WING-ROTOR AERODYNAMIC INTERFERENCE ON A TILTWING AIRCRAFT IN THE FIRST PART OF CONVERSION MANOEUVRE

摘要

A tiltrotor is an hybrid configuration aircraft that can alternatively fly like a helicopter and an aeroplane being able to take-off and land vertically and to flight in cruise at high speed. Such a machine has the potential to revolutionise the air transportation since it would combine the flight performance of modern propeller driven aeroplanes with the versatility and control characteristics of common helicopters [1]. Aeronautical industries, research institutions and universities had investigated the tiltrotor concept for more than forty years, working out most of the basic engineering problems. Successful designs, such as the XV-15, V-22 Osprey and AW609, gave a new pulse to the research on this type of hybrid aircraft but several different areas need further development and analysis. One of the most important features characterising tiltrotors is represented by the aerodynamic interaction between wing and rotor. This phenomenon has been broadly investigated using both experiments [2, 3] and calculations [4], although analyses were mainly focused on helicopter operative mode and hovering condition. Moreover, many research activities have been developed in order to reduce the download force acting on the wing caused by the interaction with the rotor wake [5, 6]. In this framework, the research project ERICA (Enhanced Rotorcraft Innovative Concept Achievement [7]) founded by the European community was started at the beginning of the 2000s. The main objective of this project was the design of an innovative aircraft employing the tiltwing concept [8] and using a modular wing that can be partially rotated. Even though this aircraft configuration was widely studied [9, 10], an in depth analysis of the partial tiling wing solution in conversion manoeuvre is necessary.