Mr Van Milligan, I am building a completely scratch built rocket out of what I measured to be 2 bt-80 tubes both 18" long, with a nose cone I designed to be another 12" so the over all length from aft to tip of nose would be 48", I made a home made baffle which will act as a coupler between the two body tubes. I plan to use a quick link to attach the shock cord which will be made out of 5/8" nylon webbing, the issue I am trying to figure out is that according to Professor Dave Thomas' channel, he says if not using an elastic shock cord you should use 3x the overall length of a rocket for the length of the shock cord... that being the case I would need a 144" strip of nylon webbing, I added 6" more for the loops I plan to sew into either end of the shock cord for the quick links, and the loop I will knot into the shock cord for the offset parachute mounting connection..... with 150" the shock cord looks rather long... would this be a problem, and since the shock cord is essentially being connected 18" onto the eyelet at the coupler of the baffle which will be connecting the forward and aft tubes together could this still work? and if you have a suggestion how long the shock cord for said rocket should be I am willing to entertain your suggestion :-)
That should be sufficient length. My preference is that longer is better if you can keep it from tangling. Since you're using wide webbing, there is no need to wouldn't worry about a zipper. I think your rocket will be fine. Go for it.
Experienced my first zipper last weekend. An Aerotech F44-8 blew its ejection charge almost immediately after burnout. Talk about a high-speed deployment!
This is new to me. I have always used an elastic shock cord to absorb the shock when it tightens. I never liked the slingshot effect of the nose cone though.
Where ever you put the drogue, use the long shock cord there. I put the drogue in the back so that I have the rocket motor's ejection charge to act as a back-up to the altimeter. Having a back-up is good. You don't get that if you put the drogue in the front of the ebay section.
Only your local club can get you certified. There are no other alternatives. To find a local club, go to the National Association of Rocketry, or Tripoli Rocketry Association.
Mr Van Milligan, I am building a completely scratch built rocket out of what I measured to be 2 bt-80 tubes both 18" long, with a nose cone I designed to be another 12" so the over all length from aft to tip of nose would be 48", I made a home made baffle which will act as a coupler between the two body tubes. I plan to use a quick link to attach the shock cord which will be made out of 5/8" nylon webbing, the issue I am trying to figure out is that according to Professor Dave Thomas' channel, he says if not using an elastic shock cord you should use 3x the overall length of a rocket for the length of the shock cord... that being the case I would need a 144" strip of nylon webbing, I added 6" more for the loops I plan to sew into either end of the shock cord for the quick links, and the loop I will knot into the shock cord for the offset parachute mounting connection..... with 150" the shock cord looks rather long... would this be a problem, and since the shock cord is essentially being connected 18" onto the eyelet at the coupler of the baffle which will be connecting the forward and aft tubes together could this still work? and if you have a suggestion how long the shock cord for said rocket should be I am willing to entertain your suggestion :-)
That should be sufficient length. My preference is that longer is better if you can keep it from tangling. Since you're using wide webbing, there is no need to wouldn't worry about a zipper. I think your rocket will be fine. Go for it.
@@apogeerockets thank you sir
where can i find different type of shock cords? i.e pros and cons of kevlar and nylon
Nice! You’re always a great help, Tim.
What's the best way to attach a shock cord to the engine mount for deployment? Should the connection be fire proof? Cool video. Thanks for the info.
Define "Best."
Experienced my first zipper last weekend. An Aerotech F44-8 blew its ejection charge almost immediately after burnout. Talk about a high-speed deployment!
Yesssss, new tips! I have 3 (non-highpower) rockets in my back seat, on my way to a field for launch. I wish Massachusetts had more of a rocket scene.
This is new to me. I have always used an elastic shock cord to absorb the shock when it tightens. I never liked the slingshot effect of the nose cone though.
What if we attach the drogue to the nose cone and make its shock cord shorter and the main chute in the back and make its shock cord longer?
Where ever you put the drogue, use the long shock cord there.
I put the drogue in the back so that I have the rocket motor's ejection charge to act as a back-up to the altimeter. Having a back-up is good. You don't get that if you put the drogue in the front of the ebay section.
Question, where do I need to go to get a level 1 certification
Only your local club can get you certified. There are no other alternatives. To find a local club, go to the National Association of Rocketry, or Tripoli Rocketry Association.