This depends on the fuels used (Liquid Oxygen, Hydrazine, etc) the design contours of the nozzles (if we are talking about liquid fuel rocket engines, and pressure pumps, turbo-chargers etc in the...
It depends on what Crotch Rocket you buy, but most can hold one liter of the gas/oil mixture required to run it. One liter of gas/oil mixture will get you about 10 miles. CORRECTION:I have no idea...
The answer to your question is determined by the type of rock that you are referring to. There are many types that have specific purposes. There are homemade rudimentary rockets that are composed...