[FFT] Dual chute question

Run a nylon line as long as the shrouds themselves (typically 1-1.5x the diameter) fromthechutetotheattachpoint. This will allow the airflow around the chutes a bit of extra wiggle room.

When you fold them, fold them TOGETHER so when they deploy they cannot tangle.

Tech Jerry

Re: "fold them TOGETHER"

Jerry, by this, do you mean one on top of the other, rolling them up as one unit? If so, how does this make them less likely to tangle? (Never having used two chutes, I am uneducated in the science behind this...lol)

Yes.

I have seen separately rolled chutes twist lines (rocket spinning) or one open essentially insude the other.

Tech Jerry

Thanks, Jerry.

I can imagine the setup, but what keeps the chutes apart? I did a couple catapult tests (without the additional cord) and the two (stock Estes) chutes both inflated directly above the NC.

I was thinking there might be something to cause an asymmetric flow around the chutes, like unequal shroud lengths, an offset spill hole, a trimmed canopy skirt, etc.

I'll try the extra cord and see what happens.

On ny lonchutes I also use a slide ring to slow deployment.

But then again, unlike some here, I actually fly rockets.

Jerry

Hi Gary, I've flown two rockets with dual chutes. Both are the Estes Gemini DC design. When both chutes deploy, they naturally pull away from each other, I'm not sure why. On my big DC, 4X the Estes kit, the twin chutes are each on a 30 foot tether and are separated by many 15? feet.

steve

Aha.

I'd looked around trying to find some "method" that made the chutes separate, but couldn't find anything (at least, nothing applicable to my modrocs and flat canopy chutes).

Thanks for the info.

It's simply a matter of the airflow around the 'chutes.

The air 'coming up' within the diameter of the 'chute has to go somewhere. It flows radially and spills out the sides. That airflow forces the 'chutes apart.