Depends on many things, especially the TR thrust required, Soave. In a hover OGE, the losses might be: TR 4 to 5%, Transmission losses 2 1/2%, accessory loads 1%. Total 8% or so. In cruise, the TR is perhaps 2% and the rest that same.
Anyone flying a Bell with mast torque vs engine torque needles want to provide some more precise data?
Thanks, that's what I had in mind it would be (around 10%).