Hurricane

The Hawker Hurricane

Type : Single Seat Fighter
Description : Low Wing Monoplane

Wingspan : 40 ft 0 inches ( 12.19 m )
Length : 31 ft 11 inches ( 9.73 m )
Height : 13 ft 1 1/2 inches ( 4.0 m )
Wing Area : 257.5 sq feet ( 23.92 m sq )

Power Plant : Rolls Royce Merlin II or III V12 liquid cooled
piston engine
B.H.P. : 1030 bhp
Armament : 8 wing mounted 0.303 Browning machine guns
Weight empty : 4670 lb ( 2119 kg )
Weight Loaded : 6,600 lb ( 2995 kg )

Performance
Max Speed : 330 mph (531 kph ) at 17,500 ft ( 5335 k )
Initial Climb Rate : 2,300 ft per min ( 700 m per min )
Service Ceiling : 36,000 ft ( 10,950 m )
Range : 425 miles ( 684 km )

Service
First Flight : 6 November 1935 ( prototype )
Mk 1 on the 12 October 1937
Service Entry : December 1937

HAWKER HURRICANE single-seat fighters of the Royal Air Force have seen more action in the Second World War than has any other type and they have shot down more enemy aeroplanes than any other fighter. The success of the Hurricane in a year of War has placed it among the great aeroplanes of all time. Hawker Aircraft Ltd., through its fine designing team, came to the forefront among the World's builders of aeroplanes when it turned out the famous Hart series. The Hurricane has made its name on active service and so has come triumphantly through an ordeal with which no peacetime design can ever compete. The design of the Hurricane was the product of team work, a co-operative effort by a loyal staff working under Mr. Sydney Camm, Hawker's Chief Designer. In its early stages in the Spring of 1933 the design for the aeroplane which eventually became the Hurricane was known in the Hawker design office as the " Fury Monoplane." The early General Arrangement drawing, of December, 1933, shows a graceful little low-wing monoplane with a fixed cantilever spatted undercarriage. It was designed for the 660 h.p. Rolls-Royce Goshawk steam cooled motor, which accounts for the absence of a radiator. In plan form the wing is remarkably like that of the Hurricane. The design loaded weight was only 3,807 lb. the span 38 feet. In 1934 the design crystallised when Rolls-Royce Ltd. produced their P.V.12 engine which had an output of 1,025 h.p. at 15,000 ft. This motor later became the Merlin " C " and then the Merlin II, the engine installed in the Hurricane I. About the middle of 1934 the Air Ministry specification F.36/34 was designed to fit in with the general layout of the new Hawker monoplane which had by then acquired a retractable undercarriage. And as the F.36/34 the Hurricane was known until it went into production early in 1936. The decision to build the prototype was taken in December, 1934, and the first machine was flown for the first time, only eleven months later, on November 6, 1935. Its retractable undercarriage and enclosed cockpit were both new to British fighters at that time. Although when it first appeared in public even experienced pilots believed that it must be difficult to fly.

In the original design the armament chosen was 4 machine-guns housed in the fuselage and firing through airscrew disc with interrupter gear. Not till much later this changed for the present familiar armament of eight guns, four in each wing, firing outside the airscrew disc without complication of interrupter gear. The wide track undercarriage, designed to fold up inwards, and the medium-pressure tyre's both helped towards affording the good take-off from indifferent aerodromes. The Hawker steel-tube construction had long since proved its fine qualities in maintenance and it was preserved when the designer moved forward from the biplane to the monoplane. Really rapid take-off was made possible in the later versions by controllable-pitch airscrews; and thus, three high qualities - good take-off, high rate of climb and wonderful manoeuvrability-combined with great fire-power account for the extra-ordinary successes scored by Hurricane squadrons of the R.A.F. over Great Britain. The prototype was designed to fly at a loaded weight of 5,700 lb. In the first production machine this was increased to 5,850 lb. and the first production Hurricane actually flew at 6,000 lb. loaded weight. The first flight in it was made by Flight Lieutenant P. W. S. Bulman at Brooklands on November 6, 1935. At that time the Hawker Monoplane Fighter, as it was called, was resplendent in silver dope and polished cowling. Flight Lieutenant Bulman felt so confident of its handling qualities after only a few hours of tests that he flew in close formation on the Hawker Hart to afford close-up photographs. As the first British single-seat monoplane fighter with a fully retractable undercarriage it created a sensation. Much pioneer research work was done with the prototype K5083 as there was hardly any existing data on high-speed military monoplanes at that time. The Hurricane was put into production early in 1936 and the first production machine L.1547 flew in October, 1937. The position of the radiator under the centre-section of the wing was selected to take the maximum advantage of the slipstream effect.

Eight Browning machine-guns and night-flying and navigational equipment were installed. The guns were grouped together compactly, four on each side outboard of the airscrew disc. In fact the wings were designed round the gun bay to gain the maximum efficiency. After the Hurricane had been in service for a short while the tail wheel was made non-retractable for further simplicity. In this form with a two-blade fixed-pitch wooden airscrew the top speed of the Hurricane was 330 m.p.h. at 17,000 ft. Since it first went into squadron service with No. 111 (Fighter) Squadron, R.A.F. at Northolt early in 1938 modifications have been made which distinguish the latest Hurricanes from the earlier models. First of all there was the fitting of the anti-spinning fin under the fuselage. Then came the introduction of the ejector-type exhaust manifolds which gave an increase in the top speed of about 10 m.p.h. and a corresponding gain in cruising speed and faster climb. More recently the fitting of the de Havilland and Rotol three-blade constant-speed airscrews has greatly improved the take-off and climb and added a further 5 m.p.h. to the top speed. From a structural point of view the metal-framed fabric-covered wing has been replaced by an all-metal stressed-skin wing of great structural efficiency. The new pair of wings is about 70 lb. lighter than the fabric-covered wings and has much greater stiffness although the section and plan forms remain unchanged. In this latest form, with metal wing, ejector exhausts and Rotol constant-speed airscrew the Hurricane I has a top speed of 335 m.p.h. at 17,500 ft.

The Structure The wings are divided into three main components, the centre section and the two outer wings. The centre section consists primarily of two continuous spars, the polygonal rolled-steel booms and steel plate webs, connected by ribs and drag bracing. It houses the retractable undercarriage and main fuel tanks. The outer wings of the prototype and early production Hurricanes were built up on two main spars similar in construction to the centre-section spars, and braced torsionally by a system of strong diagonal members between the spars. The wings were fabric covered over a framework of light metal ribs. . In 1938 a completely new stressed-skin outer wing was designed. It was introduced on the production Hurricanes in 1939. The new outer wings are built up on two main spars of extruded s-section booms with double webs at the inboard end which are reduced to T-sections with single webs towards the tip. A diagonal bracing system in the gun bay was found to be convenient. The diagonals are now made of T-section extrusions with plate webs. Immediately outboard of the gun bay the wing is of the fully-stressed-skin type and has two light auxiliary spars as well as the two main spars. The whole wing is covered with a stressed skin of light alloy, 20gauge thick on the top surface and 22 gauge on the bottom. The ribs are pressed from sheet. The loads are diffused from the diagonally braced gun bay to the stressed-skin portion through a torsionally stiff box rib made up of two heavy gauge plate ribs with extruded T section booms immediately outboard of the gun bay. There is an extra covering of 16 gauge light alloy as a reinforcement underneath the normal skin covering. The ailerons, which have a metal framework and fabric-covering, are built up on a tubular steel spar. They are the same as on the earlier wings. The fuselage is built up on a basic rectangular structure of steel and light alloy tubes with squared ends. The tubes are connected by the standard Hawker method of flat plate fittings secured by tubular rivets or bolts. The whole is rigidly braced. This basic structure is faired to an oval section covered with detachable metal panels forward, and aft with fabric over light wooden formers and stringers. The whole of the cantilever tail unit has a metal frame and fabric covering. The fin is built integral with the rear fuselage. The rudder is mass balanced. The tailplane is of the fixed type. The aerodynamically balanced elevators have trimming tabs. The retractable undercarriage has two semi-cantilever Vickers shuck-absorber struts hinged at the outboard ends of the centre section front spar, and retracted inwards by a Hawker mechanism actuated by Dowty hydraulic rams, which brings the wheels up between the centre section spars in the retracted position. A slight backward motion is provided by a hinged rear strut which slides on a guide at right angles to the spar of the wing. Emergency extension is by gravity. Dunlop wheels and pneumatic brakes are fitted as standard. The Dowty tail wheel unit is not retractable. Power Plant The standard 1,030 h.p. Rolls-Royce Merlin III is mounted on a tubular structure similar in construction to the main fuselage. The motor drives a Rotol three-blade constant-speed airscrew of 11 ft. diameter. The Rotol is now standard on the Hurricane, the De Havilland airscrew on the Spitfire. Some Hurricanes have de Havilland airscrews and can be recognised by the more pointed spinner as compared with the rounded spinner of the Rotol. These Rotol airscrews have wooden blades as standard. The fuel is carried in two main tanks in the centre section between the spars with a total capacity of 69 gallons. A further 28 gallons is carried in the reserve tank in the fuselage in front of the pilot. The oil tank, with an effective capacity of 7 + gallons, is in the port leading edge of the centre section. The eight Browning machine-guns mounted in the wings, fire at a total rate of 9,600 rounds per minute. Complete night flying equipment, with landing lights in the wing leading edge, navigation lights, oxygen, radio, flare tube, etc., is fitted as standard equipment. The main glycol radiator is housed in a duct under the fuselage below the cockpit. The oil cooler is sandwiched between the two elements of the glycol radiator. The enclosed cockpit has a sliding canopy, immediately over the centre section to give the pilot a good forward view. A bullet - proof windscreen and armour protection for the pilot are provided. The seat is adjustable for height, and the rudder bar for length of leg. With full tanks the Hurricane has a range of 830 miles at 168 m.p.h. cruising at 5,000 ft. Cruising at 232 m.p.h. at 25,000 ft. the range is still 695 miles.

Squadrons allocated the Hurricane

No 1 Squadron	No 1 (RCAF) Squadron
No 3 Squadron	No 17 Squadron
No 32 Squadron	No 43 Squadron
No 46 Squadron	No 56 Squadron
No 73 Squadron	No 85 Squadron
No 87 Squadron	No 111 Squadron
No 145 Squadron	No 151 Squadron
No 213 Squadron	No 229 Squadron
No 232 Squadron	No 238 Squadron
No 242 Squadron	No 249 Squadron
No 253 Squadron	No 257 Squadron
No 302 Squadron	No 303 Squadron
No 310 Squadron	No 312 Squadron
No 501 Squadron	No 504 Squadron
No 601 Squadron	No 605 Squadron
No 607 Squadron	No 615 Squadron

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