page_title: Hawker Hurricane
section_title: Prototype and trials
hierarchical_section_title: Hawker Hurricane / Development / Prototype and trials
caption_attribution_description: K5083, the prototype Hawker Hurricane at Brooklands prior to its maiden flight. Construction of the first prototype, K5083, began in August 1935 incorporating the PV-12 Merlin engine. The completed sections of the aircraft were taken to Brooklands, where Hawker had an assembly shed, and re-assembled on 23 October 1935. Ground testing and taxi trials took place over the following two weeks, and on 6 November 1935, the prototype took to the air for the first time, at the hands of Hawker's chief test pilot, Flight Lieutenant P.W.S. Bulman.
context_page_description: The Hawker Hurricane is a British single-seat fighter aircraft of the 1930s–40s that was designed and predominantly built by Hawker Aircraft Ltd. for service with the Royal Air Force. It was overshadowed in the public consciousness by the Supermarine Spitfire's role during the Battle of Britain in 1940, but the Hurricane inflicted 60 per cent of the losses sustained by the Luftwaffe in the engagement, and fought in all the major theatres of the Second World War.
  The Hurricane originated from discussions between RAF officials and aircraft designer Sir Sydney Camm about a proposed monoplane derivative of the Hawker Fury biplane in the early 1930s. Despite an institutional preference for biplanes and lack of interest from the Air Ministry, Hawker refined their monoplane proposal, incorporating several innovations which became critical to wartime fighter aircraft, including retractable landing gear and the more powerful Rolls-Royce Merlin engine. The Air Ministry ordered Hawker's Interceptor Monoplane in late 1934, and the prototype Hurricane K5083 performed its maiden flight on 6 November 1935.
context_section_description: In July 1934 at a meeting chaired by Air Commodore Tedder, Air Ministry Science Office Captain F.W. ("Gunner") Hill presented his calculation showing that future fighters must carry no fewer than eight machine guns, each capable of firing 1,000 shots a minute. Hill's assistant in making his calculations was his 13-year old 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 Air Ministry's Operational Requirements branch, 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.
  By the end of August 1935, work on the airframe had been completed at Hawker's Kingston upon Thames facility 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. 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. 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. 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.
  By March 1936, the prototype had completed ten flying hours, covering all major portions of the flight envelope. Early 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. 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 favourable, stating that: "The aircraft is simple and easy to fly and has no apparent vices" and proceeded to praise its control response.
  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.
  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. Hawker's response to the issue was to request that spinning tests be waived, but the Air Ministry refused the request; 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 
caption: K5083, the prototype, photographed before its first flight in November 1935
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