Originally Posted by birddog
SAS, could you please elucidate what you mean by the above for those of us who are less erudite than yourself?
birddog,
As SASless said (about auto RPM checks), there is an auto RRPM checking procedure within the maintenance manual for nearly all helicopters.
Basic procedures are to set a stable auto at flat pitch (minimum collective) and datum IAS, then record at a specific Density Altitude the aircraft weight, OAT and RRPM (and maybe one or two other parameters). After landing a check with the appropriate graph in the MM will give the target auto RRPM for that height and temperature which is corrected for weight. Compare target auto RRPM to the recorded auto RRPM, and adjust equally all blades to increase/decrease auto RRPM. Repeat check flight until autorotation RRPM is within set parameters.
If the helicopter isn't set up iaw the manufacturer's auto RRPM specs, you'll be chasing your tail trying to perfect your auto technique, IMO. You may have either a high auto RRPM or worse, very low auto RRPM, and be unable to get the required autorotational performance from your helicopter.