The Spitfire V units continued to take heavy casualties, often inflicting little damage in return, throughout 1941 and well into 1942. Once the Mk IX started arriving in sufficient numbers this trend started to even out, although the 190s in particular continued to be a serious threat. [61] Hans "Assi" Hahn claimed 53 of his 108 kills against Spitfires and Josef "Pips" Priller claimed 68 of his 101 victories against the type, making him the highest scoring "Spitfire killer" in the Luftwaffe. Most of these victories were against the Mark V. Merlin development might have stagnated after 1940, any further power increases needed a more efficient means of transferring the heat away from the engine. Rolls Royce responded with a mixture of water and Ethylene Glycol which was put under pressure. This mixture also reduced the fire risk associated with using pure Ethylene Glycol. This system was first used in the Merlin XII used in the Spitfire Mk II. The rapid introduction of this system was only made possible by everything Rolls Royce had learnt about pressurised cooling when developing the Goshawk and early Merlin condenser systems. The first production Mk 21s used the same airframe as the Mk XIV. The first true Mk 21 prototype, PP139 first flew in July 1943, with the first production aircraft LA187 flying on 15 March 1944. The modifications over the Mk XIV made the Mk 21 sensitive to trim changes. LA201's poor flight control qualities during trials in late 1944 and early 1945, led to a damning report from the Air Fighting Development Unit Although the Griffon entered service long after the Merlin, in many ways it was an older design, based on the Buzzard which first ran in 1928 and which itself was a scaled-up version of the Kestrel. The big Buzzard ran at only 2,000 rpm and was mostly used to power large flying boats, but was developed into the "R" engine that ran at 3,400 rpm for short periods. The "R" powered the Supermarine S6 to its Schneider wins in 1929 and 31. A derated version of the "R" was being developed in 1933 but this was dropped so that Rolls Royce could concentrate on the Merlin. It is perhaps surprising that work on the Griffon did not start again in earnest until 1939, 10 years after the "R" engine flew. However, once restarted, work on the Griffon proceeded at a fantastic rate and the new engine was put to good use in the Spitfire. The Griffon ran at 2,750 rpm, a remarkably high speed for such a big engine. Spitfire PR.X1, EN685, of No.542 Sqn force-landed on 13 May 1944 in Germany. It was repaired and joined Zirkus Rosarius, marked T9+EK.

Spitfire Mk 19 PS583 takes off Spitfire Mk 19 (PS583) shows its elliptical wing planform Mk XIX (Mk 19) (types 389 and 390) [ edit ] One problem which did arise in service was localised skin wrinkling on the wings and fuselage at load attachment points; although Supermarine advised that the Mk XIVs had not been seriously weakened, nor were they on the point of failure, the RAF issued instructions in early 1945 that all F and FR Mk XIVs were to be refitted with clipped wings. [33] After the Normandy landings, some Spitfires (Griffon and Merlin engine marks) were retained in Britain to counter the V-1 flying bomb offensive in mid-1944 as part of the ADGB. [94] Supplies of a new aviation fuel, which was called "150 Grade", arrived from America in March 1944 and sufficient quantities were available to be used by ADGB fighters as the V-1 offensive started. The new fuel enabled the Rolls-Royce Merlin and Griffon engines to operate at higher boost pressures, especially at lower altitudes, for the duration of the anti-V-1 campaign. [95] Spitfire night fighter [ edit ] Spitfire Mark I of 602 Squadron at the gun butts having its eight .303 Brownings sighted in, early 1940. On 4 December 1939, the Supermarine design staff produced a brochure which mooted the idea of converting the Spitfire to use the Rolls-Royce Griffon engine. A top speed of 423mph (681km/h) at 18,500ft (5,639 m) was predicted. However, constant problems with the development of the Griffon meant that the decision to proceed with building a Spitfire with this engine didn't come to fruition until 1942, with the successful flight trials of the Mk IV. [12]The Mk XIX was the last and most successful photographic reconnaissance variant of the Spitfire. It combined features of the Mk XI with the Griffon engine of the Mk XIV. After the first 25 (type 389s) were produced, later aircraft were also fitted with the pressurised cabin of the Mk X and the fuel capacity was increased to 256 gallons, three-and-a-half times that of the original Spitfire This version was the type 390. [38] From surviving records it would appear that the most successful individual Spitfire was EN398, a Mk IX fitted with a Merlin 63. [83] [84] This aircraft was built at Chattis Hill, a Shadow factory run by Supermarine, making its first flight on 13 February 1943. Five days later EN398 was delivered to No. 402 Squadron RCAF which was part of the Kenley Wing. [nb 7] On 16 March Acting Wing Commander "Johnnie" Johnson arrived to take command of the four Canadian units based at Kenley. EN398 was still undergoing acceptance tests in a hangar: [83]

Although the Merlin III engine of Spitfire Is had a power rating of 1,030hp (770kW), supplies of 100 octane fuel from the United States started reaching Britain in early 1940. [28] [29] This meant that an " emergency boost" of +12 pounds per square inch was available for five minutes, with pilots able to call on 1,310hp (980kW) at 3,000 rpm at 9,000 feet (2,700m). [30] This boosted the maximum speed by 25mph (40km/h) at sea level and 34mph (55km/h) at 10,000ft (3,000m) and improved the climbing performance between sea level and full throttle height. [31] [32] The extra boost was not damaging as long as the limitations set forth in the pilot's notes were followed. As a precaution, however, if the pilot had resorted to emergency boost, he had to report this on landing and it had to be noted in the engine log book. [33] The extra boost was also available for the Merlin XII fitted to the Spitfire II. [34] Spitfire Mk IA, K9791, failed to return from a sortie over the Ruhr on 17 August 1940. The captured Spitfire was displayed with other Allied equipment at the Victory in the West exhibition in Vienna towards the end of 1940. inches manifold pressure at a modest 2,850 rpm was used for the record attempts. The engine was potentially capable of 3,900 horsepower. Steve Hinton related to me that each additional 50 rpm yielded another 5 inches of manifold pressure. Coolant temperature was held to 100 degrees C and oil was kept at 80 degrees C. in (7.7 mm) Browning machine guns, 350 rpg. Replaced by 2 x .50 in (12.7 mm) M2 Browning machine guns 250 rpg Mk XIVE and FR Mk XIV. When the German forces invaded France the French Spitfire was at Orleans and was to have been burnt to stop it falling into enemy hands. [179]

The Development of the Rolls-Royce Griffon

The first Spitfire to be posted to the Mediterranean theatre was one operated by 1 PRU which arrived on Malta on 22 September 1941. This aircraft was then grounded for three weeks while awaiting replacements for its badly worn tyres. PR Spitfires continued to operate off Malta in ones and twos, usually being re-allocated while en route to North Africa. [145]