Flying in turbulence (long)

[sducoach 0]

Myth or Legend?

Centrifugal: "Acting in a direction away from a center or axis." As away from the center of the turn.

Centripetal: Acting in a direction toward a center or axis." As towards the center of the turn.

Chris this is just too much fun!!!!!!

Love ya bro!

PS.

Any chance of you making it into Missouri this year?
Hillibilly Boogie is in June??

J.E.

[diverdriver 5]

Quote

Myth or Legend?

Centrifugal: "Acting in a direction away from a center or axis." As away from the center of the turn.

Centripetal: Acting in a direction toward a center or axis." As towards the center of the turn.

Chris this is just too much fun!!!!!!

Love ya bro!

PS.

Any chance of you making it into Missouri this year?
Hillibilly Boogie is in June??

J.E.

I'll send ya a PM........

[rendezvous 0]

very impressive and informative. Would you happen to know any books that cover such topics and the dynamics of flying through them in the detail you have.

[billvon 2,995]

Bumping this up due to a thread in the Incidents forum about flying in turbulence.

[itllclear 1]

Other option -- recognize the conditions that often will produce turbulence (landing downwind of a large stand of trees, dust devils, etc.) and stay on the ground.

"Harry, why did you land all the way out there? Nobody else landed out there."

"Your statement answered your question."

[diablopilot 2]

Shhhhh....don't let the newbs and DZO's hear ya.

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You're not as good as you think you are. Seriously.

[ianmdrennan 2]

This Sunday, I had an opportunity not only to discuss this topic with Scott Miller, but also got to test some of the practical side.

It was agreed that FULL FLIGHT in turbulence was the best course of action. Should the wing be affected by any sort of turbulence the pilot's course of action should NOT be to slow down with 1/4 or more brakes but rather concentrate on 2 things:

1) Keep the wings level, whatever that may require.
2) Slow the descent rate just above the ground - using whatever input's that would require.

Slowing the canopy down, unnecessarily, in turbulence worsens the situation. Additionally there isn't a 'fix all' solution to a canopy affected by turbulence, so instead contentrating on keeping the above 2 points in mind is the best the pilot can do. Finally remember that canopy collapses in turbulence normally involve 1 side of the wing folding under. It will naturally reinflate (by design) so keeping the wings level should be the priority.

My next jump I was subjected to some pretty nasty turbulence and concentrated on applying those 2 simple rules to the scenario with great success. A number of other jumpers followed the same rules through even worse turbulence with great success.

Blues,
Ian

Performance Designs Factory Team

[billvon 2,995]

>It was agreed that FULL FLIGHT in turbulence was the best course of action.

I agree. If the canopy actually collapses and must be reinflated, then 1/4 to 1/2 brakes will speed that process up.

[ianmdrennan 2]

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then 1/4 to 1/2 brakes will speed that process up.

Like I said, Scott and I had an indepth conversation about this. There isn't a fix all configuration and its far better to have the pilot concentrate on the 2 rules above - not just blindly go into 1/4 brakes.

Blues,
Ian

Performance Designs Factory Team

[billvon 2,995]

>not just blindly go into 1/4 brakes.

?? Again, I agree. You should NOT "blindly go into 1/4 brakes." You should do that only when your canopy has collapsed and needs to be reinflated.

[ianmdrennan 2]

Bill,

When was the last time you saw a canopy 100% and totally collapse?

I've seen different sides collapse but never the entire thing. In fact, most collapses happen, and re-inflate so quickly that it's over before the pilot can do anything about it - what they're left with is the after effect of the partial collapse (dive, sink, whatever)

Keeping the wing level is more important that 1/4 brakes. Maybe I'm just misreading what you're saying but it sure seems like you're advocating simply going to 1/4 brakes if a side collapses.

Once again, I don't believe there's a specific configuration fix, but rather believe the pilot should be concentrating on keeping the wing flying level, and if close to the ground at a survivable descent rate.

Having people believe 1/4 brakes fixes all turbulence problems, leaves them unprepared when their 'goal' (1/4 brakes) doesn't fix the issue. Rather, having the pilot realize the 'goal' is to keep the wing level and, if low to the ground, descending survivably and doing whatever it takes to do so (be that one toggle stroke, 2 toggle strokes, a full flare, half flare or no flare).

Maybe you never intended it to read that way, but that's the way I read your post.

Blues,
Ian

Performance Designs Factory Team

[billvon 2,995]

>When was the last time you saw a canopy 100% and totally collapse?

Never. I have seen perhaps 15 cases where it collapsed enough that it needed to be reinflated. Two led to cutaways, neither jumper used 1/4 brakes, so the canopy surged enough to (in one case) put it into line twist and (in the other case) get the PC around a line.

>Having people believe 1/4 brakes fixes all turbulence problems, leaves
>them unprepared when their 'goal' (1/4 brakes) doesn't fix the issue.

Right. Full flight is the best bet in most cases. If your canopy actually collapses, then 1/4 brakes will reinflate it more rapidly.

[ianmdrennan 2]

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If your canopy actually collapses, then 1/4 brakes will reinflate it more rapidly.

Junk science. Sorry.

Please, reread what I wrote. You're hung up on 1/4 brakes fixes all.

edited to add link: http://www.performancedesigns.com/docs/Turbulence-Hazard.pdf

Blues,
Ian

Performance Designs Factory Team

[rehmwa 2]

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Another suggested that ram-airs are somehow different now, so what worked 10 years ago doesn't work any more.

I was one that said something like that (but the 10 year note is likely too small - and the "doesn't work any more" is just plain misquote vs the real comment that keeping the canopy pressurized may require speed and levelness prioritized over partial brakes for newer canopies.) The inlet dynamics of modern canopies are much better than older designs like Mavericks, Cruislites, Pegasus, etc. A bit of brakes (actually rear risers?) would increase AOA and "open the nose" (present the nose) better for inflation for the old timers.

My first canopy was a Pegasus. Best 5 out of 7 cell canopy I every owned. On occasion, it would even allow me 6 of 7 cells if the air was smooth. That was nice. A real treat.

See the PD articles it seems to agree.http://www.performancedesigns.com/...urbulence-Hazard.pdf Sorry, the actual statement I can't cut and paste, it's a locked .pdf

I'm with Ian, but I like your advice anyway, the important part is to keep flying the thing and if you have time to make a 'reinflate' decision, then calm and smooth application of brakes may help the cause. Especially if doing nothing isn't working.

I also think you two are agreeing, except Ian is talking about turbulance and partial stalls, and you're talking about total stalls and full recovery. But, the total stall close to the ground, one would likely still attempt to flare before landing using Ian's criteria - you'd still get some amount of brakes, thus, before touchdown, to mitigate the surge.

...
Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants

[billvon 2,995]

>Please, reread what I wrote.

I did.

>You're hung up on 1/4 brakes fixes all.

I have a feeling you have a need to "prove me wrong" or something. Which is fine, but we are saying the same things.

If your canopy is flying, and you hit turbulence, then full flight is your best bet.

IF YOUR CANOPY HAS COLLAPSED, then 1/4 to 1/2 brakes will help reinflate it safely.

1/4 brakes does not "fix everything." It only helps reinflate a collapsed canopy.

Do this experiment:

Take your canopy and stall it hard, until it is quite bow-tied and you're descending rapidly. Now let the brakes all the way up to full flight. (Do this above 1500 feet!) See how it recovers.

Now take your canopy, stall it hard, and go to 1/2 brakes. See if the canopy recovers more quickly, and which recovery you'd rather have close to the ground.

This (essentially) simulates the sort of tailwind shear that causes a collapse. It dramatically reduces your airspeed and in some cases will actually stall your canopy.

[pchapman 279]

Note also that because many canopies have slack in the brake lines, one can pull the brakes down a small amount without taking the canopy out of full flight. If meant in that way, putting on "a little brakes" doesn't oppose the concept of "full flight in turbulence".

By pulling enough to start feeling a little pressure on the toggles (beyond what's needed to remove the slack) one might get a better feel for what the canopy is doing ("is it well pressurized or not?"), by force feedback through the toggles. Steering inputs would be more direct too, without having to move through several inches of slack.

This is analoguous to having a better 'road feel' in a car with a very direct steering system, or 'active flying' in paragliding.

(One downside might be that if bounced around in turbulence, one might have unintended arm movements and thus brake inputs too. Pilot Induced Oscillations so to speak.)