neubie need engine size explanations
ok lets see
.12 to .26 engines are usually used for nitro cars and trucks
.12 way up to 3 can be used for airplanes
.30 to .90 engines are for helicopters
now as far how much horse power a engine procuce depends on a lot of things first is manufaturer...You can buy an high quality .21 engine that will beat the crap out of a cheap .26 engine....
you would have to be more specific on what information you are looking for...