Comparing helicopter performance...
If I wanted to make a comparison of the "max performance takeoff" capabilities of various twin-engined helicopters, is there an easy way to 'normalize' the numbers for a quick comparison, utilizing a few parameters ?
In other words, its obviously not sufficient, nor accurate, to just compare max hover ceiling, or max engine SHP numbers off a manufacturer's spec sheet when trying to decide which aircraft will have the largest power margin suitable for your mission in a max performance takeoff scenario.
I figured if you knew certain parameters, you could roughly calculate a power required to hover, and a max power available, and the difference between the two showing up as available rate of climb.
Parameters such as the aircraft's transmission torque limits, rotor RPM, rotor diameter, your mission gross weight, and your atmospheric conditions would be involved... The answer is probably staring me in the face, I just cant find the equations I'm looking for. I didn't want to get into a full-blown "thrust coefficient / power coefficient" hover perf data reduction scenario, I just wanted rough numbers I could more easily compare aircraft in a given scenario.
Thanks.