Royal Air Force History

Supermarine Spitfire - History of a Legend

Part 3 - 1940 - Battle for survival

The 'Phoney War' continued for the first few months of 1940 until, on 9 April, the Germans invaded Norway and Denmark. One month later, they invaded the Low Countries and France.

From 10 May, Spitfire squadrons were authorised to carry out offensive patrols across the Channel. Spitfires first met Bf-109s and Bf-110s on 23 May: two of each type of Messerschmitt were lost, as were three Spitfires of 92 Squadron. Air Chief Marshal Sir Hugh Dowding, head of Fighter Command, successfully resisted pressure from the highest levels to reinforce the fighters in France with Spitfire squadrons, thus preserving the Spitfire force for the forthcoming sterner battles in defence of Britain. Despite this, 67 Spitfires were lost during the Battle of France and the Dunkirk evacuation. Some of the RAF squadron commanders learned valuable lessons from these experiences, including the realisation that the Luftwaffe's tactical formation of the 'finger four' was superior to the RAF's traditional vic of three aircraft and that it was advantageous to harmonise the fire of the guns to converge at 250 yards rather than 400. All benefited from the replacement of 87 octane petrol with 100 octane, which allowed the engines to run at higher boost, and increased the Spitfire's speed by 25 mph (40 km/h) at sea level and by 34 mph (55 km/h) at 10,000 feet.

After the fall of France, photographic reconnaissance came under the control of Coastal Command, using types including Spitfires, Wellingtons and Hudsons. The duck-egg blue camouflage gave way to deeper PR blue for high-altitude operations and a pale pink for low level work.

The Battle of Britain was fought between 10 July and 31 October 1940. At the beginning, Fighter Command had 27 squadrons of Hurricanes and 19 of Spitfires and it was the Hurricanes that bore the brunt of the fighting. Between the beginning of July and the end of October, 565 Hurricanes and 352 Spitfires were lost.

During the Battle, 19 Squadron was issued with half a dozen cannon-armed Spitfires, designated Mk IB as opposed to the eight machine gun-armed Spitfire, the Mk IA. The cannon's hitting power was recognised but jamming was still a problem and little success was achieved. Nevertheless, further cannon-armed Spitfires were issued to 92 Squadron and it was eventually realised that the best mix was an aircraft with two cannon and four machine guns.

The performance of the Spitfire Mk I and the Messershmitt Bf-109E was very similar. The former possessed a better turning radius at any height and was slightly faster below 15,000 feet, but the Messerschmitt was superior in the climb and marginally faster above 20,000 feet. The Messerschmitt's Daimler-Benz DB 601A engine had the advantage of fuel injection which enabled the aircraft to bunt (push negative g at the top of a manoeuvre or climb) without losing power. The Merlin engine of the Spitfire had a float-type carburettor which necessitated the aircraft performing the longer manoeuvre of rolling inverted before diving to maintain positive g, thus preventing the engine from cutting out as a result of fuel starvation.

In August 1940, the chief test pilot of Supermarine, Jeffrey Quill, arranged to be posted to No 65 Squadron for operational experience. He joined on 5 August but was recalled to Supermarine 19 days later to test the Spitfire Mk III. Nevertheless, he saw considerable combat in this short period and his experiences led to two important changes in the Spitfire. At high speed, the stick force from the ailerons had been very heavy and this was eventually found to be due to the fabric covering of the ailerons ballooning and causing a thicker trailing edge section. This was cured by fitting stiffer, metal-covered ailerons. This was a major improvement, but high stick forces at high speed continued to bedevil the Spitfire for the rest of its life. Quill also initiated an improvement in the optical quality of the cockpit side panels. He was concerned about rearward vision from the cockpit and this subsequently led to changes to the canopy and rear fuselage. One recommendation not implemented, however, was the installation of ammunition round counters, so the pilots still had no means of knowing how much ammunition they had left.

On 24 September, the Luftwaffe raided the Supermarine works at Woolston, on the outskirts of Southampton. Little damage was done to the factory, but nearly 100 workers were killed when a shelter was hit. The area was bombed again two days later, killing 30 more and severely damaging the factory, halting production. This resulted in plans being implemented for the large scale dispersal of production facilities to some 60 different sites. On 30 September, the Westland factory at Yeovil, which had just begun to prepare for Spitfire production, was bombed by He-111s. As a result of these raids, only 59 Spitfires were produced in October, less than half the total for August - indeed, such was the need for fighters that a Spitfire fitted with a pair of Blackburn Roc floats was reconverted to a standard Mk I. The trial of the Spitfire as an amphibian had been mounted because of the lack of suitable airfields during the Norwegian campaign and the need to seek alternatives. Never again did production fall so low. The Castle Bromwich factory was starting to manufacture Spitfire Mk.II aircraft in quantity by then, especially after key Supermarine staff were sent to oversee the production lines. These aircraft were little different to Mk.Ias, but had Coffman cartridge starters to replace the unreliable electric starters of the earlier mark. By now the engine was a Merlin XII of 1050hp.

In August, VHF radio was fitted to a Mk I of 19 Squadron for the first time. However, HF equipment was not fully replaced for another two years.

Late in 1940, the first examples of the Bf-109F were encountered over Southern England. it proved far superior to the Hurricane and more manoeuvrable than the Spitfire above 25,000 feet. The Spitfire Mk III was still in the development stage and thus there was an urgent need to fill the gap.

After winning the Battle of Britain, Fighter Command quickly went on to the offensive. On 20 December, two Spitfires of No 66 Squadron flew the Command's first patrol over France since its fall. Such operations by pairs of fighters were known as 'rhubarbs'. They were to prove expensive.

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