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Страна: Великобритания

Год: 1912

S.Ransom, R.Fairclough English Electric Aircraft and their Predecessors (Putnam)

Coventry Ordnance Works Military Trials Biplanes

   During the summer of 1911, Col J.E.B. Seely, Under Secretary for War, announced that the War Office was considering offering prizes for an aeroplane suitable for military use. By October, plans for a competition were being formed, and early in December, an Aeronautical Society meeting, held at the Royal United Services Institute, London, provided an opportunity for open discussion between the Army and aircraft constructors regarding the requirements of military aircraft. Among those present at the meeting were W.O. Manning and Howard T. Wright, representing the Coventry Ordnance Works Ltd, which had just taken over Wright's business under the railway arches at Battersea. The meeting proved so successful that a second one was arranged but before this took place the War Office announced the conditions and prizes for its competition to be held at Larkhill in August 1912. The directors of the Coventry Ordnance Works, on hearing the details of the competition, decided to enter aircraft for what became known as the Military Trials and accordingly authorised Manning and Wright to proceed with the design and manufacture of suitable machines.
   Manning set to work immediately after the decision had been made and soon produced two designs, both of unequal-span tractor biplanes, one having its two crew seated side-by-side and the other with its two crew seated in tandem. Powerplants chosen were the 100 hp Gnome, fourteen-cylinder rotary and the 110 hp Chenu inline water-cooled engine. Their installation was decided from consideration of frontal area and the Chenu engine was therefore fitted to the tandem-seat design, which had a narrow fuselage with a short rounded top-decking immediately behind the open cockpit. The fuselage of the Gnome-powered biplane was untapered in plan and necessarily broad but tapered rearwards in side elevation two faired head-rests being provided for the crew. Both machines had their fuselages mounted above the lower wing, which was attached at its centre-section by four pairs of short struts, the centre pairs forming a framework for a streamline fairing that enclosed the petrol tank. The upper wing of each biplane was carried solely by four pairs of interplane-struts and was made in five sections. The outboard sections of the upper wing were braced from kingposts and could be warped for lateral control. The wings of the Gnome-powered biplane were tapered in plan and those of the other machine were of parallel chord. There was no centre-section cut-out in either wing of the Gnome-powered aircraft when it first appeared at Brooklands but they were incorporated within a month of its debut. The fixed tail surfaces of the Gnome-engined aircraft were semi-elliptical in planform, and those of the other of triangular shape. The elevators, fin and rudder of the two machines were distinctive in arrangement. The Gnome-powered biplane had three-quarter circular elevators, with the forward quarter forming a horn-balance, small twin triangular fins, each mounted in line with the fuselage sides, and twin elliptically-shaped rudders, which each had two horn-balances. The Chenu version had a single triangular fin and horn-balanced rudder and elevators of shark's fin shape. Each machine's undercarriage was unsprung and relied upon its low-pressure balloon tyres to absorb landing shocks.
   Construction of the Gnome-powered Military Trials Biplane started at Battersea early in 1912 with the manufacture and assembly of its fuselage, the metal fittings for which were made at COW's factory at Coventry. The fuselage was a wire-braced box-girder structure with four ash longerons and spruce spacing-struts. The forward ends of the longerons were bent using steam and fitted into two steel pressings, which carried the engine and propeller shaft, the latter being mounted above and driven by a 1 1/2 in Renold roller chain through a 2: 1 reduction gear from the engine. The Gnome engine was fitted with Bosch dual ignition and could be started from the cockpit. Nine laminations of teak were used for the Manning-designed two-blade propeller, the inner region of which gave low thrust to reduce drag and pilot discomfort from the slipstream. The propeller hub had the additional refinement of a spinner. Engine and nose fuselage cowling was cut from sheet aluminium and attached by means of car-hood fasteners. A 10 Imp gal gravity petrol tank and a 22 Imp gal oil tank were carried in the bay behind the engine, the gravity tank being supplied with fuel pumped from the 40 Imp gal tank carried in the fairing between the fuselage and lower-wing centre-section.
   Pilot's controls comprised a wheel at the top of a pivoted control column and a rudder bar. Dual rudder control was later installed. Both wings were built-up on two I-section ash spars and a thinner intermediate spar, and had solid ribs of Eiffel No. 8 aerofoil section, lightened with holes between the spars. The fabric-covered wings were internally braced by wires, inspection of their joints and those of the spars being made through sliding aluminium panels. Interplane-struts and kingposts were of streamline section and made from silver spruce. Stranded cable was used for external bracing and warping wires, the latter passing through pulleys housed in streamline fairings. All tail surfaces had flat wooden frameworks and were fabric covered. Undercarriage and nose skid struts were made of Honduras mahogany, the skid itself being of hickory. A small tusk was fitted inboard of each spoked wheel to prevent the apex of each undercarriage leg from digging into the ground in the event of the spokes breaking. The tailskid was of bent cane and was fitted with a simple but effective braking device, comprising a spring-steel claw which was always operative unless drawn clear of the ground by the pilot pulling the wire attached to it and fastening this to a hook near his seat.
   About the end of April 1912, the components of the Gnome-powered biplane were taken to Brooklands and there assembled in hangar No.32, which had also been taken over by COW from Howard Wright. Its debut at Brooklands created considerable interest and an aviation journalist writing for Aeronautics was later to record: 'In strength, in neatness and finish of design, in minute attention to detail, nothing finer than this splendid biplane has ever been produced m the country.' The biplane's first flight was made shortly afterwards by T.O.M. Sopwith, whose services as test pilot had been secured by COW. The flight was successful, Sopwith being particularly impressed by the machine's remarkable rate of climb, and was soon followed by a second with Manning as passenger. On the following day, the biplane was entered for an impromptu take-off competition and cross-country race held at Brooklands, Sopwith taking three passengers aloft for the first event, two of the passengers sitting at each side of the fuselage on the lower wing. From this time the biplane was nicknamed, Wombus (W.O. Manning's omnibus). The biplane was flown throughout the summer in preparation for the Military Trials but persistent trouble was experienced with the chain drive to the propeller, which resulted in the fitting of three 1-in roller chains instead of the single chain. Elevator area was also found to be inadequate and was increased.
   With the completion of the first COW biplane, construction of the Chenu-powered version progressed more quickly but this was not delivered to Brooklands until July 1912, when it was tested by Sopwith. The second biplane's structure was similar to the first, changes being dictated by the biplane's configuration only. Besides having a smaller span, the fuselage was shortened by the removal of one bay behind the cockpit. The fuselage was also mounted higher in the wing gap since the propeller was directly driven and propeller ground clearance had to be maintained without lengthening the undercarriage legs. The Chenu engine was fully cowled and its radiators were mounted on each side of the forward cockpit. A four-blade propeller, made from a pair of superimposed two-blade propellers, was fitted, this somewhat unusual arrangement possibly arising from the transport and crating requirements of the Military Trials, although Manning may have considered the economics of being able to replace one two-blade propeller in the event of damage. The only other noticeable changes were the fitting of two short skids behind the undercarriage wheels and skids below the lower wingtips.
   The first COW Biplane, which had been allotted Trials No. 10, arrived at Larkhill in good time for the start of the Military Trials but its sister machine, given Trials No.11, had not reached Larkhill by 31 July, the stipulated deadline for all competitors. It had been delayed in its journey by road but despite its late arrival, was not disqualified from the competition. The Trials included twelve tests of which No.10 attempted only the first three, covering constructional requirements, quick assembly tests and the three-hour test, and No.11 failed to compete owing to engine trouble. In the quick assembly test No. 10 came fourteenth, five men taking 1 hr 51 min 45 sec to assemble the biplane ready for flight. The three-hour test was attempted on 22 August with F.P. Raynham at the controls but was abandoned after one hour when he was forced to land owing to a leak in the pressure pump, which transferred fuel from the ventral tank to the gravity tank. Further trouble with the propeller of No.10 prevented it from entering more of the tests. Unfortunately, Manning was abroad at the time these difficulties were encountered, and it was not until his return, late in August after the Trials, that he was able to investigate the faults. Howard Wright had left the Coventry Ordnance Works, about this time, to become chief designer to J. Samuel White & Co Ltd, of Cowes.
   Further test flights with No. 10 made at Brooklands, where both biplanes returned after the Trials, were unsatisfactory and led Manning to modify the machine using as many of the original components as possible. The modified biplane bore a slight resemblance to No.10 owing to the use of the latter's fuselage, fixed tail surfaces and rudder. The Gnome engine installation was retained but a new propeller of the same diameter was made. New wings of increased and unequal span and constant chord were fitted together with elevators of larger area. The upper-wing had inversely-tapered split ailerons and was carried by eight pairs of interplane-struts of reduced length, the lower-wing being attached close to the lower surface of the fuselage. The undercarriage legs were lengthened to maintain propeller ground clearance and again balloon tyres were used.
   Reconstruction of No. 10 was undertaken late in 1912 and the modified biplane was flown for the first time, by Raynham at Brooklands on 13 January, 1913. The new biplane proved more successful than the original but the chain drive to the propeller still gave trouble. A smaller diameter two-blade propeller was fitted directly to the engine, and, at the same time, the engine cowling was reshaped by the addition of two rounded fairings on each side of the propeller attachment. Thereafter the biplane was flown successfully throughout 1913.
   The fate of No. 11 remains unknown.

No.10
   Span: upper 40 ft, lower 24 ft 8 in; overall length 33 ft 3 in; height 12 ft 8 in; wing root chord upper and lower 6 ft; wingtip chord: upper 4 ft 6 in, lower 5 ft 2 in; gap 8 ft; tailplane span excluding elevators 8 ft, tail plane root chord 7 ft 10 m;. elevator span: original 4 ft, final 5 ft. 3 m, maximum elevator chord 3 ft 4 in; rudder height 4 ft; maximum rudder chord 3 ft, propeller diameter 11 ft 6 m; undercarriage track 6 ft 9 in; wheel diameter 2 ft 10 in; wing area: original 336.7 sq ft, final 319.7 sq ft; tailplane area excluding elevators 30.9 sq ft; total elevator area: original 17.3 sq ft, final 27.4 sq ft; total fin area 4 sq ft; total rudder area 15.6 sq ft.
   Weight empty 1,200 lb; weight loaded 1,950 lb.
   Maximum speed 60 mph; landing speed 20 mph.

No.10 Modified
   Upper wing span 56 ft; wing area 630 sq ft.
   Weight empty 1,100 lb; weight loaded 1,900 lb.
   Maximum speed 60 mph; landing speed less than 20 mph.

No. 11
   Span: upper 35 ft, lower 22 ft; overall length 31 ft 3 in; height 13 ft 2 in; wing chord upper and lower 5 ft 6 m; gap 8 ft; tailplane span excluding elevators 10 ft; tailplane root chord 6 ft 9 m, elevator span 6 ft 6 in; maximum elevator chord 4 ft; rudder height 5 ft 3 in; minimum rudder chord 4 ft 6 in; propeller diameter 11 ft 6 in; undercarriage track 6 ft 3 in; wheel diameter 2 ft 10 in; wing area 290.5 sq ft; tailplane area excluding elevators 35.8 sq ft; total elevator area 24 sq ft; fin area 4 sq ft; rudder area 108 sq ft
   Weight empty 1,250 lb; weight loaded 2,050 lb.
   Maximum speed 68-70 mph.


Coventry Ordnance Works Admiralty Type 54

   In 1913, the Coventry Ordnance Works received contract No. CP 40633/13 from the Air Department of the Admiralty for one seaplane. It was powered by a 160 hp Gnome rotary, and allotted serial number 54. The seaplane was fitted with wireless and allotted the call sign NO6 in August 1913. No record has been found of the aircraft in Service or ever being completed.

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Описание:

  • S.Ransom, R.Fairclough English Electric Aircraft and their Predecessors (Putnam)
  • H.King Sopwith Aircraft 1912-1920 (Putnam)
  • M.Goodall, A.Tagg British Aircraft before the Great War (Schiffer)
  • P.Lewis British Aircraft 1809-1914 (Putnam)
  • Jane's All The World Aircraft 1913
  • Журнал Flight