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  #1  
Old 10-25-2019, 11:08 PM
vulcanitebill vulcanitebill is offline
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Join Date: May 2011
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Default interchangeable recovery system?

I'm sure there are people here with useful experience to share in this area-

I've got about 5 rockets that use G motors. I built most of these nearly 20 years ago to use wide elastic that I bought at a sewing shop but I've not had very good luck with this stuff. I would like to convert everything to kevlar. I've seen good results using fairly long kevlar cords, probably 10' or more for this size rocket, but 100' of this size kevlar is fairly expensive so I'm thinking about having only maybe 2 sets of cord and switching from rocket to rocket.

My thought is to use short kevlar in the airframe to extend to the front of the tube with a loop tied in it. Then have a 15' length of kevlar with loops in both ends. Now the question is how to connect at each end. These are not large rockets, mostly about 2.6" diameter, so maybe a quick link is overkill but are snap swivels big enough? I thought about putting a barrel swivel in the cord in the airframe then the shock cord can connect to that.

I may do a similar thing with my B-size rockets but those can use standard snap swivels.
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  #2  
Old 10-25-2019, 11:19 PM
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tbzep tbzep is offline
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Even the larger snap swivels are prone to coming apart if there's much speed at ejection. A 2.6" heavy wall airframe and the usual ply fins and 29mm mount has quite a bit of inertia even though it doesn't seem like it would. A small quick link is the way to go.
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Old 10-26-2019, 11:04 AM
L3Excalibur L3Excalibur is offline
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Quote:
Originally Posted by tbzep
Even the larger snap swivels are prone to coming apart if there's much speed at ejection. A 2.6" heavy wall airframe and the usual ply fins and 29mm mount has quite a bit of inertia even though it doesn't seem like it would. A small quick link is the way to go.

Along with the barrel swivel attached to the end of short line that you mentioned, above. The swivel really helps in reducing tangled chutes. And 700 pound test Kelvar shouldn't be that expensive. Should be well under $2 per rocket for 10-12 ft. I see some 1/8" Kevlar core with polyester jacket (800 lb test) going for about .16/ft.
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Old 10-28-2019, 09:46 PM
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PaulK PaulK is offline
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Look on Amazon for EmmaKites braided kevlar cord. For 500 lb, it's $40/500', and for 750lb, it's $40/300'.
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