Pusher Propeller And Fuselage Wind Tunnel Testing Of A Generic Launched Effects Uninhabited Aerial Vehicle

Abstract

Aft-mounted, pusher propellers have become commonplace on fixed-wing uninhabited aerial vehicles (UAVs). The U.S. Army has a growing interest in these vehicles, as evident by the Launched Effects (LE) program. An experimental test was completed in the U.S. Army 7- by 10-ft Wind Tunnel at NASA Ames Research Center. A new test apparatus was constructed to evaluate the interactional aerodynamics of a generic LE vehicle fuselage and propeller. Pusher propeller performance data was collected and compared to isolated propeller data collected in the tractor orientation at various rotational speeds, wind speeds and pitch angles. General propeller thrust, power and efficiency trends were found to be consistent with previous works. The installed pusher propeller was found to consistently consume more power than the isolated at the same conditions, but only produced marginally more thrust at low advance ratios. This resulted in a small efficiency deficit for the installed pusher propeller, which decreased with increasing wind speeds. A computational fluid dynamics (CFD) model was created of the test apparatus in both pusher and tractor orientations and exercised at one wind speed and pitch angle. The CFD captured the magnitude of the efficiency well and displayed some of the trends seen in the experimental data.