Ataching TN to already built rkt.

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rocketkid88

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Well, a while ago (b4 i found this forum and learned allot about MPR) i built a rocket (24mm mount) and all. i put this skimpy little shock cord in it, which I wouldn’t' even trust most of my lpr with. I tried launching the thing on an E9 (it really needs more motor than that, but..) any way it suffered a messed up 'cute (24" estes piece o plastik, what can you ask?) but was still OK. now i want to try an AT motor or something (mabye a D12 would be able to kick it up there a few hundred ft.. I’m not sure tho) but there is no way i'm launching it with this junky shock cord. How do you think is the best way to attach TN to an already built rocket? if i was building it again I’d go with Kevlar from the mmt, but there's no way i could get down there so i don't see y bother with the Kevlar.
Maybe i could just put two slits in the bt and run the TN out the upper one and back in the lower one, with a knot on the end. that would be a bit ugly tho..
what are your opinions? thanx, Nate

pix: static
launch on E9
 

kgholloway

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What you need to do is to make yourself a LOC style shock cord mount. I use these as replacements when I can't reach down to the MM.

Get yourself a length of braided nylon line, about 1/8" diameter is the right size. Cut about a 6" to 8" length of the line, the actual length depends upon the diameter of the airframe tube and how far down you can reach into it. Tie knots in the ends of the line, use "figure 8" knots if you know how to tie one, overhand if you do not. Next take the ends of the line and tie them together using a square knot. What you want to end up with is a loop of line about 2" long with two loose ends about 1" long.

Lay your rocket on it's side and tape the loop, with masking tape, to the inside of the rocket as far down as you can comfortably reach. It must be further down the body tube than the shoulder of the nosecone reaches when it's fully inserted. Put the masking tape across the loop leaving the loose ends of the line exposed. Now carefully epoxy the loose ends of the line to the side of the rocket. Just be careful not to epoxy the loop to the tube.

When the expoxy hardens remove the strip of masking tape. The loop should now be free to move and it should not interfere with the fit of the nosecone. The loop now becomes your attachment point for your shock cord. OBTW this is a very strong method of attaching a shock cord. I've had cords fail in this type of application but I've never had the LOC mount fail me.

Ken Holloway, NAR #78336, L-1
 
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