Originally Posted by
Uplinker
Would a simulated engine failure and subsequent auto-rotate landing dangerously unload the head?
In case of a (simulated) engine failure a 'typical' way to get to mast buming in an R22/44 is idfferent to what I described above. Normal procedure in an engine failure would be to lower collective and move cyclic aft. The latter will ensure continued loading of the disc.
Especially the R22 has a second feature that may lead to critical situations in case of (simulated)engine failure. It has a low inertia rotor. This means that Rotor RPM will drop off quickly in case of (simulated)engine failure. If lowering of the collective and aft cyclic isn't applied quickly enough, Rotor RPM will drop quickly to a point where progressive retreating blade stall (noth the whole balde will stall at once - it will start at the inner part and progress outward) will occur. As you know from fixed wing a stall means massively increased drag and reduced lift. This will further reduce RRPM down to the point where the rotor blade will stall over a wide span on the retreating side while the advancing side still happily produce lift. This will massively tilt the disc towards the rear on the side of the retreating blade. Again this can develop to a point where a blade would hit the teeter stop and slice through the tail.