Originally Posted by
Jack Carson
As a quick reference one can calculate the power required to drive the complete system based on the flat pitch torque. As examples – the B206L L4 takeoff limit is 100% Q 450 ESHP. Typical flat pitch Q is 15% or 67.7 ESHP. Similarly the H-53E takeoff limit is 137% or about 13000 ESHP. The H-53E flat pitch torque on all three engines is approximately 20% each or about 1900 ESHP just to drive the system.
But of this 15-20% a big part comes from drag. If you run it at 100% Rpm without main- and tail blades you get a much lower value on torque.