Shock Cord - Northern Colorado Rocketry

This topic has 7 replies, 5 voices, and was last updated 13 years, 10 months ago by Warren B. Musselman.

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November 17, 2011 at 5:39 pm #41407
Sparky2
Participant
How about what size of Kevlar shock tube for a 30 to 35 lb. rocket? Does anyone use swivels on the parachute connection to the shock cord?
November 17, 2011 at 5:46 pm #54970
John A. Wilke
Participant
John, I personally NEVER use swivels – but that is a personal choice. For shock cord on a rocket like that, the 1/2″ tubular would work great – It is 7,200# test.

Shameless plug- you can get that for $1.25/foot with free shipping on orders of 30′ or more from http://www.3dogsrocketry.com 😀
November 17, 2011 at 6:18 pm #54971
Sparky2
Participant
Thanks. How about rail buttons? Railbuttons.com is belly up.
November 17, 2011 at 11:57 pm #54972
Warren B. Musselman
Moderator
Talk to me baby – I have stainless steel railbuttons for both 1515 and 1010 rail with stainless steel screws. $10 a pair for 1010 and $20 a pair for 1515. Got you covered.
November 18, 2011 at 1:14 am #54973
MikeS
Moderator
make sure it is kevlar shock cords.

I used (used nylon) on one rocket and it seperated
at apogee.
November 18, 2011 at 4:05 am #54974
Sparky2
Participant
Thanks Mike, I am going with Kevlar from 3 dogs and Warren I am interested in your railbuttons. Still in planning stages but I will take a pair of 1010’s and a pair of 1515’s. Thanks.
November 18, 2011 at 8:54 pm #54975
Steve Jensen
Participant
just be sure to get a well rated one. I use the Rosco ones from Fruity Chutes.

In my experience, they keep the main from wrapping up with the NC.

I’ve also not used swivels. Sort of a matter of taste.
November 19, 2011 at 2:09 pm #54976
Warren B. Musselman
Moderator
Swivels that work and are capable of handling rockets over 3-5# are essentially unavailable in the hobby. The only source I know of is the sailing industry and they are extremely expensive as well as quite heavy. Given that several thousand pounds of force may be exerted during deployment in a rocket that weighs over 30#, you’d probably experience what I did – watching parts of your rocket come in ballistic while others go floating away towards the horizon.

For smaller rockets, there are some saltwater fishing swivels that rate up to 500# or so. I personally wouldn’t use them for anything over a couple pounds.
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