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Originally Posted by C Sean Watts
...by that answer your research does not include Wankel, turbine or any propeller driven airplane? I ask to be sure we are all on the same page IE: ONLY piston/direct (no electric) drive, as there are VERY few constants accross the board. But, as always, F=MA, E=IR, PV=nRT etc. the rest are only 'favorite flavors'  BTW here's a little aside to muddy up the mix. In Gemrnay, and most EU, car engine max output is listed in kW (you mean they went back to the original derivation) - power defined in watts? |
...doesn't make any difference. If you have power at a shaft, HP= TxN/5252. You can get the same horsepower with high torque and low revs or low torque and high revs. Aircraft engines are rated by "shaft horsepower", which is the power at the output shaft that drives the propellor, so it includes the reduction gearbox, which is required for turbines and big recips.
To drive a ship or aircraft the power is applied to a propellor that delivers a propulsive force. In a car the propulsive force is generated at the tire/pavement interface.
At steady vehicle speed on level ground (or level flight) the required horsepower is equal to force times velocity in feet per second divided by 550. If you know the total drag force, that times velocity times propellor efficiency (in the case of aircraft and ships) times the proper conversions for dimensional homogeneity is delivered shaft horsepower. If more power is delivered the vehicle accelerates, if less it deccelerates.
Duke