J.Wegg General Dynamics Aircraft and Their Predecessors Since 1912 (Putnam)
The United States had received a sample Bristol F.2b Fighter in September 1917 and immediately started work to convert it with a Liberty 12 engine. This resulted in an aircraft weighing 3,600 lb and the programme had been abandoned after twenty seven were completed by Curtiss. Instead, lighter engines were adopted including the 300hp Wright-Hispano and the Liberty 8.
At McCook Field, the Engineering Division designed a new plywood fuselage, lighter and stronger than the original, and with the 300hp Wright-Hispano H engine the conversion was known as the XB-1A. Armed with two Browning and two Lewis guns, three Engineering Division prototypes were built, the first flying on 3 July, 1919. Dayton Wright completed four more (64115/P-171, 64300/P-180, 94107/P-150, and 94108/P-151). These were followed by a contract for forty XB-1As (64156/64194, 64300) placed with Dayton Wright on 28 June, 1920. Four of these were tested at McCook (64158/P-179), 64160/P-181, 64161/ P-182, 64177/P-205) and two were transferred to the Navy (BuA 5974/5975). The others were assigned to the 12th Observation and 13th Attack Squadrons in Texas.
Span 39ft 4in; length 25ft 6in; height 9ft 10in; wing area 406sq ft.
Weight empty 2,155 lb; gross weight 3,791 lb.
Maximum speed 130mph; cruising speed 101mph; climb 6,500ft/7.5 min; service ceiling 18,900ft; range 495 miles/4hr at 10,000ft (100US gal fuel capacity).
C.Barnes Bristol Aircraft since 1910 (Putnam)
The Bristol Fighter F.2A and F.2B
When the United States entered the war in 1917 the Bristol Fighter was among the British types proposed for large-scale production in America; 2000 were ordered first from the Curtiss Aeroplane and Motor Corporation of Buffalo, N.Y., and later from a group of other firms to be supervised by the Engineering Division of the Bureau of Aircraft Production at McCook Field, Dayton, Ohio; all were originally to be fitted with the 300 h.p. Hispano-Suiza, licence-built by the Wright-Martin Corporation. These plans met with approval from the Company, and several of the Filton staff went to America to supervise the arrangements, taking with them two sample airframes. To their dismay, they found that the engine actually chosen was the 400 h.p. Liberty 12, which was too heavy and badly installed. Capt. Barnwell predicted trouble but was overruled; when the first Curtiss-built F.2B flew and crashed he was proved correct, but the U.S. Army blamed the aircraft rather than the power plant, and only 27 of the contract were built, the rest being cancelled. Technical opinion at McCook Field was less biased and the two Filton-built aircraft were flown, one (P 30) with a 300 h.p. HispanoSuiza and the other (P 37) with a 290 h.p. Liberty 8. P 37 crashed before any performance tests could be made, but on 18 November 1918 P 30 was flown by Major Schroeder to a height of 29,000 ft. above Dayton, an unofficial world's altitude record for which homologation was never sought. A Hispano-Suiza-engined F.2B variant with semi-monocoque veneer fuselage was built at McCook Field with the designation XB-1A (P 90) in July 1919, and 40 more were produced for the U.S. Army by Dayton-Wright in 1920.
P.Bowers Curtiss Aircraft 1907-1947 (Putnam)
Following several serious crashes of early test models, the Curtiss contract was cancelled after 26 Bristols had been completed (US Army serial numbers 34232/34257). This did not kill off official US interest in the design, however. While Curtiss tried to develop its own version of a Bristol replacement, the CB, the Air Service Engmeenng Division at McCook Field developed lower-powered versions with 300 hp Wright-Hispano engines and new laminated wood monocoque fuselages. Thirty of these were eventually produced by the Dayton-Wright Aircraft Company under the designation of USXB-1A.
J.Bruce British Aeroplanes 1914-1918 (Putnam)
Bristol F.2A and F.2B
The United States of America entered the war on April 6th, 1917, and set about the production of aircraft on a characteristically ambitious scale. The initial “Procurement Program” planned for the immediate acquisition of 7,375 aircraft, and the ultimate aim was the production of no fewer than 20,475 machines in twelve months. A substantial number of these aircraft were of British design. Towards the end of 1917 it was arranged that the Bristol Fighter would be produced by the Curtiss Aeroplane and Motor Corporation, and 2,000 were ordered. Two Bristol-built airframes were sent as samples to the Curtiss works.
The Curtiss-built machines were to have had the 300 h.p. Wright-built Hispano-Suiza engine, but political pressure was brought to bear in favour of the American Liberty 12, which was substituted for the Wright-Hispano. This was done in defiance of the strenuous opposition of the British & Colonial Aeroplane Co., for Captain Barnwell knew that the Liberty was too bulky and too heavy for the aeroplane.
Responsibility for the engineering behind the production of the Liberty-powered Bristol Fighter rested with the U.S. Government until the production programme was well advanced. Even when the Government relinquished that responsibility, the Curtiss company were not allowed to make changes of any magnitude. At an early stage, Curtiss engineers realised that Barnwell was correct in thinking that the installation of the Liberty engine in the Bristol Fighter would not be satisfactory; they therefore began to design a completely new aircraft (the Curtiss CB) to use the Liberty and to perform the same duties as the Bristol.
The installation of the Liberty engine in the Bristol Fighter was clumsy; the radiators were badly placed; and the aeroplane was nose-heavy and thoroughly unpleasant to fly. The first machine was completed in March, 1918, and was delivered to the U.S. Air Service during the following month. Twenty seven were built before production was halted and the remainder of the contract cancelled. Blind to their own blunder in fitting the Liberty to an aeroplane unsuited to the engine, the U.S. Army shifted the blame on to the innocent aircraft and condemned the Bristol Fighter as dangerous.
Another version of the design was, however, ordered in large quantities in America. The Engineering Division of the Bureau of Aircraft Production undertook the fairly extensive re-design of the Bristol Fighter and evolved two designs, both for aircraft which had completely re-designed structures: one version was powered by the 300 h.p. Hispano-Suiza, and was designated USB-1; the other was designed for the 290 h.p. Liberty 8, and was designated USB-2. An optimistic order for 2,000 machines of the USB type was placed.
These aircraft had veneer-covered fuselages of faired contours, and the area of their vertical tail assembly was increased. Many other detail modifications were made, and the equipment of the machines was different from that of the standard British-made Bristol F.2B.
Some standard Bristol Fighter airframes had been sent to America for experimental purposes. One was fitted with a 300 h.p. Hispano-Suiza, and had the McCook Field Project No. P.30; a second had one of the first eight-cylinder Liberty 8 engines of 290 h.p., and the Project No. P.37. The latter Bristol crashed before performance tests were carried out. These two Bristol Fighters have been referred to as the USB-1 and USB-2 respectively, but that is incorrect. In the summer of 1918, the construction of twelve Bristol Fighters was begun at McCook Field. The intention was to build eight machines to the basic Bristol design, four with Hispano-Suiza engines and four with the new and re-designed Liberty 8; and the remaining four were to be structurally similar but with veneer-covered fuselages, two having Hispano-Suizas and two Liberty 8s. Work lagged badly, however, and the construction of the first eight aircraft was finally stopped in September, 1918.
Work was still proceeding on the design of the USB-1 and USB-2, which were re-designated USXB-1 and USXB-2 at about this time. A number of fuselages of slightly different design were tested statically, and construction of two prototypes was begun.
The four Bristol F.2Bs with veneer-covered fuselages were still in hand, but in October, 1918, the construction programme was altered to consist of only two USXB-1s and two USXB-2s. This plan was retained until the Liberty 8 engine was abandoned in 1919, whereupon the USXB-2s were modified to take the 300 h.p. Hispano-Suiza, and all four machines emerged in July, 1919, under the designation Engineering Division XB-1A.
The order for 2,000 aircraft of USB type was cancelled at the time of the Armistice, but during 1920 and 1921 forty XB-1As were built by the Dayton-Wright concern. These production machines had the 330 h.p. Wright H engine, and their all-up weight was about 800 lb greater than that of the original XB-1A. In 1921, one of the production XB-1As was fitted with the 350 h.p. Packard 1A-1237 engine; and another (A.S.64156) was used as a test-bed for the Curtiss D-12.