Originally Posted by
Fly Aiprt
Just to get a feel of it, the post above, of which helicopter descends faster, rotor turning or rotor stopped seems a fairly good analogy.
Not really an applicable comparison - when a helicopter looses power, the pilot is constantly varying the pitch of the rotor blades during the descent - initially it's to accelerate the rotors, then at just the right moment it's changed to convert the rotational energy of the rotor to lift in order to cushion the impact. Helicopter pilots constantly practice a simulation this maneuver since if they need to do it, they only get one chance to get it right...
Dave, I also have an old memory that a seized fan was a critical case for EROPS/ETOPS range due to increased overall aircraft drag - I can't readily resolve that against some of the comments here.
I do remember a reason the fan was locked in place during an engine failed ferry flight was that there may not be sufficient oil pressure generated to protect against bearing damage during an extended windmill.