How do counter-rotating helicopter blades work?

Question

At first guess, from looking at photos of counter-rotation blades, I would imagine that there is a gear system which changes the rotation of one set of blades (on a common shaft) in the opposite direction to the other set of blades.

Does anyone have a clear way of explaining this to me? Or better yet, does anyone have a diagram of the internal workings of the counter-rotation process?

Answer 1

Some Soviet helicopters actually had one rotor mounted over another on the same transmission, but with two rotor shafts, one inside the other. Not a very popular design. The U.S. Military uses only one chopper with dual rotors, mounted fore and aft, this is the CH47 Chinook. This aircraft uses two separate transmission systems. The obvious goal is to increase payload, while eliminated rotor torque (rotors turning opposite of each other cancel out torque). However, most designs have proven to be highly maintenance intensive, and therefor too costly for civilian use. The rest of us are stuck with a tail rotor.

Answer 2

Counter Rotating Helicopter

Answer 3

This Site Might Help You.

RE:
How do counter-rotating helicopter blades work?
At first guess, from looking at photos of counter-rotation blades, I would imagine that there is a gear system which changes the rotation of one set of blades (on a common shaft) in the opposite direction to the other set of blades.

Does anyone have a clear way of explaining this to me? Or...

Answer 4

Hi. Imagine an eggbeater. The blade rotate in opposite directions but are geared so as to not hit each other. This would be like the two bladed helicopters you have seen. The V22 Osprey has two blades that tilt and at least one has two stacked blades that rotates in opposite directions. : http://www.cybercom.net/~copters/mech/tail_rotors.html and http://en.wikipedia.org/wiki/Kamov_Ka-50