Print Email Facebook Twitter Wing deformation measurements of the DelFly II in different flight conditions Title Wing deformation measurements of the DelFly II in different flight conditions Author Heitzig, Dorian (TU Delft Aerospace Engineering) Contributor van Oudheusden, B.W. (mentor) De Breuker, R. (graduation committee) de Wagter, C. (graduation committee) Olejnik, D.A. (mentor) Degree granting institution Delft University of Technology Programme Aerospace Engineering Date 2019-08-30 Abstract This study investigates the wing deformation of the flapping-wing micro air vehicle (MAV) DelFly II in various flight configurations. Experiments were carried out with the MAV tethered in a windtunnel test section. To determine the best suited measurement approach, a trade-off study was carried out which showed that a point tracking approach with background illumination is most suitable. The therefore used high-speed camera pair and illumination were mounted on the same rotating frame with the DelFly, which allowed adequate viewing axes of the wings at for all pitch angles. Processing was done a purpose-build algorithm, allowing 136 points per wing to be measured simultaneously with an average lost point ratio of 3.4 % and an estimated accuracy of 0.25 mm. Results of hovering flight show some previously unnoticed behaviors. First, it was noted that the upper and lower wing on each side do not deform purely symmetric but show some considerable asymmetric behavior like heave and camber production. Furthermore, the upper wing shows a torsional wave and recoil behavior at faster flapping frequencies, which was shown to be beneficial in insect flight. Lastly, it was found that an air-buffer remains present between the wing surfaces at all times of the clap-and-peel motion (apart from the root trailing edge). This air-buffer increases once freestream velocity is added, which is investigated during the climbing flight study. Here, the reduced angle of attack of the wing is assumed to reduce the wing loading at faster climb, resulting in lower deformations outside the clap-and-peel motion. The isolated effect of a body pitch angle is also studied. Here, the asymmetrical freestream direction results in larger asymmetries such as wing alignment with the freestream direction and reduced camber and even camber reversal during the upstroke. In forward flight the pitch angle is changed simultaneously with the flapping frequency and freestream velocity. Due to the non-linear properties the wing deforms not directly as a superposition of the individual effects. Deviations are mostly present in increased asymmetry in incidence angle, while the camber behaves more linear and the clap-and-peel motion also remains relatively unchanged. The torsional wave and recoil are here however reduced. Descending flight was also tested. Velocities below 1m/s result in relatively minor deformation changes, while faster descent leads to large flapping frequency fluctuations, making interpretation of the results impossible. Subject DelFlyFlapping WingDeformationFluid Structure Interaction To reference this document use: http://resolver.tudelft.nl/uuid:cc607dbb-7116-4c9f-991f-988d832833a9 Part of collection Student theses Document type master thesis Rights © 2019 Dorian Heitzig Files PDF Thesis_Dorian_Heitzig.pdf 34.87 MB Close viewer /islandora/object/uuid:cc607dbb-7116-4c9f-991f-988d832833a9/datastream/OBJ/view