P-47D serial 44-90219 bailed to the National Advisory Committee on Aeronautics (NACA) at Langley Field, Virginia following an inflight oil leak. Visible on the fuselage is the "buzz number" (PE219) and the first two letters of "TEST." The aircraft was used to test a number of different propeller configurations, this one being a 3-blade Curtiss Electric model. 1947.