Introduced in 1942, the O-290 was a four-cylinder version of the six-cylinder O-435. The engine was also developed as a ground power unit (GPU).

models

• O-290: 125 hp (93 kW)

specifications

• Horizontally opposed, 4 cylinder, piston engine
• Air-cooled
• Displacement: 289 cubic inches(4.7 litres)
• Bore x stroke: 4.875 x 3.875 inches

used by

• Piper PA-23 prototype