Chapter Review

This chapter has summarized the unique technical characteristics of the autogiro or gyroplane. A truly innovative form of rotorcraft, in 1923 it was the first powered, heavier – than-air aircraft other than a conventional airplane to fly successfully. It was also the very first type of successful rotating-wing aircraft and was really the genesis of the helicopter. While the early autogiros certainly had many shortcomings and encountered many technical hurdles, the developers adopted a systematic, step-by-step approach and made many engi­neering contributions to rotorcraft technology on both practical and theoretical fronts. The most significant was clearly the development of the articulated rotor hub, with the incorpo­ration of flap and lead-lag hinges and later the complete control of the aircraft by tilting the rotor plane by using cyclic blade pitch. The autogiro era also produced the first theories of rotor aerodynamics, rotating blade dynamics, structural dynamics, and aeroelasticity and provided the foundation for many of the rotating-wing analyses that are used today.

While the autogiro has not yet become a commercial success, today its principles are being combined with current technology and innovative forward thinking to create ambitious new autogiro designs. If the innovations of the autogiro can be combined successfully with the capabilities of the helicopter and also the speed and range attributes of a fixed-wing aircraft, then modem gyroplanes could be used to meet a wide variety of military missions and civil applications. Clearly, significant gains in the performance of the autogiro are possible using optimized airfoil sections, blade shapes and planforms, composite structures, advanced flight controls, and efficient new engines. However, to achieve the flight speeds necessary to operate effectively in military applications or as a short-range transport will require load sharing with a conventional fixed wing. Only time will tell, but a renaissance of interest in the unique capabilities of the autogiro and gyroplane can only but benefit from both the technical knowledge and the powerful mathematical design tools that have evolved over the last fifty years of helicopter development.