Armstrong Whitworth Whitley

The Armstrong Whitworth A.W.38 Whitley was a British medium/heavy bomber aircraft of the 1930s. It was one of three 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 In 1942 it was superseded as a bomber by the larger four-engined "heavies" such as the Avro Lancaster.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 Armstrong Whitworth's Whitley plant.

Development

Origins

thumb|Scale [[comparison diagram of the trio of British twin-engined medium bombers at the outbreak of the Second World War; the Whitley (pink), the Vickers Wellington (blue) and the Handley Page Hampden (yellow)]]

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. This combination bomber/transport was part of the RAF's concept of fighting wars in distant British Empire locations, where the aircraft would fly into the theatre of action carrying troops and then provide air support.

John Lloyd, the Chief Designer of Armstrong Whitworth Aircraft, chose to respond to the specification with the AW.38 design, which later was given the name Whitley after the location of Armstrong Whitworth's main factory. The design of the AW.38 was 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 . One of the novel 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. Flaps were included late in the design stage, but the wing incidence remained unaltered; as a result, the Whitley flew with a pronounced nose-down attitude when at cruising speed, resulting in considerable drag.

The Whitley holds the distinction of having been the first RAF aircraft with a semi-monocoque structure in its fuselage, which was built slab-sided to ease production. Another Whitley Mk I, K7208, was modified to operate with a higher () gross weight.

K7211, the 29th production Whitley, served as the prototype for a further advanced variant of the aircraft, the Whitley Mk III. The Whitley Mk III featured numerous improvements, such as the replacement of the manually operated nose turret with a single powered Nash & Thompson turret and a powered retractable twin-gun ventral "dustbin" turret. The ventral turret was hydraulically-powered but proved to be hard to operate and added considerable drag, thus the Whitley Mk III was the only variant with it. Other changes included increased dihedral of the outer wing panels, superior navigational provision and the installation of new bomb racks. A total of 80 Whitley Mk III aircraft were manufactured.

While the Tiger VIII engine used in the Whitley Mks II and III was more reliable than those used in early aircraft, the Whitley was re-engined with Rolls-Royce Merlin engines in 1938, giving rise to the Whitley Mk IV. Three Whitley Mk I aircraft, K7208, K7209 and K7211, were initially re-engined to serve as prototypes. The new engines are credited with producing greatly improved performance. The bombs 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", two groups of two in the fuselage and four groups of three in the wings, plus two smaller cells for parachute flares in the rear fuselage. 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, 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; 196 Whitleys were on charge with the RAF. 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 Hampdens, the Whitley conducted the first bombing raid on German soil, attacking the Hörnum seaplane base on the Island of Sylt.

On the night of 11/12 June 1940, the Whitley carried out Operation Haddock, the first RAF bombing raid on Italy, only a few hours after Italy's declaration of war; the Whitleys bombed Turin and Genoa, reaching northern Italy via a refuelling stop in the Channel Islands. Having evaluated the Whitley in 1942, the Fleet Air Arm operated a number of modified ex-RAF Mk VIIs from 1944 to 1946, to train aircrew in Merlin engine management and fuel transfer procedures.

Variants

thumb|A Whitley prototype, circa 1936

thumb|Personnel loading 250lb bombs into a Whitley Mk V of [[No. 502 Squadron RAF|No. 502 Squadron, 1940]]

Following the two prototypes (K4586 and K4587), at the outbreak of the war the RAF had 207 Whitleys in service ranging from Mk I to Mk IV types, with improved versions following:

;Mk I

:A.W. Type 188. Powered by Armstrong Siddeley Tiger IX air-cooled radial engines, 4 degrees of dihedral incorporated into each outer wing panel, with earlier aircraft being retrospectively modified: 34 built.

;Mk II

:A.W. Type 197 (some Type 220). Powered by two-speed supercharged Tiger VIII engines: 46 built.

;Mk III

:A.W. Type 205. Powered by Tiger VIII engines, retractable "dustbin" ventral turret fitted aft of the wing root armed with two .303 in (7.7 mm) machine guns, hydraulically operated bomb bay doors and ability to carry larger bombs: 80 built.

;Mk IV

:A.W. Type 209. Powered by Rolls-Royce Merlin IV inline liquid-cooled engines, increased fuel capacity, extended bomb-aimer's transparency, manually operated tail and retractable ventral turrets replaced with a single Nash & Thompson powered tail turret equipped with four .303 in (7.7 mm) Browning machine guns, produced from 1938: 33 built.

;Mk IVA

:A.W. Type 210. Mk IV variant powered by Merlin X engines made by fitting Merlin X engines on last Mk IV's on production line: seven built.

;Mk V

:A.W. Type 207. The main wartime production version based on the Mk IV, modified straight-edged fins, leading edge de-icing, tail fuselage aft or empennage extended by 15 in (381 mm) to improve the tail gunner's field of fire.

No. 138 Squadron RAF between August 1941 and October 1942.
No. 161 Squadron RAF between February 1942 and December 1942.
No. 166 Squadron RAF between July 1938 and April 1940.
No. 295 Squadron RAF between August 1942 and November 1943.
No. 296 Squadron RAF between June 1943 and March 1943.
No. 297 Squadron RAF between February 1942 and February 1944.
No. 298 Squadron RAF between August 1942 and October 1942.
No. 299 Squadron RAF between November 1943 and January 1944.
No. 502 Squadron RAF between October 1940 and February 1943.
No. 612 Squadron RAF between November 1940 and June 1943.
No. 619 Squadron RAF between April 1943 and January 1944.
No. 1419 Flight RAF
No. 1473 Flight RAF
No. 1478 Flight RAF
No. 1481 Flight RAF
No. 1484 Flight RAF
No. 1485 Flight RAF
No. 1486 Flight RAF
No. 1 (Coastal) Operational Training Unit RAF
No. 10 Operational Training Unit RAF
No. 81 Operational Training Unit RAF
No. 19 Operational Training Unit RAF
No. 24 Operational Training Unit RAF
No. 29 Operational Training Unit RAF
No. 58 Operational Training Unit RAF
No. 81 Operational Training Unit RAF
No. 83 Operational Training Unit RAF
Parachute Training School
Parachute Section, 13 Maintenance Unit
Fleet Air Arm
734 Naval Air Squadron operated Whitleys between February 1944 and February 1946.

Civil operators

;

British Overseas Airways Corporation

Surviving aircraft

thumb|Whitley Squadron War Memorial, [[Coventry, 2010]]

No complete aircraft of the 1,814 Whitleys produced remains. The Whitley Project is rebuilding an example from salvaged remains, and a fuselage section is displayed at the Midland Air Museum (MAM), whose site is adjacent to the airfield from where the Whitley's maiden flight took place.

Specifications (Whitley Mk V)

thumb|Merlin-powered Whitley Mk.V drawing with inset profile of the Tiger-powered Mk III with retractable "dustbin" turret.

Armstrong Whitworth Whitley

Development

Origins

Variants

Civil operators

Surviving aircraft

Specifications (Whitley Mk V)

See also

References

Notes

Bibliography

External links