After sending off these
details of the Type 150, the Bristol design team came to the conclusion
that it would be possible to meet both of the Air Ministry's
specifications by a single aircraft evolved from the Blenheim, and
immediately prepared a new design outline, the Type 152. By comparison
with the Blenheim Mk IV, the new design was increased slightly in
length to allow for the carriage of a torpedo in a semi-exposed
position, provided a navigation station, and seated pilot and navigator
side-by-side. Behind them were radio and camera positions which would
be manned by a gunner/camera/radio operator. The Type 152 was more
attractive to the Air Ministry, but it was considered that a crew of
four was essential, and the accommodation was redesigned to this end.
The resulting high roofline, which continued unbroken to the dorsal
turret, became a distinguishing feature of this new aircraft, built to
Air Ministry Specification 10/36, and subsequently named Beaufort.
Detail design was
initiated immediately, but early analysis and estimates showed that the
intended powerplant of two Bristol Perseus engines would provide
insufficient power to cater for the increase of almost 25 per cent in
gross weight without a serious loss of performance. Instead, the newly
developed twin-row Taurus sleeve-valve engine was selected for the
Beaufort, the only concern being whether it would be cleared for
production in time to coincide with the construction of the new
airframe. The initial contract, for 78 aircraft, was placed in August
1936, but the first prototype did not fly until just over two years
later, on 15 October 1938. There had been a number of reasons for this
long period of labour, one being overheating problems with the
powerplant, and another the need to disperse the Blenheim production
line to shadow factories before the Beaufort could be built.
A Bristol Type 152 Beaufort Mk I with No. 217 Squadron RAF Coastal
Command. In June 1942, the squadron moved to Malta.
Test flying of the
prototype revealed a number of shortcomings, leading to the provision
of doors to enclose the main landing gear units when retracted,
repositioning of the engine exhausts, and an increase to two
machine-guns in the dorsal turret. These and other items, added to
continuing teething problems with the new engine, delayed the entry
into service of the Beaufort Mk Is, these first equipping No. 22
Squadron of Coastal Command in January 1940. It was this unit, which on
the night of 15-16 April 1940, began the Beaufort's operational career
by laying mines in enemy coastal waters, but in the following month all
in-service aircraft were grounded until engine modifications could be
Earlier, the Australian
government had shown interest in the Beaufort, and following the visit
of a British Air Mission in early 1939, it was decided that railway and
industrial workshops could be adapted to produce these aircraft,
resulting in the establishment of two final assembly plants (at
Fishermen's Bend, Melbourne, and at Mascot, Sydney) with the production
backing of railways workshops at Chullora, Islington and Newport.
Twenty sets of airframe parts and the eighth Bristol built Beaufort Mk
I (L4448, which became A9-1001) was imported for trials, but at an
early stage the Australians decided they did not want the Taurus
powerplant. Accordingly, they had obtained a licence from Pratt &
Whitney to build the Twin Wasp (already being licence built by the
Commonwealth Aircraft Corporation in Australia), and these were to
power all Australian-built Beauforts, which eventually totalled 700. As
from May 1941, several notable long distance flights were carried out
by this experimental prototype and all expectations were exceeded. The
first DAP Beaufort was tested in August 1941, and was one of a batch of
180 ordered by the RAF for use in the Far East.
began in 1940, the first Australian Beaufort Mk V making its initial
flight in May 1941. Apart from the change in engines, these were
generally similar to their British counterparts except for an increase
in fin area to improve stability with the powerful Twin Wasp engine. In
fact, engine and propeller changes accounted for most of the different
variants produced by the Australian factories. These included the
Beaufort V (50) and Beaufort VA (30), both with licence-built Twin Wasp
S3C4-G engines; Beaufort VI (40 with Curtiss propellers) and Beaufort
VII (60 with Hamilton propellers), all 100 being powered by imported
SlC3-G Twin Wasps due to insufficient licence production; and the
Beaufort VIII with licence-built S3C4-Gs. This last mark was the
definitive production version, of which 520 were built, and had
additional fuel tankage, Loran navigation system and variations in
armament, with production ending in August 1944. Some 46 of the last
production batch were subsequently converted to serve as unarmed
transports; designated Beaufort IX, this variant had the dorsal turret
removed and the resulting aperture faired in. The powerplant rating of
all the Australian versions was 1,200 hp (895 kW). The Beaufort was
used extensively by the Royal Australian Air Force in the Pacific
theatre, serving from the summer of 1942 until the end of World War II.
The early trials of the
Australian Beaufort V with Twin Wasp engines induced the Air Ministry
to specify this powerplant for the next contract, and a prototype with
these American engines was flown in November 1940. The first production
Beaufort Mk II flew in September 1941, and by comparison with the
Beaufort Mk I revealed much improved take-off performance. However,
because of a shortage of Twin Wasps in the UK, only 164 production Mk
IIs were built before Mk Is with improved Taurus XII engines were
reintroduced on the line. In addition to the powerplant change, this
version had structural strengthening, a changed gun turret, and ASV
radar with Yagi aerials. When production of this version ended in 1944,
well over 1,200 Beauforts had been built in Britain.
The final two Beaufort
designations, Mk III and Mk IV, related respectively to a version with
Rolls-Royce Merlin XX engines of which none were built, and a version
with two 1,250 hp (932 kW) Taurus XX engines of which only a prototype
Beauforts were the
standard torpedo-bomber in service with Coastal Command during 1940-43,
equipping Nos. 22, 42, 86, 217, 415 and 489 Squadrons in home waters,
and Nos. 39, 47 and 213 in the Middle East. They were to acquit
themselves well until superseded by the Beaufighter, involved in many
of the early and bloody attacks against the German battle cruisers
Gneisenau and Scharnhorst, and the heavy cruiser Prinz
Eugen, three vessels that often seemed to be invincible, at least
to aircraft carrying conventional weapons.
Type 152 Beaufort Mk I)
Type: Four Seat
General Reconnaissance (Anti-Shipping), Landed Based Torpedo Bomber,
Trainer & Transport
A normal crew of four consisting of a Pilot, Navigator/Bomb-Aimer,
Radio/Wireless Operator and an Air Gunner in the rear turret. The pilot
and navigator sat side-by-side with the navigator usually responsible
for any nose mounted armament. A navigation station/table was also
provided for his use. The radio/wireless operator was stationed
directly behind the pilot. The air gunner was responsible for the
dorsal turret but would also assist the radio/wireless operator with
any extra equipment (radar or cameras) when otherwise not engaged in
the active defence of the aircraft.
Designer Frank Barnwell of the Bristol Aeroplane Company Limited based
on the Bristol Blenheim.
The Bristol Aeroplane Company Limited based at Filton (Bristol),
Bristol County, England with secondary production facilities at Banwell
(Somerset). Australia also licence built the Beaufort using a greatly
dispersed manufacturing system. Over 400 sub-contractors delivered
parts to three main sub-assembly areas consisting of the New South
Wales Government Railway Workshops in Chullora (front fuselage, stern
frame, landing gear and engine nacelles), the Victorian Railway
Workshops in Newport (rear fuselage, tailplane, fin and control
surfaces) and the South Australian Government Railway Workshops in
Islington (centre-section and complete wings). All of these
sub-assemblies were complete with all equipment and fittings when
delivered to the two final assembly areas. Final assembly was carried
out by the Beaufort Division of the Department of Aircraft Production
(DAP) at Fishermen's Bend, Port Melbourne, Victoria and at Mascot,
Sydney, New South Wales. The British Bristol Taurus engines could not
be procured in any numbers, and the Australian built Beauforts were
modified to accept a licence built Pratt & Whitney engine already being
produced by the Commonwealth Aircraft Corporation.
Bristol Taurus II or VI 14-cylinder sleeve-valve twin-row air-cooled
radial engines using a single speed supercharger rated at 1,065 hp (794
kW) for take-off and developing a maximum power rating (with boost) of
1,130 hp (843 kW) and driving a three bladed De Havilland Hydromatic
constant-speed variable-pitch propellers. Late production Beaufort Mk
Is were powered by two Bristol Taurus XII or XVI 14-cylinder
sleeve-valve twin-row air-cooled radial engines using a single speed
supercharger rated at 1,085 hp (809 kW) for take-off and developing a
maximum power rating (with boost) of 1,130 hp (843 kW) using 100/130
Maximum speed (clean) 260 mph (418 km/h) at 6,000 ft (1830 m); maximum
speed (with torpedo) 225 mph (362 km/h); cruising speed of 200 mph (322
km/h); service ceiling 16,500 ft (5180 m); rate of climb 1,150 ft/min
Two inboard fuel tanks each with a capacity of 194 Imperial gallons
(882 litres) and two outboard fuel tanks each with a capacity of 91
Imperial gallons (413 litres) giving the aircraft a total capacity of
570 Imperial gallons (2590 litres). An auxiliary weapons bay tank of
138 Imperial gallons (626.5 litres) could also be carried internally.
Normal endurance was about 6 hours with a fuel consumption of about 80
gallons per hour at cruising speed.
1,035 miles (1666 km) on internal fuel with a maximum range of 1,600
miles (2576 km). Ordnance carried affected range.
Weights & Loadings:
Empty 13,107 lbs (5945 kg) with a maximum take-off weight of 21,228
lbs (9629 kg) including torpedo.
57 ft 10 in (17.63 m); length 44 ft 7 in (13.59 m); height 12 ft 5 in
(3.78 m); wing area 503.0 sq ft (46.73 sq m).
Originally consisted of one 7.7 mm (0.303 in) machine-gun in the nose
and one 7.7 mm (0.303 in) machine-gun in a Daimler-built dorsal turret.
This soon changed to twin 7.7 mm (0.303 in) machine-guns in the nose
and twin 7.7 mm (0.303 in) machine-guns in a Bristol power-operated
dorsal turret, two side beam 7.7 mm (0.303 in) machine-guns and in some
models a single 7.7 mm (0.303 in) backward machine-gun in a F.N.54 nose
turret with a periscopic sight and remote control. Some aircraft also
saw the installation of a single 7.7 mm (0.303 in) machine-gun in the
2 × 7.7 mm (0.303 in)
Vickers "K" forward-firing machine-guns mounted in the nose with 300
rounds per gun (6 x 50 round circular ammunition pans).
2 × 7.7 mm (0.303 in)
Vickers "K" trainable machine-guns in a power-operated Bristol B.IV Mk
I dorsal turret with 900 rounds per gun (18 x 50 round circular
2 × 7.7 mm (0.303 in)
Vickers "K" trainable machine-guns with one gun in each beam position
with 250 rounds per gun (5 x 50 round circular ammunition pans).
1 × 7.7 mm (0.303 in)
Browning fixed forward-firing machine-gun mounted in the port wing
with 500 rounds via belt feed from an ammunition box mounted in the
1 × 7.7 mm (0.303 in)
Browning trainable rearward-firing machine-gun in a remotely
controlled Frazer-Nash FN.54 nose turret with 600 rounds (optional).
4 × 7.7 mm (0.303 in)
Browning fixed forward-firing machine-guns mounted in the wings with
500 rounds per gun for ground attack or anti-shipping work (optional).
Armament: (Normal) 1,500 lbs (680 kg) of bombs or mines. (Maximum)
2,000 lbs (907 kg) of bombs or mines. A single 17.7 inch (45 cm) Mark
XII torpedo of 1,548 lbs (702 kg) could be carried semi-externally to
the left of the centreline. Commonly referred to as an 18 inch torpedo.
Variants: Bristol Type 150, Bristol Type 152 Beaufort, Bristol
Beaufort Mk I, Bristol Beaufort Mk II, Bristol Beaufort T.Mk II
(trainer), Bristol Beaufort Mk III, Bristol Beaufort Mk IV, DAP
Beaufort Mk V, DAP Beaufort Mk VA, DAP Beaufort Mk VI, DAP Beaufort Mk
VII, DAP Beaufort Mk VIII, DAP Beaufort Mk IX (transport).
Standard communications, navigation equipment and a G45 gun camera in
conjunction with the port mounted machine-gun. Some later aircraft
carried ASV Mk II radar. Aircraft used for reconnaissance carried
additional cameras in the fuselage that were operated by the Air
Unit: The wings are of a mid-wing cantilever monoplane type.
Structure consists of two spars, former ribs and stressed skin
covering. The fuselage is an oval section monocoque. Structure
comprises formers, stringers of extruded angles and a smooth flush
riveted skin. The tail unit is of a cantilever monoplane type. Fin and
tailplane constructed mainly of Alclad. Rudder and elevators have metal
structure and fabric covering.
The landing gear are a fully retractable type, with the mainwheels
carried between pairs of Vickers oleo-pneumatic legs struts and are
retracted backwards into engine nacelles. The tailwheel retracts
forwards into a recess within the fuselage.
flight (prototype) 1 October 1938; first delivery October 1939; first
flight (Australian built but using British supplied parts) 5 May 1941;
first flight (Australian Mk V) August 1941; last delivery (Australia)
United Kingdom (RAF & RN), Australia (RAAF), Canada (RCAF), Turkey.
Beaufort was the standard torpedo bomber within Coastal Command during
1940-43 equipping Nos. 22, 42, 86, 217, 415 and 489 Squadrons in home
waters. Nos. 39, 47 and 213 Squadrons saw service in the Middle East.
No. 217 was later posted to Malta, and then Burma, seeing service at
home, in the Middle East and finally the Far East. The Royal Navy's
Fleet Air Arm operated the Beaufort with Nos. 728, 733, 762, 788 and
798 Squadrons. The Royal Canadian Air Force operated two overseas
units, Nos. 404 and 415 RCAF Squadrons (although briefly) and No. 149
RCAF Squadron based in Patricia Bay, British Columbia. The Royal
Australian Air Force operated Nos. 1, 2, 6, 7, 8, 13, 14, 15, 32 and
100 RAAF Squadrons plus several training units.