Supermarine Spitfire Series

The Supermarine Spitfire is perhaps the single most recognizable fighter aircraft of the Second World War. Such fame is well deserved; it played a leading role in Britain’s duel with the Luftwaffe in 1940-41, while subsequent upgrades kept the series competitive even when the leading fighter was the American P-51 Mustang. Serving from 1938 to 1949, Spitfires made their mark as air superiority fighters, fighter-bombers and reconnaissance aircraft.

As the name suggests, Supermarine was a British concern that produced seaplanes, and was best known for the larger flying boats. The future designer of the Spitfire, Reginald J Mitchell, joined the firm (then known as Pemberton Billing, Ltd.) in 1916 and earned a key position as Chief Designer by 1919. The company’s niche was small, and in 1928, it was bought by the larger Vickers-Armstrong company. Supermarine was never assimilated into its parent company; however, it remained a subsidiary of Vickers specializing in seaplanes. The retention of Mitchell was a major priority for Vickers; the owners had hoped to encourage synergy by stimulating collaboration between Mitchell and their own best designers, notably Barnes Wallis, but differences in temperament doomed that effort and Vickers accepted its failure. The Supermarine asset was too valuable for further tampering; indeed, it consistently made money throughout the Depression.

The creation of the Spitfire was the product of two independent developments in the 1930s. The first was the establishment of new requirements by the Royal Air Force for fighter production.  Throughout the 1920s, the RAF had relied on traditional biplane designs, and it was becoming clear that research and development in aeronautics was outstripping the capabilities of the RAF. In 1930, it announced the first of a series of requirements calling for new fighter craft with specific performance capabilities. The successful design would need to balance a high rate of speed with good maneuverability and substantial armament, each of which served as a limitation of the other two characteristics. A high service ceiling, good provision for the pilot’s field of vision and a certain degree of simplicity to facilitate both production in quantity and maintenance during service filled out the terms of the original requirement, which was modified several times by 1935.

The issue of adequate armament was especially vexing, and did much to define the new generation of fighters emerging in the 1930s. During World War I, fighters routinely operated with just a single machine gun, and the exceptions rarely mounted more than two. Interwar developments had rendered such a configuration obsolete. Modern aircraft were hardier, and it required more damage to shoot them down, especially in the cases of bombers, the destruction of which was the primary job of interceptors. At the same time, the higher speeds of modern aircraft constricted the window of opportunity for a fighter to inflict telling damage on an enemy plane. The need to inflict heavy damage as quickly as possible inspired a call for eight .303 machine guns as an ideal configuration for a fighter. The 1935 requirement (F.10/35) also called for the provision of at least 300 bullets for each gun, and all armament was to be placed on the wings, avoiding the need for an interrupter gear to fire through the propeller’s path. Even so, the fighter was expected to meet or exceed 310 mph and to be able to climb as high as 30,000 feet.

The second factor contributing to the development of the Spitfire seemed much more unlikely. Nearly every year, seaplane producers competed for the Schneider Trophy in a race among the most advanced seaplanes that each could create. Success in these races depended on both more powerful engines and on a more aerodynamic frame, especially because the floats underneath the plane generated so much drag. Mitchell and his Supermarine team won the Trophy in 1922, 1927, 1929 and 1931. 1931 marked the final race in the series, because Supermarine had won three times during a five-year period. Britain’s victory was deemed permanent.

The S.6B seaplane used by Supermarine during the 1931 race achieved its high performance through the combination of a powerful engine built by Rolls-Royce and a particular fuselage and elliptical wing configuration that anticipated the curved appearance of the Spitfire. It was a combination that permitted a seaplane to exceed 400 mph; after the newest requirements in 1935, the RAF sought a fighter plane that could meet or exceed 310 mph despite its heavy armament.

Mitchell’s first effort to secure the RAF contract, the Type 224, failed signally. Its Rolls-Royce Goshawk engine was not powerful enough to compensate for the drag induced by its heavy gull-wings and non-retractable landing gear, both of which more closely resembled the design of the German Stuka dive-bomber than a successful fighter.

Gravely ill, Mitchell returned from a vacation on the continent with a firm conviction that war with Germany was coming soon, and he devoted his last few years to the creation of a fighter that would meet all of its challenges. He dropped the Goshawk engine in favor of an experimental engine being developed at Rolls-Royce, which would become known as the Merlin. He reconfigured the fuselage to accommodate the extra weight of the new engine. The wings were replaced with a wide elliptical design, reminiscent of the S.6B, but more gently tapering, offering plenty of room in the wings to mount four Browning machine guns, with ammunition, on each side and still accept the landing gear. Weight remained a concern, and the fuel tanks were limited to only 75 gallons.

The original prototype, differing from production models because of particulars like a two-bladed propeller and a flush canopy instead of a curved one, made its first flight in 1936, followed swiftly by an order for 310 examples. Fulfilling this order became difficult, and not just because of Mitchell’s death in 1937. The Spitfire was designed to be crafted, rather than mass-produced, and the Supermarine plant was not large enough to fulfill such an order by itself. Assembling pieces created elsewhere proved almost as difficult as producing everything locally because it was so difficult to standardize the complex handiwork involved in the Spitfire design. Delivery began in July, 1938, and the RAF still only had 49 examples at the start of 1939.

Quantities remained limited when the Battle of Britain began in 1940, with nine squadrons and parts of two others flying Spitfires. Numerically, the Hawker Hurricane was dominant. In terms of performance, however, the Spitfire was the clear leader. The Hurricane could reach speeds of only 318 mph, while the Spitfire could exceed 360. This made the Hurricane barely slower than the German Messerschmitt Me109D planes that saw extensive use early in 1940 (with a high speed of 323 mph), while the Spitfire beat the Me109D handily. In one respect, however, the original version of the Spitfire (known as Mark I) was noticeably weaker than its German opponent: eight machine guns were less effective than the twin 20 mm cannon supplemented by two machine guns that the Messerschmitts carried. Measured as weight of fire, the Me109 nearly doubled the Mark I’s fire, matching 17.9 lb. of projected metal against the 9.9 lb. fired by the Spitfire in a burst of the same duration. The British sought to redress this disparity in the second generation of Spitfires, specifically with the Mark IIB, which carried two 20 mm cannon and four machine guns. Conversely, the Germans boosted the speed of their newer Me109E planes to 354 mph, largely negating the speed advantage of the Spitfire. Tactics also changed, with the British abandoning their earlier V-formations in favor of the German Schwarm formation, which improved the visibility of the supporting pilots.

In the end, the Battle of Britain was decided by strategic considerations, from an ill-timed shift in German strategy from airfield destruction to the bombing of cities, to the benefits of flying over home soil, which meant that British pilots surviving a crash could return to duty, while German pilots became prisoners. Still, the Spitfire had earned its place already as a symbol of British resistance, and it still had much work to do. The Spitfire was continually upgraded during the war, branching out from its original air superiority role to perform valuable reconnaissance and ground attack duties as Britain shifted from a defensive to an offensive role in the war.

The Mark III existed in only one example, a test that was eventually abandoned. The Mark IV was built to take pictures over enemy territory, and saw only limited production (229 examples, contrasted with the 1566 Mark I Spitfires).

In March, 1941, a new generation of Spitfires appeared in the Mark V, which retained the two cannon/four machine gun weapons configuration, but sported a more powerful engine that raised its maximum speed to 374 mph. As the Mk VB, it remained the dominant British fighter into 1942, while the VC was modified to carry out the fighter-bomber role with provision for one or two bombs.

The Mark V was not superseded by the Mk VI, VII or VIII variants because these were specialized aircraft, with Mark VI and VII being designed for combat at high altitudes and the Mark VIII (fighter and fighter-bomber versions alike) being adapted to fight in warmer climates. In 1942, the Mark V was given an improved engine and produced as the Mark IX. The Mark X and XI Spitfires were strictly reconnaissance vehicles, and were not furnished with weapons. Naval versions of the Spitfire were built as the Seafire.

The next substantive step forward for the Spitfire was the Mark XII, which replaced the Merlin engines with the much more powerful Griffon IV; the Mark XII was intended as a response to the threat posed by the German Focke-Wulf Fw190. Its tenure was not long, being superseded by the Mk XIV after only 100 were produced. The Mark XIV had a pressurized cockpit for high-altitude work and a Griffon 65 engine that permitted speeds up to 450 mph. The Mark XIV routinely shot down V-1 flying bombs and claimed the first kill of a German Me262 jet.

Development continued through the war and beyond, with the Mark XVI being a dedicated tactical bomber and the Mark XVIII serving in a dual fighter and reconnaissance role. The latter appeared too late to see combat duty. Postwar development continued until 1947 with models reaching Mark 24; ultimately, the Spitfire ended its career because of the dominance of the jet.

In some respects, the history of the Spitfire represents an improbable success story, with a dominant air superiority fighter being built out of research for high-speed seaplanes, and a design created for hand-assembly by trained craftsmen being produced in numbers exceeding 22,000 (including the Seafires). During the Battle of Britain, it was outnumbered by the Hurricanes, but its impact was greater than its raw numbers, both in combat and in popular consciousness. When the Battle of Britain ended, continual development ensured that the Spitfire was never rendered obsolete until after the war. It remains as one of the most iconic weapons of World War II, especially for Britons.



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