Aircooled Motors (Franklin) 4AC-171, Horizontally-Opposed 4 Engine

Type: Reciprocating, Horizontally-opposed, 4 cylinders, Air-cooled

Power rating: 45 kW (60 hp) at 2,350 rpm

Displacement: 2.8 L (171 cu in)

Bore and Stroke: 98 mm (3.875 in.) x 92 mm (3.625 in.)

Weight: 72.2 kg (159 lb)

Several former engineers of the failed Franklin Automobile Company formed Air Cooled Motors Corporation of Syracuse, New York in 1935. Retaining the Franklin name, the new company produced a range of flat-4 and 6 cylinder aircraft engines. Head engineers Carl T. Doman and Edward S. Marks supervised the design of the Model 4AC-150 air-cooled, four-cylinder, horizontally-opposed engine that was announced early in 1938. Several models of this engine, rated at 30 and 37 kW (40 and 50 shp), were produced. The need for additional power to meet higher aircraft gross weight requirements, as well as faster climb and more speed, resulted in the higher powered Franklin 4AC-171. Certificated on August 1939, it powered the Piper J3F-65 and Taylorcraft BF-60 aircraft.

In 1975, the company disbanded and sold all rights to the Polish government, becoming part of PZL, an association of Polish aero and engine manufacturers. Following the 1989 fall of Communism, the firm became WSK PZL – Rzeszów.