Hawker Hurricane

Hurricane
Hurricane mk1 r4118 fairford arp.jpg
Hurricane Mk I (R4118), which fought in the Battle of Britain
RoleFighter
National originUnited Kingdom
ManufacturerHawker Aircraft
DesignerSydney Camm
First flight6 November 1935
Introduction25 December 1937[1]
Primary usersRoyal Air Force
Royal Canadian Air Force
Produced1937–1944
Number built14,583[2]
VariantsHawker Hurricane variants

The Hawker Hurricane is a British single-seat fighter aircraft of the 1930s–1940s that was designed and predominantly built by Hawker Aircraft Ltd. for service with the Royal Air Force (RAF). Although overshadowed in the public consciousness by the Supermarine Spitfire's role during Battle of Britain in 1940, the Hurricane actually inflicted 60 percent of the losses sustained by the Luftwaffe in the engagement. The Hurricane went on to fight in all the major theatres of The Second World War.

The Hurricane originated from discussions during the early 1930s between RAF officials and British aircraft designer Sir Sydney Camm on the topic of a proposed monoplane derivative of the Hawker Fury biplane. Despite an institutional preference at the time for biplanes and repeated lack of interest by the Air Ministry, Hawker chose to continue refining their monoplane proposal, which resulted in the incorporation of several innovations that would become critical to wartime fighter aircraft, including retractable undercarriage and a more powerful engine in the form of the newly developed Rolls-Royce Merlin engine. In late 1934, the Air Ministry placed an order for Hawker's "Interceptor Monoplane". On 6 November 1935, the prototype Hurricane, K5083, performed its maiden flight.

In June 1936, the Hurricane was ordered into production by the Air Ministry; it entered squadron service on 25 December 1937. The manufacture and maintenance of the aircraft was eased by its use of conventional construction methods, which enabled squadrons to perform many major repairs themselves without external support. The Hurricane was rapidly procured prior to the outbreak of the Second World War in September 1939, when the RAF had 18 Hurricane-equipped squadrons in service. The aircraft was relied upon to defend against the numerous and varied German aircraft operated by the Luftwaffe, including dogfighting with the capable Messerschmitt Bf 109, across multiple theatres of action.

The Hurricane evolved through several versions and adaptations, as bomber-interceptors, fighter-bombers and ground support aircraft in addition to fighters. Further navalised versions, which were popularly known as the Sea Hurricane, had modifications enabling their operation from ships. Some were converted to be used as catapult-launched convoy escorts. By the end of production in July 1944, 14,487 Hurricanes had been completed in Britain and Canada.

Development

Origins

During the era in which the Hawker Aircraft company developed the Hurricane, RAF Fighter Command comprised just 13 squadrons, equipped with the Hawker Fury, Hawker Demon, or the Bristol Bulldog, all biplanes furnished with fixed-pitch wooden propellers and non-retractable undercarriages.[3][4] At the time, there was an institutional reluctance towards change within the Air Staff; according to aviation author Francis K. Mason, some senior figures were prejudiced against the adoption of monoplane fighter aircraft, while mid-level officers were typically approachable on the subject and design concepts that made use of such configurations.[4]

In 1934, the British Air Ministry issued Specification F.7/30 in response to demands within the Royal Air Force (RAF) for a new generation of fighter aircraft. Earlier, during 1933, British aircraft designer Sydney Camm had conducted discussions with Major John Buchanan of the Directorate of Technical Development on a monoplane based on the existing Fury.[5] Mason attributes Camm's discussions with figures within the RAF, such as Squadron Leader Ralph Sorley, as having provoked the specification and some of its details, such as the preference for armaments being installed within the wings instead of within the aircraft's nose.[6]

Camm's initial submission in response to F.7/30, the Hawker P.V.3, was essentially a scaled-up version of the Fury biplane.[7] However, the P.V.3 was not among the proposals which the Air Ministry had selected to be constructed as a government-sponsored prototype. After the rejection of the P.V.3 proposal, Camm commenced work upon a new design involving a cantilever monoplane arrangement, complete with a fixed undercarriage, armed with four machine guns and powered by the Rolls-Royce Goshawk engine. The original 1934 armament specifications for what would evolve into the Hurricane were for a similar armament fitment to the Gloster Gladiator: four machine-guns, two in the wings and two in the fuselage, synchronized to fire through the propeller arc. By January 1934, the proposal's detail drawings had been finished, but these failed to impress the Air Ministry enough for a prototype to be ordered.[8]

Camm's response to this rejection was to further develop the design, during which a retractable undercarriage was introduced and the unsatisfactory Goshawk engine was replaced by a new Rolls-Royce design, initially designated as the PV-12, which went on to become famous as the Merlin engine. In August 1934, a one-tenth scale model of the design was produced and dispatched to the National Physical Laboratory at Teddington. A series of wind tunnel tests confirmed the aerodynamic qualities of the aircraft were in order, and in September 1934, Camm again approached the Air Ministry. This time, the Ministry's response was favourable, and a prototype of the "Interceptor Monoplane" was promptly ordered.[9]

Prototype and trials

An early mock-up for the Hurricane's fuselage, showing side fuselage-mounted synchronized machine gun, like earlier British biplane fighters.

In July 1934 at a meeting chaired by Air Commodore Tedder, Air Ministry Science Office Captain F.W, ('Gunner') Hill presented the findings of his calculations that showed that future fighters must carry no less than eight machine guns, each capable of firing at 1,000 shots a minute. [10] Hill's assistant in making his calculations was his teenage daughter. Of the decision to place eight machine guns in fighters, Keith says 'The battle was brisk and was carried into very high quarters before the implementing authority was given. My Branch had made out a sound case for 8-gun fighters and if this recommendation had not been accepted and we had been content with half-measures, it might indeed have gone ill for us during the late summer of 1940'. Present at the meeting was Squadron Leader Ralph Sorley of the Operational Requirements branch of the Air Ministry who played an important role in the decision. In November 1934, the Air Ministry issued Specification F.5/34 which called for new fighter aircraft to be armed with a total of eight guns. However, by this time, work had progressed too far to immediately modify the planned four-gun installation. By January 1935, a wooden mock-up had been finished, and although a number of suggestions for detail changes were made, construction of the prototype was approved, and a new specification (F.36/34) was written around the design. In July 1935, this specification was amended to include installation of eight guns.[11][6]

By the end of August 1935, work on the airframe, performed at Hawker's Kingston upon Thames facility, had been completed and the aircraft components were transported to Brooklands, Surrey, where Hawker had an assembly shed; on 23 October 1935, the prototype was fully re-assembled.[6] Ground testing and taxi trials took place over the following two weeks. On 6 November 1935, the prototype K5083 took to the air for the first time at the hands of Hawker's chief test pilot, Flight Lieutenant George Bulman.[12] Bulman was assisted by two other pilots in subsequent flight testing; Philip Lucas flew some of the experimental test flights, while John Hindmarsh conducted the firm's production flight trials.[13] As completed, the prototype had been fitted with ballast to represent the aircraft's armament prior to the acceptance of the final multi-gun wing armament.[14]

By March 1936, a total of ten flying hours had been performed by the prototype, covering all major portions of the flight envelope. Early flight testing had gone reasonably well, especially in light of the trial status of the Merlin engine, which had yet to achieve full flight certification at this time and thus severe restrictions had been imposed upon use of the engine.[6] In early 1936, the prototype was transferred to RAF Martlesham Heath, Suffolk, to participate in initial service trials under the direction of squadron leader D. F. Anderson. Sammy Wroath, later to be the founding Commandant of the Empire Test Pilots' School, was the RAF test pilot for the Hurricane: his report was favorable, stating that: "The aircraft is simple and easy to fly and has no apparent vices" and proceeded to praise its control response.[15]

K5083, the prototype, photographed before its first flight in November 1935

In the course of RAF trials, despite the Merlin engine proving to be problematic, having suffered numerous failures and necessitating several changes, enthusiastic reports were produced in the aircraft and its performance figures. The trials had observed the aircraft to possess a maximum level speed of 315 MPH at an altitude of 16,200 ft, a time-to-climb to an altitude of 15,000 ft from takeoff of 5.7 minutes, and a stalling speed of 57 mph (only marginally higher than the Gladiator biplane), the last achieved using its flaps.[6]

In the course of further testing, it was found that the Hurricane had poor spin recovery characteristics, in which all rudder authority could be lost due to shielding of the rudder.[16] Hawker's response to the issue was to request that spinning tests be waived, but the Air Ministry refused the request;[17] the situation was resolved by the Royal Aircraft Establishment (RAE), who established that the aerodynamic problem had been caused by a breakdown of the airflow over the lower fuselage, and could be cured by the addition of a small ventral fairing and extension of the bottom of the rudder. This discovery had come too late for the changes to be incorporated in the first production aircraft, but were introduced upon the 61st built and all subsequent aircraft.[18]

In early 1936, the Hawker Board of Directors had decided, in the absence of official authorisation and at company expense, to proceed with issuing the design drawings to the production design office and to commence tooling-up for a production line capable of producing a batch of 1,000 Hurricanes.[19][20]

Production

Hurricane production line, 1942
Trainee aircraft fitters working on instructional partly-assembled Hurricanes, circa 1939–1940

In June 1936, the Hurricane was formally ordered into production, the Air Ministry having placed its first order that month for 600 aircraft.[16] On 26 June 1936, the type name "Hurricane", which had been proposed by Hawker, was approved by the Air Ministry; an informal christening ceremony for the aircraft was carried out during the following month during an official visit by King Edward VIII to Martlesham Heath.[21][16]

A key reason for the aircraft's appeal was its relatively simple construction and ease of manufacture. In comparison to the Supermarine Spitfire, it was significantly cheaper and involved less labour, requiring 10,300 man hours to produce versus 15,200 for the Spitfire.[22] As a large-scale war was looking increasingly likely, and time was of the essence in providing the RAF with an effective fighter aircraft, it was unclear if the more advanced Spitfire would enter production smoothly, while the Hurricane made use of well-understood manufacturing techniques.[22] This factor was equally applicable for its use within service squadrons as well, which were experienced in working on and repairing aircraft whose construction employed the same principles as the Hurricane, and the simplicity of its design enabled the improvisation of some remarkable repairs in squadron workshops.[22] A fabric-covered wing patterned upon traditional Hawker designs was initially adopted in order to speed up production; a higher-performing stressed-skin metal wing took its place in late 1939.[16]

On 12 October 1937, the maiden flight took place of the first production Hurricane I, which was powered by a Merlin II engine and flown by Flight Lieutenant Philip Lucas. Production deliveries had been delayed by roughly six months due to a decision to equip the Hurricane only with the improved Merlin II engine, while the earlier Merlin I had been prioritised for the Fairey Battle and the Hawker Henley.[16] By the following December, the first four aircraft to enter service with the RAF had joined No. 111 Squadron, stationed at RAF Northolt. By February 1938, No. 111 Squadron had received 16 Hurricanes.[16] Upon the outbreak of the Second World War, over 550 Hurricanes had been produced, which had equipped a total of 18 squadrons, while a further 3,500 aircraft were on order.[23][24]

During 1940, Lord Beaverbrook, who was the Minister of Aircraft Production, established an organisation in which a number of manufacturers were seconded to repair and overhaul battle-damaged Hurricanes. The Civilian Repair Organisation also overhauled battle-weary aircraft, which were later sent to training units or to other air forces; one of the factories involved was the Austin Aero Company's Cofton Hackett plant. Another was David Rosenfield Ltd, based at Barton aerodrome near Manchester.

A major manufacturer of the Hurricane was Canadian Car and Foundry at their factory in Fort William, Ontario, Canada. The facility's Chief Engineer, Elsie MacGill, became known as the "Queen of the Hurricanes".[24] The initiative was commercially led rather than governmentally, but was endorsed by the British government; Hawker, having recognised that a major conflict was all but inevitable after the Munich Crisis of 1938, drew up preliminary plans to expand Hurricane production via a new factory in Canada. Under this plan, samples, pattern aircraft, and a complete set of design documents stored on microfilm, were shipped to Canada; the RCAF ordered 20 Hurricanes to equip one fighter squadron and two more were supplied to Canadian Car and Foundry as pattern aircraft but one probably did not arrive. The first Hurricane built at Canadian Car and Foundry was officially produced in February 1940.[24] As a result, Canadian-built Hurricanes were shipped to Britain to participate in events such as the Battle of Britain.[24]

Overall, some 14,487 Hurricanes and Sea Hurricanes were produced in England and Canada.[25][clarification needed] The majority of Hurricanes, 9,986 were built by Hawker (who produced the type at Brooklands from December 1937 to October 1942 and Langley from October 1939 to July 1944), while Hawker's sister company, the Gloster Aircraft Company, constructed 2,750. The Austin Aero Company completed 300 Hurricanes. Canada Car and Foundry was responsible for the production of 1,451 Hurricanes[26].

In 1939, production of 100 Hurricanes was initiated in Yugoslavia by Zmaj and Rogožarski.[27] Of these, 20 were built by Zmaj by April 1941. Recognising that the supply of British-made Merlin engines might not be guaranteed, it was decided to fit one of the Yugoslavian Hurricanes with a Daimler-Benz DB 601 engine instead; this aircraft was test flown in 1941.[24] In 1938, a contract for 80 Hurricanes was placed with Fairey's Belgian subsidiary Avions Fairey SA for the Belgian Air Force; it was intended to arm these aircraft with an arrangement of four 13.2 mm Browning machine guns. Three were built and two flown with this armament by the time of the Blitzkrieg in May 1940, with at least 12 more constructed by Avions Fairey armed with the conventional eight rifle calibre machine gun armament.[28][24]

Other Languages
Afrikaans: Hawker Hurricane
العربية: هوكر هوريكان
asturianu: Hawker Hurricane
български: Хоукър Хърикейн
brezhoneg: Hawker Hurricane
čeština: Hawker Hurricane
Ελληνικά: Hawker Hurricane
Esperanto: Hawker Hurricane
français: Hawker Hurricane
Lëtzebuergesch: Hawker Hurricane
Bahasa Melayu: Hawker Hurricane
Nederlands: Hawker Hurricane
português: Hawker Hurricane
русский: Hawker Hurricane
Simple English: Hawker Hurricane
slovenčina: Hawker Hurricane
slovenščina: Hawker Hurricane
српски / srpski: Хокер харикен
srpskohrvatski / српскохрватски: Hawker Hurricane
українська: Hawker Hurricane
Tiếng Việt: Hawker Hurricane