L3 experiences, advice, or just general ponderings…

[Warren B. MusselmanModerator]

12 grams may seem excessive on a 6″ airframe, but it depends on the length of the bay and as I recall Conway’s bird was a bit long. The UprOar project, a 7.5″ project with an inner airframe of 6″” and it used 13.5 grams as I recall for main deployment – confined in 5/8″ or 3/4″ surgical tubing and that was not too much. The chute bay was about 48″ long as I recall. JW may be able to comment here – I can’t recall or find my old notes. Now we did have concerns about binding during separation since that wasn’t an all-composite bird.

[Bruce R. Schaefer]

There you go, Chris! To each his own. YouWarren M. were not there to see my L3, lessons learned and a perflect flight! We are all brothers in this.

[Chris LaPanse]

12 grams may seem excessive on a 6″ airframe, but it depends on the length of the bay and as I recall Conway’s bird was a bit long. The UprOar project, a 7.5″ project with an inner airframe of 6″” and it used 13.5 grams as I recall for main deployment – confined in 5/8″ or 3/4″ surgical tubing and that was not too much. The chute bay was about 48″ long as I recall. JW may be able to comment here – I can’t recall or find my old notes. Now we did have concerns about binding during separation since that wasn’t an all-composite bird.

Yep – that’s why I said that it depends on the rocket, and I was assuming a fairly standard 6 incher. On a longer or heavier rocket than usual, more of a charge will be needed.

[John A. WilkeParticipant]

Well, JW, I agree with you on LONG shock cords, my L3 100 foot can attest to that. Although this guy, JW, doesn’t use masking tape to reef the Kevlar, he uses electrical tape! I have yet to use latex glove fingers–as many in this club do, but that seems reasonable for highest of altitudes, and lower.

1.) Latex glove fingers will NOT work at really high altitudes… note that this was tried here http://www.wimpyrockets.com/page16.html. It is clean and tidy and all, but it doesn’t hold the pressure long enough. Tony2 verified this in the chamber he built.

2.) I do indeed reef every few folds with electrical tape… at least on the bigger rockets. It would stand to reason that this would absorb the energy more, as it is harder to break. As you will see in the ground test, it works splendidly. I aways sorta bite my lip when I do this – and it always works!

JW

[Anonymous]

Yep..that’s what I do too.

Tony

[Warren B. MusselmanModerator]

Personally I’m a masking tape Z-fold guy…1 layer where I want it to break first, then 2, then 3, then 4… in 4 bundles. Has worked well so far. I use masking tape because it is cheap and biodegradable.

[James Russell]

I think this has become one of the best threads I have seen here in a long time!

[Bret PackardParticipant]

Thanks for the pic Tony. Warren, can you explain the “z-fold” a bit please? This is great information guys and I really appreciate it!

[James Russell]

the z fold is like what you see but laying flat going back and forth in a z like fashion. It is easy to do with the nylon cord that a lot of us use and also the Kevlar flat or tubular that a lot of us also use. It looks neat and deploys cleanly. Just bundling the cord up and taping it you have more of a chance of tangling. These methods not only help in a cleaner slower deployment but also helps make things easier to pack and fit into your airframe.

[Doug GerrardParticipant]

Here is a couple of pictures of Z-fold

[Author]

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