1912 military aircraft family by the Royal Aircraft Factory
The Royal Aircraft Factory B.E.2 is a British single-engine tractor two-seat biplane, designed and developed at the Royal Aircraft Factory. Most of the roughly 3,500 built were constructed under contract by private companies, including established aircraft manufacturers and firms new to aircraft construction.
Early versions entered squadron service with the Royal Flying Corps in 1912 and the type served throughout the First World War. Initially used as a reconnaissance aircraft and light bomber, as a single-seat night fighter the type destroyed six German airships between September and December 1916.
By late 1915, the B.E.2 was proving to be vulnerable to the recently introduced German Fokker "Eindecker" fighters, leading to increased losses during the period known as the Fokker Scourge. Although by now obsolete, it had to remain in front line service while replacement types were brought into service. Following its belated withdrawal from combat, the B.E. continued to serve in training, communications, and coastal anti-submarine patrol roles.
The B.E.2 became the subject of controversy. From the B.E.2c variant onward, it had been developed to be inherently stable, which was helpful for artillery observation and aerial photography duties. However this stability was achieved at the expense of manoeuvrability; moreover the observer, in the front seat ahead of the pilot, had a limited field of fire for his gun.
Development.
Background.
The B.E.2 was one of the first fixed-wing aircraft to be designed at what was then called the Royal Balloon Factory (the organisation was formally renamed as the "Royal Aircraft Factory" on 26 April 1911). The team responsible for its design came under the direction of British engineer Mervyn O'Gorman, the factory's superintendent. The "B.E.2" designation was formulated in accordance with the system devised by O'Gorman, which classified aircraft by their layout: B.E. stood for "Blériot Experimental", and was used for aircraft of tractor configuration (although in practice, all B.E. types were biplanes rather than the monoplanes typical of the Blériot company).
At first, the activities of the Factory were limited to aeronautical research and the design and construction of actual aircraft was not officially sanctioned. O'Gorman got around this restriction by using the factory's responsibility for the repair and maintenance of aircraft belonging to the Royal Flying Corps, so that existing aircraft needing major repairs were nominally "reconstructed" but often appeared as new designs, retaining few original components aside from the engine.
The first pair of B.E. aircraft were flown within two months of each other and had the same basic design, the work of Geoffrey de Havilland, who was at the time both the chief designer and the test pilot at the Balloon Factory. Its first public appearance was in early January 1912. With the contemporary Avro 500, the B.E.2 helped to establish the tractor biplane as the dominant aircraft layout for a considerable time.
B.E.1.
This was ostensibly a rebuild of a Voisin pusher biplane, powered by a water-cooled Wolseley engine; however, the B.E.1 used only the powerplant of the Voisin.
It was a two-bay tractor biplane with parallel-chord unstaggered wings with rounded ends and used wing warping for roll control. The wings were of unequal span with the upper wing's span being and the lower . The fuselage was a rectangular section fabric-covered wire-braced structure, with the pilot seated aft behind the wings, and the observer in front under the centre section. This arrangement allowed the aircraft to be flown "solo" without affecting the aircraft's centre of gravity. Behind the pilot's position, a curved top decking extended aft to the tail, although the forward decking and cowling of later variants was not fitted at this stage. The tail surfaces consisted of a half-oval horizontal stabiliser with a split elevator mounted on top of the upper longerons and an ovoid rudder hinged to the sternpost. There was no fixed vertical fin. The main undercarriage consisted of a pair of skids each carried on an inverted V-strut at their rear and a single raked strut at the front while an axle carrying the wheels was bound to the skids by bungee cords and restrained by radius rods. A similarly sprung tailskid was fitted, while the wings were protected by semicircular bows located beneath the lower wing tips. The radiator being mounted between the front pair of cabane struts
It was first flown by de Havilland on 4 December 1911. but was not flown again until 27 December, following the substitution of a Claudel carburettor for the original Wolseley, which had allowed no throttle control. Other minor modifications were made over the following weeks: the undercarriage wheels were moved back , the wings (which originally had no dihedral), were re-rigged to have 1° dihedral, and the propeller was cut down in an attempt to increase the engine speed. Later, the Wolseley engine was replaced by a air-cooled Renault which eliminated the need for a radiator.
The B.E.1 had a long career as a research aircraft: trialling many of the modifications made to later B.E.2 variants. By the time it was finally struck off charge in 1916 it resembled a contemporary B.E.2b. Among other equipment tested for the first time in this airframe was early radio apparatus.
B.E.2.
The B.E.2 was almost identical to the B.E.1, differing principally in being powered by a air-cooled V-8 Renault and in having equal-span wings. Its number was not allocated as a separate type, but numbers allocated to early Royal Aircraft Factory aircraft were the constructor's numbers rather than type designations. Sometimes described as a "rebuild" of either a Bristol Boxkite or a Breguet, it seems to have been the first aeroplane built at the factory without the subterfuge of being a "reconstruction". It first flew on 1 February 1912, again with de Havilland as the test pilot. The Renault proved a much more satisfactory powerplant than the Wolseley fitted to the B.E.1, and performance was further improved when a model was fitted that May.
The B.E.2 flew extensively at the Military Aeroplane Competition on Salisbury Plain during August 1912. It was barred from competing officially as O'Gorman was one of the judges, but its performance was clearly superior to the other entrants and on 12 August 1912 it achieved a British altitude record of while being flown by de Havilland with Major Sykes as a passenger.
Other prototypes of the production B.E.2 series were produced, including the "B.E.5" and the "B.E.6". These mainly differed in the powerplant, initially an ENV liquid cooled engine, and both were eventually fitted with Renaults, becoming effectively standard B.E.2.s
B.E.2a.
The designation B.E.2a was assigned to the first production aircraft having first appeared on a drawing showing an aircraft with unequal span wings with slight dihedral dated 20 February 1912. These differed from the B.E.1 and B.E.2 in possessing a revised fuel system, in which the streamlined gravity tank below the centre section of the wing was moved to behind the engine although the main fuel tank remained under the observer's seat.
Early production aircraft had unequal span wings, similar to those fitted on the B.E.1, and at first there was no decking between the pilot and observer's seats, although this was added later. Sandbag loading tests revealed that the safety margin of the rear spar was somewhat less than that of the front; to remedy this, a revised wing was designed with a deeper rear spar, and consequently a different aerofoil section. Later production aircraft also had equal-span wings. These modifications were retrofitted to the majority of the remaining earlier production aircraft.
The first production order was placed with British manufacturing conglomerate Vickers; shortly afterwards a second order was issued to the Bristol Aeroplane Company. The first contractor-built B.E.2as appeared during the first weeks of 1913; during February of that year, at least two such aeroplanes were delivered to No.2 Squadron of the Royal Flying Corps. These were possibly the first examples of the type to enter service.
B.E.2b.
The B.E.2b which followed the original production standard benefitted from various improvements. It had a revised cockpit coamings, which gave better protection from the elements, and revised controls to both the elevator and rudder. Some aircraft ordered as B.E.2bs were completed as B.E.2cs, and others were built with some of the B.E.2c modifications, such as sump cowlings and "V" undercarriages.
At the outbreak of war, these early B.E.2s formed part of the equipment of the first three squadrons of the RFC to be sent to France. A B.E.2a of No.2 Squadron was the first aircraft of the Royal Flying Corps to arrive in France after the start of the First World War, on 26 August 1914.
B.E.2c.
The B.E.2c was a major redesign, and was the result of research by E.T. Busk which aimed to provide an inherently stable aeroplane. This allowed the crew's full attention to be devoted to reconnaissance duties and was also desirable for safety reasons. The first example, a converted B.E.2b, flew on 30 May 1914 and the type went into squadron service just before the outbreak of war. Relatively large orders were placed for the new version, with deliveries of production aircraft starting in December 1914. During 1915, this model replaced the early B.E.2s in the squadrons in France. The B.E.2c used the same fuselage as the B.E.2b, but was otherwise really a new type, being fitted with new staggered wings of different planform, while ailerons replaced the wing warping used on earlier models. The tailplane was also new, and a triangular fin was fitted to the rudder.
After the first few aircraft, production machines were powered by a development of the Renault engine, the RAF 1a, and the twin skid undercarriage was replaced by a plain "V" undercarriage. A streamlined cowling covering the sump was fitted to improve streamlining. Exhausts were also modified with two vertical exhaust pipes (one for each cylinder bank) discharging above the upper wing.
B.E.2d.
The B.E.2d was a dual control version of the "c" variant and was provided with full controls in the front cockpit as well as in the rear.
This meant that there was no room for the fuel tank under the observer's seat; instead a centre section gravity tank was fitted. To ensure adequate endurance this tank was large, adding drag that reduced performance, particularly in the climb. Most B.E.2ds were used as trainers, where their dual controls and five-hour endurance were of benefit.
B.E.2ds supplied to Belgium were not only re-engined with Hispano engines, but at least some of them had the pilot and observer's seating positions reversed, giving the latter a much better field of fire. Some Belgian B.E.2cs were similarly modified, and at least one was fitted with a Scarff ring on the rear cockpit.
B.E.2e.
During 1916, the B.E.2cs began to be superseded by the B.E.2e. This variant had new sesquiplane wings, similar to those used on the Royal Aircraft Factory R.E.8, which were braced by a single pair of interplane struts per side as a "single-bay" biplane, and with the lower wing panels having a much reduced span. Ailerons were fitted to upper and lower wings and were joined by connecting rods. The horizontal tail was also new, replacing the semicircular unit of the B.E.2c and d with an angular unit with straight leading and trailing edges and angled tips, while the large curved fin and the rudder of the late B.E.2c was retained.
It was intended to fit the new, uprated RAF 1b but this engine did not achieve production status, and the B.E.2e used the same engine as its predecessor, considerably reducing the expected improvement in performance.
B.E.2c and B.E.2d aircraft still under construction when the new model entered production were completed with B.E.2e wings. To rationalise the supply of spare parts these aircraft were officially designated as the "B.E.2f" and "B.E.2g".
About 3,500 B.E.2s were built by over 20 different manufacturers. An exact breakdown between the different models has never been produced, if only because so many B.E.2s were completed as later models than originally ordered.
The "B.E.9" and the "B.E.12" were variants developed to provide the B.E.2 with an effective forward-firing armament. The B.E.12 (a single-seater) went into production and saw squadron service, mainly as a Zeppelin interceptor, however neither variant was ultimately a great success as both designs had been superseded by the time they were completed.
Operational history.
Prewar service.
During the pre-war period, those B.E.2s that had reached service were primarily flown by No 2, No 4 and No 6 Squadrons, who rapidly accumulated an unusually high number of flight hours on the