Collapsible Pilot Chutes

[JaapSuter]

Is there any data or experience on how much collapsible pilot-chutes affect large seven cell canopies? Especially once you start going to the 48 inch range?

Is the reason nobody jumps collapsible pilot-chutes because it just adds complexity to the system, and the effect of a dragging pilot-chute while flying is not big enough due to the size of the canopy?

I guess especially at the 48 range, canopy flights tend to be short anyway, so I suppose it doesn't matter enough.

Thanks,

Jaap Suter

[r2hubert]

I would be curious to see how to design a collapsible pilot chute without DBag... Do you have an idea in mind... when would the pilot chute would collapse and how?

[JaapSuter]

That's a good point that I hadn't even considered. I'm sure somebody could come up with a system to make it work though.

I'm mostly curious if the amount of drag created by pilot chutes right now is simply not a problem. Apparently it is not. My own canopy flying experience is not broad enough to answer the question myself.

[baseninja]

I have had an idea after seeing a kill cone from a CRW canopy...

Pretty much a disc, made of a heavy layer of denim, with a oversized grommet. When the canopy opens, the drag from the denim will slide that choker over the base of the PC and essentially choke it.

I have tried to think of scenarios where this would suck, which it really would. But, I think it will not even have a chance to move until after the pins are popped and the canopy is well on its way to inflation.

And I've often wondered how much payoff the choker would provide for the extra complexity, but my Zero-P Ace flies like a dream, glides forever- I would imagine a jump at MB/Moab, or anything else that is a 2ish second delay with a 500-700' canopy flight would benefit?

[Tom Aiello]

From personal experience, the difference between a 48" PC and no PC (dbag deployment) on the canopy flight is _barely_ noticeable. I don't think it's anywhere near a noticeable enough difference to spend good skull sweat on getting rid of it.

[tfelber]

I agree. With the generally large size and F-111 material (slower forward speed) of BASE specific canopies the effect of pilot chute drag should be negligable. When you get into smaller/faster HP canopies the drag of the pilot chute is greatly magnified and becomes even more of a factor as the ratio of canopy size to PC size decreases.

[BASE_689]

I would agree with Tom. I can say, from our personal experience, that a difference between a 48" PC and no PC (D-bag or McConkey deployment) could be noticed in very special cases, for example, a downwind flight on final approach, between freefall with a 48" and McConkey (with no PC), but then again, you cannot do any comparison at all between flight paths of two flights: McConkey deployment starts flying much higher than freefall deployment. Yes, in those cases of downwind landing of parachutes with a 48" and parachutes without PC (McConkey deployments), the parachutes without PC were slightly faster.
Positive issue about "collapsible" BASE PC: slight increase in distance flown with a 48" Collapsible with respect to a standard 48", yes, but who cares? If you are using a 48", you are freefalling an object in the range of 75÷65 m - 246÷213 ft or lower, so in this low freefall cases distance flown is NOT an issue, because if you are freefalling these low objects, their landing area MUST be easy (=well clear), so it doesn't really matter where you put your feet on landing, it doesn't really matter if you put your feet "there" of few meters shorter. Otherwise, if you had to take into account distance flyable to get to landing, in case of a 90° (just to make an example), the correction needed to take parachute back into original flight path would fu(k you up.
Negative issues about "collapsible" BASE PC: huge negative issues!!!! First, it would be a nightmare to design a collapsible PC for BASE, granted that there is no bag; second, a bigger nightmare to design it to be easily removable (remember that us BASE jumpers change PC nearly at each jump); third, being so complicated to manufacture and to assemble, it would be: 1) time consuming to assemble it; 2) jolly easy to make a (deadly) mistake in assembling it (remember, if you are using a 48", you must be frefalling a very low object where EVERYTHING must work perfectly).
Just my 0.02€