You do actually see them occasionally in amateur rocket use:
https://www.dinochutes.com/Dino-Chutes-36-Helicopter-Parachute-Heli.htm
They’re nice, but as you mentioned, they don’t deploy as cleanly, and
clustering them sounds like a recipe for disaster.
NASA, as well as the commercial providers, seem to all be using relatively
simple elliptical parachutes. Looks like the added complexity of a rotating or
pull down apex parachute isn’t worth the decrease in weight.
On Jan 9, 2020, at 11:38 AM, David McMillan
<skyefire@xxxxxxxxxxxx<mailto:skyefire@xxxxxxxxxxxx>> wrote:
Well, this is an interesting amateur experiment (8-min video):
https://youtu.be/saWIxN05QFU
Although I don't entirely agree with his conclusions as to why we don't see
them in use by NASA. My off-the-cuff thought is that you either want to avoid
spinning the payload on the way down, or the issues involved when multiple
chutes are required -- spinning parachutes, used in pairs/triples/more seem
awfully likely to tangle each other up.
The other "obvious" reason would seem to be that, just looking at it, a VRD
is probably harder to pack and deploy reliably, which probably explains why we
don't see them in amateur rocket use (that I've ever seen, anyway). When you
need reliability above all else (and simplicity a close second), I imagine a
VRD wouldn't offer enough benefits to outweigh the risks.
That said, it sure looks cool. And seems to have better oscillation
stability. Would it have better wind immunity as a side effect?
