The Convair 580 also runs an Allison. Because the aircraft is not supported by a proper simulator, we only got to pretend we were asymmetric in the real aircraft and at low training weights. We never got to explore the NTS range - in fact we never got below 400 hp because apparently there was a risk of the drive decoupling if the prop got into a range where it was 'driving' the engine.
During the flare, if the power was pulled off too quickly it sure felt like a lot of prop drag was affecting things. The aeroplane would fall to earth like a ton of bricks,as I found to my great embarrassment one day when I had a Boeing flashback and pulled it to flight idle at about 30 feet. Quite the worst landing I have ever done in a transport aeroplane!
Some Garrett aircraft appear to behave the same way. I vaguely recall that a Metro crashed on final approach somewhere in Australia due to either the NTS not working or somehow being over ridden. More recently we lost a Brasilia during a training exercise where it appears that the windmilling prop contributed to a loss of control on takeoff.
All the RR Dart setups will go to the flight fine pitch stops at low power lever angles and they also have a minimum torque limitation in flight to protect the reduction gears .
So, I dunno, but I think most prop installations end up producing drag with power lever(s) deliberately set to flight idle, otherwise how do we get the aircraft to achieve its advertised landing performance?. Obviously from the post above, there are some aircraft where that is not the case. Maybe the aerodynamic experts can wade in with a more erudite explanation.
Last edited by Mach E Avelli; 1st May 2014 at 23:21.