"Controlling yaw in a helicopter." Topic

Obviously with a conventional help with a tail mounted torque rotor or NOTAR blower it is easy, but what about the twin main rotor designs?
With main rotors fore and aft like the Sea Knight or Chinook I'm wondering if the pedals control a differential cyclic so if you want to yaw right the tail rotor cyclic is pulling the tail of the helicopter left while the front rotor is pulling the nose to the right.
Then there are twin rotor designs such as the Helix, Hokum and Kaman Huskie. They have conventional tail planes, but you need airflow over the control surfaces for them to operate so how do you control yaw at slow speeds or in the hover?
Any chopper jocks out there?

slow news day?

but what about the twin main rotor designs?

Don't the rotors contra-rotate for that very reason?

Yes they contra rotate to stop the main rotor torque turning the helicopter, but you need to yaw the helicopter to change its heading. That's why helicopters have pedals to control the tail rotor.

I always go to TMP for free legal and medical advice.
Now I can get free lessons in flying helicopters!

Wow everyone is in a real helpful mood today!

Mind you I am not a helicopter pilot, however a quick search for "how does a C-47 yaw" resulted in:
For helicopters with contra-rotating rotors—also known as Coaxial mounted—one over the other on the same rotor shaft (Like a Kamov KA-50), helicopter control requires interaction between the two rotors. However, a helicopter with tandem rotors—counter rotating rotors on different rotor masts (Like a Boeing CH-47 Chinook) uses differential collective pitch to change the pitch attitude of the aircraft. To pitch nose down and accelerate forward, the pilot decreases collective pitch on the front rotor and increases collective pitch on the rear rotor proportionally. Conversely, the synchropter and transverse-mounted rotor counter rotating rotorcraft have two large horizontal rotor assemblies mounted side by side, (like a Bell/Boeing V-22 tilt rotor) helicopters use differential collective pitch to affect the roll of the aircraft. All of these configurations use differential cyclic pitch to control movement about the yaw axis, tilting the rotors in opposite directions to cause the aircraft to spin in the direction of the tilted rotors.

A another detailed description can be found at:
link

Thanks. So I was right about the Chinook, differential cyclic pitch to control yaw. Looks like the the Hokum/Helix type helos use differential collective pitch to control yaw. Which makes sense as if my physics is right increasing the pitch of a rotor increases the torque it generates. So you increase the pitch of one rotor while decreasing the pitch of the other, the difference in torque between the two will cause the helo to yaw.

the rotor can change their pitch to swing the body around.

Yaw is controlled by pedals in a CH47 just like any other helo. They tilt the rotor disk to induce left or right yaw.

Los