When the fins are bonded into the carbon fibre airframe, some extra carbon fibre will be laid up tip-to-tip to strengthen the fins. We wanted to practice doing this lay-up and make sure that the C-F fabric that we cut is the right shape, so we made a mockup of the fin can.
A quick lay-up with some unidirectional C-F fabric and some fibreglass on the inside gave us a tube of the correct diameter for the airframe (quite large!).
A quick effort with a hacksaw gave us so mock fins made from plywood, with the edges near the body tube filed to the same angle as the machined aluminium edge will be. An alignment jig was knocked up on the CNC router to keep the mock fins at 120 degress for them to be bonded to the C-F tube. The mock-up will be tested with a lay-up later this week.