Royal Aircraft Factory B . E . 3 The Royal Aircraft Factory B . E . 3 was a single - engined rotary engined biplane developed by the British Royal Aircraft Factory prior to the First World War . The B . E . 4 and B . E . 7 were virtually identical aircraft that differed only in the engine fitted . Design and development . In December 1911 , the Royal Aircraft Factory started work of a new biplane of similar layout to its B . E . 1 and B . E . 2 , but powered by a rotary engine to allow comparison with the water - cooled and air - cooled V8 engine powered B . E . 1 and B . E . 2 . Detailed design of the new aircraft was the responsibility of John Kenworthy , who drew up plans for a two - bay biplane with wings similar to those of the B . E . 2 , but more heavily staggered . Lateral control was by means of wing warping , while the fuselage , which was wider than that of the B . E . 1 and 2 to accommodate the rotary engine , was mounted between but clear of the upper and lower wings . Two aircraft were built in early 1912 , numbered B . E . 3 and B . E . 4 , but as at the time the Royal Aircraft Factory was forbidden from building aircraft , the two aircraft were officially rebuilds of a Paulhan biplane and a Bristol Boxkite respectively , but the only parts reused were the engines . First to fly was the B . E . 3 , powered by a 50 hp ( 37 kW ) Gnome Omega engine , on 3 May 1912 with Geoffrey de Havilland at the controls . Testing was sufficiently successful for de Havilland to take several passengers up in the B . E . 3 later that day , and the aircraft was delivered to the Royal Flying Corps ( RFC ) on 13 May 1912 . The B . E . 4 , also initially powered by a 50 hp Gnome , flew on 24 June that year , and was handed over to the RFC on 8 August . It was re - engined with a 70 hp Gnome in September 1912 . At least two , and possibly three more similar aircraft powered by 50 hp Gnomes were built in late 1912 – early 1913 by private contractors . Kenworthy modified the design to allow fitting of a more powerful ( 140 hp ( 104 kW ) ) two - row Gnome engine , which was built as the B . E . 7 , flying for the first time on 28 February 1913 . The final development of the rotary engined B . E . types was the B . E . 8 / 8a types of 1914 / 15 . Operational history . The B . E . 3 and B . E . 4 , allocated the serial numbers " 203 " and " 204 " became part of the inventory of No . 3 Squadron RFC , with the B . E . 3 , nicknamed " Goldfish " , being used for various trials , including air - to - ground signalling with both radio and lights . Two more aircraft ( serial numbers " 416 " and " 417 " were delivered to the Central Flying School in December 1912 , while serial number " 303 " , which may have been similar , was delivered to No . 4 Squadron in January 1913 , although wrecked in a crash in February that year . The B . E . 7 was also taken on charge by the Central Flying School , serving until November 1913 , at which time its engine bearers were found to be damaged by the heat of its exhaust fumes . " 204 " crashed on Salisbury Plain on 11 March 1914 when its rudder failed , possibly due to metal fatigue , killing its crew of two . To avoid similar failures , the remaining aircraft were fitted with modified tails based on that fitted to the H . R . E . 2 , this allowing the Central Flying School aircraft to remain in use until the summer of 1914 .