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petetheladd

Planned dynamic stall of your canopy

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Just curious, as it used to be a basic canopy exercise

By a dynamic stall, I mean to the point you completely collapse the canopy, kinda fall backward into a semi freefall and re-inflate.

Elliptical is used in the sense of a minimum high performance mark

P.S. common wisdom is not to try this on an elliptical re: cutawayB|
Though I'd love to hear from any trepidacious souls who may have tried it

No, Not without incident

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theres me thinking this is summin we should all do when we jump a new canopy, or at least flare as much as possible to see if the canopy has shorter than expected brake lines.
obviously this should only be done at altitude, if possible and you are gonna try this then plan on pulling high, get all this playing outta the way before you get to a higher than normal hard deck, If I decide to play then i check with Manifest and then the pilot , just for safety and will pull at 7000, this gives me all the time in the world:P well almost before I even get to my normal pull alti, then I get back onto my normal landing pattern.

Just make sure the higher alti winds are not doing summin strange, otherwise you could be heading somewhere strange whilst playing,B|

dont do this on the first load of the day, cos that is the wind sock load:D
Fly like an aardvark

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Complete rear riser stall on my Sam, toggle stalls on the Jedei. As long as its perfectly even and smooth on the recovery and stall it never had an issue.



Hmmm... I have done stalls on squares with toggles but I have'nt tried the rear riser stall on my xfire2 though now I want to :)

No, Not without incident

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> What's a "dynamic" stall?

Strictly speaking, it is a stall above normal stall speed due to higher G loadings seen during manuevering. Most skydivers define it as a violent stall.



This is a new term to me - how would you go about doing it, and what would the lesson be?
_________________________________________
you can burn the land and boil the sea, but you can't take the sky from me....
I WILL fly again.....

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>This is a new term to me - how would you go about doing it, and what
>would the lesson be?

A dynamic stall, in a normal aircraft, is a stall that occurs at a higher than normal airspeed due to G-loading from manuevering or turbulence. You need X pounds of lift to maintain level flight, and all other things being equal a wing will stall at a certain speed because the angle of attack you need to generate that lift exceeds the stall angle. If you're pulling 2 G's, you are generating 2X pounds of lift and the wing stalls at a higher airspeed. It's important to know, because if you're flying near stall (say, you're trying to clear the trees with a dead engine) and you manuever, you may stall at a higher than expected airspeed. Such a manuever killed a friend of mine several years back when he tried to turn final for a dead-stick landing; he stalled and spun in.

But that's not how most skydivers use the term. Most skydivers use the term "dynamic stall" to describe an exciting stall, one that is violent and sudden. You can get an exciting stall in most canopies by just taking wraps on the brake lines until it starts to deflate and fly backwards. In its true sense, you might see a dynamic stall if you started a toggle turn up high, waited until the canopy built up a lot of speed, then buried both toggles so you pulled a lot of G's. The canopy might stall at a higher airspeed than you expect it to.

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According to the SIM (what students should be learning), they are not defining it as a high speed stall. They mean what most of us would call a stall. Although technically a basic stall on a canopy would be sinking down (no longer creating lift due to low airspeed) just prior to the backward falling of the canopy.

The high speed stall would be more of a concern for swopping. Higher speeds and G's creating a higher stall speed. This could be associated with the risk of using rear risers in a swoop.

Todd


I am not totally useless, I can be used as a bad example.

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I would stick with the rear riser stall on the xfire there laddy, though you could get away with a toggle one, you'ld better pray you get an even recovery on the inflation.

Ask grouper how he lost one of PD's demo canopies after he was putting into practice what scott miller had told him to go try on that jump (practice stalls). When he got down scott said "I didnt tell you to do that!" hehe

Johnny
--"This ain't no book club, we're all gonna die!"
Mike Rome

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> What's a "dynamic" stall?

Strictly speaking, it is a stall above normal stall speed due to higher G loadings seen during manuevering. Most skydivers define it as a violent stall.



Isn't the term for this actually a high-speed stall (as some others have posted) or an "accelerated stall"?

I think dynamic stall (on a canopy) is just the regime where the canopy changes orientation significantly (e.g. it drops back and down all of a sudden).

-=-=-=-=-
Pull.

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Maybe I should read the sim.:$

All airfoils stall at a certain angle of attack, the actual angle depending on the airfoil design. That angle of attack can be achieved by maneuvering too quickly at high speeds (high speed stall) or by attempting to fly to slowly (low speed stall.) Maybe the SIM could rename nondynamic as "approaching stall point" and dynamic as "complete stall". That would seem to line up with what pilots learn, wouldn't it?

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Test jumped a Firebolt 146 yesterday. Did a couple of kick ass stalls on it on each jump. (opened high of course)

Everytime I'm jumping a new canopy, I find the stall point. I then go deep and collapse the canopy and reinflate it while maintaining a heading. When you've got some choppy air, being able to control your canopy and maintain heading while on the verge of collapse is a great skill to have.

:)
I would rather be a superb meteor, every atom of me in magnificent glow, than a sleepy and permanent planet.

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Just felt I should point something out for the less experienced who may be reading this and are now ready to run out and try it. When stalling HP canopies to the point of collapse, be careful not to let up suddenly and completely on the toggles to recover. Your canopy will surge forward quite aggressively. This has resulted in one entanglement and ensuing fatality that I know of. Better to let up slowly until the canopy is flying in deep brakes, and then continue with the recovery to full flight.

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Just to add - like anytime you plan to try anything new to you in skydiving, seek advice from your instructors, mentors and S&TA's about it.

I dont believe once you are prepared that it is inherently dangerous but it definitely is not a normal canopy ride if you have'nt recieved some training and done it before.

That said, I encourage people to ask their instructors about this manouver and try it on a regular large square canopy.

P.T.L

P.S. Looking at the poll, it seems the majority of people claim to have done it. This does not jibe with my personal experience in skydiving

No, Not without incident

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> What's a "dynamic" stall?

Strictly speaking, it is a stall above normal stall speed due to higher G loadings seen during manuevering.



This is a new term to me - how would you go about doing it, and what would the lesson be?



Because most of us have a very clear idea where the stall point is along our toggle stroke, and because we have arrived at this impression by achieving a stall at normal g loadings, we are in danger of dynamically stalling our canopy when we are confronted with the corner and are 'stabbing' our way out of it.

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Back when all canopies were "square", I don't recall a single person (at least at Raeford) who didn't regularly perform reverse spins and intentionally collapse their canopies (at altitude) for fun. I have done it with Stillettos as well and never experienced any irrecoverable linetwists. The key is in keeping your toggles pulled down evenly. I don't recommend trying this below 2000 feet (or whatever your hard-deck is).

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Do it on a regular base, under any sport canopy I've flown from student canopy till Stiletto 107 (take care with the last one).

Never stalled a tandemcanopy on purpose (No plans to do it either)

++++++++++++++++++++++++++++++++++++++++++++
Using your droque to gain stability is a bad habit,
Especially when you are jumping a sport rig

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Stalled a big ol' fat Manta yesterday during some instructor traing. Man, they really vibrate with only five inflated cells!

:)
I would rather be a superb meteor, every atom of me in magnificent glow, than a sleepy and permanent planet.

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