Production of some 40 different variants of this aircraft took place throughout the war and after. They served in every combat area, operating as fighters, fighter-bombers, reconnaissance aircraft and carrier-based fighters with the Royal Navy.
Deliveries of production this plane began in June 1938, just over two years after 'Mutt' Summers flew the prototype at Southhampton on the 5th of March, 1936. In the two years preceding production, the manufacturer laid out their Woolston factory for large-scale production and organized one of the largest subcontract schemes ever envisioned in Britain. Until that time, as it was becoming increasingly obvious that there was no limit to the likely demand for this aircraft. It was also obvious that one factory alone was not going to be able to meet the demand even with subcontracting. Large scale plans were laid during 1937 for the construction by the Nuffield Group of a large new shadow factory at Castle Bromwich near Birmingham for production. On April 12,1938 a contract was placed for 1,000 planes to be built at this new factory, of which the actual construction had not then even begun. By the time of the Munich crisis on 12-13 September, 1938, only five planes had been completed.2 In the following year, on April 29 further contracts were placed with the manufacturer for 200 planes and on August 9 for 450. When Britain went to war on September 3,1939 a total of 2,160 aircraft were already on order.
Structurally the plane was a straightforward design with a light alloy monocoque fuselage and a single spar wing with stressed-skin covering and fabric-covered control surfaces. The design was adapted from Reginald Mitchell's aesthetically pleasing 1925 F.7/30 design. To preserve the clean nose-cowling lines originally conceived by Mitchell, the radiator was located beneath the starboard wing with the smaller oil cooler causing some asymmetry beneath the port wing, and the carburetor air intake under the center fuselage. A DeHavilland two-blade wooden fixed-pitch propeller was employed by the prototype and the first plane had the Airscrew Company's wooden fixed-pitch two-blade. Later a DeHavilland three-blade, two position propeller was adopted after trials on the first prototype. The new propeller gave a 5 mph increase in speed. In 1940 DeHavilland three-blade constant-speed propeller were substituted. Production planes had a fixed tail wheel and triple ejector exhaust manifolds. 4 The PV.12 engine which became the X80 HP Rolls-Royce Merlin II and later the Merlin III engine was installed.
The plane weighed 5,280 lb. had a wing
loading of 24 lbs/ft sq. and a fuel capacity of 85 Imperial gallons. Its
maximum speed was 362 mph its maximum diving speed was 450 mph its
initial climb rate was 2,500 ft./min. and it took 9.4 minutes to climb
to 20,000 feet. Its combat range was 395 miles and its roll rate was 140
deg/sec. Standard armament in what was known as the A wing was eight
0.303-in. Browning machine-guns with 300 rounds of ammunition.
The speed of this plane I was marginally higher than that of its
principal opponent the Luftwaffes
Messerschmitt Bf 109E and it was infinitely more maneuverable than
the German fighter although the
109E could out climb and out dive the British fighter and its
shell-firing cannon had a longer range than this plane's machine-guns. 6
In the normal course of development,
means were sought to increase the altitude performance of the plane
which was inferior to that of the
Messerschmitt Bf 109E . This called for two principal modifications,
the introduction of a pressurized cabin and the use of an engine
suitably rated for higher altitude. The first version so equipped was
the Mark VI derived directly from the Mark VB as a result of work on
pressure cabins at the Royal Aircraft Establishment and the manufacturer
during 1940-41. At the R.A.E., R7120 was fitted with a Merlin 47 (the
high rated version of the Merlin 45) with a four-blade Rotol propeller
with Jablo blades and a pressure cabin. The same engine was employed by
the 100 VI (Type 350) fighters built by the manufacturer the first two
of these AB176 and X4942 serving as prototypes. The production VI
version also had an increase in wing area to improve controllability at
high altitudes the wing being of pointed planform with a span of 40 ft.
2 in. The pressure cabin was contained between the bulkheads fore and
aft of the cockpit and a special non-sliding hood was fitted to simplify
the sealing problem. A Marshall blower provided a cabin differential of
2 lb./s. in. reducing apparent altitude from 40,000 feet to 28,000 feet.
In other respects including armament the VI version was similar to the
Mark VB. 9
Production of some 40 different variants
of the plane took place throughout the war and after. They served in
every combat area, operating as fighters, fighter-bombers,
reconnaissance aircraft and carrier-based fighters with the Royal Navy.
Griffon engines replaced Merlins after a time, and the XIX
reconnaissance version became the fastest of all the wartime planes with
a speed of nearly 460 mph (748 km/h). The last aircraft was built in
1947. As a fighter, at all altitudes it had proved superb, while
continuous edges gained firstly by German Bf
Wulfs 190s and then by different versions of the plane led to
closely-matched battles throughout the war.