Armstrong Whitworth Whitley

https://en.wikipedia.org/wiki/Armstr...tworth_Whitley

The Armstrong Whitworth A.W.38 Whitley was one of three British twin-engined,
front line medium bomber types that were in service with the Royal Air Force
(RAF) at the outbreak of the Second World War. Alongside the Vickers Wellington
and the Handley Page Hampden, the Whitley was developed during the mid-1930s
according to Air Ministry Specification B.3/34, which it was subsequently
selected to meet. In 1937, the Whitley formally entered into RAF squadron
service; it was the first of the three medium bombers to be introduced.

Following the outbreak of war in September 1939, the Whitley participated in the
first RAF bombing raid upon German territory and remained an integral part of
the early British bomber offensive. In 1942 it was superseded as a bomber by the
larger four-engined "heavies" such as the Avro Lancaster. Its front line service
included maritime reconnaissance with Coastal Command and the second line roles
of glider-tug, trainer and transport aircraft. The type was also procured by
British Overseas Airways Corporation as a civilian freighter aircraft. The
aircraft was named after Whitley, a suburb of Coventry, home of one of Armstrong
Whitworth's plants.

Origins

In July 1934, the Air Ministry issued Specification B.3/34, seeking a heavy
night bomber/troop transport to replace the Handley Page Heyford biplane bomber.
John Lloyd, the Chief Designer of Armstrong Whitworth Aircraft, chose to respond
to the specification with a design designated as the AW.38, which later was
given the name Whitley after the location of Armstrong Whitworth's main factory.
The design of the AW.38 was in fact a development of the Armstrong Whitworth
AW.23 bomber-transport design that had lost to the Bristol Bombay for the
earlier Specification C.26/31.

Lloyd selected the Armstrong Siddeley Tiger IX radial engine to power the
Whitley, which was capable of generating 795 horsepower. One of the more
innovative features of the Whitley's design was the adoption of a three-bladed
two-position variable-pitch propeller built by de Havilland; the Whitley was the
first aircraft to fly with such an arrangement. As Lloyd was unfamiliar with the
use of flaps on a large heavy monoplane, they were initially omitted from the
design. To compensate, the mid-set wings were set at a high angle of incidence
(8.5°) to confer good take-off and landing performance. Although flaps were
included late in the design stage, the wing remained unaltered; as a result, the
Whitley flew with a pronounced nose-down attitude when flown with the wings in
the cruising position, resulting in considerable drag.

The Whitley holds the distinction of having been the first RAF aircraft with a
semi-monocoque fuselage, which was built using a slab-sided structure to ease
production. This replaced the tubular construction method traditionally employed
by Armstrong Whitworth, who instead constructed the airframe from light-alloy
rolled sections, pressings and corrugated sheets. According to aviation author
Philip Moyes, the decision to adopt the semi-monocoque fuselage was a
significant advance in design; many Whitleys surviving severe damage on
operations.

In June 1935, owing to the urgent need to replace biplane heavy bombers then in
service with the RAF, a verbal agreement was formed to produce an initial 80
aircraft, 40 being of an early Whitley Mk I standard and the other 40 being more
advanced Whitley Mk IIs. Production was initially at three factories in
Coventry; fuselages and detailed components were fabricated at Whitley Abbey,
panel-beating and much of the detailed work at the former Coventry Ordnance
Works factory, while wing fabrication and final assembly took placed at Baginton
Aerodrome. During 1935 and 1936, various contracts were placed for the type; the
Whitley was ordered "off the drawing board" - prior to the first flights of any
of the prototypes.

Design

The Armstrong Whitworth Whitley was a twin-engined heavy bomber, initially being
powered by a pair of 795 h.p. Armstrong Siddeley Tiger IX radial engines. More
advanced models of the Tiger engine equipped some of the later variants of the
Whitley; starting with the Whitley Mk IV variant, the Tigers were replaced by a
pair of 1,030 h.p. Rolls-Royce Merlin IV V12 engines. According to Moyes, the
adoption of the Merlin engine gave the Whitley a considerable boost in
performance.

The Whitley had a crew of five: a pilot, co-pilot/navigator, a bomb aimer, a
wireless operator and a rear gunner. The pilot and second pilot/navigator sat
side by side in the cockpit, with the wireless operator further back. The
navigator, his seat mounted on rails and able to pivot, slid backwards and
rotated to the left to use the chart table behind him after takeoff. The bomb
aimer position was in the nose with a gun turret located directly above. The
fuselage aft of the wireless operator was divided horizontally by the bomb bay;
behind the bomb bay was the main entrance and aft of that the rear turret. The
offensive armaments were stowed in two bomb bays housed within the fuselage,
along with a further 14 smaller cells in the wing. Other sources state there
were 16 "cells" total: two groups of 2 in the fuselage, and four groups of 3 in
the wings, plus two smaller cells for parachute flares in the rear fuselage.
Bomb racks capable of holding larger bombs were installed on the Whitley Mk III
variant.

The early examples had a nose turret and rear turret, both being manually
operated and mounting one Vickers 0.303 machine gun. On the Whitley Mk III this
arrangement was substantially revised: a new retractable ventral 'dustbin'
position was installed mounting twin .303 in (7.7 mm) Browning machine guns and
the nose turret was also upgraded to a Nash & Thompson power-operated turret. On
the Whitley Mk IV, the tail and ventral turrets were replaced with a Nash &
Thompson power-operated turret mounting four Browning machine guns; upon the
adoption of this turret arrangement, the Whitley became the most powerfully
armed bomber in the world against attacks from the rear.


Role
Medium bomber, night bomber

National origin
United Kingdom

Manufacturer
Armstrong Whitworth Aircraft

Designer
John Lloyd

First flight
17 March 1936

Introduction
1937

Retired
1945

Status
Retired

Primary user
Royal Air Force

Number built
1,814

Developed from
Armstrong Whitworth AW.23

Military service

On 9 March 1937, the Whitley Mk I began entering squadron service with No. 10
Squadron of the RAF, replacing their Handley Page Heyford biplanes. In January
1938, the Whitley Mk II first entered squadron service with No. 58 Squadron and
in August 1938, the Whitley Mk III first entered service with No. 51 Squadron.
In May 1939, the Whitley Mk IV first entered service with No. 10 Squadron and in
August 1939, the Whitley Mk IVA first entered service with No. 78 Squadron. By
the outbreak of the Second World War, a total of seven squadrons were
operational, the majority of these flying Whitley III or IV aircraft, while the
Whitley V had only just been introduced to service; a total of 196 Whitleys were
on charge with the RAF.

At the start of the war, No. 4 Group, equipped with the Whitley, was the only
trained night bomber force in the world. Alongside the Handley Page Hampden and
the Vickers Wellington, the Whitley bore the brunt of the early fighting and saw
action during the first night of the war, when they dropped propaganda leaflets
over Germany. The propaganda flight made the Whitley the first aircraft of RAF
Bomber Command to penetrate into Germany. Further propaganda flights would
travel as far as Berlin, Prague, and Warsaw. On the night of 19/20 March 1940,
in conjunction with multiple Hampdens, the Whitley conducted the first bombing
raid on German soil, attacking the Hörnum seaplane base on the Island of Sylt.
Following the Hörnum raid, Whitleys routinely patrolled the Frisian Islands,
targeting shipping and seaplane activity.

Unlike the Hampden and Wellington, which had met Specification B.9/32 for a day
bomber, the Whitley was always intended for night operations alone and thus
escaped the early heavy losses received during daylight raids carried out upon
German shipping. As the oldest of the three bombers, the Whitley was effectively
obsolete by the start of the war, yet over 1,000 more aircraft were produced
before a suitable replacement was found. A particular problem with the
radar-equipped Mk VII, with the addition of the drag-producing aerials, was that
it could not maintain altitude on one engine. Whitleys flew a total of 8,996
operations with Bomber Command, dropped 9,845 tons (8,931 tonnes) of bombs, and
269 aircraft were lost in action.

Specifications (Whitley Mk V)

General characteristics
Crew: 5
Length: 70 ft 6 in (21.49 m)
Wingspan: 84 ft 0 in (25.60 m)
Height: 15 ft 0 in (4.57 m)
Wing area: 1,137 sq ft (105.6 m2)
Empty weight: 19,300 lb (8,754 kg)
Max takeoff weight: 33,500 lb (15,195 kg)
Powerplant: 2 × Rolls-Royce Merlin X liquid-cooled V12 engines, 1,145 hp (854
kW) each

Performance
Maximum speed: 230 mph (370 km/h, 200 kn) at 16,400 ft (5,000 m)
Range: 1,650 mi (2,660 km, 1,430 nmi)
Ferry range: 2,400 mi (3,900 km, 2,100 nmi)
Service ceiling: 26,000 ft (7,900 m)
Rate of climb: 800 ft/min (4.1 m/s)

Armament

Guns:
1 × .303 in (7.7 mm) Vickers K machine gun in nose turret
4 × .303 in Browning machine guns in tail turret

Bombs: Up to 7,000 lb (3,175 kg) of bombs in the fuselage and 14 individual
cells in the wings, typically including 12 × 250 lb (113 kg) and
2 × 500 lb (227 kg) bombs
Bombs as heavy as 2,000 lb (907 kg) could be carried




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