Nick,
Thanks for your response, very little is written about the tail rotor, and I got some pretty blank expressions on the faces of other drivers who couldn't explain it either,being an engineering student and a rather curious person, my enquiries drew a blank, particularly the flapping.
On the Dauphin, stationary, the tip clearance around the fenestron varies, like an oval, in flight this distortion is evened out by the distortion of the fin.
In Commanche, is this the case, where flight loads 'twist' the tail and change clearance of the blades, or has technology beaten the old French design?
Would I be correct in saying that Frank Piaseckis flying jeeps were the same principles of two fenestrons turned over, or where they different too?