A Hawker Typhoon IB with underwing bomb load and early cockpit hood.
It is an accepted maxim for successful aircraft development that future
requirements should always be the principal concern of the chief designer
and his project design team. The company which allows itself to become
wholly preoccupied with the development of an established design may
produce, as a result, an outstanding aeroplane, but the policy is a
shortsighted one if no new prototype is following to consolidate this
success. Thus, the fact that Sydney Camm, Hawker Aircraft's chief
designer, was at work on a new fighter as a potential replacement for the
Hurricane
as early as 1937, when the first production aircraft of that
type had still to fly, reflected no lack of confidence in the
Hurricane's
potentialities but the natural desire to ensure that its service successor
would be a product of the same stable.
This massive new fighter, the heaviest and most powerful single-seat
single-engined warplane envisaged at the time of its design, was to suffer
a long gestatory period. It was to be pressed into operational service
before it was fully developed and, in consequence, acquire a worse
reputation among its pilots than that of any fighter preceding it. It was
fated to be rarely employed in the interceptor role for which it was
originally conceived. Yet, despite its vicissitudes, it was to blossom
into one of the most formidable weapons evolved during the Second World
War; a close-support fighter that was to turn the scales in many land
battles and upset many conceptions of land warfare.
In January 1938, barely two months after the debut of the first production
Hurricane
Hawker Aircraft received details of specification F.18/37,
calling for a large single-seat fighter offering a performance at least
20 per cent higher than that of the
Hurricane
and achieving this with the
aid of one of two 24-cylinder engines in the 2,000 h.p. class then under
development --the
Napier Sabre "H" type and the
Rolls-Royce Vulture "X"
type. Sydney Camm had commenced investigating the possibilities of just
such a fighter in March 1937, and had already roughed out a design built
around the
Napier Sabre
engine and housing twelve 0.303-in.
Browning
guns with 400 r.p.g. in its 40-foot wings. At the proposal of the Air
Ministry, Camm also prepared studies for an alternative version of his
fighter powered by the
Rolls-Royce Vulture
engine, and increased the ammunition capacity of both machines to 500 r.p.g.
Further discussions over military loads and equipment followed, and
revised tenders were submitted to Throughout 1938 the Air Ministry at the
beginning of 1938 for both the Type " N " and the Type " R ", as the
alternative
Sabre and Vulture
powered fighters had become known. These
tenders were formally accepted on April 22, 1938, and four months later, on
August 30, two prototypes of each fighter were ordered. Structurally both
types were similar: the wings were all-metal, the front fuselage was of
steel tubing, and the aft section consisted of a stressed-skin,
flush-riveted monocoque--the first Hawker designs to employ this form of
construction. Uniformity between the two fighters was, in fact, achieved
to a remarkable degree, but the designs did differ in one important respect
initially--the
Vulture
-powered fighter made use of a ventral radiator while the
Sabre-
driven machine had one of "chin" type.
Construction of the two massive fighters proceeded in parallel, and work
progressed simultaneously on the preparation of production drawings. As a
result of the slightly more advanced development status of the Vulture
engine which had been designed along more conventional lines than the
Sabre, the Type " R " was the first of the two fighters into the air,
flying in October 1939. Named appropriately enough Tornado, the initial
flight trials of the prototype were promising, and a production order for
1,000 Tornados was placed at the beginning of November, it being proposed
that the new fighter should be built both by Hawker and by A. V. Roe at
Woodford. However, the flight test program soon began to run into trouble.
Compressibility effects, about which little was known at that time, began
to manifest themselves, and it was decided that the ventral radiator bath
was unsuitable for the speeds approaching 400 m.p.h. that were being achieved
for the first time. The radiator was, therefore, moved forward to the nose,
a position already selected for that of the Type " N ", by now dubbed
Typhoon; but the first prototype Tornado (P5219) only flew long enough to
indicate the beneficial results of the change before it was totally
destroyed.
Meanwhile, on December 30, 1939, the first
Napier Sabre
engine had been
delivered to Hawker Aircraft, and the first prototype Typhoon (P5212)
emerged from the experimental shop to fly on February 24, 1940. It too
became the subject of a quantity production order which, it was planned,
should become the responsibility of Gloster Aircraft, whose assembly lines
were emptying of
Gladiator
biplanes and whose design office was already
immersed in the development of the
Gloster Meteor ,
the first British turbojet-driven aircraft.
Although, like those of the Tornado, the first flights of the Typhoon
prototype indicated a promising fighter, the machine proving relatively
easy to fly at high speeds, its low speed qualities left much to be desired,
and it had a marked tendency to swing to starboard during take-off. The "X"
form of the Tornado's
Vulture
engine had not permitted installation above
the front spar as was the Typhoon's
Sabre
and, in consequence, the overall
length of the former was 32 ft. 6 in. as compared with the 31 ft. 10 in. of
the latter. Owing to the size and weight of the Sabre and the need to
preserve c.g. balance, the Typhoon's engine was fitted so close to the
leading edge of the wing that severe vibration was experienced as the
slipstream buffeted the thick wing roots. On an early test flight the
stressed-skin covering began to tear away from its rivets, and the
Typhoon's pilot, Philip G. Lucas, only just succeeded in bringing the
prototype in to a landing.
Apart from structural teething troubles, the
Sabre
engine, although a
compact and exquisite power plant, called for a considerable amount of
development, and it was perhaps fortunate for the future of the Typhoon
that, in May 1940, the grave war situation led to the cancellation of all
priority for Typhoon and Tornado development in order to allow every effort
to be put into the production of sorely needed Hurricanes. Design
development was allowed to continue, however, and during 1940 three
alternative engine installations were proposed for the Tornado--the
Fairey Monarch, the
Wright Duplex Cyclone , and the
Bristol Centaurus--and experimental drawings for the
Centaurus installation were completed.
Development on the Typhoon included the design of a modified wing containing
two 20-mm.
Hispano cannon in place of the six 0.303-in.
Brownings, the
construction of an experimental set of wings containing a total of six
cannon, and the initiation of a design study of a Typhoon variant with
thinner wings of reduced area and lower profile drag. This latter study was
later to arouse interest at the Air Ministry and eventually result in the
Tempest. However, by October 1940 enthusiasm had been revived and
production of the Tornado and Typhoon reinstated, production deliveries of
both being scheduled for the following year.
The Tornado weighed 8,200 lb. empty and 10,580 lb. loaded. Its maximum
speed was 425 m.p.h. at 23,000 feet. A. V. Roe had prepared a production
line at Woodford, and the first production Tornado (R7936) was delivered
early in 1941. But this was fated to be the only production Tornado, for
difficulties with the
Vulture resulted in the decision to remove this
power plant from the aero-engine development program, this decision also
canceling production of the Tornado. However, in February 1941, Hawker's
received a contract to convert a Tornado to take a
Bristol Centaurus radial
engine. Among the modifications required were a new center fuselage and
engine mounting. The new prototype (HG641) was assembled from Tornado
production components and flown for the first time on October 23, 1941.
The first
Centaurus installation had an exhaust collector ring forward of
the engine from which a single external exhaust stack pipe led back under
the root of the port wing. This arrangement soon proved unsatisfactory, so
the oil-cooler duct was enlarged and led forward to the nose, while twin
exhaust pipes led back from the front collector ring through this fairing
to eject under the belly of the fuselage. A level speed of 421 m.p.h. was
attained with the
Centaurus-Tornado, and this was slightly higher than that
attainable by the Sabre-powered Typhoon, but the Typhoon airframe could not
be adapted to take the radial engine. The second prototype Tornado (P5224)
had, in the meantime, been completed, and the sole production Tornado
(R7936) later played a useful role as a test-bed for deHavilland and
Rotol contraprops.
The first production Typhoon IA (R7082) with the 2,200 h.p. Sabre IIA
engine was completed by Gloster and flown on May 26, 1941. Production of
this version, with its twelve
Browning guns, was in limited quantity, and
those built were used principally for the development of operational
techniques. But the cannon-armed Typhoon IB was following closely on the
heels of the Mark IA, and the Air Ministry was pressing for its rapid
service introduction to counter the new Focke-Wulf Fw 190. Nos. 56 and 609
Squadrons based at Duxford began to receive their Typhoons in September
1941, before the fighter was fully developed, and these squadrons were
forced to take on part of the onus of unearthing the new machine's numerous
faults.
The decision to use the Typhoon before it was adequately developed for
operational use was ultimately justified by the results, but the price of
its premature introduction was high. In the first nine months of its service
life far more Typhoons were lost through structural or engine troubles than
were lost in combat, and between July and September 1942 it was estimated
that at least one Typhoon failed to return from each sortie owing to one or other
of its defects. Trouble was experienced in power dives--a structural
failure in the tail assembly sometimes resulted in this component parting
company with the rest of the airframe. In fact, during the Dieppe
operations in August 1942, when the first official mention of the
Typhoon was made, fighters of this type bounced a formation of
Fw 190s
south of Le Treport, diving out of the sun and damaging three of the German
fighters, but two of the Typhoons did not pull out of their dive owing to
structural failures in their tail assemblies.
Despite this inauspicious start to its service career and the unenviable
reputation that the Typhoon had gained, operations continued and the
accident rate declined as the engine teething troubles were eradicated,
although the tail failures took longer to solve, despite immediate
strengthening and stiffening as soon as the trouble manifested itself. In
November 1942 No. 609 Squadron, led by Wing Commander Roland Beamont, was
moved to Manston in an attempt to combat the near-daily tip-and-run raids
which were being made by Fw 190s and could rarely be intercepted by
Spitfires. The Typhoon enjoyed almost immediate success. The first two
Messerschmitt Me 210 fighter bombers to be destroyed over the British Isles
fell to the guns of Typhoons, and during the last comparatively ambitious
daylight raid by the Luftwaffe on London, on January 20, 1943, five Fw 190s
were destroyed by Typhoons.
On November 17, 1942, Wing-Commander Beaumont had flown a Typhoon on its
first night intrusion over Occupied France and, subsequently, the fighter
was employed increasingly for offensive duties, strafing enemy airfields,
ships and railway transport. The success of the Typhoon in the ground-attack
role led to trials with two 250-lb. or two 500-lb. bombs which were carried
on underwing racks. This load was later increased to two l,000-lb. bombs,
but the Typhoon was not to find its true element until it was adapted to
carry airborne rocket projectiles--four under each wing. By D-Day, in
June 1944, the R.A.F. had twenty-six operational squadrons of Typhoon IBs.
Without its underwing load the Typhoon IB weighed 11,300 Ib.; and with two
500-lb. bombs and the necessary racks, 12,400 Ib. Maximum speed was 398
m.p.h. at 8,500 feet and 417 m.p.h. at 20,500 feet, and an altitude of
20,000 feet could be attained in 7.6 minutes. Between the prototype and
production stages several design changes had been made. These included the
re-design of the fin and rudder, the redisposition of the wheel fairings
and the introduction of a clear-view fairing behind the cockpit. On the
first few Typhoon IAs the solid rear fairing was retained; later a
transparent fairing was fitted, but this was abandoned in favor of the
first sliding " bubble " hood to be used by an operational fighter.
The Typhoon IB, by now affectionately known as the "Tiffy", distinguished
itself particularly in the Battle of Normandy, where it decimated a large
concentration of armor ahead of Avranches, disposing of no fewer than 137
tanks, and opening the way for the liberation of France and Belgium. For
use in the tactical reconnaissance role, the Typhoon F.R.IB was developed
early in 1945. In this version the two inboard cannon were removed and
three F.24 cameras were carried in their place. One Typhoon was also
converted as a prototype night fighter, with A.I. equipment, special
night-flying cockpit and other modifications. Production of the Typhoon,
which was entirely the responsibility of Gloster Aircraft, totaled 3,330
machines.
Work had been going on in the Hawker design office since 1940 on the
development of a new thin wing section. It had already been established
that the N.A.C.A.22-series wing section employed by the Typhoon was entirely
satisfactory at speeds in the vicinity of 400 m.p.h. but encountered
compressibility effects at higher speeds. In dives approaching 500 m.p.h.
a very sudden and sharp increase in drag was experienced, accompanied by a
change in the aerodynamic characteristics of the fighter, which affected
the pitching moment and rendered the machine nose heavy. No actual design
work on the new wing was begun until September 1941, and the wing section
eventually adopted for development had its point of maximum thickness at
37.5% of the chord. The thickness/cord ratio was 14.5% at the root and 10%
at the tip, giving a wing five inches thinner at the root than that of the
Typhoon.
This thin wing could not contain a comparable quantity of fuel to that
housed by the Typhoon's wing, so a large fuselage tank had to be adopted.
This necessitated the introduction of an additional fuselage bay, increasing
the overall length by twenty-one inches forward of the c.g. This added
length found its inevitable compensation after initial prototype trials in
a larger fin and tailplane. The wing area was also increased, and an
elliptical planform was adopted, presenting a chord sufficient to permit the
four 20-mm. Hispano cannon to be almost completely buried in the wing. All
these modifications added up to a radically changed Typhoon, but it was as
the Typhoon II that two prototypes were ordered in November 1941. However,
in the middle of the following year the name Tempest was adopted.
Alternative installations of the
Sabre engine were designed for these
prototypes; the first (HM595) had a
Sabre II and a front radiator similar
to that of the standard Typhoon, while the second (HM599) had a
Sabre IV
engine and wing leading-edge radiators.
Piloted by Philip Lucas, the first prototype Tempest was flown on
September 2, 1942, but prior to this, in February 1942, a production order
had been placed and the first production machine flew in June 1943 with
Bill Humble at the controls. During flight trials the first Tempest
prototype had exceeded 477 m.p.h. in level flight, and the first production
model was essentially similar to the first prototype with the chin-type
radiator. This was designated Tempest V, and the initial production batch,
the Series I, had Mk. II cannon which projected slightly ahead of the wing
leading edge, but the Series II had the short-barrelled Mk. V cannon which
did not project, and also featured a detachable rear fuselage,
small-diameter wheels and a rudder spring tab. Powered by a 2,420 h.p.
Sabre IIB engine, the Tempest V attained a maximum speed of 435 m.p.h. at
17,000 feet. The 820-mile range of the Tempest V in clean condition was an
appreciable improvement over that of the Typhoon, and was due not only to
the small additional quantity of fuel carried but to the aerodynamic
refinement of the later machine which permitted a higher cruising speed
for the same power.
The first squadrons to be equipped with Tempest Vs were Nos. 3 and 486 at
Newchurch, Dungeness, the first of these receiving its equipment early in
1944. By May five Tempest Vs had been lost due to engine failure, and this
was discovered to be due to an over speeding of the propellers, resulting
in an uncontrollable increase in engine revolutions, the failure of the
bearings and the collapse of the oil system. In June modified propellers
were fitted which solved the problem, and two days after the invasion of
the Continent, on June 8, 1944, the Tempests met enemy aircraft in combat
for the first time, destroying three
Bf 109G
fighters without loss to
themselves. On June 13 the first
V1 flying bombs were launched against England,
and the Tempest, being the fastest low-medium altitude fighter in service
with the R.A.F., became the mainstay of Britain's fighter defense against
the pilotless missiles, destroying 638 of these weapons by the beginning of
September. The Tempest V was also employed on the Continent for
train-busting and ground-attack duties.
A production Tempest V series I with the protruding Mk. II cannon.
Meanwhile the second prototype (HM599), designated Tempest I, had proved
sufficiently promising for production plans to be initiated. In the light
of experience gained with the
Centaurus-powered Tornado and the suitability
of the Tempest fuselage for the radial engine, a
Centaurus version of the
Tempest was also initiated as the Mark II, and production drawings were
prepared in parallel with those of the Mark I. In the event, the Tempest I
was later abandoned while the Mark II was allowed to proceed to the
production stage following the successful flight trials with the prototype,
LA602, which commenced on June 28, 1943. The first production Tempest II
flew fifteen months later, but the first unit, No. 54 Squadron, was not
equipped with this fighter until November 1945, and was thus too late to
participate in the war. The Tempest II was powered by the 2,500 h.p.
Bristol Centaurus V
or VI eighteen-cylinder, air-cooled, two-row radial,
and attained a maximum speed of 440 m.p.h. at 15,900 feet and 406 m.p.h.
at sea-level. Its range on internal fuel was 775 miles and initial climb
rate was 4,520 ft./min.
Schemes for the utilization of the
Griffon IIB and the
Griffon 61 engines
accounted respectively for the Tempest III and Tempest IV designations,
neither passing the project stage. Nor did an alternative armament proposal
based on the use of 0.5-in. machine-guns. The final Tempest variant was the
Mark VI, which, appearing in 1945, was powered by the 2,700 h. p.
Sabre VA
engine and, except in having small intake ducts in the wing roots, was
outwardly indistinguishable from the Tempest V. By and large, both the
Typhoon and Tempest escaped the fate of so many aeroplanes of being used as
test-beds for a variety of experiments. The Typhoon was designed in a naval
fighter variant to meet the requirements of specification N.11/40, and one
prototype was converted to this standard under the Hawker project
designation P.1009. Another Typhoon modification, the P.1010, was to have
had leading-edge radiators and a turbo blower, but work on this was not
proceeded with.
As part of their engine development program, Napier's designed an annular
cowling for the Sabre to replace the familiar chin-type radiator bath. The
first such installation was on a Typhoon IB (R8694), but most of the
development was undertaken with a Tempest V (NV768) which flew with several
different types of annular radiator and hollow spinner. Another experimental
Tempest V (SN354) had a 40-mm. gun under each wing in a long fairing.
As the Typhoon's immaturity faded it achieved widespread acclaim as a
"rocketeer", being transformed from a fighter of dubious reliability into
one of the Allies' most potent weapons. Likewise, its progressive
development, the Tempest, gained for itself a place in the history of the
air war for its part in reducing the depredations of the
V1 flying bombs against England.
The final Tempest variant, the Mk VI, powered by a Napier Sabre VA.
Specifications: Tempest F.Mk.V Series II
Powerplant:
One Napier Sabre IIB 24-cylinder, liquid cooled, horizontal-H engine
providing 2,420 hp (1,804 kw) @ 3,850 r.p.m @ sea-level, and 2,045 hp
(1,524 kw) @ 13,750 ft (4,191 m)
Dimensions:
Length: 33 ft 8 in (10.24 m)
Height: 16 ft 1 in (4.90 m)
Wing span: 41 ft 0 in (12.49 m)
Weights:
Empty: 9,250 lb (4,195 kg)
Max T/O weight: 13,500 lb (6,123 kg)
Performance:
Maximum speed: 435 mph (700 km/h) @ 17,000 ft (5,181 m)
Service ceiling: 36,000 ft (10,972 m)
Range: 820 miles (1,319 km) @ 210 mph (000 km/h) @ 5,000 ft (1,524 m)
Armament: Four 20-mm Hispano Mk. V cannon with 150 rounds per gun,
and eight 60-lb. rocket projectiles or two 1,000-lb. bombs.