Final internal reinforcement

I've seen many a high-power rocket fail at the coupler between the payload and sustainer sections.  Many folks forget to reinforce the inside of the coupler so that's the weak point that buckles under the tremendous forces of flight.  I cut three 2" wide strips of 45˚-oriented glass, soaked them in epoxy, wrapped them one at a time around a 3/8" dowel, then unwound each inside the coupler against the forward bulkhead:

I pressed all three layers down onto each  other and I think you'll agree that looks much stronger than a bare piece of phenolic tubing.  Keep in mind that the bottom of that bulkhead is about 1" above the payload/sustainer interface so I think I have things covered.

     I also repeated the above procedure as the final reinforcement in the nose cone.  I poured one more pool of epoxy in there and now the nose cone is really ready to finish.