I did not like what i saw there.... I hope this is not a sign of bad trim/canopy issues similar to the original Crossfire...
Sweet jebus!
That was so sudden and violent that it looked like a line broke. Since the perspective doesn't show it, is there anything that would roll a rotor like that out there or were the conditions right for dust devils? Were any other canopies bouncing?
Remember when the JVX came out every few months a new version was released? It always made me wonder about what level of R&D was conducted before something was released. PD has made some flops, but you can't say that they test the snot out of their product before it is let loose in the wild.
Dec 1, 2011, 8:01 PM
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Sweet jebus!
That was so sudden and violent that it looked like a line broke. Since the perspective doesn't show it, is there anything that would roll a rotor like that out there or were the conditions right for dust devils? Were any other canopies bouncing?
Wind was off the water and the direction put them downwind on distance and quartering cross on speed runs. These were all practice rounds. Temp was about low 80's winds were gusty at times but always from the same direction.
FS teams were landing on the palm and wind seemed consistent there, at least when we were landing.
Dec 1, 2011, 8:15 PM
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From looking at a download of the video of what I guess is a Petra collapse in Dubai:
In the turn, it is the leading edge of the wing on the outside of the turn that folds under. In paragliding parlance, it would be a frontal collapse - asymmetric at first but leading to a full frontal.
It doesn't take long until the whole wing folds under and is inverted before things go crazier.
It isn't a case of hauling down too fast on a front riser, as that would normally be on the inside side of the turn.
The turn initiation isn't sudden, and indeed the turn seems to slow shortly before the collapse. One does of course wonder about the trim design on that canopy and what kind of turbulence may have been about. More likely thermals in that area than rollers off obstacles? I dunno.
Whatever the cause, the angle of attack at that part of the wing got too low...
Attached is a zoomed video capture series, with time stamps added in seconds.
Edit: Start of canopy distortion @ 2.6 sec, start of sudden movement of the pilot @ 2.9 s, first sign of cutaway @ 5.4 sec (2.5 s later), full reserve inflation (still with a twist) approx @ 7.4 s (2.0 s later).
(This post was edited by pchapman on Dec 1, 2011, 8:23 PM)
Dec 1, 2011, 9:30 PM
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Re: [ianmdrennan] JPX Petra - stability issues?
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That's an extremely violent loss of airflow. Scary stuff, glad the pilot is ok - good reaction time and good promo for the skyhook.
Ian
Good promo for PD canopies as well since he stated: "Needless to say, I will be using my VC 79 for the DIPC an not the petra... Thanks to UPT for the epic gear... Skyhook saved me today for sure".
Dec 1, 2011, 10:28 PM
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PG wingovers require some outside brake to keep that from happening. Fortunately the result of an asym on a PG isn't quite so violent. Holy crap.
collapses on small stuff get nasty really fast for sure. no way out of that one so low without a chop.
in PG it really depends on what wing you are flying, some wings will flip you over and eat you, not just spin up. and it's more than just "outside brake" to do coordinated wingovers.
Dec 2, 2011, 8:10 AM
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Seems way too high for a blue devil, but the way it spun up looked like one.
As I stated earlier winds were varying I would say between 5mph on the lulls to maybe 10-12 on the gusts. All the turns were made over light colored sand, and temps were in the 80's. Over 100 other competitors made practice jumps with no problems.
Dec 3, 2011, 11:35 AM
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There's no decent details on this issue, so judging it by being an R&D failure is too soon
ianmdrennan (D 25821)
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Dec 3, 2011, 12:23 PM
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There's no decent details on this issue, so judging it by being an R&D failure is too soon
Agreed. I'd hardly call any issue with a R&D canopy a failure. That's the purpose, to iron out all the kinks or to learn about what does and doesn't work.
I think, what is most alarming about the collapse is how sudden and violent it was. It reminded me of the "Foxy" revision (I think it was that one).
Dec 3, 2011, 1:06 PM
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One of the Babylon guys(Fred or Kuri but a while ago so can't be sure) 2002/2003 Hot day in August. The collapse happened at altitude above 2000'. Flying normally then it just folded and spun up. Stardard Velo i believe as the comp Velo hadn't been conceived then. Happened at Empuriabrava Spain which does suffer with some funky winds from time to time.
Dec 3, 2011, 2:01 PM
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That was so sudden and violent that it looked like a line broke.
That was my first thought, but in the vid caps a few posts down it looks more like the nose rolled under and it swallowed itself.
One thing's for sure. I'd want to do a sh*tload of research before jumping it again. If that happened a bit lower there would have been a lot of paperwork.
Dec 4, 2011, 5:35 PM
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That was so sudden and violent that it looked like a line broke.
That was my first thought, but in the vid caps a few posts down it looks more like the nose rolled under and it swallowed itself.
Yeah, I know, I was saying that the canopy collapse was just that violent when the nose of the canopy folded.
I've seen Velos do some odd stuff before, but never anything that violent and sudden. Also in each of the times I've seen a Velo do something really odd, there were bad wind conditions or the canopy had serious trim issues from an old lineset.
. To my knowledge the Petra is STILL a prototype so who knows. 
Petra collapse - vidcap series.jpg
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