just a little more on props, as most of you will probably already know....... but here goes.....the prop has to absorb the engine power, the bigger the engine the bigger the prop and or more blades, ok so far?... but..... the blades can only be of a certain length because of the tips speeds, ie if they approach the speed of sound you get all sorts of aerodynamic problems, so add another blade he says, then the problem is when the blades are too close together the air is too disturbed for the next blade to obtain any 'lift'. next answer was the counter rotating prop but by then the gas turbine eng was taking over........the rest is history.
cheers guys, us girls aint all dumb blondes
