The Engineering Division TP-1 was a two-seat biplane fighter designed by Alfred V. Verville and Virginius E. Clark at the United States Army Air Corps Engineering Division.

[1] The XTP-1 was armed with five .30 in (7.62 mm) machine guns and fitted with a 423 hp (315 kW) Liberty 12 engine.

The aerofoil was Joukowsky StAe-27A, a heavily cambered wingshape with a thick leading edge.

[3] On October 10, 1928, Bill Streett and Albert William Stevens achieved an unofficial altitude record in the XCO-5 for aircraft carrying more than one person: 37,854 ft (11,538 m); less than 1,000 ft (300 m) short of the official single-person altitude record.

[5] With frozen controls, Streett was unable to reduce altitude or to turn off the engine until some 20 minutes later when it ran out of fuel, after which he piloted the fragile experimental biplane down in a gentle glide and made a deadstick landing.