The Hawker Hurricane Source: http://www3.ns.sympatico.ca/hurricane/hurricane/image039.jpg GENERAL FACTS 14,500 Hurricanes built 1939-45 Used in all combat zones from Africa to Asia to the skies over Britain Responsible for the destruction of more enemy aircraft in the Battle of Britain than all other British fighters combined Sturdier than the Spitfire, though less advanced BACKGROUND The story of the Hurricane begins during World War I, when Sopwith Aviation Co. designed and produced biplanes (airplanes with both upper and lower wings). Its most successful model was the Camel, which shot down more enemy aircraft than any other British fighter. These planes usually had wooden frames covered by canvas and were not very aerodynamic. Sopwith Camel http://www.theaerodrome.com/aircraft/gbritain/sopwith_camel.html Sopwith Aviation shut down after the war, but its premises (hangers, field, and a skating rink-turned-production-center) came under the control of a new organization: Hawker Engineering Co. It was run and named after a former student of the Sopwith flight school, Harry Hawker. In the 1920’s, Hawker Engineering Company focused mainly on production of motorcycles, with a little work on airplane design. When Sydney Camm joined the design team, the company really began to advance in innovation. His first work was on improving biplanes, including introducing metal framing. The new planes were ordered in large numbers, at which point the company name became Hawker Aircraft Limited. What had started out as a humble airfield with a collection of equally modest buildings became the powerhouse for the Battle of Britain. DESIGN AND DEVELOPMENT In 1933, the Hawker design staff decided to respond to a challenge from the Air Ministry to all UK manufacturers. The challenge was to design a new frontline fighter for the Royal Air Force (RAF). Sydney Camm and company made a big leap in giving this new design only one set of wings, rather than the traditional biplane design. In order for the monoplane to work, the wing had to be thick, with a thickness at each point proportional to the distance from leading edge to trailing edge of the wing at that point. (This is called the chord.) In the original design, there was to be a fixed undercarriage (landing gear) and a Rolls-Royce Goshawk engine. The engine soon changed to a Rolls-Royce Merlin I engine, because it had a system to cool it using glycol, which allowed it to work at a higher operating temperature, and required a smaller radiator (thus creating less drag). For the sake of aerodynamics, designers also made the landing gear retractable. During tests, the doors that enclosed the retracted equipment tended to come loose, so they were removed. Just having the undercarriage pulled up into the body of the plane did a great deal for speed. At first the pilots had to operate the pump by hand, but a hydraulic later made it much easier Source: http://www3.ns.sympatico.ca/hurricane/hhp.jpg MILITARY ADAPTATIONS Up until this point, the Hurricane had been a private venture. In 1935, the government officially ordered a batch of them. However, before it was ready for combat, it needed further adaptations. The sliding canopy, which covered the pilot in his cockpit, blew off during several tests, so it had to be stiffened. At the same time, engineers designed a way to eject the canopy in an emergency, in case the sliding mechanism became stuck. The motivation to complete the Hurricane increased as Germany built up its air force with Bf109 fighters, which were also (inexplicably and distressingly) powered by Rolls-Royce engines. The Hurricane’s engine, meanwhile, was still unreliable—though one could rely on it to leak a lot of oil. Production was held up while waiting for the improved Merlin II engine to be developed. Surprisingly, it was only now that the wooden propeller design that had been used since the First World War was replaced by a three-bladed metal prop. To make the Hurricane into a true fighter, armor was added to resist enemy fire, and eight guns were mounted on the wings. A later version had 12 guns, and used a less flammable cooling solution in the engine. In 1936, the government ordered 600 planes, a decision they would not regret. The Hurricane continued to be improved throughout the war, but it was difficult to test the alterations, because the planes were in so much demand for actual combat. Click here for specifications about the Spitfire and Hurricane.