What is the allure of the Spitfire? Is it the beauty of that elliptical wing, the sound of the Rolls Royce Merlin engine, or just the sheer beauty of the overall design? Whatever it is, the Spitfire remains one of the easiest aircraft for the casual observer to recognise and it has captured the hearts of generations of people.
As has been rightly said on many occasions, it just looks right, and according to many pilots who have had the privilege of piloting her, she flies right too. It is light on the controls yet almost flies itself. The Spitfire is generally very forgiving, and the only testing part when flying her is the approach and landing, in part to the long nose and those narrow undercarriage legs.
More than 20,000 examples of this legendary fighter have been built across all marks, making it one of the most produced ‘British’ fighters of World War Two – but not the most produced fighter of World War Two. That distinction is held by another aircraft.
The Spitfire was produced from the Mark (Mk) 1 to the Mk 24, and she was also modified and built as the Seafire, Spiteful and Seafang.
The Spitfire flew in many configurations from fighter, fighter-bomber, dive-bomber, ground attack, photo-reconnaissance (PR) and even as a race plane.
Besides various types of Rolls Royce Merlin powered Spitfires, later models had the more powerful Rolls Royce Griffon engines, and one captured example had a German Daimler DB605A engine fitted as used on the Messerschmitt Bf109.
Spitfires wore many types of propellers, from two blades through to five blades, and even six blade contra-rotating propellers.
The Spitfire has also had floats fitted, worked as a tug aircraft, and some were converted into two-seaters.
HISTORY AND DEVELOPMENT
In October 1931, the Air Ministry issued Specification F7/30 aimed at providing the RAF with a replacement aircraft for the Bristol Bulldog biplane fighter. Working with Rolls Royce, RJ Mitchell of Supermarine and his team designed the Type 224. Seemingly forgetting what they had learned in the Schneider races, the Type 224 had a thick cranked wing profile, with corrugated leading edge sections, was overweight, underpowered, and had lots of drag due to the wing and fixed undercarriage fairings.
Unsurprisingly, Supermarine lost the contest against their competitor Gloster, who produced the winning design, becoming the last biplane fighter for the RAF – the Gloster Gladiator.
While unsuccessful, the Type 224 was the true ancestor of the Spitfire.
Contrary to the legend, the famous race planes of the Schneider Trophy Races were not the ancestors of the Spitfire, as they had no common parts or designs employed in the Spitfire. Nonetheless, the knowledge gained by RJ Mitchell and Supermarine were very beneficial in further aircraft designs.
Supermarine tried to get the Air Ministry to bestow the name ‘Spitfire’ on any production examples of the Type 224 produced, but this was not to be.
Supermarine decided to go it alone with further ongoing development of the Type 224. They removed the cranked wing and reduced the span and fitted retractable undercarriage under Specification No.425a. At the time, Rolls Royce were developing the PV12, a 27 litre V12 engine which Mitchell then had fitted to what had now become the Type 300.
Air Marshall Sir Hugh CT Dowding of the Air Council issued an order in December 1934 for a single prototype of the Type 300 from Supermarine. Specification F.37/34 was issued on 3 January, 1935 to cover development and purchase of the Type 300. The fighter was to have eight machine guns in the wings, the undercarriage able to withstand four and a half times the fully loaded weight of the aircraft, a tailwheel, and carry 75 Imperial gallons (341 litres) of fuel.
Credit for the famous elliptical wing of the Spitfire must go to Joseph Smith. The wing was a stressed skin design with a single main spar. This was covered forward of the spar with a heavy gauge, light alloy sheet to form a torsion box. Aft of the spar, thinner gauge metal was used with girder ribs. The shape of the wing was difficult to build, but the aerodynamic qualities were considered so beneficial that the design was kept.
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 leading to the lowest amount of induced-drag. The ellipse was skewed so that the centre of pressure, which occurs at the quarter-chord position, aligned with the main spar, thus preventing the wings from twisting.
Mitchell and Smith have sometimes been accused of copying the wing shape of the Heinkel He70, which first flew in 1932. Beverly Shenstone, the aerodynamicist on Mitchell’s team, explained, “Our wing was much thinner and had quite a different section to that of the Heinkel. In any case it would have been simply asking for trouble to have copied a wing shape from an aircraft designed for an entirely different purpose.”
It is a sad fact that RJ Mitchell did not live to see the Spitfire fly, as he died on 11 June, 1937, aged 42. He had fought cancer since being diagnosed in 1933.
Joseph Smith, who had worked on the project since inception, now became Chief Designer at Supermarine.
A Legend takes to the skies
In overall silver/grey and given the markings of K5054, on 5 March, 1936, piloted by Joseph ‘Mutt’ Summers, the Type 300 made its maiden flight, lasting between 15 and 20 minutes. For this flight the wheels (what the British then called ‘the chassis’) were left extended.
On landing, Summers was quoted as saying, “Don’t Change anything.”
The second flight occurred on 10 March, this time with the wheels retracted.
The type 300 officially only received its name of ‘Spitfire’ on 10 June, 1936.
The K5054’s flying career ended abruptly one day into World War Two on 4 September, 1939, being ground-looped on landing and ending up on its back, unfortunately killing the pilot Flt Lt GS White.
Many people incorrectly believe that the prototype Spitfire was a wooden aircraft, with only production examples being alloy. Confusion comes from the following history: A non-flying wooden mock-up of the Type 300 existed in 1935 which had a cruciform tailplane located halfway up the fin. This was later changed to under the fin to aid recovery in spins.
The original Type 300 was of metal alloy construction, with the rudder, ailerons and elevator covered in fabric.
A replica K5054 Spitfire (G-BRDV) which was constructed mainly of wood had a brief flying career. She still exists today and can be seen at Solent Sky, Hampshire. An all-metal replica exists at the Battle of Britain Museum, Hawkinge, Kent.
Various Mk’s and conversions
Production Spitfires were built from the Mk I to the Mk 24 with various sub-marks, excluding the Seafire, Spiteful and Seafang aircraft.
The Spitfire brought down its first German plane, a Heinkel He111 bomber, over the Firth of Forth in Scotland on 16 October, 1939.
The Spitfire first saw action over foreign soil at the evacuation at Dunkirk in 1940.
Early Spitfires had a flat sided overhead canopy which restricted visibility and made the cockpit cramped. In January 1940, a Spitfire Mk II (K9791), a modified Mk I, was tested with a new blistered hood canopy based on the PR variants to improve rear visibility for the pilot.
It was deemed a success, and it was recommended that all future production examples be fitted with this new type of canopy.
One of the most important modifications was the cut-down rear fuselage and tear-drop canopy.
Work on this was started on an Mk VIII (JF299) in January 1943. The aircraft was sent to North Africa for part of its evaluation, and on its return was returned to stock Mk VIII configuration. First production examples of the tear-drop canopy were introduced on some models of the Mk IX, notably the SAAF receiving some of these aircraft.
The first two-seater Spitfire was a South African example, a Spitfire Mk V serial number ES127 wearing the codes ‘KJ-I’. This was a field modification done in 1943 with a second open cockpit located directly in front of the original cockpit. The top front fuselage fuel tank was removed, with possibly the lower fuel tank also removed. No controls were fitted, and she was used as a taxi or for air experience flights. Because she had no canopy fitted, it was a very breezy Spitfire and no doubt gave very memorable, if not frightening air experiences for many.
Later two-seater Spitfires were modified and built at the factory with the second seat behind the main seat with dual-controls. The main seat was moved slightly forward to deal with the Centre of Gravity issues and to give the second seat better elbow room. Some of the two seat Spitfires had raised seats and canopies.
The first Seafire produced was known as the Mk 1. Ex standard Mk Vb’s equipped with arrestor gear for operations from aircraft carriers were used. Additionally modifications also involved adding slinging gear for catapult operations and strengthening mountings where required. Various other Marks of Seafires were produced from Mk II, Mk III (Folding-wing), Mk XV (Griffon-powered), Mk XVII (cut-down rear fuselage and tear-drop canopy), Mk 45, Mk 46 (contra-rotating propeller) and the ultimate Mk 47 (Super Seafire) with six-blade contra-rotating propellers powered by one Rolls Royce Griffon producing 2,375 hp (1,772 kW).
The Spiteful was also known as the Laminar Spitfire, as it took the fuselage of the Mk XIV and mated it to a new laminar wing. This was designed to increase performance by reducing drag and increasing lift by delaying the breakaway of the boundary layer over the surface of the wing. The thickest point of the wing was near as possible to mid-chord, and the elliptical wing design was discarded in favour of a tapering shape. The undercarriage was changed from retracting outwards to retracting inwards towards the fuselage, giving the Spitfire, for the first time in its history, a stable wide landing gear.
Two naval prototypes of the Spiteful were ordered to produce the Seafang. It was the ultimate example of the Spiteful. However, as the jet-age had arrived, only 16 were built.
A development of the Spiteful with a jet engine was built, resulting in the Royal Navy adopting it as its first carrier-based jet fighter, the Supermarine Attacker.
The first export customer was the French Air Force, requesting three examples, but receiving a single example on 18 July, 1939. This aircraft was the 251st Spitfire off the production line. Unfortunately at the fall of France the aircraft was supposed to be burnt at Orleans, but fell into German hands, albeit in a non-flyable state.
Other nations to fly the flag on the Spitfire were Israel, Egypt, South Africa, India, Australia, USA, Canada, Rhodesia, Portugal, Belgium, Poland, Malta and even
China. Many other nations not listed here also received Spitfires in various Mks.
About 240 examples of the Spitfire are displayed in museums across the world and over 50 Spitfires are in flyable or near flyable condition. It seems as if this iconic aircraft will see its 90 and 100 year anniversary.
Happy 85th Birthday Supermarine Spitfire.