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Module 12. Helicopter aerodynamics, structures and systems

How do the rotors turn on a co-axial rotor system?

  • They counter-rotate on a common shaft.
  • Both rotate in the same direction on a common shaft.
  • They counter-rotate on separate shafts.

Explanation

A co-axial rotor system has two main rotors mounted one above the other on concentric (separate, nested) shafts turning in opposite directions. The counter-rotation cancels torque so no tail rotor is needed. They are not on a single common shaft and do not turn the same way, otherwise their torques would add instead of cancelling.

harbhla asking:

Ithink they counter rotates on seprate shafts

Community Comments (4)

D
dimky Posts: 514 23.09.2012 / 20:42
I also think so, changed to "separate shafts".
B
Bruno Santos Posts: 1 23.03.2017 / 15:55
If you look at helicopter Kamov is co axial and counter rotates on same shaft
D
dimky Posts: 514 23.03.2017 / 16:16
Bruno, maybe you mean on same axis but different shafts?
J
Jordi Posts: 198 01.09.2021 / 11:29
the correct answer is that generally and not in Kamov in particular as Bruno mentions,is that they counter rotate on seperate shafts.

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