Several engineers of the failed Franklin Automobile Company of Syracuse, New York, a manufacturer of air-cooled automobiles, formed Air Cooled Motors in 1935. By 1938 a range of flat-4 and 6 aircraft engines was being produced, retaining the Franklin name.

Installed vertically, with a fan providing additional engine cooling, the O-335-5D powered the Bell TH-13M Sioux helicopter and its civil counterpart, the Model 47.

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.

 Display Status

This object is not on display at the National Air and Space Museum. It is either on loan or in storage.
Object Details
Date Circa 1950 Country of Origin United States of America Type PROPULSION-Reciprocating & Rotary Manufacturer Aircooled Motors Corporation (Franklin)
 Physical Description Type: Reciprocating, 6 cylinders, Horizontally opposed, Air-cooled Power rating: 157 kW (210 hp) at 3,200 rpm Displacement: 5.5 L (335 cu in.) Bore and Stroke: 114 mm (4.50 in.) x 89 mm (3.50 in.) Weight: 130.6 kg (288 lb) Dimensions Height 65.4 cm (25.75 in.), Width 78.4 cm (30.88 in.), Depth 91.4 cm (36 in.)
 Materials Steel
Paint
Aluminum
Rubber
Cadmium Plating
Copper Alloy
Plastic
 Inventory Number A19870202000 Credit Line Transferred from the U.S. Marine Corps, Marine Corps Air-Ground Museum and Museums Branch Activities Data Source National Air and Space Museum Restrictions & Rights Usage conditions apply
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