By the end of January 1912, B.E.1 had been joined by a sister ship that was identical in every way to B.E.1 except that it was powered by a Renault engine. The engine mounting tubes were slightly longer so that it was mounted slightly further forwards, moving the centre of gravity and reducing the tail heaviness. Also, it was fitted with a four-blade propeller. This turned at half-engine speed as, in the Renault design, was mounted on an extensive of the camshaft drive rather than directly on the crankshaft.
The new machine was designated B.E.2, not because it was a new design, but simply to denote it as the second machine built in the B Class. Only later, when the design entered volume production did B.E.2 become a type classification since the drawings issued to manufacturers bore that designation, although O’Gorman in his diary referred to the new machine as a ‘Military Biplane of the B.E.1 Type’, logically considering the earlier machine as the prototype.
B.E.2 was never passed off as being anything but a new machine, copied from B.E.1., without any ‘reconstruction’ ruse to account for its existence. However, permission to build it appears to have only been obtained retrospectively, for as late as 26January 1912 when it was virtually complete, O’Gorman included it a memo to the War Office entitled ‘Suggested Aeroplanes for Construction’.
De Havilland took B.E.2 up for its initial flight at 11.00 am on 1 February making a total of four flights, including one with F. M. Green, the Factory’s chief engineer, as a passenger, covering a total of twenty miles and noting that it seemed faster than its predecessor. The new machine performed perfectly without the need for any modification, all the necessary development work having been done with B.E.1. Although from then on, de Havilland largely concentrated his efforts on the new machine, leaving flying of B.E.1 to his new assistant, E. W. Copeland Perry. B.E.2 was later described by Flight magazine as being:
One of the neatest biplanes ever built, and one moreover that impresses the engineering sense with an immediate satisfaction in the quality of the design.
The same article also stated:
…it is difficult to describe in words the precise quality of the design that calls forth the admiration of the engineer, and it is certainly not in any way due to the smart finish of superficial details, although the workmanship is excellent, the hand of the experimenter is on it still. The fact remains, that for a well designed tractor biplane, the B.E.2 of the R.A.F. is hard to beat, and some points in it may well be worth copying by those in search of Army orders.
On 5 February, B.E.2 was proudly shown to members of the Advisory Committee for Aeronautics who were paying a visit to the Royal Aircraft Factory. De Havilland made numerous short flights in it during the next few weeks, not to carry out specific tests, but to give air experience to senior Factory design staff. Towards the end of February, de Havilland, accompanied by Green, flew it to Brooklands attracting further favourable comments from the press, Flight magazine commenting:
…unfortunately it was, in two senses, a flying visit, for the machine departed before everyone had a chance to examine it. It did, however, create a very favourable impression, its finish, workmanship, and climbing power leaving all being considered praiseworthy.
Without having to hand B.E.2 over to the Air Battalion or the Royal Flying Corps, the Factory made the most of their aeroplane. It was retained at Farnborough and became the subject of a number of tests and trials.
In March, it was fitted with a wireless transmitter developed by Mr R. Widdington, aerials for which were fixed along the leading edges of the wings. Trials began on 26 March when four flights were made before the apparatus broke down. With the wireless repaired, tests resumed and continued until 11 April with a number of different operators, its signals being clearly received at ranges of two miles. During these experiments, B.E.2 took part in the first wireless-controlled artillery shoot, shaping the way for its future role.
By 22 April, B.E.2 had flown over twenty hours, covering 1,350 miles and the engine was replaced with another Renault, up-rated to 70 hp by increasing the bore from 90 to 96 mm. This, unusually for the Factory, had been purchased new, demonstrating just how important the B.E.2 was considered to be. Although 23 lbs heavier, the new engine was otherwise little different from its predecessor, the only changes to the installation were a slightly taller air scoop and the exhaust pipes re-routed to run outside the fuselage. Although brackets were provided for them, there is no evidence that the silencers, which had caused so much interest on B.E.1, were fitted to its sister ship. The engine change was completed on 28 April when de Havilland took it up for a brief test flight finding everything satisfactory.
The extra power was to prove useful for the next experiment in which B.E.2 was fitted with floats. On 11 May, de Havilland flew it to Fleet Pond, the largest body of water in the area, and the floats that had been brought by road were fitted. After some adjustments to the machine’s balance, and to cope with the shallowness of the pond, a take-off was made towards evening and the machine flew successfully. However, the floats, and possibly the aeroplane, were damaged during the landing and B.E.2 was left in situ for repairs, Perry flying it back to Farnborough on 14 May. The experiment had proved its point and there were no further attempts to fit the B.E.2 with floats although trials continued with other types.
During the next few weeks, B.E.2 was flown to test a thrust meter, and on 31 May, flew with a tension meter fitted to the warp wires, collecting experimental data to aid the Factory’s programme of research all of which was later published by the Advisory Committee for Aeronautics. Later the same day, de Havilland, flying solo, climbed to over 6,000 feet in just fifteen minutes, probably the greatest height the type had thus far obtained. B.E.2 was also used to test an accelerometer and the ‘Trajectograph’, an instrument designed by the Factory for use in the forthcoming Aeroplane Competition that combined an altimeter with a timing device and so measured glide angle.
Many of these trials were reported not only in aviation magazines but in the national press as the following paragraph from The Times for 4 June illustrates:
An experiment in bomb dropping was carried out at Farnborough last evening by Mr de Havilland, of the Army (sic) Aircraft Factory. The ‘bomb’ carried was an ordinary ringed square weight of 112lb, which was suspended by a trigger hook to the chassis of Army biplane B.E.2. Mr de Havilland detached the weight at a height of about 200 feet. The release had no perceptible effect upon the flight or equilibrium of the biplane.
On 19 June, in a brief departure from his official duties, de Havilland took his wife for a brief joyride in B.E.2, the first time she had flown. What greater endorsement of the comfort and safety of the design, and of its designer’s confidence in it could there have possibly been?
Short of aeroplanes and unwilling to wait to see the outcome of the Military Aeroplane competition, the War Office placed orders for three Avro biplanes, four Flanders monoplanes and four examples of the B.E.2. However, the B.E.2s were ordered not from the Royal Aircraft Factory, but from Messrs Vickers Ltd. who were well established as armament contractors with the Factory providing all necessary drawings to ensure that these contractor-built machines would be identical to the original. With the competition over, further orders were placed with a number of contractors for additional examples of the type. Therefore, B.E.2 came to designate a type rather than an individual machine, although only the original ever bore the designation on its rudder.
Production examples were fitted with a 70-hp Renault engine with the taller air scoop and exhausts which ran outside the fuselage, turning down and back to discharge behind and below the rear cockpit. No silencers were fitted, probably because experience had shown that the ‘chatter’ of the engine’s roller bearings, if not louder than the exhaust, could be heard further away.
Early examples had unequal span wings of NPL3a aerofoil section, set at an angle of incidence of four-and-a-half degrees, but these were changed from early 1913 to RAF6. This was developed when it was discovered that the rear spar of the original section had a factor of safety lower than that possible for the main spar and lower than the designers at the Royal Aircraft Factory thought appropriate. The new aerofoil section not only overcame this problem, having spars of equal strength, but when set an angle of incidence of three-and-a-half degrees, gave the same lift with a slight reduction in drag, marginally enhancing performance.
The teardrop-shaped gravity tank, which in early models was suspended below the upper centre section, was eliminated and replaced with a tank mounted within decking at the rear of the engine as introduced in the erstwhile B.E.6. The main tank remained under the front seat with a hand pump provided to maintain pressure if necessary. The ignition switch, a simple household type brass-domed light switch, was mounted outside the pilot’s cockpit on the port side where it could be clearly seen by the mechanic swinging the propeller. An ‘Elliot Bros.’ instrument board comprising a column-type air speed indicator rather like a thermometer, a revolutions counter and altimeter was mounted on a board under the decking between the cockpits.
In order to maintain the existence of the fledgling aircraft industry and encourage its growth – or so the War Office believed – small orders were placed with a wide number of contractors including W. G. Armstrong Whitworth and Co., Vickers and the Coventry Ordnance Works. These were better established as armaments contractors than aeroplane manufacturers, although the British & Colonial Aeroplane Company and Handley Page Ltd. also secured orders.
Modification of the original B.E.2 continued throughout its career. By December 1912, it had been fitted with decking behind the engine as introduced in B.E.6, improving the passenger’s comfort. It was, at one point, fitted with a spade-shaped tailplane, increasing its area from thirty-four square feet to fifty-four. Fitting this necessitated shortening the rear fuselage decking by one bay and although, with the experiment concluded, the original, smaller, tailplane was replaced but the shortened decking was retained, becoming a distinguished feature of the machine. Its wheels were covered with fabric to improve streamlining and increase side area, an innovation that was quickly adopted for almost all aeroplanes in service.
At this point, B.E.2 disappears from the Royal Aircraft Factory records as an individual machine, further experiments being conducted on a machine with the serial number 601, the first of a batch of numbers assigned to the Royal Aircraft Factory. From photographic evidence, B.E.2 appears to have suffered an accident on 11 December 1913, but with the Factory’s occasionally obscure record keeping, it is unclear whether the original machine was rebuilt or 601 was a new machine.
However, it is possible that the serial number, although assigned earlier, did not appear on the machine until March 1914 when the rudder was replaced by a new component. This was as a result of problems with rudders bending under stress as later described in the following memo distributed by the Royal Aircraft Factory to all units operating the type:
It has been found with B.E.2 type aeroplanes that when doing extremely sharp turns, or when flying under extreme weather conditions, the rudders become slightly bent. This has never in any way caused any inconvenience to the pilot, but it is thought that, by straightening , the rudder could eventually become damaged. Accordingly the rudders and rudder post of all B.E.s are being strengthened.
The problem led to the type being briefly grounded awaiting the new rudders. At a conference on 26 March, it was agreed the type was safe to fly provided that rudders that might have been bent and re-straightened were immediately replaced in case they had been weakened by the process. By June, it had still not been possible to replace the rudders of all B.E.2s in service and pressure was put on all contractors in order to speed up delivery. In March 1914, it was decided to replace a few of the wooden members, which had been formally made from ash, with similar components of spruce. This was done as the quality of ash varies considerably and, although theoretically stronger than spruce in practice, there was often little or no difference in actual compressive strength. Spruce was also lighter. Several squadron commanders complained that the spruce members occasionally appeared to have pockets of ‘half dried gum’ and expressed concern that they would be weakened by this. Both the Aeronautical Inspection Directorate and the Royal Aircraft Factory responded with assurances that fibres would be continuous around the gum pocket and the components had a factor of safety of between eight and nine, so a little loss of strength could be tolerated. Development of the pneumatic undercarriage that O’Gorman had included in his list of desirable features before B.E.1 was even completed was also undertaken. The first example, modelled on the undercarriage of a contemporary Breguet, was fitted to 206 in October 1912, the machine built as B.E.6 which was in service with 2 Squadron.
This unit was also based at Farnborough so the efficiency of the new undercarriage could be tested under service conditions and yet still be monitored by the Factory. This undercarriage incorporated a single central skid, ending in a spoon-like projection at its forward end. Its work over, it was replaced by a standard twin-skid wooden chassis when the machine was overhauled the following spring.
An oleo undercarriage of a different design, with hook-like steel skids projecting forwards, was fitted for a time and remained in place while the machine was used to conduct other experiments. The final design of oleo undercarriage – with a central nose wheel serving the same function as the skids fitted to early designs – was also tested on a B.E.2, but found its true home on the larger F.E.2b and the twin-skid unit remained the standard undercarriage for early B.E.2s. This design, in which retained the axle that was bound in place with rubber shock cord to provide an element of springing, was less efficient than the oleo types but far lighter and easy to maintain.
At the end of 1913, crew comfort was improved by the introduction of new fuselage decking with smaller cockpit cut-outs which offered better protection from the elements. This new model, designated B.E.2b, also introduced exposed control cables simplifying inspection and maintenance in the field. No further orders for the B.E.2a were placed and only a limited number of the improved machine were manufactured as something even better was on the way.
O’Gorman, who had expanded the Royal Aircraft Factory to better carry out its research role, frequently recruited graduates from Cambridge University dedicated to such subjects as physics, chemistry and metallurgy. One such student was Edward Teshmaker Busk who had obtained first-class honours in mechanical engineering in 1907, and after a period working in the electrical industry, joined the physics department in June 1912. Busk made a special study of aeroplane stability, carrying out a number of experiments, chiefly with the B.E.2, in order to test his theories. Before he joined the Factory, he had learned to fly at the Aeronautical Syndicate School at Hendon and was able to conduct his own test flights. At the time, stability was considered to be a highly desirable quality for an aeroplane to possess. In an unstable aeroplane, the pilot must, like the rider of a unicycle, be constantly adjusting the balance of his mount, whereas the pilot of a machine that is inherently stable can take his hands off the controls from time to time to do other things. For example, in a military aeroplane, stability would allow the pilot to look around and note troop movements. Lateral stability, as was already known, could be achieved by introducing dihedral by placing the wings at a small angle above the horizontal so as to form a shallow vee. Then, should a gust tip the machine up at one side, the down-going wing would automatically generate lift and so right the machine. Stability in pitch could be achieved by having the tail, not as a lifting surface but as a stabilising one, set at the correct angle to provide a similar righting moment in pitch to that created laterally by dihedral. The elegant tailplane, in whose upper surface O’Gorman had chosen to retain some curvature, i.e. to create lift, was replaced with a plain surface, rectangular in plan and mounted directly on the top longerons, and braced from a kingpost mounted above the rear fuselage. This new stabilising surface was designated T3 or ‘Tailplane No. 3’, the large and small curved surfaces previously fitted designated T1 and T2 retrospectively. This new tailplane, T3, provided the righting moment Busk needed to achieve longitudinal stability.
Directional stability was another matter and while Busk knew that the solution lay in having a sufficient vertical surface, he had first to establish how best to arrange it. A vertical tail would provide an answer but was it the best or only answer? He first tried modifying the interplane struts, increasing width at their upper ends so as to provide an additional vertical surface close to the machine’s centre of pressure. In another experiment, triangular fins with vertical leading edges were fixed above the centre section struts and the machine flown by Busk to collect data on their effectiveness before deciding that a vertical tail fin was, after all, the best option.
The Royal Aircraft Factory was still a research facility and how many of these experiments were expected to be adopted for use and how many were conducted to see what happened is unclear. But Busk had experimented enough to discover that all he needed to design was a truly stable aeroplane without resorting to the excessive sweepback or similar oddities other designers had thought necessary. His first creation was the R.E.1 (Reconnaissance Experimental No. 1) whose inherent stability caused a sensation, especially when flown ‘hands off’ before the King and Queen.
He then turned all that he had learned upon the B.E.2 by creating the inherently stable B.E.2c. It was completed at the end of May 1914 by modifying 602, which had then flown for forty-four hours. The fuselage of the new design was similar to that of the B.E.2b, the tailplane replaced with a rectangular surface comparable to the T3, but mounted midway between the upper and lower longerons and wire braced from the rudder post. A triangular fin was added ahead of the rudder. The wings had a redesigned tip profile and were staggered, the lower moving back twenty-four inches with the lower longerons of the forward fuselage modified to provide attachments in the new locations. The wings were still rigged in two bays, but new struts of increased chord were introduced and the wings rigged with three degrees of dihedral. Ailerons were fitted to all four wings, replacing the warping of earlier versions, improving lateral control and allowing the introduction of cross bracing between the interplane struts, thus increasing strength. Later, streamlined wires were introduced that replaced the standard cable, thereby finally completing the list of features O’Gorman had sought to include from the start.
De Havilland’s design had been refined into its definitive version, although it was now a very different aeroplane from the one he first flew in December 1911. It was frequently demonstrated by flying ‘hands off’, sometimes for a considerable time. Pilots were impressed but found flying it so strange after machines that required constant attention to the controls they nicknamed it ‘Stability Jane’, and later, ‘The Quirk’.