Originally Posted by
John Eacott
For you to allude to a drop to 60%Nr can be considered is a bad move on a helicopter forum, since it can morph into an assumption by some and then, before you know it, we're into the 30 minute S92 run-dry scenario where it becomes a firm belief.
I hope that you can see the sense in modifying your post to remove your reference before it becomes assumed to be valid.
Hmm, I'm a bit confused. My Point was exactly that I think assuming 60% might be recoverable is very dangerous grounds. I would consider everything below 75 - 80% sustained as potentially irrecoverable.
When doing the Maths 1g at 60% corresponds to 2,78g at 100%. Even taking into consideration drag effects of the cabin /airframe itself in a rapid descent this means a very significant AoA of the rotor system. Doubtful if you can achieve autorotation at such angles.