Parachute Packing for a Zipperless Baffled System

[Aero B]

OK, here goes.
I put together the recovery gear for my LOC IV that I am building for my Level 1 flight in the "Certify with Us" program.
The system was put together with 750lb braided Kevlar and 3/16" steel quick links.

The parts are.... 15' of Kevlar from the body to the parachute link, and 6' from that link to the nosecone.
The ends of the Kevlar were tied with bowline knots and then covered with heat shrink tubing.
I did several searches on the forum and I picked up a lot of info, but I came up with some questions.

So...

I have packed a few chutes in the past and that part was not too much of an issue.

Stretch out and align.



Pull shroud lines back on top the canopy.


This section is 6' so it is longer than the parachute and shroud lines.
Then fold the canopy over the shroud lines and then tri-fold the canopy.


The packing would go like this...
The Kevlar from the parachute connection to the nosecone would be dropped loosely into the upper section.
Then I would insert the folded chute into the body tube.
Here is where the questions started popping up.
Now, would I insert the parachute like this, with nothing wrapped around it?
Would it unfold in the body tube enough to create an issue, or......


....would I put a few turns of the lower kevlar around it like this?
It seems like this may cause a problem.



The lower section of the Kevlar would then be bundled like this and held with small sections of masking tape.
This would then be put into the upper tube then the upper tube placed on the lower section.


Any thoughts or suggestions?

Hope I explained this well enough!

 

[troj]

Personally, I'm not a fan of the "zipperless" method of deployment, especially with motor ejection.

The reason for this is that your charge is doing two things -- first, it's shoving the parachute further up into the tube that you want it to come out of, and second, it's throwing that tube off. Now, you're depending on the upper tube having enough inertia to pull itself off of the parachute, which is depending on how tight the chute is in there, along with the length of the leader to the chute.

For that reason, going that route, I would use a short tether between the baffle and the chute, and a much longer one between the chute and the upper tube.

I also highly recommend against wrapping lines around a nylon chute. It's a recipe for disaster, and even more so to do it with Kevlar, which is highly abrasive.

-Kevin

 

[Handeman]

I totally agree with Kevin on this. I would put the chute about 3 ft. from the booster and attach the upper section 12 ft up from that. I would only use the 15' of cord.

 

[Aero B]

Thanks for the replies!
I had thought over the points you brought up. I had done a good bit of digging around and really didn't find much on the recovery system for this type of rocket. Loads of folks talking about them, but not much precise info.
I did pick up the useful bits on making sure the line to the nose cone was longer than the chute and shrouds, and bundling the Kevlar into a short package.
The 9" of 4" tube pretty much swallows the chute and lines. I may fill a good bit of that with something. I have enough room to put in a bulkhead and leave space for an altimeter under the nose cone.
I am going to keep digging for info.
All input appreciated.

 

[DRAGON64]

Your design looks sound; do not wrap the shock cord around the chute, that could be bad... If this were my rocket, and I wanted to enure that I get my chute out into the stream, I would pack all of the shock cord in first then the chute. Since the shock cord will be pulled by the falling booster, the first fabric to hit the air stream is the chute. Use dogbarf, nomex or baffle to protect the chute from burning.

 

[Aero B]

Dragon,
I have a baffle system in the upper section of the booster.
The shock cord will be bundled with masking tape into a section that will be about 18" long and that will be packed next to the chute itself.
I am going to take pics and video of the packing and the flight and I am hoping to get some useable video of the deployment.