Then, like a single, oddly shaped helicopter rotor, the blade begins to turn, slowly at first but then with more speed.
From the newscientist.com
Like a conventional helicopter, the single-turbine Cheyenne has a main rotor and tail-mounted stabilizing rotor for hovering and vertical takeoffs and landings.
From the time.com
Most helicopters have a single main rotor, but torque created as the engine turns the rotor against its air drag causes the body of the helicopter to turn in the opposite direction to the rotor.