Originally Posted by
donut king
Yes, all works as described. Have used the 107nr in cruise when remaining fuel was on the minimums. easily "made" 50-80 lbs on landing from long sectors. Nick, isn't there also a TAS gain in cruise........107nr for same power setting as 100nr yields "flatter" blade pitch....less drag????
DK
That is one way to describe it donut king (love the name!), but it is easiest to see it as the fact that with higher tip speed at higher Nr, the retreating tips are quite a bit less stalled (yes, less collective pitch as well) and so they don't waste as much power on induced power from the excessive angle of attack.
This is the big compromise for helo designers, having a very efficient hover rotor (which favors heavily loaded blades and higher collective, near the optimum L?D) vs high speed cruise (which favors wide blades, lightly loaded and nowhere near stall.)