Forward fin attachment..

Well, here's my first (recoverable, i'm sure) "oops" on my Level 1 rocket that I'm going to ask some advice about. I am building a Yank 3" dia. Black Brant X. I decided that I was going to use the anti-zipper design that's diagrammed in InfoCentral. No problem, right? Well, that part of it won't be a problem. It's pretty easy. BUT, the small forward fins were supposed to be epoxied to the coupler that was to be epoxied to the forward tube. Well, the coupler is now firmly in place in the AFT tube and, after cutting the slots for the fins, I suddenly realized that I have nothing to attach them to except the sides of the BT. I figure I have a couple of options for the fix and was wondering which one you guys liked best:

1) I could glass the inner side of the tube, sand the coupler to fit, and attach the fin roots to the glass.

2) I could glass the fins to the tube on the outside of the tube and lay a fillet over the glass.

3) Both 1 and 2

4) Tell myself that I'm overly paranoid, I probably won't ever use more than an I in the thing, the fins are small, they're not the part that are going to hit first anyway, that I'm most certainly NOT in denial, and just epoxy them into the open slots figuring that Murphy and his laws aren't so tough after all.


Any thoughts? Please note that this is only a Level 1 rocket, and it'll never be a level 2 rocket (already got that one sitting in the basement waiting for next spring), so I really don't need it to survive the energy and forces that some of you guys get to play with.

I haven't looked at the InfoCentral article for a while but it should work just fine.

As for the forward fins, I assume you meant they provided a coupler which would supply a backing for the forward fins? I think you should be fine just inserting them into the slots, flush with the inside of the tube, and add good epoxy fillets, of course. Glassing the inside and then sanding a coupler is WAY too much work. Glassing the joint will certainly add strength, but shouldn't be required. On the other hand, if you are glassing any part of this rocket, this added step will be trivial.

The main risk to these fins is having one of them pop off in touchdown and as you point out they won't hit first on landing. They could also pop if hit by the cone before the recovery system deploys. If they are on straight and have solid fillets, they prolly would handle an L2 flight also.

Thanks for the advice. I am actually going to reinforce the aft fins with fiberglass, as they're only 1/8" ply and they're swept back trapezoids, so they WILL hit the ground first.