Future rotorcraft control systems

[Graviman]

MaxTork,

I've been thinking about your system, and i think it may have merit. It might be worth sketching out some of your ideas, so Dave can post them on his site. It would struggle with some of the inverted flight threads on this forum, but we are only talking R22. It would need careful packaging, but may well be possible to incorperate it into the gyro system i am proposing.


"The flyweights would be allowed to swing outward with increased RRPM and when they do they would be linked to the pitch horns and could increase blade pitch."

The system "gain factor" needs to be very high. Since RRPM is constant in theory flyweights would be at same swing. This means that autorotation may still be lower than nominal RRPM, albeit marginal. Ideally you want the RRPM to be controlled by error correction, which implies active.

"With this system if you lost engine power the collective would automatically be lowered due to the flyweights retracting (under action of a spring) from reduced RPM."

True enough. I think you need a robust mechanism for flaring though, which must feel natural to a pilot already potentially stressed. I can see problems triggering the magnetic clutch.

I suspect in the real world this system may be an ideal candidate for electric control though (like throttle already is). Probably the pilot needs direct control over collective, with a system to assist the pilot make the right choices. Gas turbine power curve lagging could be cured with the system i'm proposing resisting pilot input (although he can over power it). The pilot would soon learn to anticipate the response, but would not feel he was only taking a vote in collective control.

Actually gas turbine lag is a good justification for a hybrid helicopter, using electric motors as suggested by Dave J. Motors would be directly coupled to gearbox, and would make up RRPM errors left by turbine response. If powerful enough variable RRPM strategies allow much higher figure of merit across rotor required thrust range.

Mart

[Edit: speelin]