Royal Aircraft Factory B.E.12

Evolved at Farnborough during 1915 as a marriage of the B.E.2c airframe with the then-new R.A.F.4 air-cooled 12-cylinder Vee-type engine of 140hp, the B.E.12 prototype began test flying at the end of July that year. Although flown from the start as a single-seater, it was at first unarmed and was intended for such roles as bombing and photography rather than as a fighter. The prototype was tested in France in September 1915 and its generally satisfactory performance encouraged the War Office to order production of the B.E.12 in that same month. Delivered from March 1916 onwards, production aircraft had the R.A.F.4a engine (with increased stroke), twin upright exhaust stacks, an auxiliary gravity fuel tank under the port upper wing and, after the first few, an enlarged rudder with curved leading edge. At first serving with RFC squadrons in France for general duties, the B.E.12 was fitted with a 7.7mm Lewis machine gun on an oblique mounting on the fuselage side, or over the wing centre section, but several other experimental installations were tried at Farnborough before the decision to adopt the newly-available Vickers-Challenger interrupter gear, using a Vickers gun firing through the propeller disc. Difficulties with the gear, combined with the excessive stability of the B.E.12 (to overcome which the B.E.2e-type tailplane and elevators were used on some B.E.12s), made the type ineffectual as a fighter, however, and it was soon withdrawn from France, having served with only two squadrons. B.E.12s remained in service with Home Defence squadrons through 1917, many alternative armament installations being tried, including a quartet of Lewis guns, and sets of Le Prieur rockets on the interplane struts. One Zeppelin was shot down by a B.E.12, in June 1917. At Farnborough, one was tested with a Davis six-pounder recoilless gun, firing upwards at 45° for anti-Zeppelin use, but this was not adopted for production. Contracts were placed with two companies for B.E.12 production, Daimler building 200 and Standard Motor Co, 50, against the original orders placed in 1915, and Daimler receiving a contract for 200 more in August 1917. Many of the latter, however, were completed as B.E.12b's.