Drag polars for three Micro Air Vehicles (MAVs) were measured at Reynolds numbers of 70,000, 50,000, 30,000, and 10,000 and compared to predictions generated using the classical approach. The MAVs tested had different configurations and aspect ratios varying from 1.2 to 1.6 and ratios of wetted surface area to planform area from 2.6 to 3.9.
A force balance was used to measure the lift and drag on the MAVs at angles of attack ranging from -5 degrees (or -10 degrees) to 10 degrees. The force balance allowed the MAVs to rotate in the pitching axis. The MAV angle of attack was set using an elevator installed on the MAV and controlled using a standard radio control used by RC plane enthusiasts. Uncertainty analysis performed on the data showed the uncertainty for high Reynolds numbers was dominated by velocity uncertainty, and uncertainty for the lower Reynolds numbers was dominated by uncertainty in the force measurements.
Agreement between measured and predicted drag polars was good with the measured drag never being more than two times the predicted drag. For the majority of the tests, the drag coefficients followed the expected Reynolds number trend: increasing with decreasing Reynolds number.
College and Department
Ira A. Fulton College of Engineering and Technology; Mechanical Engineering
BYU ScholarsArchive Citation
Luke, Mark Elden, "Predicting Drag Polars For Micro Air Vehicles" (2003). All Theses and Dissertations. 108.
Micro Air Vehicle, MAV, low Reynolds number, drag polar, predicted vs. measured, wind tunnel, force balance, Cfe, equivalent skin friction coefficient, e0, oswald efficiency, CL, minD, lift coefficient, drag coefficient, drag polar prediction, angle of attack, wetted surface area ratio, wing loading, aspect ratio, parasite drag coefficient, drag due to lift, aerodynamics