Direction of Rotation

Most modern American helicopters have rorors that turn so that the advancing blade is on the right, but many European helicopters use the other rotation. At one time, it was thought that a pilot trained in one type would have trouble making the transition to the other because the pedal motion required to compensate for changes in rotor torque would be different. Today, enough pilots can fly both types on the same day that the argument seems no longer valid. The explanation is that the pilot instinctively does the right thing with his feet to hold heading. This is certainly true near the ground with good visibility, where the directional cues are very strong. Only at high altitude or in degraded visibility conditions might he revert, when making power changes, to pedal actions more appropriate to the helicopter he learned to fly than to the one he is now flying. It is thought that this should not be a strong factor and that the designer should feel free to choose the direction of rotation that will result in the lightest transmission, especially if the design also includes mechanical coupling between main and tail rotor pitch to minimize the pilot workload, as is true of many of the recent Sikorsky designs.