Originally Posted by
Ascend Charlie
Thinking out loud here:
The rotor is at idle or below.
The engine starts out at idle.
Agile pulls up on lever, the correlator will try to add throttle
Must hold throttle closed against the spring to keep correlator out of it, and engine stays at idle.
Agile then pulls pitch to get off ground. Supposedly gets to the hover.
How the fork can an idling engine, with 40% rotor RPM, lift the machine off the ground? It has enough trouble doing it at 100% engine and rotor RPM.
If engine is at idle, how can he get max MAP?
If he has max MAP, then he sure isn't at idle, which is around 13" by memory.
If the engine isn't at idle, then the RRPM aren't either.
I think this whole story smells of bovine excreta.
You got me thinking: with lift as a function of V^2, the rotor at 40% (this is back of the napkin math) isn't 4/10ths of normal (100% rpm) it is closer to ... 0.16 or so; granted, drag is also a function of V^2, so perhaps .20 to .25 rated lift/thrust/power is available from the rotor system ... if the rotor blades somehow retain their stiffness at 40% ... which they most likely won't. (Per the post much earlier about coning). My quick napkin calculation leads me to the following puzzle for our friend Agile: are we to believe that with about a quarter of the rated lift being available that the rotor has enough thrust to pick the bird up off of the ground (all other hazards and issues ignored for the time being)? There is only so much Angle of Attack increase that you can achieve, and I doubt that simple pitch increase would quadruple the available/potential lift. (I think blade stall would happen first). I'd love to see Agile's calculations on that.
Conclusion: your verdict of the
excretus bovus strikes me as spot on.