Criteria for Control and Response Characteristics of Helicopters and VTOL Aircraft in Hovering and Low-Speed Flight

Criteria for satisfactory control and response characteristics of low-speed aircraft are presented and discussed. The basis for the discussion is the results of a study of the effects of various control power (angular acceleration per unit control deflection) and angular velocity damping on pilots' opinions and on pilots' ability to perform precision tasks during hovering and low speed. The control response characteristics resulting in large improvements in the capability of the pilot-helicopter combination, particularly during instrument flight are discussed. A variation of the criteria with aircraft size is presented. The applicability of the criteria to aircraft of varying types is illustrated