What happens at the end of the Scott Miller Nav220 video?

[obadz 0]

I've posted my question directly on skydivingmovies but who knows when someone will ever see it..

This is in reference to
http://www.skydivingmovies.com/ver2/pafiledb.php?action=file&id=1628&string=scott%20miller
(Scott Miller swooping a Nav 220)

I'm trying to understand something about this video: towards the end, Scott yanks on the toggles and the canopy dramatically slows down (horizontally), the angle of attack increases significantly but the canopy does NOT pop back up. How does he achieve that? Is it because of the slight turn that he seems to induce? Is it some form of a dynamic stall? (I realize I should take the canopy course... and I will!
Thx,
David-

[jerm 0]

looks like at that point he was transitioning from rears to toggles. the control range for rears is much shorter than that for toggles (especially on something that big.. looong toggle stroke), so when letting off the rears he has to get to the equivalent spot in the toggles' control range just to maintain his flare (especially since he's toward the end of the swoop... lower airspeed,lift, etc..). hence the large, abrupt input.

take a close look at sonic, OP, me, johnk, shatalov, etc... sometime. we do the same thing, but since the canopies are smaller, the control ranges are (generally) shorter, hence the movement is smaller.

Landing without injury is not necessarily evidence that you didn't fuck up... it just means you got away with it this time

[obadz 0]

I see.. I understnad what you're saying but the phyics of it is puzzling to me.

I suppose the toggles distort the canopy and change its flight characteristics.. Maybe among other things it would reduce the speed at which that same amount of lift is being produced? (so that he can fly on the same plane, but slower..)

Thanks jerm-

[jerm 0]

exactly. the rears change the angle of attack by basically changing the trim of the canopy with minimal wing distortion and thus minimal increase of parasitic drag. it is not, however, conductive to low-speed flight and therefore has a much higher stall speed than flaring with toggles. by pulling down on the trailing edge of the canopy (toggles) you're more dramatically changing the shape of the wing, giving it different more lift for the given airspeed and allowing you to bleed off more speed before touchdown. this also causes a lot more drag, so the added lift comes at the cost of time/distance.

so rears are best while you have lots of speed because they help you preserve that speed by giving you high lift with low drag.

in the video, once Scott bangs the toggles, he's at a point in the swoop where he has used up most of his lift and uses that action just to stay aloft. any earlier and he would have popped up, he has just expended too much energy at that point pop up.

there's lot more physics to this than i've gone into here... i suggest you go get a copy of Brian Germain's book at the pro shop. He explains it all far better and in more depth than i have.

will you be around this weekend? i'll be there all day Saturday at the very least if you wanna discuss this in person (with visual aids)

it's late... hopefully i haven't botched any of the major concepts above.

Landing without injury is not necessarily evidence that you didn't fuck up... it just means you got away with it this time

[ianmdrennan 2]

Quote

it's late... hopefully i haven't botched any of the major concepts above.

Nah, sounds like a pretty good description to me

Performance Designs Factory Team

[obadz 0]

Yep I'll be at the ranch tomorrow. Thanks a lot for the explanations that makes total sense. We'll catch up tomorrow!

[crazydiver 0]

Can anyone tell what type of unput he is using to initiate the dive? Front riser? outside a-b line? other?

Cheers,
Travis