there is very little force available to open the pod. (Remember that this force this force goes up with falling speed power of two). (Kok5 video)

Just for your knowledge, my experience says that the slower the glider is falling, the longer the falling distance needed for the parachute to open.

But what does this matter with swivels? It does matter, in my opinion, but I want to point out that what follows is just theoretical and is not backed by any tests on the influence of swivel position on parachute deployment. I’ve never made any test on swivels because, as I already told, I think in my parachutes the advantages of a swivel are out weighed by the disadvantages.

A swivel adds more or less 200 grams (0.5 lb) to the bridle (weight of the short webbing included) which is a good percentage of the whole suspension system (bridle + lines); moreover it's concentrated in a single point. Let's see what will happen in the three cases if the swivel is, more or less, at the junction between lines and bridle:

If the deployment bag falls down compared to the pilot, the weight of the swivel helps the bag falling down but then the canopy (stretched but still closed) has to lift the swivel weight to get above the pilot. This, for sure, will slow down the opening and will slightly increase the time the canopy is level with the broken glider, thus increasing the chances of tangling. Moreover the swivel weight, concentrated at the junction bridle-line, tends to shape bridle and lines making a V, thus bringing the canopy closer to the wreckage.

If the deployment bag goes up compared to the pilot, the weight of the swivel will slightly slow it down (compared to the pilot) until the bridle is stretched then would make no difference. It would be practically impossible to measure any difference in opening time, especially if the tests are done at high speed. These, as far as I understood, are the tests made by Rob and that's why he didn't find any problem adding the swivel at the junction bridle-line.

If the deployment bag falls down at the same speed of the broken glider the weight of the swivel would counterbalance (at least partially) the drag on bridle and lines. Moreover the swivel weight, concentrated at the junction bridle-line would shape them like an m thus bringing the canopy closer to the wreckage.

Now you know why I feel it would be better to have the swivel at 1 or 1,5 m (3-5 ft) from the pilot where it would not make any problem.

I would like to point out again that what I wrote is absolutely theoretical. I never wrote (nor intended to mean) that a parachute with the swivel at the junction bridle-lines will not work or is dangerous. There have been lots of saves with this configuration to prove the system is, for sure, safe enough. I only meant to say that, in my opinion, in some particular cases, the opening time could "slightly" increase and the chances of tangling could "slightly" increase too. Slightly is quoted simply because it's practically impossible to value it. On the other side the swivel at the junction between bridle and line is in the perfect position to avoid any twisting of the canopy. Like always any solution has advantages and disadvantages and it's up to the manufacturer to find "his" best compromise.

Hope this mail would be considered as an attempt to improve parachute design and not the start of a useless polemic (I didn't even know the Lara had the swivel in that position). It is not my intention to denigrate anybody else’s design. To make it in easy words: logically I would prefer my Conar, but I would have no problem flying with a Lara, even with the swivel in the "wrong" :-) position.

Discuss "Paraswivels" at the Oz Report forum   link»

Fri, Jun 20 2003, 2:03:05 pm EDT

Betty Pfeiffer|bridle|gear|parachute|Sandy Dittmar

Red <red@xmission.com> writes:

I agree with Betty, about sequenced deployments for reserve parachutes being a great idea.

I agree with Angelo, about the real advantages of a "diaper" deployment system, and that a sequenced "diaper" system is the -best- of all possible choices. I will shortly be buying exactly that.

I had one like that for most of my HG flying so far, but my gear was stolen, a couple of years ago. So, I bought a sack-deployed reserve; it was a "deal", and delivery was rapid. Hey, I'm not rich, and I was needing airtime… :-)

My new 'chute arrived with the deployment handle installed at the wrong end of the sack! I was shocked. My retailer called the company, and only after some discussion, the defective sack was replaced. Every reserve in that same shipment came, like mine, with the handle at the wrong end, also.

If the handle is installed at the open end of the sack, that is correct. You should be able to toss this parachute cleanly. If the handle is at the closed end of the sack, however, that can be hazardous! A hard toss may break the elastic bands securing the sack (even if they are new ones). The empty bag might go flying, but the pilot can have lines, bridle and a scattered canopy billowing around them.

From my own experience: At an indoor parachute clinic, in Sandy, Utah, several pilots with "wrong-handled" sacks experienced this "empty bag toss" parachute malfunction, in one evening. For one of these malfunctions, the pilot's canopy draped itself over the pilot's head and shoulders. Every pilot fell silent at the sight of this prone form, enshrouded in white. Not one person in the hall laughed. The pilot himself was frozen in thought.

Would everybody with a sack deployment system, just go check that they have a sack with the handle at the correct end? Thanks; every pilot is somewhat "family", to me. While we are throwing "experience" times around, I was flying, and building HG for a living in 1975. I worked at one of the only two HG shops in Denver for a bit, building airframes and harnesses. I was a certified instructor for over a decade in SLC, Utah; h4 with all endorsements. Coupla thousand hours, now, and counting.

Not relevant, but free advice, and maybe worth the price, for new and low-time HG pilots, at my website: http://www.xmission.com/~red/

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Tue, Jun 17 2003, 2:03:06 pm EDT

altitude|battery|crash|equipment|fire|Flytec USA|lightning|Oz Report|parachute|picture|power|record|Rob Jacobs|Shane Nestle|smoke|Steve Kroop

Steve Kroop at Flytec USA <flytec@earthlink.net> writes:

We received quite a few guesses on “name that disaster”. Below is a listing of the various ideas with the number of people that guessed each possibility.

9 - Hit by lightning
6 - Melted by the sun on car dashboard
5 - Contact with power line
5 - Fell in campfire/BBQ pit
3 - Attempting to charge the non rechargeable batteries through one of the data ports
3 - Reversed battery polarity
3 - Automobile fire
2 - Placed in conventional oven
2 - Brush/forest fire
2 - Friction from flying too fast
2 - Excessive climb rate
1 - Melted by leaky battery acid
1 - Crash and burned
1 - Burned by a wind direction smoke bomb
1 - Microwave oven
1 - Car heater
1 - House fire
1 - Burnt by ballistic reserve
1 - Baked in over for 45 minutes
1 - Too close to catalytic converter in a P/U truck bed
1 - Was it left out in direct sunlight in the map holder, and the sun did the rest
1 - “The owner closed the car door with the vario left outside the car hanging on the string and bounced along the highway after a long flight… but then it would have been scratched also, and it’s like only melted…”

1- “The owner was a hang gliding (not a paragliding) pilot, that was testing a new topless model for the next worlds on Brasilia (where I’m willing to go) and that the pilot was flying so fast that the air friction heated up the instrument until it melted like that. Fortunately the pilot had those excellent speed sleeves that Flytec offers so he could glide effortlessly and with no drag thus friction involved so he didn’t notice the heat caused by the high speed air friction.”

1 - “It was dropped from 1500 feet into a plowed field, buried several times by the plow over two years, and finally dug up by a cow, who probably stepped on it at least once. The owner had originally looked for it, but never did find it. He was lucky that the farmer finally found it.”

And the correct answer is…Hit by lightning (the most popular guess) and the winner is… Rob Jacobs (the first one to guess).

(editor’s note: It’s great to see that Rob Jacobs, the hang gliding list moderator, it right on top of the most current Oz Report. Always happy to have committed readers.)

Honorable mention goes to…Shane Nestle with the following explanation:

These damn Flytec varios are so good that the pilot, whose name happened to be Icarus, got a little too carried away with the lift being indicated. Having tried other varios in his lifetime that just didn’t have what he needed, he was amazed at how well he was able to find the lightest of lift and stay with it.

His father, Daedalus, also a pilot and a long time Flytec user, had often bragged of the ease of it’s use and superior response. He would often fly high above his son, Icarus, taunting him to try and follow. When Icarus finally acquired his Flytec Variometer, at a very affordable price I might add, he immediately noticed the barograph feature and insisted on trying it out that day. Daedalus could see Icarus’ excitement and warned him to fly carefully, for today would likely be a record day for Icarus, even though the conditions were the same as always.

Icarus headed off to the local hill and proceeded to launch into light conditions. He immediately knew that he had something great as he was able to detect lift like never before. Soon he found himself able to actually out climb his father! In his exuberance of gaining altitude, slowly at first and then rocketing into the heavens as he centered in on the core, he failed to take heed of his father’s words to be careful. Before he knew it, he had gained so much altitude that the sun began melting his equipment. Unfortunately, Icarus flew an old, dilapidated wing developed in the beginning of hang gliding and no parachute (he didn’t need the parachute because he never got anything higher than a sled run prior his new Flytec vairo) and poor Icarus didn’t survive the re-entry into the lower atmosphere.

The picture presented is the vario used by Icarus and recovered by his father. I hear that Daedalus is trying to trade it in along with his older, but still great, Flytec vario for the new 4030Race. I also hear he is going to be entering a lot of competitions now that he does not have family responsibilities. He’s hoping to get those cool, blue Flytec speed sleeves so everyone will know just who is helping him to win all those races.

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Mon, Jun 16 2003, 6:03:03 pm GMT

accident|altitude|Angelo Crapanzano|Betty Pfeiffer|bridle|harness|job|nylon|parachute|Rob Kells

Angelo Crapanzano <angelo@metamorfosi.com> writes:

It's difficult to answer Betty Pfeiffer because she has a preconceived negative attitude and her letter looks more like a personal attack than anything else, quite a different behaviour from Gary Douris and Rob Kells. I'm going to answer in detail hoping this would not bring to a never ending debate.

"… revealed the importance of controlled deployment sequence"

I agree, but it could be achieved (or not) both with an envelope or a diaper.

"…a properly designed deployment bag … can allow the pilot a second (or third) throw if he/she did not clear the wreckage"

How can one make a second (or third) throw? The only way is to pull back the bag using the bridle, but a "properly designed deployment bag" (regardless if envelope or diaper) would not allow it because it will open before you get it back!

"Systems that allow parachute components to "dump" into the air to various degrees, such as diaper systems, risk tangling with the wreckage, out of sequence deployments which can cause temporary partial inversions, canopy inversions, line over situations and other problems."

I totally agree, but the proper deployment sequence could be achieved (or not) both with an envelope or a diaper. Anyway, why a properly designed diaper should "dump" into the air more than a properly designed envelope? Betty perfectly knows old style envelope bags (those with the opening on the opposite side of the handle) gave lots of problems, "dumping" the parachute in the air (or even into the harness!). It's the same with old style, flour flap diaper bag (but I never manufactured one of those).

My "five flap" diaper (which has been copied by many parachute manufacturers all over the world) has a perfectly staged and obliged opening sequence: bridle - lines - canopy. Of course one could prefer envelope or diaper (like Gary Douris and me) but this is quite different from saying a system is bad just because has a different name, if it does the same job.

Once the parachute is in clear air with a suspended weight, it will want to organize itself. In the process friction can cause heat, which can cause damage. This will not happen with the proper opening sequence: bridle-line-canopy, which could be achieved (or not) both with a diaper or an envelope.

"Last month a HG pilot threw his emergency reserve packed in a "diaper". It took him 1500 feet of altitude loss untangling lines so the parachute could open…"

I'm sure that's true as I'm sure Betty knows similar stories with emergency parachutes packed in an "envelope". If she doesn't I could tell her some.

"The use of line sleeves is analogous to a slider used on parachutes. It slows parachute inflation by restricting the line spread."

That's not correct: the sleeve is short enough not to make any difference in opening time. It does not restrict the lines spread. On the contrary a longer bridle, for sure, will make the opening time longer because of the longer distance needed to stretch the parachute.

Where is the correct compromise? Out of 276 openings that I know with Metamorfosi chutes, I know of one case only where the parachute got tangled: the glider was spinning very fast but coming down quite slow and the pilot was not able to throw the bag. The bag fell down, the parachute came out correctly, but below the glider, and got tangled while moving up (the pilot landed on flat ground uninjured). It would have happened the same regardless of the kind of deployment bag or bridle length. Actually, in a similar situation, an American pilot managed to get two parachutes tangled: both packed in an envelope (landed in trees and survived).

"Melting Point of Nylon. Nylon does not melt at 200°F. It melts at 480 to 500°…"

I agree Nylon doesn't melt at 200°F because I intended 200°C. Sorry I forgot to make the transformation in Imperial Units but you could expect a non American was not using Fahrenheit :-) As a matter of fact melting point of a solid block of Nylon is between 230°C and 250°C (446-500°F) and softening point is between 180°C and 210°C (356-410°F) depending on the kind of Nylon.

When speaking of fibres things change slightly and, for Nylon ropes, Marlow (http://www.marlowropes.com/yachting/material.htm) gives a melting point of 210°C (410°F). Line length can be duplicated well within tolerance of course, but will it remain within tolerances? Nylon stretches and shrinks quite a lot with temperature and humidity and my experience says its behaviour depends on the batch too. Still it's possible to make a reasonable good job, but I would just prefer a parachute where it's cheap to replace the whole set of lines.

V-Tabs Just because you have v-tabs on your parachute does not mean they are going to do the job especially if they are sewn to the outside of the parachute! Looks like they do the job. Possibly because they are in between two rows of Kevlar?

"Paraswivels have been very effective in stopping parachute lines from winding up and closing the parachute as the wreckage rotates. The rotation of the broken hang glider has nothing to do with parachute design."

I partially agree but my opinion is somehow different. If you are interested have a look at (https://OzReport.com/toc.php?Ozv6n27.shtml)

"Much of my information comes from over 20 years of first hand hang gliding accident reports involving parachutes…"

My one comes from 26 years of first hand experience. Does that mean I'm 30% better? :-( :-(

Discuss "Parachutes - Angelo responds to Betty" at the Oz Report forum   link»

Sat, Jun 14 2003, 2:03:06 pm EDT

accident|altitude|Betty Pfeiffer|bridle|equipment|G.W. Meadows|harness|history|job|nylon|parachute

Betty Pfeiffer<BettP@aol.com> writes:

Deployment bag verses Diaper Controversy

Deployment issues have been studied throughout the history of parachutes. In the 1970's G.W. Stevens of Great Britain developed anti-inversion netting in an attempt to reduce round parachute malfunctions.

A byproduct of extensive testing by US and British troops on anti-inversion netting revealed the importance of controlled deployment sequence.

Parachutes were tested using a variety of deployment systems including Deployment bags, Diaper systems, "Banana-Peel" Bags, Deployment Sleeves, and Skirt Hesitator Quarter Bags to name a few.

The results clearly show that the deployment bag kept the deployment sequence organized far better than the other methods resulting in consistent deployments with fewer malfunctions.

For our application, with a high risk of entanglement, a properly designed deployment bag protects the parachute from snagging on the wreckage, can allow the pilot a second (or third) throw if he/she did not clear the wreckage, maintains the momentum of the throw since only the required amount of parachute snakes out of the deployment bag, and keeps the parachute organized so chances of malfunctions are reduced.

Systems that allow parachute components to "dump" into the air to various degrees, such as diaper systems, risk tangling with the wreckage, out of sequence deployments which can cause temporary partial inversions, canopy inversions, line over situations and other problems.

Once the parachute is in clear air with a suspended weight, it will want to organize itself. In the process friction can cause heat, which can cause damage.

The process of organizing itself will give the parachute system a greater rate of descent than when it finally stabilizes.

Last month a HG pilot threw his emergency reserve packed in a "diaper". It took him 1500 feet of altitude loss untangling lines so the parachute could open. Fortunately the pilot had the presence of mind to stay on task and was able to land safely under a full parachute minus 2 lines. It is even more fortunate that he had the altitude to deal with the tangled mess.

Parachute Bridle Issues

When a hang glider tucks, tumbles, spins or breaks we cannot be sure of what position the pilot will be in when he/she throws the parachute. We do know that the chance of the parachute bridle coming into contact with the pilot or wreckage is likely.

Bridle Length

Too many pilots have experienced the consequences of bridles too short to clear the wreckage of the hang glider. The 15-foot bridle has lead to at least three pilots impacting the ground with the parachute streaming behind (one hip replacement). Even with longer parachute bridles, pilots have watched in horror as the bridles have tangled in the wreckage sometimes barely managing to get the parachute into clear air.

If you take the measurement from the carabineer to your parachute container on your harness under the control bar then to your furthest wing tip and your bridle is that length or a little longer, you have helped reduce the risk of your parachute not clearing the wreckage.

Our standard parachute bridle is 25 feet long. By shortening it to 15 feet we only increase the risk of the parachute not getting into clear air.

Use of Line Sleeves to Extend Effective Bridle Length

The use of line sleeves is analogous to a slider used on parachutes. It slows parachute inflation by restricting the line spread. In addition, if the line sleeve contacts broken tubing or other sharp objects during deployment, you risk damaging the lines inside the sleeve. If the line sleeve gets hooked on wreckage it is conceivable lines can remain hooked and distort the parachute on opening.

If the parachute line length is too short i.e. the effective line length has been reduced by the "bridle bundle", access to the air channel can be restricted and slow down inflation.

If we look at the importance of shortening the bridle 5 feet verses the consequence of increasing your risk of not having an open parachute, the design decision is obvious.

Melting Point of Nylon Nylon does not melt at 200°F. It melts at 480 to 500° and slightly yellows at 300° when held for 5 hours.

Parachute line Replacement

A competent rigger can easily replace parachute lines sewn directly to the parachute. You do not have to throw away the whole parachute if you need to replace a damaged line. Line length can be duplicated well within tolerance. On a properly constructed parachute you will not loose strength with a line replacement.

V-Tabs Just because you have v-tabs on your parachute does not mean they are going to do the job especially if they are sewn to the outside of the parachute!

Paraswivel

Paraswivels have been very effective in stopping parachute lines from winding up and closing the parachute as the wreckage rotates. The rotation of the broken hang glider has nothing to do with parachute design.

In conclusion:

Much of my information comes from over 20 years of first hand hang gliding accident reports involving parachutes, years of involvement with the Parachute Industry Association, our testing of various parachute designs and well respected parachute design sources.

I have always believed that we should not reinvent the wheel but learn from other similar industries. I also believe that we don't have to wait until someone gets hurt or killed before we can recognize a potential problem with a system.

At parachute clinics I teach how parachutes work and have pilots apply that information to how their parachute is constructed. There are some construction techniques that are "unconventional" and others that are just plain scary.

In a society of extremely powerful marketing minds, pilots really need to understand and agree with the philosophy behind the design of their life saving equipment.

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Sat, Jun 14 2003, 2:03:05 pm EDT

advertising|Angelo Crapanzano|bridle|certification|cost|DHV|equipment|glide ratio|Juan Lara|nylon|parachute|Rob Kells|safety|site|Wills Wing

Angelo Crapanzano <angelo@metamorfosi.com> writes:

It almost looks like Rob Kells felt my article as an attack to the Lara. :-( :-) I'm really sorry because it was, not at all, my intention: I do consider Wills Wing a true safety conscious manufacturer and the Lara a safe parachute.

I do agree with Gary Douris on everything. What I actually wanted to point out is that a good diaper pod could be as good as a good envelope one, and there could be quite bad envelope or diaper designs.

The debate between diaper and envelope is worthless. What really counts is to have an exactly staged deployment sequence: bridle-lines-canopy, and a pod which holds firmly the parachute until you throw it but opens and lets out the canopy easily. This could be achieved (or not…) both with a diaper or an envelope. The other differences are, in my opinion, more a matter of tradition and philosophy than practical ones.

I mainly wanted to push pilots to test the reliability of their equipment (as explained in my previous mail) and to check if their pod works good (regardless if it's a diaper or an envelope).

I agree with Rob Kells too: Kevlar or Spectra significantly reduce bulk and weight but increase the price. Cost is important but (as Rob says) "the lowest cost is not at the top of the list in decisions we make on emergency reserves" too. For example, since 1982 I use Kevlar on Metamorfosi canopies while the Lara Gold uses Spectra and Kevlar on lines and bridle. Lara and Conar parachutes are simply quite different designs and require different solutions. It is not mandatory that one is good and the other is bad… even if I believe my one is better… while Rob and Gary, I'm sure, think the contrary :-) :-)

I have to apologize if my English was misleading: what I wanted to say is that, given the same parachute design, the use of Spectra or Kevlar increases the opening shock, thus reduces the "strength" of the parachute (considered as the maximum acceptable speed). This lower maximum speed could be perfectly acceptable for our use, or a slightly slower opening time (for example using more porous fabric) could counterbalance the loss of strength. In this example the use of a more porous fabric would increase the sink-rate, thus one would need a bigger area and more bulk (which could be higher or not of the one saved using Kevlar lines and bridle) to get the same performances. It is just a matter of compromise and it's even possible to get similar results with very different designs.

For sure it was not my intention to say that a Kevlar bridle would break and a Nylon one will not. I'm sorry if I could have been misunderstood. I just wanted to point out that, because of the reduced elasticity of a Kevlar bridle, there need to be something to compensate in the parachute design to get the same parachute "strength".

Of course, as Rob says, both a properly designed Kevlar or Nylon bridle, likely, would not break: since the one inch tubular webbing disappeared from the market I heard of very few cases of a bridle failure (possibly due to uncoated cables?). Still people must know of the problem because there are too many obsolete parachutes around and many bridles which are not properly protected from sunrays which, regardless if they are in Kevlar or Nylon, should be replaced.

I also agree with Rob about the DHV test: it leads to bad deployment bag design (regardless if they are envelope or diaper…). This test is made letting fall a dummy and the deployment bag at the same time, from 60 m high: the parachute has to open before hitting the ground. To pass this test it's only important to add drag to the deployment bag and to let out the canopy as soon as possible. This is not exactly what we need in a true emergency with a broken glider!

I agree the ultimate test is: "at what speed has it been tested without failure?" The Lara has proven to be good and, for example, the Conar 18 has been certified throwing it from an airplane at 150 km/h (93 mph) with 100 kg (222 lb) load, and tested without failure with 80 kg (178 lb) load, after a free fall of 150 m where it achieved 180 km/h (112 mph). Again, Lara and Conar are two totally different design but both proved to be strong enough.

I also agree that descent rate tests of parachute have a great deal of scatter and some manufacturers declarations are well beyond reality: I still remember the Cyclon (an English manufacturer's hang glider from 1978) was declared to have 14 of glide ratio, like a modern topless glider! I've also seen parachutes with 28 square meters of fabric declared as 35 :-( By the way, I have made lots of accurate sink-rate tests and in my web site I do declare for my Conar parachutes about 5% worse sink-rate than what officially measured during AFNOR certification.

As Rob says "any emergency reserve system that saves a life is a good one" but I'm sure he doesn't mean any parachute is a good one. As with everything there are several good, many acceptable and, unfortunately, some bad ones. It is up to the pilots to make the choice and to the manufacturers to give correct information, not just advertising.

I'm glad to hear there have been more than 400 saves with Free Flight parachutes because, added with the 276 reported saves with Metamorfosi parachutes, makes quite a lot of happy… and still alive… costumers :-)

Well Rob, up to now it looks like we practically agree on everything… maybe except the way to skin the cat? :-) :-)

Rob you're right: I don't know of any malfunction which could be clearly in relation with the swivel at the junction between lines and bridle but, in my opinion, there could be problems, at least in theory and in some particular cases, with this setting. Unfortunately this mail is already long (and tiring for everybody) enough. Moreover to explain what is the problem would take some time and I would like to make it clear; please could you wait a couple of days?

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Thu, Jun 12 2003, 2:03:02 pm EDT

Angelo Crapanzano|Betty Pfeiffer|bridle|cost|DHV|equipment|Ernie Camacho|Europe|exhibit|FAA|landing|military|nylon|parachute|PG|release|Rob Kells|Roy Haggard|safety|sport|Wills Wing

Gary Douris <gary77douris@yahoo.com> of Free Flight Parachutes writes:

Addressing the letter from Angelo Crapanzano (https://OzReport.com/toc.php?Ozv7n132.shtml#7)

His seven points for a good deployment bag are right on. As he guessed, it is only his feeling that a four-flap diaper is better than an envelope type deployment bag that I disagree with.

The best way to deploy a parachute is to have it extracted from the container by some method attached to the apex. It must have the skirt contained until all the lines are extended and there is tension on the whole system. Because this sequence is not possible with a hang glider deployment, some other ideas had to be used.

More than 20 years ago, Free Flight's Ernie Villanueva used his skydiving and rigging experience to develop the deployment bag with a side pouch for line stowing. The canopy was secured in the bag with 2 line stows and the lines were secured with 2 stows of the bridle.

When Angelo's diaper is deployed, the bridle goes first followed by the lines. When the diaper is opened the canopy is left sitting there all nice and neatly folded just like it was in the diaper. It must now unfold then deploy.

The envelope system we use does one thing that the diaper does not. When the envelope is deployed, the bridle goes first followed by the lines. Then the canopy unfolds and is more or less straight lengthwise and then deploys.

This is the best of a world which is not perfect due to the cables, tubing and such that can catch a canopy on its way to a good deployment leading to a nice safe landing.

I commend Angelo on his letter, I should have written it myself.

Rob Kells <Rob@willswing.com> at Wills Wing writes:

I'd like to address a few comments contained in Angelo's most recent letter on parachutes, and offer a few of my own.

A little background: Since 1978, Wills Wing has sold parachutes designed and manufactured by Free Flight, and thus we have a clear bias. We have always trusted in their design expertise and build quality. They have been manufacturing FAA certified skydiving parachutes for more than twenty-five years.

Envelope Deployment Bags vs Diapers

There are two different deployment systems commonly used for hang gliders, and as you'd expect, each has advantages and disadvantages. The Envelope provides a more secure stowage of the paraswivel, and a more staged deployment, but requires regular rubber band maintenance, while most Diaper bags do not.

The DHV drop test that is done from a bridge favors the Diaper bag because it can be packed in such a way as to require a very low pull force on the bridle to release the lines and parachute from the bag. The Envelope bag does not do well in this test because there are four separate stows to undo before the parachute can deploy, compared to one on most Diapers. Because most of Europe follows the DHV testing methods, it is logical that most European pilots are flying with the Diaper D-bag instead of the Envelope type commonly used here in North America.

Both Envelopes and Diapers are designed to get the parachute clear of the wreckage, and if properly packed, both systems accomplish this objective. The market here in the US has chosen the Envelope type system for two main reasons. First, between the two of us, Betty Pfeiffer of High Energy and I have done the majority of formal parachute deployment seminars in North America. We both believe in the Envelope system. We saw many more Diaper equipped parachutes fall out on the floor below the pilot when an attempt was made to throw it in a practice deployment than Envelope equipped parachutes. This was usually the result of the closing stow being too loose.

We have also seen a number of Envelope systems exit the bag prematurely when the rubber bands were old. In recent years changes such as relocating the deployment handle so the force of the pull and throw did not load the rubber bands directly, and using a double over flap at the opening end on the Envelope, are design improvements that have made the condition of the rubber bands much less critical.

Kevlar and Spectra vs Nylon

It's true that Kevlar and Spectra have much lower stretch than Nylon. It is not true that an emergency reserve must have a slower opening time to exhibit an acceptable opening shock. It depends on the construction of the parachute.

If we were to use it as a sport parachute that was designed for repeated openings, the Kevlar/Spectra blend would not be appropriate. But let's remember what the design purpose is. If you are unlucky, you may deploy your reserve once in a lifetime, if you are careless or stupid, maybe a few times in a lifetime of flying.

Roy Haggard designed the LARA (Low Aspect Ratio Annular) for the US Military, and licensed Free Flight to built it for Wills Wing to sell in the HG/PG community. The LARA (Nylon Type 18, 6000 pound bridle, with nylon lines) was repeatedly drop tested from an airplane at speeds up to 90 knots without failure.

FFE's Ernie (cited in Gary's letter as the designer of the original Envelope deployment bag) has jumped the LARA from an airplane at 90 miles per hour a number of times, again without failure. Next came the LARA Gold, which was also drop-tested from an airplane without failure. We choose to name it "Gold" because the Kevlar bridle and Spectra lines added significantly to the cost.

The important point is that using Kevlar and Spectra reduces the weight by more than 1.5 pounds, and the pack volume by about 35% giving you a very light weight, small pack volume with a large parachute, and it's associated slow decent rate. The Kevlar bridle is a woven flat 6000-pound webbing that, because of the weave, has some stretch. I'm not sure if it is because English is Angelo's second language, but his historical note regarding pilots breaking cable hang loops in the 1970s seems to imply that pilots can expect to break Kevlar parachute bridles.

In the real world, the ultimate test is: at what speed has it been tested to without failure? Does the opening shock fail the parachute, or not? I am not aware of any structural failures on FFE emergency reserve.

I agree with Angelo that a one-inch tubular bridle is not acceptable. We know of several cases when parachutes with one-inch tubular bridles were cut away on deployment. Free Flight has used a minimum of one inch Type 18 flat 6000-pound material since the early 1980s, with no cut-aways that I'm aware of. I also agree that a Kevlar bridle is less subject to being cut by heat from friction because it has a much higher melting temperature.

Speaking of Swivels

Angelo does not make it clear why he writes about 'swivels that "they should not be put near the junction between lines and canopy, but this is another story :-)".

The implication here is that there is a problem with paraswivels, so please tell us this story. I believe that the majority of hang glider reserves sold in the US for hang gliding utilize a paraswivel, while most sold in Europe do not.

There have been several instances that we know of where a spinning glider twisted the bridle so many times that eventually the shroud lines also twisted and closed the parachute. Wills Wing felt so strongly that the swivel was a necessary piece of safety equipment, that we bought the US patent to make them in volume, so as to reward it's inventor, reduce the cost, provide them as standard equipment on all HG reserves, and of course to sell more of them.

The 'swivel is mounted just eighteen inches from the lines. All the airplane drop tests and hundreds of real world emergency deployments have not shown any problems with this mounting location. We do not want the 'swivel on the pilot's end of the bridle, because if the bridle gets caught on spinning glider wreckage between the 'swivel and the parachute, it cannot serve its purpose.

Virtually all-skydiving canopies utilize hardware to attach the lines to the risers, so I'm very curious what information Angelo has as to why this mounting location is a problem. We have made over one thousand 'swivels. The only problem I am aware of was with a batch that was made with the setscrew hole not drilled deep enough in the barrel.

For more information on the advisory issued in May 2000, see any of the parachute pages at www.willswing.com

Just as Angelo could use our ideas if he thought they were better than his own, we could use his. If we found that his deployment bag, materials used in the bridle, or lack of a swivel was a better way to go, that's what we would be selling. In all three examples it would be less expensive to manufacture, but the lowest cost is not at the top of the list in decisions we make on emergency reserves.

For more information on the LARA reserve see: http://www.willswing.com/prod2.asp?theClass=parachutes&theModel=lara

Descent rate data FFEs drop test data has a great deal of scatter. The descent rates range from 14 - 19 feet per second. We publish (what we think is) a conservative number of 17.5 feet per second for the LARA.

To put the performance data you find on manufacturer's web sites in perspective: in the early 1980s we stopped publishing glider performance data, because regardless of the real numbers being achieved, some manufacturers published performance data that was well beyond reality, just to sell more gliders. (Imagine that :')

As the saying goes "there's more than one way to skin a cat". Any emergency reserve system that saves a life is a good one. There have been more than 400 "saves" with Free Flight parachutes.

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Wed, Jun 11 2003, 2:03:05 pm EDT

advertising|Angelo Crapanzano|bridle|Europe|harness|magazine|nylon|parachute|PG|safety

Angelo Crapanzano <angelo@metamorfosi.com> writes:

I've gotten some emails congratulating the article on deployment bags (thanks a lot to everybody!) and asking some more info about rescue parachutes.

In particular there was an interest on bridle and lines length. They did wonder how is possible to have bridle+lines shorter than the sum of the two. :-)

At the beginning of parachutes, it was common to define the parachute size by the number of lines. This is now wrong because parachutes of different design could have gores from 60 to 180 cm (2 to 6 ft) wide, which will make quite a difference in parachute sizes, still having the same number of gores!

What counts in a parachute is the actual projected area (not easy to calculate) and the shape and design of the canopy (not so easy to judge).

Right now most manufacturers of HG and PG parachutes declare the fabric area, which gives quite a good idea of how bulky a parachute is (but, unfortunately, many declarations are quite wrong) but it's only good to compare parachutes of the same design but different size. Unfortunately it tells very little while comparing parachutes of different design.

One of the most important characteristics of a parachute is its sink-rate. To give a physical idea of a parachute sink- rate I do prefer to quote the "equivalent height" which is the height of a jump equivalent to the sink-rate under canopy.

Knowing the sink-rate it's quite easy to calculate the equivalent height (with a bit of approximation):

EqHeight = Sinkrate2/20 (sink-rate in m/s and result in m)

(For those interested in mathematics it comes out from the equation between kinetic energy and potential energy).

It is much easier to visualize that, coming down under canopy, would be like jumping down from 1,5 m high (5 ft) than to say your sink-rate would be 5,42 m/s (1076 ft/min).

Another advantage of using the equivalent height is that makes things linear instead of having square roots involved:

• jumping down from 2 m height you'll hit the ground twice as hard than jumping down from 1 m

• doubling the load under the same canopy, the equivalent height doubles

• using a parachute of the same design but double area, your equivalent height would be half and the opening distance, reaction times excluded, would be 1,41 times longer… sorry one square root is still there :-)

Just for your knowledge, opening distance (to be more correct "filling distance") is the distance needed for a parachute to open in ideal conditions, from lines stretched to fully open parachute.

Filling distance depends on parachute design and size; it's independent of speed (unless at very low airspeeds where a smaller and lighter parachute gets probably an advantage) and, given the same design, it's linear with parachute diameter.

Opening distance is much more interesting for us than opening time because, when we toss a parachute in a real emergency, we are not really interested in how much time it would need to open… but if it would open before we hit the ground!

Sink-rate depends on parachute size only for parachute of same design. Parachutes of same size and different design have not the same sink-rate, as much as an old Rogallo glider of 14 square meters has not the same sink-rate of a modern topless glider of same surface.

Just to give you an idea, at the test made by Vol Libre Magazine, the Conar PG18 (28 m2) was the smallest parachute tested but did show the best sink-rate (4,8 m/s with 97 kg pilot's flying weight). The only other parachute to match this sink-rate was 43,4 m2 (i.e. 55% bigger).

Advertising corner :-)

If you want more info on parachute performance comparison have a look at www.metamorfosi.com/compara_en

Let's go back to the lines:

The first HG parachutes had as low as 10 lines (one every two panels) to make cheaper and lighter parachutes, but definitively weak ones; fortunately, they disappeared quite soon from the market.

Generally speaking, given the same canopy, more lines means a better shape of the canopy and a better sink-rate but, of course, with more lines there is an higher chance of a line getting tangled. A compromise, like always, is mandatory. Consider that the more the lines the bigger the bulk and the higher should be the safety margin on each line because of possible overloading.

Lines and bridle must absorb the opening shock. On round parachutes they are usually made in Nylon because it has a good strength and a very good elasticity under load. Very strong fibres (like Kevlar, Spectra or Dynema) are very good in absorbing static loads but not so much for shock loads. (Spectra and Dynema are practically the same fibers with a different name, one in US and the other in Europe).

Let's make a, very simplified, example to find out the different behavior between Spectra and Kevlar or Nylon, letting fall a 10 kg load (22 lbs) attached to a 5 m rope (16 ft).

After 5 m of free fall the load gets a speed of 9,9 m/s.

• If the line is in Kevlar or Spectra the elasticity is about 2% (10 cm elongation for a 5 m rope). This means we have to stop the load within 10 cm and, with some calculations, we get an average load of 50 g but, actually, the peak load would be higher (which means, with a margin of safety, we need a Kevlar or Spectra rope of 1000 kg).

• If we use a Nylon line instead, the elasticity could be over 15% which means it has to stop the load within 75 cm. The same calculations bring to an average load of 6.7 g only (with the same margin of safety a 135 kg nylon rope would be enough).

Of course in these calculations we did consider the rope attached to a solid stiff body (like to make the test tying the line to a bridge), not a parachute. Nevertheless we see the advantage of using nylon, both in lines and bridle, to control peak shock loads. Of course it's possible to design a good parachute with Spectra lines but, to get an acceptable shock load, it needs to have a slower opening time (i.e. longer opening distance).

Just an historical note: this is the reason why steel hang loops, quite common in hang gliding up to 1977, disappeared after provoking several fatalities.

Unfortunately Nylon, especially under tension, is easily cut when sliding against a cable. This happens because the friction heats up the Nylon which melts at about 200°. Spectra is not better, but Kevlar is definitively resistant to wear and burns at over 500°. A well dimensioned Kevlar bridle would likely survive any sliding against a cable but will significantly increase the opening shock too because Kevlar has almost no elasticity.

Tubular webbing, quite common in old parachutes, is dangerous and very likely to cut sliding against the cables and there are several stories (some funny, most sad) to prove it. The normal solution is to use an over dimensioned webbing or, better in my opinion, a braid bridle. Compared to a webbing, a braid bridle is less likely to break against a cable and, because of the different construction, has the advantage of being more elastic too. Of course there is a disadvantage too: it's thicker and less aerodynamic.

Please remember that the first meter of bridle stays outside of the parachute container and must be well protected from UV rays while the eye to connect the bridle to the carabineer must be protected against abrasion too. A good UV protection is important for the whole parachute too because a parachute is like a chain: it is only as strong as it’s weakest link. If something is not protected from UV rays or is damaged, the whole parachute will lose strength.

Be careful: the harness parachute container often is not good enough to protect the parachute, while protections or deployment bags covered with a deposit of aluminum powder, are often more a selling argument than functional. Here’s a test: have a look at the sun through your deployment bag material and check if the light passes through…

Rescue parachutes lines could be directly sewn directly to the canopy or could be connected with a knot like on parachuting or paragliding. Lines sewn directly to the canopy are definitively cheaper but, in case one is damaged, you practically have to throw away the whole parachute. Technically it would be possible (only by the manufacturer) to unstitch and replace the line with a new one, but results could be dangerous: how can you be sure the new line is (or better will be) as long as the old ones? Nylon stretches and shrinks quite a lot with temperature and humidity (up to 30 cm in a 5 m long line). It's not a real problem if all lines shrinks the same, but the only way to get it in a parachute, is to cut all of them from the same roll (including the apex lines) and, if one line is damaged, the full set of lines should be replaced (which is very easy and cheap to do in those parachutes where the lines are knotted to the canopy).

If lines and apex line are made with different rope dimension (or, even worse, with different materials) there could be a problem of different shrinking. If the apex line gets longer the parachute would have a worse sink rate, while if it gets shorter it may become unstable. When packing your parachute check the respective length of lines and apex line did not change from the original setting; if in doubt ask the manufacturer (just to avoid tons of mails, in the Metamorfosi Classic the apex line must be slightly longer than the other lines while in the Conar both apex and gore lines have the same length).

The connection between lines and canopy is quite important: it's important that the line is sewn for a long while over the canopy (much better if it goes continuously all over the canopy) and is almost mandatory that the connection between line and canopy leading edge is reinforced with a V tab (other good systems could be acceptable but the V tab is the best known).

Speaking about lines and bridle length we have:

- a long bridle is useful to reduce the chance of the lines getting tangled in the wreckages.

- long lines are useful to better absorb the opening shock and to get a better sink-rate, given the same canopy, because of a bigger projected diameter.

- a short sum of lines + bridle is useful to get a faster opening time.

At first, it looks like a compromise is necessary but there is a simple (and clever) workaround: in my parachutes the "bridle" itself is about 5 m (16.5 ft) long and the lines about 5 m too, but the first 2 meters (6.5 ft) of the lines are covered with a lightweight fabric sleeve. This means during deployment, when you need a long bridle to get the lines clear of any spinning wreckage, the "bridle" is 7 m (23 ft) long (i.e. longer than the standard 20 ft American bridle) and the lines 3 meters (10 ft) only to reduce chance of tangling but, once the canopy opens and such a long bridle becomes unnecessary, the sleeve slides down (or breaks at high speed) and leaves the long lines free.

Metamorfosi parachutes have, in practice, a 7 m (23 ft) long bridle and 5 m (16.5 ft) long lines but the sum of the two is 10 m (30 ft) only!

Please note a long bridle is not mandatory after the canopy has opened because it's enough to have the bridle almost as long as half the span to avoid any chance of a tangled line; moreover, after the canopy has opened, there are much less chances of a line getting tangled and any spinning of the hang glider will slow down substantially.

Speaking about bridles, just a quick note on swivels: depending on parachute design they could be useful or not but, for sure, they should not be put near the junction between lines and canopy… but this is another story :-)

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Wed, Jun 4 2003, 6:03:01 pm GMT

altitude|C.J. Sturtevant|competition|landing|Oz Report|parachute|PG|Thayer Hughes|Tom McCune

C. J. Sturtevant <georges@nwlink.com> writes about her deployment on the first day of the Canadian PG Championship (as earlier reported in the Oz Report):

Thayer, Tom McCune and I were just setting out on course when my glider took a massive asymmetrical (Tom, who was thermaling right next to me, says at least 70%), thrashed me about quite a bit and went quickly into a spiral. I thought, "OK, I know how to get out of a spiral", and tried to pull on the outside brake to slow down.

Of course at the same time I let up on the inside brake - and noticed that there was not a bit of pressure on that inside brake! In fact, I could let up on both brakes and the spiral just went on spiraling. I tried pulling the outside brake to no avail, took a wrap and then another wrap, but I just didn't have the strength to pull any brake at all. All this time I'm whipping around with the earth right in front of me and my LE facing straight down.

Thayer, who was just a bit above me, was quite impressed with the spiral - says he's never seen me do one so aggressive (and now probably never will!!) - but got concerned when I'd done maybe 8 or 10 revolutions and lost tons of altitude and not come out. He radioed, "Reserve! reserve! reserve!" so I quit trying to fix the problem and hucked that parachute out.

It deployed cleanly, and slowed the spiral, but now the problem was that the wing was still right out there in front of me, clearly down planing. And again I did not have the strength to pull in and disable the wing. I worked on that till I was nearly down, then gave it up and tried to prepare myself for a hard landing and a PLF in a clear cut.

Luckily I missed all the stumps, but somehow I got swung a bit just before landing and didn't hit on my feet at all, but on my hip and side. Hard. The amount of pain on impact convinced me that I was not going to walk away from this one, and since I didn't get up and gather my wing, Thayer was down within seconds.

A hang glider pilot drove to the area and walked in to help, and then Tom also landed (although Thayer radioed to him that we were doing OK, so I'm not sure why Tom came down). I was glad to see all of them, though! I did walk out to where George was able to drive to, but very slowly!

I'm still feeling battered and stiff, but I was able to fly every day during the comp, although I essentially blew off the third day because I was feeling too beat up to want to pay attention to gaggles and active flying. I actually placed 14^th for the day after my deployment (2^nd task) , and 9^th for the day on the 4^th task and probably could've done better that day had I not gotten freaked out in turbulence and gone out to land. Oh, well. I do this for fun, and when it moves irrevocably beyond the fun stage I'm outta there!

I did manage to come home with a 4^th place Standard class medal, and a check for $75 Canadian (which is maybe $1.13 US?) Actually, it's $53.18 - I put it in my bank account this morning ;o) AND I got a bottle of champagne for hucking the reserve during a comp and surviving. Not bad, eh?

Discuss "My Deployment" at the Oz Report forum   link»

Tue, May 27 2003, 2:03:01 pm EDT

Bob Trampenau|bridle|dust devil|Florida|landing|parachute|safety|Seedwings|tuck|tumble

Tim Locke <tlocke@optonline.net> writes:

I am the pilot with the dubious distinction of tumbling May 18^th at Mt. Greylock, Massachusetts. I have been hang gliding for 29 years and have had my fair share of turbulence and getting dumped. It was a rude awakening without warning to be pitched over and under in a series of 3 tumbles. They were so rapid that I had no recollection of doing them.

Ended up at the trailing edge/keel in a surreal moment of watching my Sensor 142 topless glide along upside down with me trailing like swimmer on the transom of a boat. Just previous I had climbed 2000 feet in two minutes after hooking a powerful thermal coming off the spine of this 3000ft mountain.

I had cored it without any hint of serious thermal shear in my short lived flight of eight minutes. Closing in on Tom Nejame overhead I started scanning to catch a glimpse of him. As I reduced my left hand bank angle to shift my circle I was pitched violently over.

From Tom's description of my right wing going down as I went ass over teakettle, it would appear as if I had found the edge of a nasty swirl of air. His next description of me is seeing my undersurface with arms extended. I have known for years about keeping your weight forward, but in spite of his criticism I had no time for even a knee jerk reaction like pushing out. Thank you Davis for confirming that in your experience.

I had been climbing at up to 980 fpm and my vario registered 1920 fpm sink. That would be a 30 mph. differential at the interface of the thermal. Maximum registered air speed was only 34mph. If I had just reduced the bank angle just as the right tip found the shear it could have lead to the pitch over.

(editor’s note: I have invariably found that max values shown on vario logbooks are much higher than what I actually experience as there seems to be no dampening of the values by choosing a reasonable time period, like one second, over which to find an average value.)

It is perplexing as not all pilots complained of extraordinary turbulence. But some pilots did. A pilot on a cross country flight from Mt. Ascutney said he was petrified of going into the sail at any moment.

At Greylock there were some partial paraglider collapses and some other paragliders going on nice x-c's. There was a large sighted dust devil and a barn in Maine damaged by a dust devil. There was also height gains over 12,000ft that day. But apparently we have to rule out the atmospherics, as a recent post has leveled the finger at Seedwings for the incident.

I am not ruling all possibilities, but let’s not jump to conclusions until all the facts are in. I admit I am biased because I have owned 4 Sensors. I recently put a new sail on that has more double surface, shear rib length and tip chord than its predecessor. Yes, it was not factory flown and I accepted that.

I put hours on it in Florida, found that the center of gravity had not changed to any degree and it had pitch pressure at speed (not only valid consideration). I cannot say if the sail change had anything to do with it. I will say that I believe that is up to the manufacturer to deliver a proven glider and will asking for that now for assurance. Bob Trampenau is very safety conscious and to rule out every thing he is checking the glider out and will be performing pitch tests.

The glider is built solid and survived the tumbles with no damage to the airframe or sail. The violence of the tumbles beat the washout system up and he thinks the negative g tests for all gliders is too low in light of what happened. I use the same cable braced washout tube configuration as others, and get this.

I bent a 1"tube to 45°, snapped a washout tube brace wire, and snapped both outboard heim joints in a downward motion. This was not done on landing as I had a very soft landing in the flexible droopy limbs of a hemlock tree. He has already e-mailed 5 modifications that he going to do as soon as he receives the glider.

I appreciate that he sews Kevlar in the trailing edge as the parachute bridle did not cut into it. Seedwings takes a lot of heat for a small company that engineers a nice wing. Have not tumbles occurred on other popular wings. Much doubt could be dispelled by providing the test rig documentation. Let the facts speak and let’s continue addressing tumble/tuck issues.

Discuss tumbles at OzReport.com/forum/phpBB2

Discuss "Tumbling my Topless Sensor" at the Oz Report forum   link»

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

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

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

Discuss "Aerotowing PGer’s" at the Oz Report forum   link»

Thu, May 15 2003, 3:00:07 pm EDT

Alessandro "Alex" Ploner|Alex Ploner|Angelo Crapanzano|bridle|Europe|Gerard "Gerry" Farell|harness|insurance|Laurent Thevenot|parachute|Rich Pfeiffer|safety|spin

Angelo Crapanzano <angelo@metamorfosi.com> writes:

Recently, while speaking about rescue parachutes, Alex Ploner told me in US there is quite a bad reputation for "diaper" deployment bags (flat pods with, normally, four flaps), while there is a good one for "envelope" ones (a bag normally opened on one side only). I already knew in US there was a preference for envelopes (while in Europe there is for diapers) but I didn't know it was so strong.

The deployment reliability of a rescue parachute depends mainly on the pod design; that's why I feel important to point out the differences between different concepts and, even more important, what makes a good or bad pod. I'm a manufacturer and of course my own design is my preferred one (otherwise I would make it different), but I'll try to be as general and objective as possible.

In a good deployment bag we need to have: easy extraction from the harness very low risk of accidental deployments, lines stowed inside the pod before deployment, ease of throw, very low risk of untimely opening, easy opening of the pod, staged deployment sequence.

1) An easy extraction may concern more the harness parachute container design than the pod itself. We need to have a big enough handle (remember it's always easier and safer to catch the handle using the thumb) and reachable with both hands (one could be injured or one hand could be better than the other in case of a spin).

The use of Velcro to keep the container closed is not reliable: often holds too little or too much. The Velcro should also avoided to keep the handle in place because if the pilot, at first try, peels out the Velcro but misses to catch the handle, then the handle could become unreachable (this is especially true in paragliding for dorsal mounted parachutes).

Be extremely careful there is not male Velcro on the handle itself: it may stuck on the lines loop holding the pod closed, thus impeding the opening. It's not only a theory: I've seen this happening during parachute clinics and, unfortunately, a German pilot died in Castelluccio di Norcia a few years ago, because of it.

There is one way only to know if your parachute is easy enough to extract: hang into your harness and try! Don't be too much surprised if you cannot get it out: during parachute clinics I've seen several pilots not at all able to extract their parachute.

2) Low risk of accidental deployments means the parachute must not come out by itself. The biggest improvement on this subject were the safety pins (introduced in the hang gliding world long time ago by Rich Pfeiffer) used at first as a safety for the Velcro but, if properly designed, are perfectly safe by itself. In some cases one could add an elastic or a sewing tread to hold them in position (check you are strong enough to break it pulling the handle!).

Be sure there is no way for the handle to get tangled in the side cables or in the base mounted instruments (there have been several accidental openings this way). Be also sure the pins are not too long (longer than the slack in the handle) otherwise there is no way to pull the parachute out of the container. Pins should be properly curved or flexible (straight pins could stuck if pulled in the wrong direction, as shown in several accidents) and be careful the head of the pin cannot pass through the loop (there have been several accidents this way too).

3) The lines stowed inside the pod before deployment are mandatory to reduce the chances of lines getting tangled into the wreckage (one line tangled is enough to get the parachute useless). Unfortunately there are several old pod designs where the lines are exposed.

4) The ease of throw depends on parachute weight but also in handle shape and length. A long handle makes it difficult to control the throw and could tangle on cables (some handles designed as an anchor don't certainly help). A handle attached to the pod in two points gives a more solid hold compared to the, unfortunately now common, single point attachment.

Never attach the pod to the canopy: to save some dollars in case of deployment, you definitively increase the risk of a tangled parachute!

5) Low risk of untimely opening means the deployment bag shall not open before you throw it and let it go. This can easily happen in an old style envelope pod where the handle is in the opposite side of the opening because only the elastics are holding the canopy inside the bag: if they are too old or weak the canopy will fall out before one throws it while, if they are too strong, the pod would be hard to open.

A good envelope pod design is to have both the handle and the opening on the same side, so the elastics don't have to hold the weight of the canopy. On some diaper pod designs the canopy or the lines can fall out if one shakes the pod (still holding the handle). In any case it's important to leave the right amount of slack in the bridle: the pod must not open until you let it go!

6) Easy opening of the pod is mandatory because, in case we cannot throw it forcefully (much easier to say than to do in reality), there is only the difference in sink-rate between broken hang glider and closed pod to open it. Please note that, in most common accidents, the closed pod falls faster than a broken hang glider or paraglider.

In case both glider and pod are falling at the same speed there is still the aerodynamic drag on the bridle which could open the pod. It's clear we are never speaking of big forces, so we need to have the pod open with a very light pull.

7) The correct staged deployment sequence is: bridle - lines - canopy. We first want to have the bridle coming out because we want the pod (still containing lines and canopy) to go away as far as possible to reduce the risks of entanglements. Then we want to have the lines, and finally the canopy must come out only when bridle and lines are stretched. This is the best way to reduce the chances of canopy malfunctions and to reduce the opening shock on the parachute. In a well designed pod, regardless of the strength of the elastics, the lines shall not come out until the bridle is stretched and the canopy shall not come out until the lines are stretched. Speaking of lines and bridle, I would like to point out that we need:

- long bridle to reduce the chances of a tangled parachute,

- long lines to get better sink-rate and stability from the same canopy

- short sum of lines plus bridle to get a faster opening time (it looks impossible at first, but there is a clever solution to this problem).

IMPORTANT: To check out the extraction, hang into your harness, put your thumb into the handle, grab it and pull it out slowly: the pod must come out effortlessly.

To check out a pod for untimely opening, while still hanging, stretch your arm sideway to check the slack in the bridle, then shake the pod without leaving the handle: the pod must not open.

To check out if a pod opens easy enough, put the pod on the floor then pull up slowly the bridle and then the lines: the pod must open easily without lifting the parachute and the canopy must get out easily. The deployment sequence, during the previous test must be: bridle - lines - canopy and must be correctly "staged" (should be the same regardless of the relative strength of the elastics used).

These simple test doesn't take more than 10 minutes (plus repack, which is always useful to get a fast opening) but could save your life: much cheaper and much more useful than a life insurance, but your partner could think different :-) :-)

While you are there, check out how old is your parachute: if it's more than 10 years old consider replacing it. An old parachute behaves exactly as a new one, of the same model, if you are going to deploy it at low airspeed. However parachute fabric is quite sensible to aging and ultraviolet rays: an old parachute cannot withstand the same high speed as a new one.

If your deployment bag doesn't work as it should, fix the problem if possible (and check it again!) or, much better, have an expert professional check and fix it (but check what the professional is doing too. It's your life which is involved!).

I practically didn't speak about the differences between envelope and diaper pods because it's not much important. What is important is that a pod works in the correct way and you can get it both with an envelope or a diaper one. Remember:

- Pods which don't stow the lines inside increase the chance of a line getting tangled.

- Old style envelope pods with the handle on the opposite side of the opening are dangerous because, in case of warn-out elastics, the canopy can easily fall out untimely (it happened to Gerard Thevenot: the pod came out of the harness but the parachute stayed inside!)

- Pods without a correctly staged opening sequence, bridle - lines - canopy, increase the risk of entanglement and malfunctioning.

Well… of course I do prefer my 5 flaps diaper pods because they fulfill all the previous requirements (as a good envelope one) but are "softer" to better adapt to the harness container, require less force to open and, when open, let immediately the canopy fully free.

If you ask a good American manufacturer I bet he would agree on everything… except the last sentence :-)

Discuss parachutes at OzReport.com/forum/phpBB2

Discuss "Deployment bags" at the Oz Report forum   link»

Sun, Apr 27 2003, 2:00:03 pm EDT

aerotow|cart|cartoon|cloud|Cloud 9|competition|cost|David Maule|donations|Dragonfly|equipment|FAA|flight park|Florida|Flytec USA|food|foot launch|game|glide ratio|government|harness|instruction|landing|Maureen Grant|Moyes America|Moyes USA|parachute|photo|record|release|Rick Agudelo|Rob Kells|safety|site|sport|Sport Aviation|Spot|spot landing|storage|students|tandem|tow|towing|Tracy Tillman|training hill|transport|travel|tug|USHGA|weather|Wills Wing

aka the Dragonfly Cup - a new comp with a tall attitude and monster-size prizes.

by Tracy Tillman and Lisa Colletti

(from Reality Check cartoon series)

While working in the laboratory late one night, we created a new hang gliding competition for 2003, the Dragonfly Cup. The comp will take place at Cloud 9 Field in Michigan, home of the Draachen Fliegen Soaring Club. The value of prizes to be awarded is over $6000. Major sponsors include Wills Wing, Moyes USA, Flytec USA, High Energy Sports, AV8/Icaro, and Cloud 9 Sport Aviation.

Hot Comps

Many of the most successful meets taking place across the world use aerotowing as the primary means of launch. At a good site, it allows launching into any wind direction, and enables a large number of pilots to launch in a short period of time (provided that there are enough tugs and tug pilots available). The large cross-country meets that have been hosted by our friends in Florida and Texas over the last five years are a great example of the popularity and success of aerotowing as a launch format. The mass launches are an awesome site to behold, and participation in those comps is an experience that one will never forget. By all means, one should try to get to one or both of the Florida meets, as a participant, tug pilot, volunteer helper, or spectator.

The good flying conditions and high-level of competition at these meets bring together some of the best pilots in the world. These are relatively complex, work-intensive, and expensive comps to run, which results in entry fees being near $400, not including tow fees. With travel, food, lodging, and support crew costs added, the overall cost for a pilot to participate in one or both of the Florida meets is significant. Never-the-less, registration for both of these meets fills up almost immediately after opening.

Despite the popularity of these meets, it has been difficult for some clubs to run a successful meet in other parts of the county. Here in the Great Lakes/Great Plains region of the country, poor weather and low pilot turnout has resulted in the cancellation of meets more often than not. We can experience great soaring conditions across the summer flying season in this part of the country, but the weather patterns are not as consistent as in Florida or Texas. Also, many average Jo/Joe hang glider pilots who live in this part of the country are more interested in participating in a lower-cost, fun-type comp, rather than in a higher-cost, intensely competitive cross-country competition; and, it may be difficult for some pilots to take many vacation days away from work to attend a meet.

The Dragonfly Cup

With these issues in mind, and after some discussions with Rob Kells of Wills Wing, we created the Dragonfly Cup hang gliding competition for the summer of 2003. Aerotow and hill slope will be the primary means of launch. The comp will be hosted by the Draachen Fliegen Soaring Club (DFSC) at Cloud 9 Field in Michigan. It is a low-cost comp to benefit the DFSC, with large prizes sponsored by major hang gliding companies.

(A good summer day at Cloud 9. Photo by Rick Agudelo)

To avoid weather cancellation issues, the Dragonfly Cup is running season-long, from May 15 through September 1 (Labor Day), 2003. To avoid weather-related cross-country task problems, there are five different task categories: Race, Distance, Duration, Spot Landing, and Glide Ratio. To avoid retrieve problems, all task landings are at Cloud 9 Field. To reduce expenses, the cost is only $10 or $20 per comp flight, depending upon the task(s) declared by the competitor, plus the cost of the tow for that flight. A pilot can enter and declare a flight as a comp flight as many times as he/she likes across the season. To enable any level of pilot to win, a handicap system will enable lower-performance gliders to release from tow at higher altitudes. Pilots will foot launch from the newly-constructed training hill at Cloud 9 Field for the glide ratio task, which will enable non-towing student pilots, and even paraglider pilots, to compete in the meet. (Note: It is not a large hill; using a light, slow, high-lift wing may offer an advantage for this task.)

Results will be recorded across the season. Those who finish at the top of each category will be eligible to win one or more of the major prizes available. So far, the prize list and sponsors include: (a) Falcon 2 hang glider, sponsored by Wills Wing and Cloud 9 Sport Aviation ($3075 value); (b) Contour Harness sponsored by Moyes America ($950 value); (c) 4030XL variometer sponsored by Flytec USA ($899 value); (d) Quantum 330 reserve parachute sponsored by High Energy Sports ($650 value); and (e) PVC storage/transport tubes sponsored by AV8/Icaro ($500 value).

The cost for declaring a hill flight as a glide ratio comp flight is just $10, which means that for as little as a $10 entry fee, a pilot could win a brand new Falcon 2 glider worth over $3000. The cost for declaring an aerotow flight as a comp flight is $20 (plus tow fee), but the pilot can choose two of the four aerotow task categories for that flight: (a) Race, which is the fastest out and back 16 mile round trip time to the neighboring Sandhill Soaring Club field; (b) Distance, which is the most out and back round trips to the Sandhill Soaring Club field; (c) Duration, which is the longest time aloft; and (d) Spot Landing, which is landing (by foot or wheel) within a prescribed circle. All landings must be on Cloud 9 field; out-landing flights will be disqualified. For the aerotowing tasks, the tow height limit is1500 feet AGL for rigid wings, 2500 feet for topless flex wings, 3500 feet for kingposted double-surface flex wings, and 4500 feet for kingposted single-surface flex wings.

(Lisa, Tracy, and DFSC club members. Artwork by Bob and Maureen Grant)

The DSFC will host comp parties on Memorial Day weekend, July 4 weekend, and the first weekend in August, to encourage pilots from other clubs to schedule a trip en masse to fly here with us. The grand finale party will be held on Labor Day weekend, with final results determined and prizes awarded on Labor Day.

The winners of each task category will have an equal chance at winning the major prizes. A drawing of the task winners' names will be held on Labor Day to determine who gets which prize.

We feel that events like the Dragonfly Cup can help the sport to grow, as do several major manufacturers and distributors. Wills Wing, Moyes, Flytec, High Energy Sports, AV8/Icaro, and Cloud 9 Sport Aviation are offering significant donations in support of the 2003 Dragonfly Cup. These companies are dedicated to supporting our sport with their excellent products and services, please support them in return.

Cloud 9 Field and the Draachen Fliegen Soaring Club

If you have not flown with us before, please be aware that we have a specific operations formula that may be somewhat different from what you have experienced at other aerotowing sites. Because we have a nice site with a very active club, some pilots mistakenly think of our DFSC club site as a commercial flight park-it is not.

Cloud 9 Field is our sod farm, private airfield, and home. We purchased the land specifically with the intent of building a house, hanger, and private airfield, and to create a home base for the Draachen Fliegen Soaring Club. We are on the executive board of the Draachen Fliegen Soaring Club, and are the owners of Cloud 9 Sport Aviation, which is a supplementary mail order hang glider equipment business that serves Michigan and the Great Lakes region. We are also the owners of Cloud 9 Field, Inc. sod farm.

We allow DFSC club members and guest members to camp on our property (temporarily, not permanently) at no charge, and bathrooms and showers are available in our hanger for members and guests to use. The hanger has a second-floor club house/game room/kitchenette and observation deck overlooking the field. Our airfield is flat and open, and allows smooth cart launches and foot or wheel landings in any wind direction on mowed and rolled sod grass. Last year, we also built a 30 foot training hill on the edge of the field with the help of several club members (thanks Rick, Mark, and Jim!).

(Cloud 9 Field hanger and DFSC club house.)

The DFSC has been active since 1997, and has been flying from Cloud 9 Field since 1998. Even though we gained prior approval from the local, state, and federal government for the establishment of our private airfield for aircraft, ultralight, and hang glider operations, the local township government reacted to complaints from a neighbor about our towing operations, and sued us to prevent us from flying. As a result, we purposely kept a low public profile (but did not stop flying) while battling the lawsuit over several years.

Since that time we have learned how common it is, all across the country, for legal action to be initiated against people who own or establish airstrips and conduct flying activities. We also discovered that it is very important to find attorneys who are well versed in the appropriate areas of law, and who really care about your case. At a significant cost to us, we settled the lawsuit last year. In addition to having a great pair of attorneys working for us, one of which is a hang glider pilot and now a DFSC club member, we also had to do a great deal of work to help them develop an understanding of the case and to build a solid legal argument for the court. We learned a lot, but it was very time-consuming, stressful, and expensive.

During this process, we were inspected twice by the FAA. Their visits and reports supported our legal argument by helping to verify that we are not a commercial flight park operation, that we are operating properly within FAA regulations and exemptions, and that we are operating safely and relatively quietly. After getting to know us and the nature of our operations, the FAA asked Tracy to serve as an Aviation Safety Counselor for the FAA Detroit FSDO region, which also had a positive impact for us in court.

We are both ultralight basic flight instructors, and airplane private pilots. Lisa is the main tug pilot, and Tracy is the tandem hang gliding instructor for the club. We have two Dragonfly tugs, one with a Rotax 914 engine, and one with a Rotax 912 engine. We also own a Maule STOL airplane, painted in the same colors as our Dragonfly tugs.

In consideration of our neighbors, we have been successful in significantly reducing the engine/prop noise generation levels on both of our tugs. We use quieter and more reliable 4-stroke engines, custom-designed Prince propellers that provide increased thrust and reduced noise, after-muffler silencers with exhaust stacks that direct the noise upward, and towing/flying techniques that minimize noise levels on the ground.

(Tracy and Lisa with one of their Dragonfly Tugs)

Our operations formula has been refined over time to best meet FAA, IRS, USHGA, USUA, and other federal, state, and local laws, rules, and regulations. As such, all of our hang gliding instruction and flying operations take place via the Draachen Fliegen Soaring Club, Inc., which is a not-for-profit, mutual benefit organization to promote safe hang gliding and instruction. Club members share in the cost of our operations for their mutual benefit, such as site preservation and maintenance, tow operations, and instruction. All flights conducted by the DFSC are considered instructional flights. Instruction is free, but the club collects membership dues and fees from each member to cover their own specific towing expenses (non-member pilots can fly with us a few times a year as guests of the club without paying membership dues, but club members pay less for tows).

Our field is a private airfield for non-commercial use, not a public flight park for commercial use; therefore, all pilots, students, and visitors must contact us prior to coming out to our field to fly---on each and every visit. We try to be available for flying on most good days, but will be away from the field on occasion, so call before you come. Our season runs from May 1 through October 31. We are available to tow after 10:30 AM six days a week (not on Tuesdays), and on weekends only after Labor Day (when Tracy has to resume his faculty duties for the fall semester at Eastern Michigan University). We conduct tandem instructional flights in the evening, in conditions that are appropriate for students.

Everyone who flies with us must be a DFSC club member or guest member, a member of USHGA, sign our club waiver, and follow all club rules and procedures. We are very safety and instruction oriented, and expect pilots to do what we ask of them. Anyone who does not, will be reminded that they are at our home and on our field as our guest, and will be asked to leave. We would hope that pilots understand that there are many complex factors and issues involved in the establishment and operation of a successful aerotow hang gliding club, which mandates that we do things in certain ways. So far, our approach seems to work--we have an excellent safety record, a great group of pilots, a lot of fun, and a good reputation among students, pilots, and FAA officials who know us.

In spite of the cost and effort (on top of our regular professions) that it has taken for us to create and maintain the field and buildings, equipment, and club operations for the club, we support the club and its members because we love hang gliding and flying. We have had good success in bringing new pilots into the sport and we have helped to improve the flying skills of our club members.

Now that we have settled our township-related problems, we can be more open about our club's flying activities. We are hoping that more pilots will come to learn and fly with us in 2003, and we are very much looking forward to hosting the Dragonfly Cup this year.

Instruction and continuous improvement of flying skills and safety are the prime directives of our club. We take that very seriously. Accidents and injuries are not fun-safe flying is more fun for everybody. We will continue to focus on helping all of our club pilots improve their flying skills throughout the year, and we think that the Dragonfly Cup is a great way to help make that happen.

We are looking forward to having a great flying season ahead. Come fly with us, and enter the Dragonfly Cup - you've got a good chance at winning big!

For more information about the DFSC and the 2003 Dragonfly Cup, visit our website at http://members.aol.com/DFSCinc, email us at <DFSCinc@aol.com>, or call us at 517.223.8683. Fly safe, Lisa and Tracy.

Discuss competition at OzReport.com/forum/phpBB2

Discuss "Young DraachenStein" at the Oz Report forum   link»

Wed, Apr 23 2003, 4:00:05 pm EDT

CIVL|competition|Gerolf Heinrichs|landing|parachute|safety|spin|Steve Kroop

Gerolf Heinrichs <gerolfontour@aon.at> writes:

I very much acknowledge your concerns about landing injuries where front/back wires come into play. However, I fear you blame the wrong suspect here - to my understanding cutting is not a problem of bare steel.

You are certainly not the only one under this delusion - the evidences of these accidents just look so striking. Actually a majority of pilots is under the belief that the sole purpose of this coating is to protect one from getting cut with it. Many others do think, it's meant for better protection against corrosion. But, neither one is the case! Talking to cable manufacturers, you will find out, there actually is only one reason why they coat their cables: It's to protect the wire itself from kink damage. That's all it really is!

One could now argue that maybe as an unexpected spin-off the coating still could provide additional protection for the pilot's skin. To answer this question there really is only one way to find out - make a more scientific approach and do a cutting experiment.

This experiment, in fact, has already been performed several times a while ago, but has never been properly published I suppose and thus it seems the results have been forgotten. All you need really is a chunk of meat, preferably some pork (as they say it's consistence comes closest to human skin/flesh) and a big enough saw, where you can replace the blade by different strings of wire. Here are the samples you should test:

(i) 1x19, 1.9mm steel cable, without coating, as currently in use on many competition gliders. This wire has very little texture, which corresponds to the equivalent of "teeth" of the "saw-blade", as the experiment will turn out: breaking load ~ 420kp

(ii) 1x19, 2.5mm steel cable, without coating, just thicker making: breaking load ~ 600kp

(iii) 7x7, 2.5mm steel cable, coated (steel portion = 2.0mm), a more flexible cable with a fair bit of texture due to it's weaving : breaking load ~ 400 kp

(iv) 7x7, 2.0mm steel cable, without coating, currently in use on many competition gliders, same drag as (i): breaking load ~400 kp

(v) 7x7, 2.0mm steel cable, coated (steel portion = 1.6mm), same cable, but less steel core, in order to match the drag value of cable (i) : breaking load ~ 280 kp

I presume, Steve, you are rather skeptical to my arguments and conclusions so you will want to perform this experiment by yourself. For those less suspicious or (persistent ;-) I give the results here right away: They are actually rather sobering: The plastic coated cables cut skin and flesh just as nice, if not better than bare wire. The reason may lay in the higher skin friction the plastic provides, which you can tell by the burn marks of the skin. Nevertheless, it quickly becomes apparent that the significant parameters for cutting are not so much the "blade"-material properties itself, but it's geometry: the radius of the blade's edge (= cable radius) and the size of the blades teeth (= texture of cable).

Thus, the simple equation is: the bigger the diameter of the cables, the better your chances to not cut your skin. The less texture your cable has, the better your chances again. Thinking about it for a little while, we probably would have guessed that anyway, wouldn't we?

The result helps to explain why cables with plenty of coating around it get such a good reputation among pilots. However, it's the big diameter and not the plastic wrap over the dangerous steel that saves your skin.

So, just go for bigger cable diameters then!? Currently the rules for CIVL-sanctioned competitions (Section 7) force us to use cables with a steel portion of no less than 1.9mm! This rule was designed to make sure the gliders integrity overall doesn't get harmed by too "ambitious" cable designs. I believe, it is a good rule that has probably saved a number of pilots since it was enforced.

Competition pilots are drag paranoid. If you leave them a choice they will decide for what has the least amount of drag then think about safety later on. It has a bit of a prisoner's dilemma (J.F.Naish) in it as well: If only one pilot decides to not-cooperate, all those who originally wanted to act on common sense ("use thicker cables") will finally join in and blow the gentlemen agreement in no time.

Combine all the above given information and you will find sample (i) and (iv) as the only ones that match all the "requirements" for the top guns (remember {ii) and (iii) have too much cross section, and (v) has not enough steel portion to pass the rule!)

If I had to pick between (i) and (iv), I would always prefer (i). It is stronger and - believe me - cuts skin less likely. I imagine, that's why most competition pilots have chosen it as well. If I was a beginner pilot, I would probably act on my instructor’s advice. If my skill level was somewhere in between top pilot and beginner, I would probably go with your conclusion and choose samples

(iii) or (ii), since performance issues most likely wouldn't really matter yet.

Steve Kroop <flytec@earthlink.net> responds:

The test that you refer to sounds scientific and it should be compelling however, you are right I remain skeptical. Here is why:

In the test it sounds like the cables (coated and uncoated) were used as cutting tools (i.e., the angle of the "meat" to the blade was probably near 90°). I propose that if the same test was conducted where the meat was introduced to the "cutting wire" at increasing angles of incidence it would become increasingly difficult to get the coated wire to "catch" and then cut.

It is my contention that at acute angles the coating acts like an over-sleeve roller. In certain instances (e.g., hooking the inside of your elbow around a cable) it probably wouldn't matter if the wires were coated, as your study suggests. On the other hand, in a glancing situation (which I suspect is a bit more common than the previous scenario) I believe the results would be less severe injuries. I have no test data to prove this, only observation. I have seen crashes and wreckages where coated wires were partially striped and/or rolled and there were only bruises and red marks on the pilot’s skin.

Perhaps this is only due to the fact that the wires are thicker because of the coating. Or it may be the case that it is a combination of greater surface area and "rolling action". Either way what is the harm in having coated wires if every one has them? Especially since it is relatively undisputed that coated wires are better in a parachute deployment situation.

Oh yes there is one more advantage…according to the wire manufacturers there is less kinking :-)

Discuss the coated wires at OzReport.com/forum/phpBB2

Discuss "Wires" at the Oz Report forum   link»

Wed, Apr 23 2003, 4:00:02 pm EDT

aerotow|Bill Bryden|EAA|FAA|flight park|instruction|Jayne DePanfilis|Lee Gardner|Lookout Mountain Flight Park|Orlando Stephenson|parachute|sport|Sport Pilot|Sue Bunner|survival|tow|towing|USHGA

Jayne DePanfilis <jayne@ushga.org> writes:

The recent situation at Lookout Mountain Flight Park regarding the suspension of aerotow operations by an FAA field inspector from Atlanta helped to focus the FAA on the need to either issue a new Towing Exemption to the USHGA or to revise the current Towing Exemption held by the USHGA to allow for the use of heavier ultralights for the purpose of aerotow launching hang gliders.

The FAA understands the importance of aerotow instruction/flying for the survival and growth of our sport. The FAA indicated a desire to help the USHGA address the need to revise the Towing Exemption when USHGA representatives first met with them at the Spring BOD meeting in Ontario, California in February of 2002 to discuss Sport Pilot initiatives. The USHGA Sport Pilot Task Force, members of the Executive Committee, and Sue Gardner continued to address the need for an increased weight limit for the towing vehicles at the Fall USHGA BOD meeting held in Orlando last October.

The issue of primary importance during these discussions was the (excess) weight of the ultralights that are in use at flight parks for the safer conduct of aerotow operations. The FAA understands implicitly that the Bailey Moyes Dragon Fly Ultralights currently in use at LMFP is essential to most aerotow flight park operations. They know that the Dragon Fly has recently been certificated in Germany. They know that the USHGA considers it to be a "standard" for the implementation of safer aerotowing operations. The USHGA Sport Pilot Task Force provided the FAA with documentation supporting the use of these ultralights as early as the spring of 2002. This valuable information did not fall on deaf ears. The USHGA has been working very closely with Sue Gardner for more than one year now on these matters.

On Monday of this week I spoke directly with Sue Gardner, the FAA's Program Manager and Technical Expert for Sport Pilot, and I explained the situation at LMFP to her in great detail. Sue indicated to me that she intends to immediately move forward with the USHGA's request to increase the weight limit of the ultralight vehicles used to aerotow launch hang gliders. The request to increase the weight limit of the ultralights that are used to tow hang gliders was formally submitted to the FAA by me in December of last year. The request was drafted by Bill Bryden. The situation at Lookout these past two weeks has shown Sue that the USHGA needs "immediate relief" from the FAA regarding the need to increase the weight limits of these ultralights so they can be used without question to aerotow hang gliders.

It is my hope that the revision to the USHGA's current Towing Exemption can be made within the next two or three weeks. The current weight limit for these aircraft is 254 pounds. Discussions are currently underway to increase the weight limit to 496 pounds plus allowances for (more) weight similar to those that are provided to ultralights operating now under the EAA, USUA, or ASC exemption for two-place training in an ultralight. The two-place towing exemption maintained by the EAA, USUA and ASC includes allowances for a parachute system, floats, etc. Bill Bryden is currently negotiating this new weight limit with the FAA on behalf of the USHGA.

The USHGA knows that Sue Gardner is a friend to recreational aviators and while the USHGA recently recognized her with an exemplary service award, I would like to publicly thank her once again for understanding what the USHGA needs most from the FAA to ensure that we will be able to continue to conduct flight park operations, aerotow operations, in the safer manner to which we have become accustomed.

Discuss heavy tugs and the FAA at OzReport.com/forum/phpBB2

Discuss "FAA, Lookout and their Tugs" at the Oz Report forum   link»

Sun, Apr 20 2003, 5:00:03 pm EDT

parachute

http://www.stratos07.cz/indexa.html

These are a European alternative to the BRS system. One reader writes in and states that they have never had a failure with this rocket propelled parachute system.

Discuss rocket propelled parachutes at OzReport.com/forum/phpBB2

Discuss "Ballistic chutes from Czech company Stratos07" at the Oz Report forum   link»

Sun, Apr 13 2003, 3:00:03 pm EDT

accident|battery|Brad Kushner|bridle|Dragonfly|flight park|instruction|parachute|photo|Raven Sky Sports|spin

Brad Kushner, Pres. Raven Sky Sports, Inc <Brad@hanggliding.com> www.hanggliding.com writes:

We have four Dragonflys. On our three Dragonflys with the 912-s 4-stroke motors, we have continued to mount our BRS units in the 'original' position, on the front of the root tube, over the pilot's head and forward of the wings (just like in your photo labeled, "On the Dragonflies with 583 2 stroke motors" (actually, the motor is a 582). I'd like for your readers {and the readers of the TUGS newsgroup) to be aware that it is still an option.

Of course, weight & balance is still a very important part of the decision making. If the CG is too far aft, the Dragonfly can have very undesirable spin characteristics. For this reason, we all do whatever we can to move the CG forward. I believe that the major reason that some DF owners have moved the BRS out to the front of the pilot area is to improve weight & balance.

Any weight on the Dragonfly that can be moved to the front of the pilot cage is beneficial…that's why most of us DF owners now mount the battery under the pilot's feet; every little bit helps. We suggest that, if a light pilot flies one of our Dragonflys, he should add a weight belt to the footrest. When we fly the 2-seat Dragonfly with a light pilot in the front seat and a heavy pilot in the back seat, the 'weight-belt-on-the-footrest-trick' is SOP. I believe that most of us who do dual instruction in the Dragonfly already have such a weight belt for just such an occasion.

I expect that there will be some discussion over the next few months about which position is the 'best' one to mount the BRS unit on a Dragonfly. I look forward to any new insights that this discussion will bring.

Some years ago, I was visiting at another flight park, and (of course) I was poking around in their Dragonfly to see what might be different from mine. I saw that, on their Dragonfly, the cable/bridle from the parachute was routed to a bracket/bolt attachment on the root tube (the square tube between the wings). A few inches away, the top of the pilot's seatbelt-shoulder belt was routed over the same root tube, as it should be.

However, on their Dragonfly the seatbelt-shoulder belt strap was not interlinked with the parachute bridle attachment, which troubled me. I brought it to the attention of the owner, and we discussed it, but it didn't trouble him like it troubled me, so nothing was done to change it.

My fear and concern was this: If the parachute deploys hard, and the square root tube fractures, then the parachute could become detached from the Dragonfly. With aluminum tubing, this is a very real possibility. On all of the other Dragonflys that I have inspected, the parachute bridle attachment terminates with a cable loop around the root tube, and the pilot's seatbelt-shoulder belt loop passes through the cable loop, too. With an arrangement like this, even if the square root tube fails, the parachute stays attached to the pilot's seatbelt/shoulder belt strap…far better a scenario than the other.

Please urge all ultralight owners with BRS units (or even hand-deploy parachutes) to re-evaluate the series of attachments that connect the pilot to the airplane, to the parachute, and to both. It may be that a simple thing like an extra hang-loop linking the pilot's seatbelt-shoulder belt to the parachute bridle cable may make all of the difference in the world, the next time that one of us has to deploy a BRS unit.

Here at Raven, we even have an extra bridle attachment going back to the seatbelt-shoulder belt of the rear seat, too…just in case.

It's bad enough that we learned the hard way about the pitfalls of improper re-assembly, and lost Chad; let's learn everything that we can from this tragic accident and, hopefully, prevent others in the future.

Discuss "BRS mounting and attachment" at the Oz Report forum   link»

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.

Discuss Dragonfly accidents at OzReport.com/forum/phpBB2

Discuss "The Dragonfly accident" at the Oz Report forum   link»   »

Tue, Jan 28 2003, 7:00:05 pm GMT

parachute

www.roochutes.com.au

In case you need to have your chute repacked. They are up near Brisbane.

Discuss "Repack in Oz" at the Oz Report forum   link»

Wed, Mar 13 2002, 9:00:01 pm GMT

parachute|Rob Kells|L.A.R.A.|Metamorphosi|Quantum

I’ve published quite a bit about getting the right size parachute. I await further word from Rob Kells showing the spread in the data points from manufacturer’s test. In the meantime you can do a bit of comparison at the following sites:

Lara: http://www.willswing.com/launch.asp?theCategory=
parachutes&link=frmInstCatsPage.asp?theClass=
parachutes:theCategory=parachutes

Metamorphosi: http://www.justfly.com/accessories/parachutechoose.htm and http://www.metamorfosi.com/Meta_en.htm

Quantum: http://www.highenergysports.com/Welcome.htm http://www.highenergysports.com/Quantum/QP%20Info.htm http://www.highenergysports.com/Quantum/Rate%20of%20Descent.htm

Discuss "Parachutes – where to size ‘em" at the Oz Report forum   link»  

Wed, Feb 27 2002, 2:00:06 pm EST

Angelo Crapanzano|parachute|Fred Wilson|Mart Bosman|PG|Simon Kay

You’ll’ find an article on repacking chutes in https://OzReport.com/Ozv6n33.htm

Fred Wilson «safety» writes:

The article refers to a study on skydiving repacking (reserves) which indicates that porosity (and lifespan) may be primarily dependant upon the number of times it is handled.

The study has left many unanswered questions… such as:

a) is it human body oil that is degrading the material? (If so, cotton gloves may be in order.)

b) is it the handling process itself (i.e. refolding, repacking) that degrades the porosity?

The real questions I would like to put to manufacturers are:

1. Does this factor into paraglider porosity degradation? (Given the enormous number of times a paraglider is likely to be repacked.)

2. Are some resin / color / sailcloth combinations more resistant to porosity degradation? (We are all aware that some colors of sailcloth degrade faster than others. Fleuro Pink being a classic example.)

3. Is the material used in sport parachuting (ram airs and reserves) similar to that used in our sports?

If porosity degradation rates are similar in our reserve parachutes, this article provides a strong argument to encourage pilots who own one to two decade old reserves to purchase some of the new generation reserves which have come onto the market in the past few years.

Angelo Crapanzano «angelo» responds:

The Belgian study refers to ram-air parachutes with "zero porosity" fabric. The fabric used looks the same as for round parachutes but the finish is completely different. As a matter of fact the fabric used for round parachutes is quite porous (if compared to paraglider fabric or modern skydiver's ram-air parachutes). Round parachutes need porous fabric to get stability and to reduce the opening shock to an acceptable level but, if the porosity gets too high, you lose on sink-rate. Different designs of round parachutes may need different porosity: do not measure the quality of a round rescue parachute looking at the porosity.

If measured with the standard (in Europe) porosity instrument made by JDC electronics, a good paraglider fabric, when new, has a porosity of 250-350 seconds; after two years it goes down to 60-100 seconds and the paraglider, normally, becomes dangerous at 5-10 seconds (depending on the model).

The fabric I use for my parachutes is among the lower porosity ones and, measured with the same instrument, gives a porosity around 1-1,6 seconds. The fabric used for round military parachutes has a porosity around 0,1 seconds.

Fabric for ram-air parachutes and round parachutes may look similar but need to have completely different characteristics. In my opinion the Belgian test has nothing to do with our rescue parachutes: pack your rescue chute as often as you like, but at least every three months :-)

Regardless of porosity a parachute life is limited because ageing affects the strength. For example a parachute fabric left to sunrays for a week will lose almost 50% of his strength! If opened as slow speed an old parachute will likely work as a new one of the same design, but will it hold a high speed deployment? In my opinion, even if carefully maintained and never used, it's better to replace your rescue parachute every 10 years.

Angelo Crapanzano «angelo» also writes:

Mart Bosman points out an important matter: the right compromise between sink-rate and opening speed (easy question but not so easy answer).

First of all I must say that pilots always speak about opening time but, in reality, we are only interested in opening distance (the altitude lost between throwing and opening).

To start we must know that given a certain model of round parachute in the same conditions:

• The filling distance (distance traveled from parachute fully stretched to parachute fully open) is independent of speed (if not extremely slow or fast) and is a linear function of the diameter of the parachute (double diameter, double filling distance, four time the surface).
• The impact energy is linear with the equivalent height (the height of a jump equivalent to the sink-rate) and is a linear reverse function of the surface of the parachute (double surface, half impact energy).

Of course filling distance is not everything: if we start from when the accident happens, we must add:

• reaction time (time needed to understand you need a parachute. Very important matter but independent from the parachute size).
• handle position and extraction (extremely important but depends mainly on the harness)
• stretching time (dependent on throw force, parachute weight, and parachute dimensions; for simplicity we could consider it linear with the diameter of the parachute).

From what written above we see that a parachute (of the same design) which has double the surface of another one, will likely make us land half as hard and will likely need 40% more altitude to open. I say "likely" because, given the same parachute in the same conditions, there is quite a scatter in results if we make several tests.

Does this mean "let's use a big parachute" because we gain more in sink-rate than we lose in opening distance? Well, if you deploy your chute at 1000 m from the ground it's worthless to minimize the opening distance but if you have an accident 30 m from the ground it is then the sink-rate to become less important. (I must also add that, if falling at very low airspeed, a bigger parachute opens slower than predicted compared to a smaller parachute. Note this is just my opinion and is not backed from any research or testing).

We must also consider:

• if your parachute opens very fast but your sink-rate is equivalent to a jump from 3 meters you would likely be injured.
• if your parachute brings you down like jumping from 1 m high it would be totally useless to get a bigger parachute: you will be uninjured anyway but you'll need a longer opening distance.

In my opinion it is wrong to say that a given parachute is suitable for a certain weight: the same parachute will bring down at the same speed a young karate champion 1,9 m tall, or his grandmother 1,6 m tall, if they both weight 80 kg. The impact energy would be the same, but the time spent at the hospital would not! Here is another, less drastic, example: I weight practically the same since I started hang gliding 25 years ago, but my muscles and bones, unfortunately, are not the same anymore :-( :-(

It is a personal decision: get the parachute size which will give you the highest equivalent height you are likely to accept without trouble.

Here comes a problem: there is not enough information from the manufactures or the certification standards. What about printing a number on the parachute (calculated after the certification tests) which, multiplied for your weight, will give your equivalent height under that parachute? Each pilot could then make an informed choice. It looks to me very simple but I could not convince DHV or AFNOR of the utility.

Mart Bosman says "most accidents happen on a altitude that there is plenty of time". He is probably right considering those pilots flying in the flatlands but, out of 253 real emergency opening with my chutes (those I know of, including hang gliding and paragliding), almost ½ happened below or around 100 m (I've been told) and in several cases the descent under canopy lasted just a few seconds. I know for sure of three pilots (Robbie Whittal, Karl Reichegger, Andrea Patrucco) who threw the parachute below 30 m (100 ft) and the parachute would not have opened in time if bigger. On the other side, with my parachutes, I also know of 6 cases where the pilot got injured with something broken but, luckily, without permanent damages (of course I'm not counting bruises and minor damages).

About folding and repacking I do completely agree with Henry Helmich from Parasail when he says that it's extremely important that a parachute is dry and recently folded (but this has nothing to do with parachute size: it's mandatory regardless of it). I won't be so extreme but, in my opinion, a parachute should be packed at least every three months.

Simon Kay points out that the Belgian Army has conducted an extensive long-term study of ram-air parachute wear and concluded that handling during packing was much more detrimental to fabric porosity than the actual deployment and use. As a consequence from this study they increased the packing period from 120 to 180 days.

In my opinion this research is not directly applicable to our round parachutes because we use different fabrics with much higher porosity than ram-air parachutes (round parachutes needs some porosity to help stability and reduce the opening shock). As far as I know the porosity of the fabric used for round parachutes is not significantly affected by foldings but the fabric strength is affected by ageing and sunrays (that's why it's suggested to replace the parachute every 10 years).

Remember that the most important factor is dry! A wet parachute at low speed will take ages to open.

About packing and opening time, according to some test made long time ago by the US Navy, there is quite an increment in opening time from just packed and three months. After six months, the opening time doesn't change much (sorry, I could not find out in which book I've seen this graph). Remember: our parachutes often have to open at very low airspeed where things get even worse for a long time packed or wet chute.

Scatter in the drop test data