Supermarine Seafire XV
in Flight
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The Supermarine Seafire Mk.XV was the first Griffon powered version of the Seafire to be produced, entering service just too late to reach the front line during the Second World War. The Seafire Mk.XV borrowed features from four versions of the Spitfire. It had the fuselage of the Spitfire V as used on the Seafire III, the wing-root fuel tanks from the Spitfire IX, the enlarged fin and rudder and retractable tail wheel of the Spitfire VIII and the Griffon engine installation of the Spitfire XII. The folding wings were taken from the Seafire III.
Work on producing a Griffon powered Seafire began early in 1943 when two Spitfire XIIs were given to the Fleet Air Arm. They were navalised by Supermarine in February-March 1943, and then went to No.778 Squadron (Service Trials Unit) for carrier trials. These revealed that the aircraft had good low altitude speed but poor handling characteristics at take-off and landing. In March 1943 Supermarine were given a contract to produce six prototype Mk.XVs. The first prototype was completed in November 1943, and the remaining five during 1944. The high mark number was adopted after the Air Ministry decided to combine the Spitfire and Seafire numbering sequences.
The Griffon VI had a two-speed single-stage supercharger. It was larger than the Merlin, but only has a slightly larger frontal area. The 10ft 5in diameter Rotol propeller rotated in the opposite direction that on the Merlin, which would cause some problems. Cooling was providing by two large Spitfire IX style radiators under the wings, with the coolant radiator under the starboard wing and the oil cooler and a second coolant radiator under the port wing.
The Griffon engine would cause the biggest problems with the Mk.XV. The first problem was that the powerful engine produced a great deal of torque, which tended to force the Seafire towards the right (the Griffon rotated in the opposite direction to the Merlin). This meant that the Griffon powered Seafires tended to veer towards the island superstructure of an aircraft carrier when taking off, not an idea feature for a naval aircraft. This problem would only be solved with the introduction of the Seafire Mk.46, which had contra-rotating propellers - two propellers mounted on the same engine, rotating in opposite directions.
A second problem emerged soon after the Seafire Mk.XV went to sea. The supercharger clutch developed a tendency to slip at high rpm and boost settings, making it dangerous to attempt carrier landings. This problem was finally solved early in 1947 by adopting a new clutch.
The first prototype underwent tests at the Aeroplane & Armament Experimental Establishment from February 1944 and catapult and arrester gear at RAE Farnborough from March 1944. By this time large numbers of Mk.XVs had been ordered. In July 1943 an existing order for 150 Mk.IIIs with Cunliffe-Owen was modified to cover the Mk.XV. In February Cunliffe-Owen received an order to produce another 250 aircraft, while in the same month Westland received an order for 140 aircraft. This was followed by a larger order for 500 aircraft in April 1944. Of these 1,040 only about a third were completed as Mk.XVs - sources disagree on the exact figure, giving totals of either 384 or 434 (384 is also given as the number produced with the older A-frame arrestor hook in some places). The first production machine was completed by Westland on 31 August 1944. Despite having a head-start Cunliffe-Owen didn't complete their first production machine until March 1945.
As with the earlier Seafires the Mk.XV was armed with two 20m Mk V cannon and four 0.303in Browning machine guns. It could carry one 500lb bomb on the centreline, or two pairs of Mk.VIII rocket projectors (four rockets) and an external centreline drop tank. The bombs and centreline fuel tank couldn't be carried for catapult launches. The rockets could be replaced by two 22.5 gallon combat tanks, which could be retained during combat.
The Mk.XV needed careful testing. The first carrier tests were carried out on HMS Pretoria Castle on 13-16 October 1944, and were fairly disastrous. Three prototypes were used. One was damaged when a tire burst, the second hit the barrier while landing and the third was damaged when hit by a Swordfish, ending the tests. A second set of trials in November 1944 were more successful (the navalised Spitfire Mk.21 that served as a prototype for the Seafire Mk.45 was also involved). These tests saw the A-frame arrestor hook compared to new sting-type hook, which was adopted on most Mk.XVs and all later Seafires. When released the sting-type hook moved aft and then dropped into a lowered position. The hook was in a clearer position than with the earlier A-frame system, meaning that the aircraft could be further off the deck and still catch cable, making it easier to land.
The last 30 Westland aircraft saw the distinctive Spitfire canopy replaced by a new teardrop design, with a cut-down rear fuselage. This improved visibility, and allowed the aircraft to carry an extra fuel tank behind the cockpit. Although it did have an adverse effect on handling it was adopted as standard on the Seafire XVII.
No.802 Squadron became the first to use the Seafire Mk.XV when it reformed in England in May 1945. On 11 August the squadron embarked on HMS Queen, ready to deploy to the Pacific, but a few days later Japan surrendered, and on 25 August the squadron disembarked. It did eventually move to the Far East in 1946, reaching Colombo on 13 May and remaining out until February 1947, but for most of this period the supercharger problems limited the squadron to shore based operations. The squadron was reformed in Britain later in 1947, and spent the winter of 1947-48 operating the Seafire in the Mediterranean, before returning to Britain to receive the Sea Fury.
The first squadron to receive the Seafire Mk.XV in the Pacific was No.801 Squadron (HMS Implacable), which received the new aircraft in September 1945 in Australia. The original intention had been to issue the new aircraft in preparation for the invasion of Japan. No.801 Squadron kept its Seafires until March 1946 when the squadron returned to the United Kingdom, leaving the aircraft behind.
No.805 Squadron received the Seafire XV in September 1945 and took it to the Mediterranean in July 1946, only to be limited to shore based operations in the next month. No.806 Squadron used the aircraft in the Far East from April 1946-October 1947, overlapping with No.804 Squadron, which was in the area from February-November 1947.
In December 1945 Canada decided to form an Air Branch for the RCN. This was to be based around the carrier HMCS Warrior, which was obtained from Britain and commissioned on 24 January 1946. On the same day four Canadian manned Fleet Air Arm squadrons were also transferred, amongst them Nos. 803 and 883 Squadrons with their Seafire XVs. A shortage of Canadian personnel meant that No.883 Squadron was disbanded on 23 February, and on 23-31 March the remaining squadrons sailed to Canada.
In the summer of 1947 the RCN adopted the Carrier Air Group system. Nos.803 and 825 Squadrons formed the 19th CAG and new Nos.883 and 826 Squadrons formed the 18th CAG. At first Nos.883 and 803 shared the same Seafires, before in August 1947 No.803 Squadron left for the UK to collect its new Hawker Sea Furies, leaving No.883 its aircraft. No.883 retained its Seafires until the summer of 1948, when it too converted to the Sea Fury.
The Seafire XV was also used by Burma, which ordered twenty de-navalised versions in 1951. These worked alongside the country's existing Spitfires.
Supermarine Types 377 and 386
Engine: Two speed single stage supercharged Griffon VI
Power: 1,950hp at take-off, 1,850hp at max power at 2,000ft (or 1,735hp in SAM)
Crew: 1
Wing span: 36ft 10in
Length: 31ft 10in
Height: 10ft 8in (tail up) 12ft 9in (tail down)
Empty Weight: 6,300lb
Loaded Weight: 7,960lb
Max Speed: 383mph at 13,000ft
Service Ceiling: 35,500ft
Rate of Climb: 4,750ft/ min
Range: 430 miles
Armament: Two 20mm Hispano cannon and four .303in machine guns
Bomb-load: one 250lb or 500lb bomb on the centreline or two pairs of Mk.VIII rocket projectors
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