Franklin 0-405-9 Six Cylinder opposed engine

 

Several former engineers of the failed Franklin Automobile Company formed Air Cooled Motors in 1935. By 1938 a range of flat (opposed) 4 and 6 cylinder engines were being produced under the Franklin name. The 0-405-9 was the largest model. In 1975 the company disbanded and sold all rights to the Polish government, becoming part of PZL – Rzeszow.

This is an early vertically mounted fan cooled “dry sump” helicopter engine. The Air-Cooled Motors Franklin 0-405-9 was installed in the Sikorsky XH-6A, YH-6A, H6A, Sikorsky XH-7, Kellett XH-8, and the XH-8A helicopters. The Franklin Designation for the engine was 6ACV-403.

Specifications:

  • Displacement: 425 cubic inches
  • Power Output: 245 HP @ 3275 RPM
  • Dry Weight: 458lbs
  • Bore: 4.75 inches
  • Stroke: 4.0 inches
  • Compression Ratio: 7 to 1
  • Firing Order: 1-4-5-2-3-6