Originally Posted by CPMcGraw

It took me awhile to figure out what name to give this one, but "DUALIST" kept sticking to my few brain cells...

The main diameter is ST-10, but it has twin ST-5 motor tubes. There is a lot of balsa removal in this design. Each of the motor tubes begins with a nose cone, but the cones are hollowed out to fit around another nose cone in the tail of the main body tube. This nose cone is also hollowed out to fit the two tubes. The motor tubes, obviously, need to vent into the main tube for parachute deployment.

It's not the clearest view of the arrangement, sorry, and what you'll wind up with is far less than what you start with. Hardly enough to even call them cones. An alternative is to just start with balsa blocks and sand them down to a visually pleasing shape that blends the whole mess together.

Power is two 13mm motors. You could probably use 1/2A3-4Ts and get reasonable flights (combined you get roughly the power of a single A3-4T). I don't know what the outcome might be if you only get one motor to light, but that's an issue for prepping.

Enjoy!