Low Reynolds Number, High-Lift Airfoil Design for VTOL UAVs

A complementary, theoretical and experimental effort to design and verify high-lift, low pitching-moment airfoils for VTOL UAVs is proposed. In Phase I, an accurate, rapid, test capability will be validated over the range of Reynolds numbers from 50,000 to 500,000 by investigating the E 387 airfoil, the low Reynolds number calibration standard, in The Pennsylvania State University Low-Speed, Low-Turbulence Wind Tunnel. The E 387 airfoil exhibits almost all the pertinent phenomena over the Reynolds number range of interest, making it a sensitive test case, particularly with respect to turbulence effects, a key issue for VTOL UAVs. The section characteristics measured with transition free and fixed will be compared with results from other low-turbulence wind tunnels and with predictions from the Eppler and XFOIL/MSES codes. The initial specifications for the airfoils to be designed in Phase II will be defined in cooperation with U.S. Army personnel. In Phase II, the experimental results will be used to refine existing airfoil design and analysis methods and for CFD code validation. A set of airfoils will be tailored to VTOL UAV applications and experimentally verified. The slotted, natural-laminar-flow (SNLF) airfoil concept will be adapted to VTOL UAV applications.