Experimental investigation of the rotor-wing aerodynamic interaction in a tiltwing aircraft in hover

Abstract

The hovering performance and the lifting capability of tiltrotor aircraft are strongly affected by the aerodynamic interaction between wing and rotors. The tiltwing concept represents a promising technology to increase the hover performance by reducing the wing-rotor interference. The present work describes an experimental activity carried out on a ¼ scaled tiltwing aircraft half-model to achieve a detailed insight about the main issues characterising the aerodynamic interaction between wing and rotor in hover. The results of the experimental campaign, including both force measurements and Particle Image Velocimetry surveys, enabled to evaluate both the aircraft performance for different configurations of the tilting wing and to achieve a detailed insight about the flow physics of the rotor wake in the interaction with the wing. The test activity provided a comprehensive experimental database that was obtained over a not confidential aircraft configuration.

Assessment of a Mid-Fidelity Numerical Approach for the Investigation of Tiltrotor Aerodynamics

“…Consequently, tiltrotor aerodynamics are characterised by complex interactions between the rotor wake and wing that are peculiar of the different attitudes experienced by the vehicles during their flight mission. Several experiments have been conducted to investigate rotorwing interactions, from the early stages of the JVX program [1,2] to the present day [3,4].…”

Proprotor–wing aerodynamic interaction in the first stages of conversion from helicopter to aeroplane mode

“…This solution also allowed to test alternatively the isolated rotor and the half-span model. Furthermore, the experimental rig design permitted to test the model both in hovering [27] and during the first stage of the conversion manoeuvre. A geometrical scale of 1/4 with respect to the full-scale aircraft was used to design the wind tunnel model.…”

“…The relative distance between the wing rotational axis and the rotor hub (h/R) was 0.465 and was kept constant during all the tests presented in this paper (this value corresponded to the h/R design value [27]).…”

“…A wind tunnel half-span powered model of the reference tiltwing aircraft was designed and manufactured at the Department of Aerospace Science and Technology (DAER) Aerodynamic Laboratory [25,26]. A comprehensive experimental campaign focused on the hovering flight condition, including forces and flow field measurements, was conducted by the authors [27,28] to study the effects of the partially tilting wing solution on the overall aircraft performance. Experimental data and numerical results confirmed the effectiveness of the tilting wing solution for download alleviation maintaining good aircraft performance in hover.…”

Aerodynamic shape optimisation of a proprotor and its validation by means of CFD and experiments

“…An experimental model (33,53) of the optimised proprotor was realised at the DAER Aerodynamics Laboratory of Politecnico di Milano. Since the geometrical scale of the model was ¼ with respect to the full-scale aircraft, the rotor radius of the model was 0•925m.…”