Engineering Analysis of the Helicopter Designs of the Marquis Raul Pateras Pescara

摘要

The Marquis Raul Pateras Pescara (1890-1966), an Argentine nobleman who worked on helicopters in Spain and France during the 1920s, is mostly known in the helicopter field for his technical contributions to methods of achieving effective flight control. Often heralded as the first to implement cyclic and collective blade pitch control into a prototype helicopter, Pescara was able to achieve roll, pitch, and yaw control over his helicopters solely through blade pitch variations in his rotor systems. Additionally, Pescara was the first to recognize the phenomenon of autorotation, and how a pilot should control an unpow-ered helicopter in the event of engine failure. Adopting a coaxial rotor system with biplane blades for his four helicopter variants, Pescara achieved collective and cyclic pitch angle variations through warping displacements of the torsionally compliant blades. Despite several serious crashes, and a mechanically complex and less than effective control system, Pescara was able to pilot his helicopters and demonstrate modest levels of performance. His most notable flight was the Federation Aeronautique Internationale (FAI) straight line record flight of 2,415 feet (736 meters), which was set in France during April of 1924. Pescara also dabbled in hybrid forms of aircraft, coupling vertical takeoff capabilities using a vertically thrusting rotor with a fixed wing to provide lift during forward flight. Despite his technical innovations, and over 30 patents relating to rotating wing technology, Pescara eventually abandoned his helicopter experiments in the mid-1920s. Although he never was able to refine his helicopters to a point of true practical success, Pescara was arguably the first pioneer to build a prototype helicopter that addressed all the aspects of lift, propulsion, control, and stability, both in powered flight and in autorotation.