Canopy collapse due to turbulence

[Skylark 0]

How often does this happen? And what should I do to prevent it from happening? Should I fly into the wind? Downwind?

"Into the dangerous world I leapt..." William Blake, Songs of Experience

[AggieDave 6]

Best method is to NOT jump during bad wind conditions. 2nd thing you can do is let your canopy fly, trying to keep it at half brakes or something like that won't help.

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[Skylark 0]

Obviously I dont jump if its too hairy up there. I'm talking about sudden turbulence thats unexpected. Can it collapse a canopy? What do you mean by just letting my canopy fly? Should I be facing the wind or away from it?

"Into the dangerous world I leapt..." William Blake, Songs of Experience

[CrazyIvan 0]

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Should I be facing the wind or away from it?

Into the wind...to slow down.

__________________________________________
Blue Skies and May the Force be with you.

[andy2 0]

[QUOTE]2nd thing you can do is let your canopy fly, trying to keep it at half brakes or something like that won't help.[/QUOTE]

I've heard keeping slight toggle pressure, i.e. less than quarter, is the best toggle position for turbulence. Is this wrong?

---------------------------------------------
let my inspiration flow,
in token rhyme suggesting rhythm...

[matttrudeau 0]

Aggie Dave is right. First, don't jump if you know it's turbulent. If your caught in turbulence, keep the canopy in full flight. You can use little toggle pressure to keep the canopy flying straight. If it's turbulent on landing be ready for anything. Probably a PLF.

[jlmiracle 7]

Yes, turbulance can collapse a canopy.

Full flight means arms all the way up, ready to flare.

Land into the wind.

Be prepared to PLF bacause you can easily get a down draft and slammed into the ground.

good luck.

Be kinder than necessary because everyone you meet is fighting some kind of battle.

[ERICCONNELLY 0]

Like they said. Prevention is best. Avoid landing areas that have objects that can cause turbulance if possible. Turbulance is very common downwind of any large objects like buildings or trees. A decent rule of thumb is to expect turbulance to a distance of 5X whatever the object height is.

ie. A 40' tall treeline will create turbulance 200' down wind.

The exact conditions can obviously vary but by knowing your landing area and avioding jumping in iffy conditions you can ALMOST eliminate the risk of canopy collapse due to turbulance.

[beowulf 1]

I have had a dust devil partialy collapse my canopy. They are hard to see and there isn't much you can do about them but try to avoid them if you spot dust kicking up. I just didn't do much inputs on toggles and the half of the canopy that collapsed reinflated within a couple of seconds. I am not sure what else I could have done.

[Sebazz1 2]

Also if you are really underloading a canopy I would imagine the chances of canopy collapse in windy conditions would be greater as well.

[matttrudeau 0]

That's true, the larger the canopy the more it will be affected by turbulance. I know the camera guys at my dz fly small canopies and in turbulant conditions they fly it even harder to avoid getting caught in it.

[rapper4mpi 0]

One thing to watch out in this forum is taking advice from people that might not necessarily be qualified to give advice. With that, take everything that you hear on here with a grain of salt. There are several arguments for dealing with turbulence, half brakes, let your canopy fly at full flight. But Aggie is correct, avoid turbulance by staying on the ground in questionable winds, or not landing down wind of tall objects such as buildings. Remember, turbulance travels 10 times the height of the obstacle downwind if it. So is a building is 10 feet hight, you will still see effects (although small) 100 feet downwind of the building.
My point however is this. If someone with 40 jumps or so is giving definitive advice, you best be asking questions. Your home DZ instructors who know you best are almost always the best people to ask. Good luck and stay safe.
-Rap

[AggieDave 6]

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Your home DZ instructors who know you best are almost always the best people to ask.

Exactly!

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[USPA 0]

Yes it is.

You need as much speed as possible. This way your "wing" can move as much air as possible (giving you lift).

The trouble with skydiving; If you stink at it and continue to jump, you'll die. If you're good at it and continue to jump, you'll see a lot of friends die...

[billvon 2,412]

>I know the camera guys at my dz fly small canopies and in turbulant
>conditions they fly it even harder to avoid getting caught in it.

That's foolish. Turbulence can collapse any canopy. If you're 5 feet off the ground doing 5mph when it happens you'll be OK. If you're 5 feet off the ground doing 40mph you will be lucky to get away with a broken leg. And if you hook it hard and lose lift when you're planing out you will probably end up dead.

The "canopies resist turbulence better when they're going faster" thing sounds like the "you have to hook turn to get a good flare with a stiletto" thing to me - one not founded on any real data, but an excellent excuse to go fast.

[Katzeye 0]

I agree. That's why I'm still waiting to do my next jump after my recurrency (out of sport for almost 1 year). It's been 3 weeks now with no joy.

The winter winds in Hawaii tend to be at least 6 mph difference (start at 4, gust to 10, back to 4 +/- 10 mph starting winds).

I see the experienced jumpers get thrown about and PLF alot. Even they *sweat* those kinds of conditions. NO Thanks! The sky will always be there and I can just wait for better conditions.

my $0.02

LA*

Is a chicken omelette redundant?

[billvon 2,412]

>You need as much speed as possible. This way your "wing" can
>move as much air as possible (giving you lift).

Speed will kill you if you have a collapse near the ground. If the collapse happens up higher, the best recovery position to be in is 1/4 to 1/2 brakes; that's how canopies reinflate most reliably (which is why they are designed to open that way.)

The "wing moving a lot of air" thing - we use flexible wings. They are moved _by_ air in turbulence, not the other way around. Going faster exposes the wing to more force from moving air. If that greater force collapses your canopy you're in bad shape.

[Zenister 0]

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I have had a dust devil partialy collapse my canopy. They are hard to see and there isn't much you can do about them but try to avoid them if you spot dust kicking up.

dustdevils can shrivel any canopy and drop you suddenly..what i was told was avoidance avoidance avoidance..if you see one turn 90 deg away from the DD -in a direction into the wind..(dustdevils always move downwind) to get as much seperation as possible...if it already has you..be ready to PLF and practice them on occasion so you dont have to 'think' about how to PLF

____________________________________
Those who fail to learn from the past are simply Doomed.

[wildWilly 0]

I agree completely. It's better to be on the ground wishing you where in the air than in the air wishing you where on the ground.
I would definitely recommend a canopy with air locks ( Samuri, Lotus by BIg Air Sportz) PD also makes one ( Vengence). My Samuri handles turbulence better than anything I have tried. I still feel the bumps but It cuts right through. I'm not saying that it can't collapse, just that it was designed with this problem in mind.

Blue Skies,

Willy

growing old is inevitable, growing up is optional.

[matttrudeau 0]

I know I wouldn't be hooking it during turbulant winds. I just see people doing it and getting away with it. Their philosophy was keeping the canopy pressurized. If it works for them, go for it. I'm not ready to do that yet.

[matttrudeau 0]

You can question anyone. It doesn't matter how many jumps they have. Whether you have 5 jumps or 500, each person can learn from the other. Don't you ever question more experienced jumpers?

[rendezvous 0]

One of the schools of thought and the one I normally like to follow is to keep your canopy flying full flight. Slight toggle pressure may help a bit but if the air is turbulent there's not much you can do but to wait to get out of it. To keep it simple, make slight corrections if and when required but otherwise just wait to get out of it in full flight. Be piloting the canopy at all times. Even if you are facing turbulence be aware of what the canopy is doing and be in control of things, atleast mentally. If you are tempted to make corrections to the flight using toggles do not fall prey to huge toggle input. In turbulence your toggle input may not respond like you expect it too. If you are in the process of giving a large amount of input and your canopy happens to get out of turbulence it's going to react. Close to the ground that could put you into a lot of trouble. Always try and keep piloting your canopy. In other words always be evaluating the situation and be ready to act. I don't have a ton of experience to back this but given the situation this is how I plan to react or have once or twice when some unpredictable stuff has happened.

[pchapman 262]

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One of the schools of thought and the one I normally like to follow is to keep your canopy flying full flight. Slight toggle pressure may help a bit but if the air is turbulent there's not much you can do but to wait to get out of it.

To add to this --
One debate about dealing with turbulence has been whether to fly in zero brakes or slightly braked, eg 1/4 brakes.

Whether or not 1/4 brakes is aerodynamically superior or not, there are 2 reasons why jumpers may prefer better having a little brake on in turbulence, that I haven't seen discussed:

1. By having the toggles pulling against the hands instead of up all the way against the brake rings, the jumper can feel the varying pressures on the brake lines and thus on parts of the canopy. This can help in understanding what's happening to the canopy. (Paraglider pilots, who fly canopies more sensitive to parts of the wing folding under, consider brake line pressures an important source of information on the status of their wing. Is one wingtip picking up lift and getting more pressure, or is one tip getting 'soggy'?)

2. Some canopies and jumpers have the brakes set up with a little slack in the control lines when the brakes are up all the way. Pulling down a little removes the slack from the system (ie, the tail of the canopy isn't deflected) so when the jumper wants quick response in turbulent air, moving the controls will have a more immediate effect.

So even if you think quarter brakes is the wrong way to go, just a little bit of brakes may be useful.

Peter Chapman
850 jumps, occasional paraglider pilot

[crwmike 0]

I fly my canopy up to a limit where I feel the potential from the bumps and bruises. You fly your canopy, presumably, to the same limits through more turbulent winds.

Do the air locks make you safer?

Michael

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I agree completely. It's better to be on the ground wishing you where in the air than in the air wishing you where on the ground.
I would definitely recommend a canopy with air locks ( Samuri, Lotus by BIg Air Sportz) PD also makes one ( Vengence). My Samuri handles turbulence better than anything I have tried. I still feel the bumps but It cuts right through. I'm not saying that it can't collapse, just that it was designed with this problem in mind.

Blue Skies,

Willy

[AggieDave 6]

You realize that Brian Germain himself gets fairly annoyed when people will say they'll jump in turbulence b/c they have airlocks, but wouldn't in an open canopy. His thoughts are that if you won't jump an open nosed canopy in those winds, then you shouldn't jump an airlock in them either, since it'll still be dangerous.

--"When I die, may I be surrounded by scattered chrome and burning gasoline."