Wing-Rotor Interactions on a 1/4 - Scale Tiltrotor Half-Model

In a tiltrotor aircraft, the aerodynamic interaction between wing and rotors can have a negative influence on the hovering performance and on the lifting capability. In 2011, a research activity has been started at Dipartimento di Scienze e Tecnologie Aerospaziali at Politecnico of Milano to study from both an experimental and numerical point of view the aerodynamic interference between wing and rotor on a tiltwing aircraft. A 0.25 scale model, based on the aircraft geometry defined at the very beginning of this activity, has been manufactured in–house and the experimental test rig represents only one half– wing and the corresponding rotor and nacelle. The rotor performance were evaluated in terms of figure of merit both for the isolated rotor and for the half–model configurations. Two different wing configurations (untilted and tilted) were tested to understand how the airframe affects the rotor performance. The forces generated on wing by the rotor wake were measured for a wide range of thrust coefficients for both wing configuration. Particle–image velocimetry technique was used to acquire two–dimensional images of the flow field close to the tilted part of the wing.