Early production Spitfire Mk.V manufactured in October 1941 with symmetrical lower bulges under the cannon well, enlarged

cooler, older canopy style with exterior armor and hinged window hatch. The aircraft still lacks the armament, it’s equipped with

the De Havilland propeller and newer type of radio Tr.1133 (photo: Simon Erland).

never installed on Spitfires Mk.Vc. An important change was the

introduction of the belt-fed Hispano II cannons allowing for larger ammunition load (120 bullets per cannon as opposed to 60

bullets with the older, drum-fed Hispano Mk.I (as on the earlier

b type wing). These cannons were also less prone to jamming.

The visual indication of their installation was a missing bulge

under the cannon well which on Spitfire Mk.Vb appeared in two

forms, straight, symmetrical on the older airframes and kidney-shaped, asymmetrical on the newer aircraft. In comparison,

the upper bulge above the cannon well on Mk.Vc appeared in at

least three different shapes based on the anticipated armament

variant and was also subject to a certain improvisation at the

unit level. Another fundamental change was the landing gear

re-design, featuring strengthened gear legs’ attachments and

increased rake, moving the wheels 5 cm forward in comparison to the older Spitfire versions. This solution improved the

aircraft stability during taxiing and ground maneuvers and

was visually recognizable by a new, elliptical wheel well shape.

Undercarriage retraction was already standard on all Mk.V Spitfires with a hydraulic pump driven by the engine. The wings and

fuselage design were strengthened by the application of thicker

sheet metal skin and later Mk.Vc batches featured flush rivets

on the rear fuselage. The later aircraft also featured the horizontal tail surfaces with modified weight balance, pressurized

fuel tanks, submersible fuel pump in the bottom tank and six

single exhaust pipes on each side of the engine. Later Spitfires

Mk.Vc batches were almost exclusively powered by Merlin engines series 50 and 55/56 with membrane-type carburetor. Moreover, Merlin 55/56 featured the separate piston blocks. Their

specific versions were distinguished by compressors tuned for

the optimal output at various operational altitudes.

Short wing/low level

Spitfires LF Mk.V

In the course of 1942, the number of both defensive and offensive, low altitude missions increased. It led to the requirement

to modify Spitfire Mk.V design in order to optimize their low altitude performance. Low level Spitfires LF Mk.Vb and LF Mk.Vc

received Merlin engines series M (Merlin 45M, 50M and 55M)

with smaller compressor diameter which gave the engine the

highest output at low altitudes. In case of Merlin 45M it was

1,585 hp (1,182 kW) at 838 meters altitude. Another modification was the wing’s strengthening design by means of two strips



on the wing upper surfaces above wheel wells area. Some of

the Spitfires LF Mk.V received “clipped wings”, in fact shorter

wingtips reducing the wingspan to 9.8 meters. This modification improved the rate-of-roll and moderately increased the

maximum speed. The wingtips varied, both short and long ones

could be installed. Therefore, the short wingtips do not decidedly identify the LF version.

Auxiliary fuel tanks

There were several types of auxiliary tanks of different capacity developed in order to extend Spitfire Mk.V range. The

smallest one was 30gal (136 liters) tank introduced into service

in September 1941 extending the range to 1167 km. It was followed by a larger, 45gal tank (204.5 liters). Both tanks were

of so-called blister-type (also known as slipper-type) referring

to the tank’s curved outline on the bottom and upper flat surface mating with fuselage and wing’s center-plane. Both were

droppable. The cylinder-shaped 45gal tanks were also used. In

Malta, 44gal (200 l) cylindrical tanks from Hurricanes Mk.II were

used, attached in pairs, next to each other under the fuselages.

In the end of 1941, 90gal (409 l) non-droppable fly-over tank

was introduced extending the range to 1,988 km. In 1942 even

170gal (773 l) fly-over tank arrived extending the range to 2,334

km, however at the cost of significantly worse flight characteristics. Both of these tanks were of the blister-type, there was

also a cylindrical 170gal fly-over tank. In the actual operations,

since the middle of 1942, the combination of 29gal (132 l) tank

mounted in the fuselage behind the cockpit and a 170gal drop

tank was used. This combination allowed an extended range to

2,615 km at the maximum altitude of 4,575 m.

Tropical filters

In the dusty tropical and sub-tropical environments, the engine was subject to potential damages caused by sucked-in dust.

To lower this risk Vokes company designed a voluminous, fully

covered filter which formed a typical chin under the aircraft

nose. The worsened aerodynamics together with the lower

pressure of the entering air on such modified aircraft resulted

in the maximum speed drop by approximately 12 kph, which

was actually better value than the anticipated drop by 37 kph.

These tropicalized versions were quite widely used in both Mediterranean and Far East theaters of operations. Tropicalized

INFO Eduard - January 2022