Rear Eject... Any Tips On Ensuring The Chute Unwraps?

[lakeroadster]

I'm nearing completion of my 1st rear eject rocket. The chute wraps around the motor mount sub-assy.

Any tips or tricks for ensuring the chute un-wraps? Should the chute be between the rocket and the motor mount so the rocket pulls the chute away?

18" plastic chute...


Thanks in advance!

 

[Daddyisabar]

Talc. Good packing technique.

 

[Cameron Anderson]

Make sure the motor mount assy kicks out far, and energetically.

 

[JohnCoker]

I've never done it that way so I can't answer your question, but I did want to say great drawings and nice build.

I don't think you can expect the 'chute to open itself; we generally attach it to a nose cone that helps pull it out and open. As long as you have some sort of plate protecting the parachute from the ejection charge, maybe you can make that do double duty by helping to open the 'chute.

 

[Funkworks]

Should the chute be between the rocket and the motor mount so the rocket pulls the chute away?

“Between-two-things-that-pull-apart” sounds like good approach. For what it’s worth, that’s how people-size parachutes also work: a small arm-size “pilot-chute” pulls out the main chute away from the skydiver. I’m here to write about it anyway.

 

[PBic]

Maybe a swivel between the motor mount and attach point on the rocket would assist the unfurling of the chute. Just a thought.

 

[mbeels]

If there is room, can you fold up the chute enough so that it doesn't overlap with itself (as in "C" shape, not "O" shape)? Instead on unwrapping, it just needs to fall off.

 

[lakeroadster]

Thanks.

I'm thinking if I pick a delay such that it ejects before apogee then the upper portion body will continue upward while the motor mount / chute eject downward. Assuming I use a partial "C" shape wrap of the chute around the motor mount, as discussed by @mbeels.

If I attach the chute to the upper body shock chord, that should pull the chute from the motor mount. It then blossoms and the upper body and motor mount will be hanging underneath it.

Thoughts?

​

 

[BABAR]

Couple ideas.
1. Pack right before launch with talc. If you pack early the chute can kind of get “memory” and tendency to hold its shape.

2. A small streamer attached to apex of chute (I know, already tight), should drop out into the air stream, pull chute out into the air stream, once out in the air stream should open (hopefully.)