I had some inspiration, being an "The Expanse" cable show fan, and decided to try building an MCRN (Martian Congressional Navy) torpedo. I used Rocksim for the first time, and this is what I am going to try and build...
Original picture from the show:
The Rocksim image:
Length is 24.75" long, loaded weight is 5.46 oz. Stability margin while loaded is 1.68.
I had initially thought to use clear plastic fins, but after researching the difficulties in a) finding the correct polycarbonate, and b) attaching the fins with epoxy, decided to stick with the more familiar balsa fins. I am rationalizing that while the torpedo is intended for space use (which is all we see in the show anyways), that it has small pop-up fins for use against upper atmospheric targets.
I plan to use an D12-5 to power the rocket, and it should go about 725 feet high.
The biggest challenge right now is finding suitable decals/wraps.