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Страна: Великобритания

Год: 1916

P.Hare Royal Aircraft Factory (Putnam)

F.E.4

   In mid-1915 a team led by S J Waters and Henry Folland undertook the design of a twin-engined pusher biplane designated F.E.4, the basic layout of which was based upon the results of windtunnel tests intended to establish the most effective configuration. The machine was somehow intended to meet three rather diverse requirements:
   a Ground-attack fighter, armed with a one-pounder Coventry Ordnance Works gun and with an endurance of four hours,
   b Short-range bomber, with a 1,200lb bomb load and a three-hour endurance.
   c Long-range bomber with eight hours endurance, albeit with an appropriately reduced bomb load.
   The last specification was the specific request of Brig-Gen Trenchard, Commander of the RFC in France and thus the aeroplane's ultimate 'end-user'.
   The F.E.4 was a big aeroplane, particularly by the standards of 1915, with a wing span greater than 75ft. The overhanging extensions to the upper wing were arranged to fold downwards, a feature which was intended to facilitate storage but which, in reality, merely added unnecessary complexity to the machine's structure.
   The pilot was placed in the extreme nose, with an observer/gunner immediately behind him. Dual controls were provided, a facility which most crews would consider obligatory in a machine for which an endurance of up to eight hours was planned. Since the observer would clearly be unable to defend the machine's tail against attack, a third crew position was provided behind the wings to house a rear gunner. A revised drawing was later prepared in which this gunner is repositioned in a streamlined nacelle above the top wing centre-section, giving him an enormous field of fire, but this modification does not appear to have been incorporated in an actual aeroplane. In the same drawing the auxiliary nosewheels are replaced by small semi-circular skids.
   Although it was originally intended that the F.E.4 should be powered by two R.A.F.3a engines, none was available for installation in the prototype and two lower-powered R.A.F.5s were substituted. These, the pusher version of the air-cooled R.A.F.4, had small tractor propellers to ensure that there was an adequate movement of cooling air over the engines at all times.
   The prototype, which was given the serial 7993, was completed ready for AID inspection on 8 March 1916, and made its first flight a few days later, with Frank Goodden at the controls. It proved to be woefully sluggish, as might have been expected with engines developing only three-quarters of the power for which it had been designed, and could barely exceed 80mph, compared with the 100mph anticipated by its designers.
   Despite its shortcomings, which were not apparent to a casual observer, it was demonstrated to King George V during his visit to Farnborough on 26 April. On 11 May it went to the Central Flying School for evaluation, and was found to be stable but pitifully underpowered.
   As there were still no R.A.F.3as available, a second prototype, 7994, was converted to accept 250hp Rolls-Royce Eagle engines, complete with radiators similar to those used on the F.E.2d. At the same time the total fuel capacity was increased from 193 gallons to 250. There was no rear gunner's cockpit. This machine, to which the designation F.E.4a has often, but erroneously, been applied, did not fly until 5 June 1916, again with Goodden in the pilot's seat. Despite the increased power the performance was still wholly unremarkable and, since there were many obviously superior designs available, the trials were discontinued and the Rolls-Royce engines, for which there was an insatiable demand, were removed for use in other aircraft. A production order for 100 machines, which had been placed with Daimler, was cancelled before any could be completed.
   Both prototypes were still extant in July 1917, but a suggestion that they should be pressed into service as night bombers, a duty for which their lack of speed was no real handicap, was not taken up owing to a continued shortage of suitable engines. They were eventually broken up.

   Powerplant:
   2 x 140hp R.A.F.5a
   2 x 250hp Rolls-Royce Eagle
   Dimensions:
   span
   75ft 2in (upper);
   62ft 6in (lower);
   chord
   9ft 0in (upper);
   7ft 6in (lower);
   wing area 1,032 sqft;
   length 38ft 8 1/2in;
   height 16ft 9in
   Weights
   (R.A.F.5a): 3,754lb (empty); 5,988lb (loaded)
   (Eagle): 7,825lb (loaded).
   Performance:
   (R.A.F.5a)
   max speed 84mph at sea level;
   ceiling 6,000ft
   (Eagle)
   max speed 92mph at sea level;
   ceiling 12,000ft.


F.E.5

   Although it was never completed, this ambitious project showed great potential. It was to have been a twin-fuselage, three-engined development of the F.E.4, powered by two tractor 140hp R.A.F.4as mounted in the nose of each fuselage, and a pusher R.A.F.5 mounted centrally on the lower wing. Intended as a heavy bomber, and designed with a wing span in excess of 100ft, the F.E.5 would almost certainly have been as painfully underpowered as the original F.E.4, and may well have been abandoned for that reason.
   In common with many other Royal Aircraft Factory projects, the F.E.5 was the subject of windtunnel testing during its design, the tests being described at length in the Advisory Committee's report for 1916-17.

   Dimensions Span 103ft 0in.


F.E.7

   Another uncompleted design project developed from the F.E.4 concept, this big biplane was to have been powered by two 250hp Rolls-Royce engines mounted within the fuselage, driving twin pusher propellers via gears and shafts.
   It was clearly intended for an offensive role, as proposals for its armament appear to have included the one-pounder COW gun, with which its designers seemed to be obsessed, as its main weapon. Several Lewis guns were provided for defence. It was also planned for use as a long-range or heavy bomber, but the design was not completed and no machines were built.

   Dimensions
   Span 67ft 9in

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Описание:

  • P.Hare Royal Aircraft Factory (Putnam)
  • P.Lewis The British Fighter since 1912 (Putnam)
  • F.Mason The British Fighter since 1912 (Putnam)
  • J.Bruce British Aeroplanes 1914-1918 (Putnam)
  • H.King Armament of British Aircraft (Putnam)