During FITS in Mansfield earlier this year, I ripped the HC IV in half flying with an I161; this fiasco was probably a result of poor design (unreinforced Estes BT-80 between fins and zipperless baffle) and an early delay. The fin can fell from about 3000' with no apparent damage other than about 6 inches shorter. Oops.
I bought 34" of 2.6" coupler tube and used about 6", then built a new baffle. The coupler is epoxied directly to the top centering ring on the motor mount, and the inside surface of the coupler is epoxied also. I'm going to fly this with FAR 101 motors (H123) this winter to make sure it's OK, then do some high performance flights next year.
