I'm using scrap pieces of balsa that were in shape of the fins. It must have come from waste from a larger kit. The Air Frame is BT-55 11-7/8" long which is salvaged from a scratch build that got ruined in the quick move out from the Fire back at the end of March. The 18mm Engine Mount is also a salvage part from another scratch build that also got ruined in the quick move out. The Launch Lug is a 1/8", 3" long previously mounted on Air Frame. Not the best location or length, but it is getting used and it will fly according to RocSim. I have previously papered the fins, marked and cut for the mounting tabs at 1/4" (from a scrap piece of cut off from my previous wood shop I saved, comes in handy) and 45 degree cut the front ends, and flat cut the aft ends as they will be flush with the bottom of the air frame. It's going to be a real challenge to work the fillets in the launch lug fillets, especially since that tube was previously done in TiteBond II, and is several years old. A fair amount of water soaking will have to be done to soften up the old glue so the new glue will bite in good. Also, when sanding the new glue if it doesn't bite in good, it won't feather. The new glue will roll up and pull off the air frame when sanding. Here is the design (Color is not accurate) and few of the first few pics. I'll do this one as I go and not wait until the end like the Quest Courier and Estes Alpha Butild Theards I'll be doing. Enjoy.