Merlin the Wizard!

The engineering saying ‘if it looks right, it is right’, describes the Spitfire to perfection. For a 1930s design, even today, it still looks drop dead gorgeous from any angle, from the smooth curves over the nose, to the unique elliptical plan shape of its wings.

Always referred to as a ‘she’, this charismatic lady, the ultimate aviation collectable, a national icon, was just a war machine – a military vehicle to get the man and his machine guns, cannons, cameras or bombs, onto the target. Arguably, as the aircraft was developed, its looks became more aggressive, but were always in classic proportion.

Today, enthusiasts world-wide would rank the Spitfire in the top five of the most desirable aircraft. For most in the UK it will be number one by miles. Reginald Mitchell and his design team at Supermarine in Southampton embarked on the project specification F.37/34, to become the Spitfire, in 1935. The early company background was centered around fairly ponderous flying boats. From the mid 1920s they had pioneered technology in the production of a series of racing seaplanes that culminated in the outright win of the Schneider Trophy for Great Britain in 1931. Lessons learnt coupling the tightest, sleekest airframe to the massive power of Rolls-Royce race-rated engines would pay dividends on the Spitfire design.

With storm clouds developing over Europe, the need for an interceptor defensive fighter was clear. Several companies would bid for the contract, with the production forecast as about 300 units. Mitchell and his team focused on installing eight 303 Browning machine guns in the thinnest wing possible, exceeding the initial contract specifications, to which they married a slender fuselage behind the new Rolls-Royce combat-rated machine – the Merlin. Fuel would be sufficient to intercept the enemy and return with little over an hour’s duration at combat settings. Range would always be a problem with later marks of the Spitfire, demanding greater fuel over longer periods, as the Allies moved into Europe.

Using the technology pioneered on the racing seaplanes, Mitchell utilised the monocoque style of construction. The fuselage was basically four longitudinal members, or longerons, spacing a series of some fourteen sectional formers, or frames, spaced apart by short sections called intercostals. This framework was then covered in thin aluminium sheet held by rivets, this skin effectively taking the stress loads – no different from the current Boeing 747 of today.

This technique not only bestowed the Spitfire airframe with initial lightness and grace, but also made it capable of continuous upgrading and development, amply keeping pace with the output of increasingly powerful engines available from Rolls-Royce. By contrast, the Hurricane fighter from Hawkers, designed to the same contract specification, utilised the well proven tubular space frame as used on their successful bi-plane fighters. The principal stresses were taken through the tubes, with doped fabric over wooden frames, together with a detachable panelling, forming the exterior surfacing of the fuselage. The Hurricane was immensely strong, a stable gun platform, able to hold its own with the early mark Spitfires in the Battle of Britain in 1940, but it lacked that potential for development that was the hallmark of the Spitfire.

The prototype Spitfire first flew from Eastleigh in Hampshire on 5 March 1936. The chief test pilot Capt. ‘Mutt’ Summers is reported to have said ‘don’t change anything’ after the flight. Obviously over-simplistic, but a measure as to how ‘right’ the design team had got it.

Reginald Mitchell died on 11 June 1937, aged just 42 years. The prototype, serial number K5054, was the only Spitfire he would ever see flying.

Could he ever have imagined this would be the first of sorne 23,000 Spitfires built? Almost certainly not. Designed around the anticipated short order run, the design did not lend itself particularly well to mass production. The manufacture was labour intensive, and the inspired wings were particularly complex, with not a straight line anywhere. One principal benefit of this style of construction was that the work could be subcontracted or dispersed widely: cottage industry on a grand scale.

With pressing need, barely sufficient Spitfires were produced at Southampton to equip a few squadrons before the war. Though never enough, production numbers built up rapidly in the lull before the Battle of Britain in the summer of 1940. The Southampton factory was particularly vulnerable to German bombers, and despite wide dispersal the need for a safer ‘shadow’ factory had been identified.

The Air Ministry set the Nuffield Organisation into motion to build the Spitfire, using motor industry techniques, at a purpose built factory at Castle Bromwich near Birmingham. These very buildings today house the production fine of the new S type Jaguar.

Joe Smith took over the chief designer’s mantle after the death of Mitchell. To him must go the honours of developing the basic design so far and so wide, as detailed later in the text. Only wartime conditions could generate the energies for this to happen. If you compare the photos of the production of the MK 1 Spitfire with the MK 47 Seafire, you could be forgiven for thinking there is no family connection whatsoever. Measure the basic fuselage from engine firewall bulkhead datum to the tail unit attachment frame on both and it doesn’t change a jot: nor does the position of the cockpit layout.

The ability of the basic design, suitably reinforced, to accept bigger and more powerful engines, transmitting the power through increasing numbers of propeller blades, carrying ever more armament to greater height and further range, is what separates the Spitfire from its contemporaries. The MK 1 Spitfires entered RAF service before the War with a 27 litre Rolls-Royce Merlin engine developing just over 1000hp driving a fixed pitch two-blade propeller. The Seafire MK 47 entered Royal Navy service in 1946 with a 36.7 litre Rolls-Royce Griffon engine developing 2350hp driving a six-blade variable pitch contra-rotating propeller. A spectacular development rate.

Pilots simply loved the Spitfire. It was a thoroughbred of its time. The controls were harmonious and it was an absolute joy to fly. Above all, it was reliable. As wing loadings increased with additional fuel and ordnance, and the increased engine torque needed harnessing, some flying refinement was lost, but it was a small price to pay. Spitfires operated in every major theatre of World War Two From the deserts of North Africa to the jungles of Burma, from Darwin to Archangel, the Spitfire was there, the principal RAF day fighter. Indeed it is one of the few fighter aircraft, either Allied or Axis, to be in continuous production during the whole of World War Two. Apart from the hundreds of Spitfires supplied to Russia and Australia during the hostilities, at the end of the war well over twenty countries re-equipped with the surplus Spitfires through the late 1940s, as the RAF made way for the new jet age.