In June 1939, the U.S. Navy placed a contract with the Steel Products Engineering Co. (SPECO) of Springfield, Ohio for one XB-4070-2 barrel engine, a concept also tried elsewhere, but never fully successful. In a barrel engine, the cylinders are parallel to the engine driveshaft and arranged radially around it; therefore producing a small frontal area. This version incorporated 9 cylinders having 18 opposed pistons, with the pistons rotating slowly to insure uniform heating and avoid thermal distortion. A swashplate (an inclined disc) located on the driveshaft in the center of the engine converted piston thrust to torque. This arrangement is inherently very compact and light in weight. However, the bearing problems involved in the swashplate mechanism were difficult to solve and did not result in a good high-output engine.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.
Circa 1942
United States of America
PROPULSION-Reciprocating & Rotary
Steel Products Engineering Corporation (SPECO)
Type: Reciprocating, 9 cylinders, barrel-type, two-stroke, supercharged, Diesel, liquid-cooled
Power rating: 1,491 kW (2,000 hp) at 1,750 rpm
Displacement: Unknown
Bore and Stroke: Unknown
Weight: 975.2 kg (2,150 lb)
Length 188 cm (74 in.), Diameter 88.9 cm (35 in.)
Steel
Non Magnetic Alloy
Paint
Rubber
Aluminum
Copper Alloy
Cadmium Plating
Masking Tape
A19710890000
Transferred from the U.S. Navy
National Air and Space Museum
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