The Supermarine Spitfire was a British single-seat fighter aircraft, used by the Royal Air Force and many other Allied countries before, during and after World War II. The Spitfire was built in many variants, using several wing configurations, and was produced in greater numbers than any other British aircraft. It was also the only British fighter to be in continuous production throughout the war.
Designed as a short-range, high-performance interceptor aircraft by R. J. Mitchell, chief designer at Supermarine Aviation Works, the Supermarine spitfire's distinctive elliptical wing were designed to have the thinnest possible cross-section, helping give the aircraft a higher top speed than several contemporary fighters, including the Hawker Hurricane.
In the mid-1930s, aviation design teams worldwide started developing a new generation of all-metal, low-wing fighter aircraft. The French Dewoitine D.520 and Germany's Messerschmitt Bf 109, for example, were designed to take advantage of new techniques of monocoque construction and the availability of new high-powered, liquid-cooled, in-line aero engines. They also featured refinements such as retractable undercarriages, fully enclosed cockpits, low drag and all-metal wings.
The Spitfire's airframe was complex: the streamlined, semi-monocoque duralumin fuselage featured a large number of compound curves built up from a skeleton of 19 formers, also known as frames, starting from frame number one, immediately behind the propeller unit, to the tail unit attachment frame. The first four frames supported the glycol header tank and engine cowlings. Frame 5, to which the engine bearers were secured, supported the weight of the engine and accessories, and the loads imposed by the engine.
The skins of the fuselage, wings and tailplane were secured by rivets, and in critical areas such as the wing forward of the main spar where an uninterrupted airflow was required, with flush rivets; the fuselage used standard dome-headed riveting. From February 1943 flush riveting was used on the fuselage, affecting all Spitfire variants. When combat experience showed that fabric-covered ailerons were impossible to use at high speeds, a light alloy replaced the fabric, enhancing control throughout the speed range.
The Spitfire featured a unique semi-elliptical wing shape designed to solve two conflicting requirements. The wing needed to be thin, to avoid creating too much drag, while still able to house a retractable undercarriage, plus armament and ammunition. An elliptical planform is the most efficient aerodynamic shape for an untwisted wing, leading to the lowest amount of induced drag.
The Luftwaffe were so ill prepared to counter the extraordinary attack and turning qualities of the Supermarine Spitfire that concerted efforts were made to destroy the main spitfire manufacturing plants at Woolston and Itchen, near Southampton. The first bombing raid, which missed the factories, came on 23 August 1940. Over the next month, other raids were mounted until, on 26 September 1940, both factories were destroyed, with 92 people killed and a large number injured. Most of the casualties were experienced aircraft production workers. Fortunately for the future of the Spitfire, many of the production jigs and machine tools had already been relocated by 20 September, and steps were being taken to disperse production to small facilities throughout the Southampton area to escape the lengthy German bombing campaign.
During its operational history there have been were 24 variations of Spitfire and many sub-variants. These covered the Spitfire in development from the Merlin to Griffon engines, the high-speed photo-reconnaissance variants and the different wing configurations.
The early Mk Is were powered by the 1,030 hp (768 kW) Merlin Mk II engine driving an Aero-Products "Watts" 10 ft 8 in diameter two-blade wooden fixed-pitch propeller, weighing 83 lb. From the 78th production airframe, the Aero Products propeller was replaced by a 350 lb de Havilland 9 ft 8 in diameter, three-bladed, two-position, metal propeller, which greatly improved take-off performance, maximum speed and the service ceiling. From the 175th production aircraft, the Merlin Mk III, with a "universal" propeller shaft able to take a de Havilland or Rotol propeller, was fitted. Following complaints from pilots a new form of "blown" canopy was manufactured and started replacing the original "flat" version in early 1939. This canopy improved headroom and enabled better vision laterally, and to the rear. At the same time the manual hand-pump for operating the undercarriage was replaced by a hydraulic system driven by a pump mounted in the engine bay.
The MkIA featured the original A-type wing design, with eight .303 calibre Browning machine guns, with 300 rounds per gun). The basic structure of the wing was unchanged until the C type in 1942. The one major alteration made to this wing, soon after production started, was the incorporation of a heating system for the gun bays, to prevent the guns from freezing up at high altitudes.
Other modifications soon followed including: a more simplified design of pitot tube was introduced and the "rod" aerial mast was replaced by a streamlined, tapered design. To improve protection for the pilot and fuel tanks a thick laminated glass bulletproof plate was fitted to the curved, one piece windscreen and a 3 mm thick cover of light alloy, capable of deflecting small calibre rounds, was fitted over the top of the two fuel tanks. In June 1940 de Havilland began manufacturing a kit to convert their two pitch propeller unit to a constant speed propeller. Although this propeller was a great deal heavier than the earlier types it provided another substantial improvement in take-off distance and climb rate. Starting on 24 June de Havilland engineers began fitting all Spitfires with these units and by 16 August every Spitfire and Hurricane had been modified.
One significant early modification for the supermarine spitfire and rolled out on all British aircraft was the installation of IFF (Identification Friend or Foe) Contactor Units which were a mechanical clock device with an electrical contact, which switched on the aircraft's communication transmitter for 14 seconds every minute at a special frequency channel. The direction finder stations (RDF) could then determine a fix on the aircrafts position and more accurately direct it to approaching enemy aircraft. These IFF transmitters were British versions of the American ‘Pip Squeak’ Contactor units fitted to US fighters such as the Mustang and P38 Lockheed Lightening.
Late in 1940, a Martin-Baker designed quick-release canopy mechanism began to be retroactively fitted to all Spitfires. The system employed unlocking pins, actuated by cables operated by the pilot pulling a small, red rubber ball mounted on the canopy arch. When freed, the canopy was taken away by the slipstream. Another important modifications was to replace the machine gun armament with wing mounted Hispano 20 mm cannon.
The Spitfire continued to play increasingly diverse roles throughout the Second World War and beyond. In the Mediterranean the Spitfire blunted the heavy attacks on Malta by the Regia Aeronautica and Luftwaffe and, from early 1943, helped pave the way for the Allied invasions of Sicily and Italy. On 7 March 1942, 15 Mk Vs carrying 90-gallon fuel tanks under their bellies took off from HMS Eagle off the coast of Algeria on a 600-mile flight to Malta. The Spitfire also served on the Eastern Front where approximately a thousand were supplied to the Soviet Air Force.
The Spitfire also served in the Pacific Theatre where the Spitfire met its match in the Japanese Mitsubishi A6M Zero, which could out-turn the Spitfire with ease, could sustain a climb at a very steep angle, and could stay in the air for three times as long. Over the Northern Territory of Australia, RAAF and RAF Spitfires helped defend the port town of Darwin against air attack by the Japanese Naval Air Force, suffering heavy losses largely due to the type's limited fuel capacity.
* Images shown are a guide and references only to show how the kit can be assembled allowing for modellers to add extra detail as required