[1] In 1931, the V-770 design was built, derived from the Ranger 6-440 series of inverted inline air-cooled engines, and test flown in the Vought XSO2U-1 Scout.

In 1938 it was tested in the Curtiss SO3C Seamew but was found to be unreliable with a tendency to overheat in low-speed flight, but would still be the most produced aircraft to have the V-770, with 795 being built.

[4] By 1941 a more developed V-770 was installed in the Fairchild XAT-14 Gunner prototype gunnery school aircraft, which went into limited production as the Fairchild AT-21 Gunner, of which 174 were built, not including one radial engine prototype.

The engine was used in very few aircraft, among them the short lived Fairchild AT-21 twin-engine bomber trainer,[6] and in the two Bell XP-77 light-weight fighter prototypes.

Data from Janes Fighting Aircraft of World War II (1989).