 For takeoff, landing, and low-speed flight, the rotor was driven by air delivered by the superchargers and burnt with fuel in blade-tip mounted pressure-jets.This zero-torque rotor drive did not require a compensating anti-torque system, though the collective pitch of the wingtip-mounted propellers was controlled by the rudder pedals to provide yaw control.As airspeed was gained, the rotor drive system was shut down, allowing the rotor to autorotate while the propellers provided the necessary thrust.