In my other question I was looking for a relation between the forward speed and the thrust (lift) of an auto-gyro.

I have come to the conclusion that for an auto-gyro in auto-rotation the forward speed will rotate the rotor and with that regulate its rpm. The faster an auto-gyro flies the faster the rotor rotates resulting in a higher thrust.

What I hope to accomplish is forward braking where the auto-gyro flies faster than needed to provide sufficient thrust, resulting in a higher rotation speed which will then result in more thrust and lift the auto-gyro up. This additional thrust isn't needed as the same level is required. By braking the rotor, using a generator, the rotor speed is reduced till the point it is still able to maintain level using auto-rotation. For this theory I need to understand the relation between the forward speed and the rotation speed.

But it is still not completely clear how this forward speed relates to the rotation speed. I hope someone can explain it to me or point me into the right direction.

I might be completely wrong and came to the wrong or inconclusive conclusions if so don't hesitate to tell me.

Thanks in advance!


1 Answer 1


An autogyro flies at constant rotor RPMs. In vertical autorotation, that is a particular case, the rotor revs may be 10-15% less, but in straight and level flight, the rotor revs are higher, and always the same, independently of the speed of the gyro. It cant be otherwise, since, if the rotor revs went higher with the speed, the rotor thrust would also rise, and the gyro will gain altitude, no longer flying straight and level...

It's also true that if, flying s/l, the pilot opens the throttle, he also pushes the stick slightly forward in order to reduce the AoA of the disk, and thus keep flying s/l...


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