OK, humanities guy here trying to puzzle out some possibilities for a forgotten weapon from 1863. I have an early brass torpedo measuring 72" long and, after boring out the inside, carving some channels in the outside and hollowing out part of the nose, weighs in at 480 lbs (with fuel; 274 lbs empty). For various reasons, I believe that only the nose cavity and half the bore were used for fuel, which would occupy 1.89 CF. The fuel is what used to be called "rocket composition," (RC) that being regular black powder compressed to about double its usual density. This space could therefore hold about 206 lbs of RC. This stuff expands upon combustion by a factor of 471 and would generate 889 CF of various gasses. This is all boilerplate, verified by modern and period sources. My question is: what speed and what range could be expected of this missile? Failing that, how many cubic inches (or feet) of RC might be consumed to drive the projectile "x" feet? I guess what I really need is to know is what psi of gasses will move this thing? The inventor got it up to 50+ mph and supposedly reached "cannon shot range," which was 1000 yards--phenomenal for this period.