Rotation of Kamow helis-how does it work?

[kapuhy]

I wonder how it is technically realised. I know how steering of typical helicopter works, how it rotor and blades are working, and everything should work the same in twin-rotor construction. Everything but turning around.

Any ideas? :)

[Yellonet]

I wonder how it is technically realised. I know how steering of typical helicopter works, how it rotor and blades are working, and everything should work the same in twin-rotor construction. Everything but turning around.

Any ideas? :)

Just increase/decrease the speed of one of the rotors and the the torque of the other rotor will swing the bird around.

[kapuhy]

So that would make Kamow helis only machines that use rotor rpm for steering instead of blades angle of attack. How technically realise quick rpm change? It's not very likely for me. I thought about incrasing AoA in one rotor while not changing it in the other one, but I'm not sure if it could work.

[arneh]

I'm pretty sure rotor RPM stays constant, and that it rather increases collective on one rotor and decrease on the other. That way one rotor will create more torque than the other and the helicopter will turn.

 

Increasing/decreasing rotor RPM takes too long and makes for sluggish controls, it is much faster to change collective.

[kapuhy]

You're right, incrasing AoA in every blades on one rotor should be corected by decrasing AoA in the other rotor blades-only then heli won't start to climb.

[britgliderpilot]

You're right, incrasing AoA in every blades on one rotor should be corected by decrasing AoA in the other rotor blades-only then heli won't start to climb.

 

Precisely - differential collective control is the answer.

 

This causes problems when you're not pulling any collective, though.