1/10th Scale Model Tests of a Centre-line Tiltrotor: Conversion between rotary and fixed wing modes

摘要

In the centre-line tiltrotor configuration considered here, the rotors are mounted on the aircraft centre-line to allow the wings to be optimised without the constraints of carrying wing tip mounted rotors. Both approaches (wing tip mounted and centre-line mounted) provide the major advantage of speed and range over other edgewise operating rotorcraft. As described elsewhere, the centre-line configuration offers the additional important benefits of a more compact, agile design with improved field of view. The challenge is optimising the aerodynamics and control of the proprotors and airframe for rotary and winged flight over the complete flight envelope, and in particular the conversion process between helicopter and airplane modes. A 1/10~(th) scale model of a centre-line tiltrotor is being used. The airframe will develop to have the same general layout as that proposed for the full scale aircraft but targeted for a 10 kg take-off weight and to be operated safely within the flight envelopes of conventional fixed and rotary wing radio-controlled models. The test programme has four stages of investigation: hover rig, helicopter mode, airplane mode, and conversion. For the hover rig, the airframe is reduced to just landing skids so that it is flown as a meshing rotor helicopter. For the helicopter, airplane and conversion testing, the full fuselage and fixed wing surfaces are used, with a conventional wheeled, fixed undercarriage. The conversion testing starts with the rotors tilted to different fixed. For the full mode the pilot is free to fly all the flight modes, using conversion as appropriate. Flight test results to date are discussed.