NACA altered this Fairchild 22 almost beyond recognition making it a low-wing plane! Some sources suggest that NACA had three or four F-22s, but photos prove that NACA 60 was tested in different configurations. However, a different airframe was procured through the US Navy in 1935, becoming NACA 82. That one had a Warner Scarab radial engine, USN designation XR2K-1 (not XR2L-1) and BuNo 9998. Photo by: Carl Mydans / Life

0627 was a BT-1 converted to the XBT-2, the progenitor of the Douglas SBD Dauntless. Its first flight as the XBT-2 was on 22 April 1938. It was assigned to NACA's Langley Memorial Aeronautical Laboratory in February 1939 for full-scale wind tunnel tests. The XBT-2 had the characteristic perforated flaps, but here they appear to have been replaced. Photo by: Carl Mydans / Life

The prototype of DC-5, later with registration NC21701. This sole prototype became the personal aircraft of William Boeing, who named it Rover. It was later impressed into the US Navy and converted for military use as an R3D-3 variant in February 1942. Photo: McDonnell Douglas Corporation.