Forums: Skydiving: Gear and Rigging:
Canopy collapse..airlocks!

 


ramon  (D 26115)

Sep 4, 2001, 2:30 PM
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Canopy collapse..airlocks! Can't Post

After seeing some lightly loaded canopies colapse in straight flight, and hearing of the unfortunate incident at the Ranch (poor girl), I am thinking about Airlocks again (I did just purchase a Vengeance and I jump my friends Samurai all the time). I bought the vengeance cuz it dives steep, not cus of the airlocks.

Does anyone think an airlocked canopy is really that much safer if turbulence is encountered during a med/high G dive?
Could it have some sort of mal different from a collapse (spin?).

Could a cross braced canopy (loaded 1.8 or higher) colapse due to turbulence (typical turbulence, not blustery or violent wind)?

BSBD
ramon




weid14  (D 20292)

Sep 4, 2001, 2:43 PM
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any wing, rigid or otherwise will collapse and/or lose it's ability to maintain flight given certain wind conditions. John Matthew's airlocked canopy collapsed in a weird wind condition at Z-hills and he got pretty broken up. The X-braced canopies typically are flown at higher wing loadings, which by default lead to higher pressurization, which makes it more stable in turbulence. Airlocks -- my opinion, if you need them, you probably shouldnt' be jumping in those conditions anyway.



jussi  (D License)

Sep 4, 2001, 3:02 PM
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Just to get the facts straight, John Matthews was injured at
Skydive America @ Palm Beach..

Hope he is feeling better..





roq  (D 105)

Sep 4, 2001, 3:19 PM
Post #4 of 22 (2066 views)
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There are some few canopys that has, per times, eccentric behaviors in turbulence. In times it was the Nova and Pintail.
To have or not to have airlocks doesn't solve the problem when there is defect in the conception.
Anybody hear to speak about inexplicable collapses in Extremes, Stilleto, Diablos, Spectres, Bat-Wing, Cobalt, Alpha, Viper, BT, Nitro?

The answer, I think, it is not!!!




ramon  (D 26115)

Sep 4, 2001, 3:29 PM
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hmmm. only one I have ever personally seen was a lightly loaded monarch (1.1) in straight level flight, half the canopy colapsed then reinflated a second later (the girl was scared to death afterwards).

ramon



weid14  (D 20292)

Sep 4, 2001, 3:44 PM
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sorry,. my bad, thought it was Z-hills.



weid14  (D 20292)

Sep 4, 2001, 3:53 PM
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I've seen more than one Sabre fold in on itself, then re-inflate. Heard one do it once, didn't even have to look up, asked the guy if he liked the canopy ride - he was not a happy camper. saw one fold in half from above, guy dropped about 30 feet, he was not real happy either (still had altitude to make a good landing). (my -- at the time -- seven cell had a pretty good accordian effect going on, too). These were not to lightly loaded.



OmriMon  (C 32176)

Sep 4, 2001, 4:21 PM
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It happend to me twice with a safire 169 loaded at about 0.7 i think

once during a 360 toggle turn at about 1000ft
and once just on straight flight on my downwind leg



Free Skies,
Omri A-38593 Crazy


imdskydiver  (C 2457)

Sep 4, 2001, 7:14 PM
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I have seen a prototype of the Lotus fold up , De-flate from the right side , Re-inflate and then collapsing the left side then re inflate again, It was lightly loaded ! A valve system didn't work on that occasion , One might also argue that a normal non air locked canopy would have crashed ?



skymedic  (C 33561)

Sep 4, 2001, 9:29 PM
Post #10 of 22 (1987 views)
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Only unexplained canopy colapse I saw was in sebastian with a guy who bought a PD canopy that turned out to NOT be a PD canopy. seems some one sewed on PD side panels onto a nova and the guy bought it. He was at about 150 feet when suddenly his chute collapsed in on itself and he fell straight down. I was on my 5 AFF jump at the time and was right behind and above the guy when it happened......what made it worse was my instant "gotta help the injured" mind sprung into effect and I made a tighter and faster descent than I should have. good news is the guy was still alive and only had a busted femur...bad news the guy was from aruba and didnt speak english....



Marc
Because I fly, I envy no man on earth


PhillyKev

Sep 5, 2001, 4:59 AM
Post #11 of 22 (1955 views)
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I had my student Nav 289(?) loaded at .08:1 collapse during AFF when I was about 12' up and just about to start my flare. I came down on my back and ass. Had to get multiple back xrays, internal bleeding, and they thought I broke my pelvis but it was just a really nasty bruise that showed up on the Xray. Couldn't sit for 2 weeks.

It was a no wind day so landing direction was based on agreement, not the wind socks. I was coming in to land when a light gust of wind came from behind and sucked all the air out of my canopy.

I'm now loading a Spectre at 1.07:1 and the increase in stability, control and flare feels to me so much safer. Should students really be loading canopies so lightly? Or would a 1:1 ratio be a better bet and still be forgiving enough? Problem is I see plenty of students and recent students come in to land and just forget to flare. Would that be more of a problem at 1:1 instead of .8:1??

cielos azules y cerveza fra

-Kevin


weid14  (D 20292)

Sep 5, 2001, 5:05 AM
Post #12 of 22 (1953 views)
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Re: Canopy collapse..airlocks! [In reply to] Can't Post

wow, that is underhanded (sewing the labels on).... bet "ouch" is the same in all languages though.



cobaltdan  (D License)

Sep 5, 2001, 9:12 AM
Post #13 of 22 (1919 views)
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Re: Canopy collapse..airlocks! [In reply to] Can't Post

wing loading is canopy specific.

but i agree with you completely.

underloading canopies is just as dangerous as overloading them.

many student operations signifigantly underload canopies below the minimum acceptable for their design.
i have 3 friends that were injurred this way, 2 seriously, while on aff.

underloading will only make a canopy so slow, beyond that it just make them unresponsive.

sincerely,

dan
atair



apoil  (D License)

Sep 5, 2001, 8:05 PM
Post #14 of 22 (1864 views)
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In reply to:
many student operations signifigantly underload canopies below the minimum acceptable for their design.
I have seen asian girls weighing under 90 lbs under 280 sq ft mains getting no forward speed at all in winds under 5mph.





Designer  (D 5771)

Sep 7, 2001, 9:35 AM
Post #15 of 22 (1820 views)
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Airlocked Canopies were designed to deal with light to moderate Turbulence AND high steady winds.To be able to safely jump when you really could not without Airlocks.This is were very sound,good judgment takes over!Like the man said,ANY NON-RIGID wing can collapse!(Brian,carries the reminder for the rest of his days on this earth!)There have been times and sure there will be in the future that I will not get on the plane no matter what parachute is strapped to my back.Think.



Engovatov

Sep 7, 2001, 10:35 AM
Post #16 of 22 (1809 views)
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Re: Canopy collapse..airlocks! [In reply to] Can't Post

> ANY NON-RIGID wing can collapse!(

Rigid wings can be driven to the ground by a wind shear just as well..



Jumperpaula  (D 23923)

Oct 2, 2001, 9:37 AM
Post #17 of 22 (1738 views)
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There doesn't seem to be a whole lot of support and encouragement to try this type of is canopy....hmm

Thanks

Fly Your Slot !


cobaltdan  (D License)

Oct 2, 2001, 11:23 AM
Post #18 of 22 (1721 views)
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i have been under 2 different airlocked canopies and induced a mal where the inboard turning side folded between the b& c lines. the mal is unrecoverable. interesting though is if you cut holes in the canopy (i put 1/2" holes in the top skin near the tail) the canopy will depresurize and self correxct the mal, if the vents are slightly larger the mal can not be induced in the first place.

i do not believe airlocks offer any bennifit. they sound good in laymans terms but scientifically they have not stood and there has been 2 decades of testing in the paragliding industry.

btw. does not mean that an airlocked canopy can not have nice flight characteristics


sincerely,

dan
atair



ramon  (D 26115)

Oct 2, 2001, 11:30 AM
Post #19 of 22 (1721 views)
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Paula
My fav "RW only girl" after my sig-other Wassup! PD markets their canopy wrong it should be marketed as an intermediate canopy between the stilleto and the velocity, because it does swoop better. Is it because of the airlocks...hmm..doubt it.

I jump a vengeance, but not cuz it's airlocked, cuz it dives hard.
Trey jumps a vengeance
Super Dave thinks a Vengeance is the best non cross brace canopy out there...and his opinion is probably more valid than mine.
Wane jumps one Samurai and has second on order.
James (ex-jumpmaster jumps a vengeance)
Mike Swanson (Olav's team mate) jumps a samurai.
Rabbit jumps a Jedei when not on FX.
Eric thought Vengeance is great, but...he needs a little more of course.
Josh thinks the're good although he has moved on also although his crossfire is one of the 'bad' ones.
Katrina like the jedei although she liked my FX better (109FX vs 120)

The samurai and the vengeance are both hard swoopers, but I am not sure anyone jumps them cuz of the airlocks. Consensus opinion is that if the wind is really bad they can fold up also, but I have seen mine personally land better on a blustery day, but ....my only comparison is against canopies that were loaded lighter and that may be just as important.

bloo skies sweetie.

ramon



ramon  (D 26115)

Oct 2, 2001, 11:48 AM
Post #20 of 22 (1716 views)
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Re: Canopy collapse..airlocks! [In reply to] Can't Post

and of course there is the John Matthews incident (knock on wood).

Any canopy that folds during a low or high performance turn is probably unrecoverable at that vertical speed and altitude though.Frown

BSBD
ramon



skymedic  (C 33561)

Oct 2, 2001, 1:43 PM
Post #21 of 22 (1699 views)
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what happened to john matthews...as I wasnt in the sport at the time...but see support for him at every DZ I frequent down here is FL.???

Marc
Because I fly, I envy no man on earth


apoil  (D License)

Oct 2, 2001, 7:35 PM
Post #22 of 22 (1664 views)
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Re: Canopy collapse..airlocks! [In reply to] Can't Post

John (a world class freeflyer) got busted up pretty seriously under a samurai.
Turbulent wind conditions are the culprit. What I've read so far indicates that no other canopy would have fared any better under those conditions.





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