jim beam

sorry for my bad english and this is properly not the right thread for this type of question i thinking about a alternative for a rocket turbo pump motor (just thinking) i shoud be easy to construct, reliable and "cheap" i ended with a combustion engine fed with compressed air (nitrogen/ oxygen mixture) and gasoline of corse sounds stupid, but i think i coud work. a very simplified calculation: e.g. a 1l 4-stroke engine engine shoud breathes @ 10k rpm 5000l air per minute, burning duration 240sec -> 10000l air can easy compressed to 300bar (as far as i know) -> a ~34l pressure bottle (and small amount of gasoline) should be enough for 240 sec run-time. for performance tuning of the combustion engine the use of slightly more oxgen in mixture than normal air shoud work to (until the motor burns ) advantage: - relatively lightweight - reliable - easy to constuct (modification of existing motors) - easy throttling and restating - relatively high efficiency ?! complete nonsense or something that might work ? (e.g. for projects like http://copenhagensuborbitals.com) some (usefull) respond would be nice! best regards