Pilot Chute Weight

[panavision 0]

I am thinking about this. I have two pilot chute of the same size, 46inch (same manifacture), but one have an internal handle. So the weight is relatively different (cordura cap to cover the handle, handle,..).
I am thinking about the difference of behavior, due to the different weight, in several stage of the deployment (same delay): 1) Difference in Speed of Bridle Extension 2)Difference in Pilot Chute Inflatation 3) Difference in Pilot Chute Drag
Other differences could be there........

What do you think about it?

[TomAiello 25]

The major difference is probably in PC inflation, and then it is most noticeable on zero airspeed (throw and go) deployments.

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1) Difference in Speed of Bridle Extension

With good PC toss technique, there should be no noticeable difference. With poor technique, it could go either way. If you toss the light one too soft, it might not hit bridle stretch as soon, because the heavier one has more carrying force. That ought to be a non-issue for most everyone, though.

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2)Difference in Pilot Chute Inflatation

Unfortunately, it doesn't seem to be a straight "heavier is slower" relationship. It's more like "heavier is more random," combined with "weight on the apex increases random hesitations." The heavy PC may actually inflate just as fast as the lighter one on occasion. But the variation between it's fastest and slowest inflation is going to be much greater. My personal experience (jumping, not testing) was that a weight on the apex of the PC appears to occasionally create random hesitations, expecially at zero airspeed. On an old (not the current Asylum design) CR 46" with a heavy cap, I got noticeable hesitations about 1 jump in 20. I haven't actually tested this in any controlled circumstances, but I have seen plenty of video to support this theory.

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3) Difference in Pilot Chute Drag

From my measurements, the difference in drag is negligible. The only thing that I could see reducing drag is a very oversized vent.

-- Tom Aiello

[email protected]
SnakeRiverBASE.com

[panavision 0]

Why weight on the apex increases random hesitations? Also my 46 pilot with cap handle is CR, do you think is better don't use it in the sub 300feet area?

[TomAiello 25]

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Why weight on the apex increases random hesitations?

Essentially because the apex slumps to the side when the PC is trying to inflate. More weight causes more slump. I have video and stills of this happening, but I don't really have a good scientific explanation other than that parachute deployments, even very small ones, are massively chaotic events, and random stuff just happens. I've certainly observed it happening, but as to a good explanation? I think it's going to take a supercomputer and a turbulence laboratory.

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Also my 46 pilot with cap handle is CR, do you think is better don't use it in the sub 300feet area?

I used mine down to about 220 without incident. To be safe? I'd probably get a new one without the cap, and only use the older one on stowed jumps. But I don't think it's a huge deal.

-- Tom Aiello

[email protected]
SnakeRiverBASE.com

[Faber 0]

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In Reply To
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Also my 46 pilot with cap handle is CR, do you think is better don't use it in the sub 300feet area?

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I used mine down to about 220 without incident. To be safe? I'd probably get a new one without the cap, and only use the older one on stowed jumps. But I don't think it's a huge deal.

i think it sounds like a great SL or PCA pc

Stay safe
Stefan Faber