G.Swanborough, P.Bowers United States Military Aircraft Since 1909 (Putnam)
Engineering Division XB-1
The Bristol F.2B Fighter, which served the R.F.C. with distinction from April 1917 until the end of World War I, and thereafter remained in service with the Royal Air Force until 1932, was the subject of extensive but less successful design and production development in the U.S. Its adoption for production in the U.S. followed a recommendation in August 1917 by the Bolling Commission, and a sample F.2B arrived in Washington on September 5. Powered by the standard 200 h.p. Hispano-Suiza engine, it was assigned to the Curtiss Aeroplane and Motor Co., which received contracts for 2,000 examples in October and December.
The Curtiss-built Bristols, officially known as U.S.A. O-1s, had 400 h.p. Liberty 12 engines and changes in construction necessary to accommodate the greater power. The first O-1 flew on March 5, 1918, followed by a further batch of 25 with modifications. Further production was cancelled when the re-engined F.2B proved to be over-powered and unsafe, but Curtiss completed and tested one other example - a second British-built specimen imported without an engine and fitted with the 300 h.p. Hispano-Suiza unit. This same engine was also fitted in the first British sample at McCook Field in April 1918, where it was allocated the project number P-30 and became the prototype U.S. B-1. The other British airframe, project number P-37, later flew with the Liberty 8 engine.
At McCook Field, plans were then made to produce four examples each of the O-1 with ply-covered fuselages and the 300 h.p. Wright Hispano and 290 h.p. Liberty 8 respectively. These were to be known as U.S. B-1 and U.S. B-2, while two more examples with each engine and an entirely new plywood fuselage were to be the U.S. B-3 and U.S. B-4 respectively. The original B-1 and B-2 were dropped, whereupon the B-3 and B-4 became the XB-1 and XB-2; the new XB-2 also was eventually abandoned.
The U.S. XB-1 was damaged before its flight test, and was rebuilt with Browning instead of Marlin guns. Redesignated XB-1A, and numbered P-90, it flew on July 3, 1919. With the war over, only small quantities of the aircraft were procured: a production batch of 40 XB-1As, with 300 h.p. Wright Model H engines, was built in 1920-21 by Dayton-Wright. One of these was tested in 1921 with a 350 h.p. Packard 1 A-1237 engine, and another flew with a Curtiss D-12 engine.
TECHNICAL DATA (XB-1A)
MANUFACTURER: U.S. Army Engineering Division, McCook Field, Dayton, Ohio.
ACCOMMODATION: Pilot and gunner.
POWER PLANT: One 300 h.p. Wright H. piston vee in-line.
DIMENSIONS: Span, 39 ft. 4 1/2 in. Length, 25 ft. 6 in. Height, 9 ft. 9 1/2 in. Wing area, 406 sq. ft.
WEIGHTS: Empty, 2,201 lb. Gross, 3,679 lb.
PERFORMANCE: Max. speed, 121-5 m.p.h. at sea level. Cruising speed, 107 m.p.h. at 15,000 ft. Initial climb 8-4 min. to 6,500 ft. Service ceiling, 16,750 ft. Endurance, 3-8 hr. at 10,000 ft.
ARMAMENT: Two fixed forward firing and two flexible 0-30-in. guns.