The Franklin O-335 (company designations variations on 6A and 6V) was an American air-cooled aircraft engine of the 1940s.

The engine was of six-cylinder, horizontally-opposed layout and displaced 335 cu in (5.5 L).

These engines were commonly vertically mounted and used to power many early helicopters in the United States.

In various subtypes, the 6A4 remained in continuous production from 1945 to the time Franklin's United States operations ceased in 1975, with versions continuing in Polish production into the 1990s.

Data from Wilkinson [1] Comparable engines Related lists