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 . The power output of later variants was .

Design and development

These engines were commonly vertically mounted and used to power many early helicopters in the United States. They were closely related to the 2A4 and 4A4 2- and 4-cylinder engines. 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. In 1947 this engine was modified into a

water-cooled Cooling tower and water discharge of a nuclear power plant Water cooling is a method of heat removal from components and industrial equipment. Evaporative cooling using water is often more efficient than air cooling. Water is inexpensive and no ...

version by the

Tucker Car Corporation Preston Thomas Tucker (21 September 1903 – 26 December 1956) was an American automobile entrepreneur. He is most remembered for his Tucker 48 sedan, initially nicknamed the "Tucker Torpedo", an automobile which introduced many features t ...

for use in the 1948 Tucker Sedan. Tucker liked the engine so much that he purchased the Aircooled Motors/

Franklin Engine Company The Franklin Engine Company was an American manufacturer of aircraft engines. Its designs were used primarily in the civilian market, both in fixed wing and helicopter designs. It was briefly directed towards automobile engines as part of the Tuck ...

, and it remained under the ownership of the Tucker family until 1961.

Variants

;O-335-1:Military designation of vertical installation model for helicopters : ;O-335-3:Similar to -1 but changes in starter installation ;O-335-5: ;O-335-5B: ;6A-335: at 2,800 rpm ;6AL-335: at 2,600 rpm ;6A4-125: at 2,200 rpm ;6A4-130: at 2,200 rpm ;6A4-135: at 2,450 rpm ;6A4-140: at 2,375 rpm ;6A4-145: at 2,600 rpm ;6A4-150: at 2,600 rpm ;6A4-165: at 2,800 rpm ;6A4-200: at 3,100 rpm ;6AG-335: at 3,400 rpm ;6AG4-185: at 3,100 rpm ;6AGS-335: at 3,400 rpm ;6AS-335: at 3,200 rpm ;6V-335-B: at 3,100 rpm ;6V-335-A1A: at 3,100 rpm ;6V-335-A1B: at 3,100 rpm ;6V4-165: ;6V4-178-B32: at 3,000 rpm ;6V4-200-C32: at 3,100 rpm ;6VS-O-335: at 3,200 rpm

Applications

Specifications (6AL-335 / 6A4-150-B3)

Notes

References