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Additional Information from Internet Encyclopedia

Spitfire Mk V (Types 331, 349 & 352):  Late in 1940, the RAF predicted that the advent of the pressurised Junkers Ju 86P bomber series over Britain would be the start of a new sustained high altitude bombing offensive by the Luftwaffe, in which case development was put in hand for a pressurised version of the Spitfire, with a new version of the Merlin (the Mk VI). It would take some time to develop the new fighter and an emergency stop-gap measure was needed as soon as possible: this was the Mk V.

The basic Mk V was a Mk I with the Merlin 45 series engine. This engine delivered 1,440 hp (1,074 kW) at take-off, and incorporated a new single-speed single-stage supercharger design. Improvements to the carburettor also allowed the Spitfire to use zero gravity manoeuvres without any problems with fuel flow. Several Mk I and Mk II airframes were converted to Mk V standard by Supermarine and started equipping fighter units from early 1941. The majority of the Mk Vs were built at Castle Bromwich.

Three versions of the Mk V were produced, with several sub-series:

Mk VA (Type 331):  The Spitfire Mk.VA continued to use the Type A wing with 8 × .303" Brownings. This version could reach a top speed of 375 mph (603 km/h) at 20,800 ft (6,300 m), and could climb to 20,000 ft (6,100 m) in 7.1 minutes. A total of 94 were built. One well known VA was W3185 D-B flown by Douglas Bader when commanding the Tangmere Wing in 1941. He was shot down in this aircraft (possibly by friendly fire) during a "Circus" (a wing of fighters escorting a small number of bombers) over Northern France on 9 August 1941 and spent the rest of the war as a POW. In April 1941 two Spitfire VAs R7347 and W3119 were sent to Wright Field, Dayton, Ohio USA as sample aircraft. Both Spitfires were tested by NACA; one series of tests included the fitting of special NACA "jet-propulsion" exhaust stacks.

Mk VB and VB(trop) (Type 349 and 352):  The VB became the main production version of the Mark Vs. Along with the new Merlin 45 series the B wing was fitted as standard. As production progressed changes were incorporated, some of which became standard on all later Spitfires. Production started with several Mk IBs which were converted to Mk VBs by Supermarine. Starting in early 1941 the round section exhaust stacks were changed to a "fishtail" type, marginally increasing exhaust thrust. Some late production VBs and VCs were fitted with six shorter exhaust stacks per side, similar to those of Spitfire IXs and Seafire IIIs; this was originally stipulated as applying specifically to VB(trop)s. After some initial problems with the original Mk I size oil coolers, a bigger oil cooler was fitted under the port wing; this could be recognised by a deeper housing with a circular entry. From mid-1941 alloy covered ailerons became a universal fitting.

A constant flow of modifications were made as production progressed. A "blown" cockpit hood, manufactured by Malcolm, was introduced in an effort to further increase the pilot's head-room and visibility. Many mid to late production VBs - and all VCs - used the modified, improved windscreen assembly with the integral bullet resistant centre panel and flat side screens introduced with the Mk III. Because the rear frame of this windscreen was taller than that of the earlier model the cockpit hoods were not interchangeable and could be distinguished by the wider rear framing on the hood used with the late-style windscreen.

Different propeller types were fitted, according to where the Spitfire V was built: Supermarine and Westland manufactured VBs and VCs used 10 ft 9 in (3.28 m) diameter, 3 bladed de Havilland constant speed units, with narrow metal blades, while Castle Bromwich manufactured VBs and VCs were fitted with a wide bladed Rotol constant speed propeller of either 10 ft 9 in (3.28 m) diameter, with metal blades, or (on late production Spitfires) 10 ft 3 in (3.12 m) diameter, with broader, "Jablo" (compressed wood) blades. The Rotol spinners were longer and more pointed than the de Havilland leading to a 3.5 in (8.9 cm) increase in overall length. The Rotol propellers allowed a modest speed increase over 20,000 ft (6,100 m) and an increase in the service ceiling. A large number of Spitfire VBs were fitted with "gun heater intensifier" systems on the exhaust stacks. These piped additional heated air into the gun bays. There was a short tubular intake on the front of the first stack and a narrow pipe led into the engine cowling from the rear exhaust.

The VB series were the first Spitfires able to carry a range of specially designed "slipper" drop tanks which were fitted underneath the wing centre-section. Small hooks were fitted, just forward of the inboard flaps: when the tank was released these hooks caught the trailing edge of the tank, swinging it clear of the fuselage.

With the advent of the superb Focke Wulf Fw 190 in August 1941 the Spitfire was for the first time truly outclassed, hastening the development of the "interim" Mk IX. In an effort to counter this threat, especially at lower altitudes, the VB was the first production version of the Spitfire to use "clipped" wingtips as an option, reducing the wingspan to 32 ft 2 in (9.8 m).The clipped wings increased the roll rate and airspeed at lower altitudes. Several different versions of the Merlin 45/50 family were used, including the Merlin 45M which had a smaller "cropped" supercharger impeller and boost increased to +18 lb. This engine produced 1,585 hp (1,182 kW) at 2,750 ft (838 m), increasing the L.F VB's maximum rate of climb to 4720 ft/min (21.6 m/s) at 2,000 ft (610 m).

The Mk VB(trop) (or type 352) could be identified by the large Vokes air filter fitted under the nose; the reduced speed of the air to the supercharger had a detrimental effect on the performance of the aircraft, reducing the top speed by 8 mph (13 km/h) and the climb rate by 600 ft/min (3.04 m/s), but the decreased performance was considered acceptable. This variant was also fitted with a larger oil tank and desert survival gear behind the pilot's seat. A new "desert" camouflage scheme was applied. Many VB(trop)s were modified by 103 MU (Maintenance Unit-RAF depots in which factory fresh aircraft were brought up to service standards before being delivered to squadrons) at Aboukir, Egypt by replacing the Vokes filter with locally manufactured "Aboukir" filters, which were lighter and more streamlined. Two designs of these filters can be identified in photos: one had a bulky, squared off filter housing while the other was more streamlined. These aircraft were usually fitted with the wide blade Rotol propeller and clipped wings.

Mk Vc and V (trop) (types 349 and 352/6): As well as having most of the standard Mk V features this version had several important changes over the earlier Mk V, most of which were first tested on the Mk III. These included the re-stressed and strengthened fuselage structure and the new windscreen design, which was also used on some Vb Spitfires. The Vc also introduced the Type C or "Universal" wing along with the revised main undercarriage; the tops of these wings featured large, bulged fairings to provide clearance for the ammunition feed motors of two Hispano cannon. Later, because two cannon were seldom fitted, these fairings were later reduced in size to more streamlined shapes. A deeper radiator fairing was fitted under the starboard wing and a larger oil cooler with a deeper, kinked air outlet was fitted underneath the port wing. In addition more armour plating was added, protecting the bottom of the pilot's seat and the wing ammunition boxes.

The first Spitfire to be sent overseas in large numbers was the Mk Vc (trop). The majority of these were used by Allied squadrons in the Mediterranean theatre (including North Africa), Burma and in Australia with No. 1 Fighter Wing RAAF. The Vc initially suffered a high rate of mechanical failure in Australia, due to corrosion in engine cooling pipes that were unfilled and exposed to salt air, while being shipped from the UK.

A total of 300 Mk VC(trop)s were shipped to Australia for the RAAF; the first of these arrived in late 1942. A total of 143 Spitfire VB (including Mk II conversions) were supplied to Soviet Union. Portugal was the recipient of two lots of Spitfire VBs; 33 refurbished ex-RAF aircraft started arriving in early 1944 and a further and final shipment of 60 mainly clipped wing L.F Mk VBs arrived in 1947. All were retrofitted with TR 9 HF radios and had no IFF. The last of these Spitfires were taken out of service in 1952. Twelve were delivered to Royal Egyptian Air Force.

In 1944 enough Spitfire VB (trop)s to equip one squadron were supplied to Turkey. Some were later fitted with the larger, pointed rudder developed for later Merlin-powered Spitfires. These flew alongside of the Focke-Wulf Fw 190A-3s which had been supplied to Turkey by Germany.

In total, production was 6,479, consisting of 94 Mk VA, built by Supermarine, 3,911 Mk VB, (776 by Supermarine, 2,995 Castle Bromwich and 140 Westland) and 2,467 Mk VC, (478 Supermarine, 1,494 Castle Bromwich, 495 Westland) plus 15 PR Type F by Castle Bromwich.