Hi all, I've got a scratchbuilt design in mind, using BT-80 tube. It's big and heavy (for a model rocket), so I'd like to fly it on either a D/E 24mm engine, or on a cluster of 4-5 18mm motors. My question is, can two motor mounts be made such that they can be swapped out for each other in a BT-80 tube? Seems to me that there are three problems: 1) Giving the engine mount something to push against in the rocket, 2) Making sure the engine mount won't eject itself, and 3) Making the whole thing strong enough to take these engine loads. Suppose I built one of the engine mounts (let's say the cluster) into a BT-80 tube coupler. So, let's say 5 18mm standard engine mount tubes, centered in the tube coupler with custom-cut cardboard centering rings. If I used epoxy, I'll be the engine mount itself would be plenty strong. It's not significantly different from gluing the engine mount directly into the body tube, right? If I glued a slice of BT-80 tube coupler into the rocket's body tube (like a really wide engine block), I would think that the engine mount would push nicely against this "engine block," solving problem 1. But how to keep it from ejecting itself? I'd much rather use that ejection gas to, say, deploy the recovery device Same approach would, I think, work for the 24mm engine mount. Solving problem 3 has be a bit stumped, though. Any suggestions? Thanks.