Armstrong Whitworth Albemarle

Armstrong Whitworth

Industry	Aerospace
Founded	1912 in United Kingdom
Fate	Merged into Hawker Siddeley
Headquarters	United Kingdom
Products	Aircraft
Parent	Hawker Siddeley

The Armstrong Whitworth A.W.41 Albemarle was a twin-engine transport aircraft developed in the United Kingdom by the manufacturer Armstrong Whitworth, with primary production carried out by A.W. Hawksley Ltd, a subsidiary company of the Gloster Aircraft Company. This aircraft served notably with the Royal Air Force (RAF) during the course of the Second World War.

Initially conceived to meet Specification B.9/38 as a medium bomber constructed from wood and metal without reliance on light alloys, the Albemarle underwent significant design changes during development. The original bomber concept was set aside in favour of roles including aerial reconnaissance and transport. The prototype completed its first flight on 20 March 1940, but entry into operational service was postponed due to these redesign efforts. It was not until January 1943 that 295 Squadron at RAF Harwell received the aircraft in substantial numbers. Given that more capable bombers like the Vickers Wellington were already widely deployed, the Albemarle’s use as a bomber was ultimately discontinued.

Primarily, the Albemarle fulfilled a variety of RAF roles such as general and special transport, paratroop deployment, glider towing, and other auxiliary missions. Units equipped with Albemarles took part in major operations including the Normandy landings and the assault on Arnhem during Operation Market Garden. Although it remained active throughout the war, the RAF retired its last examples shortly after hostilities ended. Additionally, in October 1942, the Soviet Air Force placed an order for 200 aircraft; however, only a limited number were delivered before the Soviets halted further shipments in May 1943 and eventually cancelled their order in favour of procuring American Douglas C-47 Skytrain transports instead.

Background

The Albemarle's inception dates back to the mid-1930s with the introduction of Specification B.9/38 by the British Air Ministry. This specification called for a twin-engine medium bomber constructed from wood and metal, explicitly excluding any light alloys to enable production by manufacturers lacking extensive aircraft industry experience. Additionally, the design required the aircraft to be segmented into relatively compact components, each fitting onto a standard Queen Mary trailer, facilitating a dispersed manufacturing approach. At that time, the Air Ministry was particularly wary that, should a major war erupt, shortages of essential materials might impede mass production efforts.

Multiple aircraft manufacturers, such as Armstrong Whitworth, Bristol, and de Havilland, were invited to submit proposals in response to this specification. Bristol presented two concepts: one featuring a conventional undercarriage with an 80 ft (24 m) wingspan capable of 300 mph, and another with a tricycle undercarriage and a 70 ft (21 m) wingspan reaching speeds up to 320 mph (510 km/h). Both iterations, named Type 155, were powered by two Bristol Hercules engines. In competition, Armstrong Whitworth developed the AW.41 design, which incorporated a tricycle undercarriage and was assembled from sub-sections to simplify construction by firms inexperienced in aircraft manufacturing. The AW.41 was primarily designed for Rolls-Royce Merlin engines but included provisions to utilize Bristol Hercules engines if necessary.

By June 1938, mock-ups of both the AW.41 and Bristol 155 had been reviewed, leading to the creation of updated specifications B.17/38 and B.18/38 corresponding to each design; de Havilland ultimately chose not to submit a proposal. The specification required an economical cruising speed of 250 mph (400 km/h) at an altitude of 15,000 ft (4,600 m), while carrying a bomb load of 4,000 lb (1,800 kg). As Bristol was heavily engaged in other projects, it ceased development of the Type 155. Policy shifts prompted the Air Staff to reclassify the Albemarle primarily as a reconnaissance platform with bombing capabilities, necessitating increased fuel capacity for an extended range of 4,000 mi (6,400 km). Additional defensive armaments were introduced, including an upper dorsal turret and a retractable ventral turret for downward firing.

Into production

In October 1938, an order for 200 aircraft was placed directly from the plans without requiring a prototype first. Initially regarded positively with high expectations regarding its capabilities, the Albemarle ultimately failed to fully meet these hopes. Aviation historian Oliver Tapper noted that fulfilling this specification posed considerable challenges for any manufacturer. Early efforts concentrated on building two lead aircraft intended for flight testing before mass production commenced. The first Albemarle, bearing serial number P1360, was assembled at Hamble Aerodrome by Air Service Training and completed its maiden flight on 20 March 1940.

This initial flight occurred somewhat unexpectedly when the test pilot inadvertently gained excessive speed during taxiing and managed to lift off just before reaching the runway's end. Several months later, P1360 sustained damage following a forced landing during testing but was quickly repaired. Test pilots generally described early flights as average yet free from significant defects. Late-stage development included numerous modifications such as a comprehensive structural redesign carried out by Lloyd in Coventry. To enhance take-off performance, adjustments included adopting a wider wing span of 77 ft (23 m) and thickening the trailing edge of the rudder to address over-balance tendencies. Persistent engine overheating issues remained unresolved; however, operational limits were adjusted by increasing the maximum allowable temperature from 280°C to 300°C.

The primary production responsibility for the Albemarle fell to A.W. Hawksley Ltd in Gloucester, a subsidiary established specifically for its manufacture under the umbrella of the Gloster Aircraft Company. Initially, Gloster had planned to produce the aircraft at its Brockworth facility itself. Both Gloster and Armstrong Whitworth belonged to the Hawker Siddeley group, one of Britain's largest aviation conglomerates. Over 1,000 subcontractors contributed parts and assemblies for the Albemarle’s construction. Among these subcontractors were companies like MG Motor, which fabricated the forward fuselage; Rover Company, responsible for building the wing center section; and Harris Lebus, which produced tailplane components. Production ceased in December 1944 after completing 602 units.

Design

The Armstrong Whitworth Albemarle featured a mid-wing cantilever monoplane layout with twin vertical stabilizers and rudders. Its fuselage was constructed in three main segments, utilizing a framework of steel tubing covered by unstressed plywood, reinforced by four circular steel longerons; most components were connected using gusset plates. This sectional design was deliberate, allowing easy removal and replacement of damaged parts sustained during combat. The wing’s center section was a single integral piece passing through the fuselage, built around a steel tube girder; it served as the mounting point for the central and nose fuselage sections, engines, main landing gear legs, and wing extensions. Most of the wing surface was covered with plywood, except for a portion of the leading edge which incorporated light alloys. The wing extensions were predominantly wooden structures, reinforced only by steel tubing supporting the two spars; similarly, the Frise-type ailerons and tailplane were wooden. To minimize interference with magnetic compasses, the forward fuselage framework employed stainless steel tubing.

A distinctive feature of the Albemarle was its Lockheed-designed, hydraulically operated retractable tricycle undercarriage. The main wheels retracted rearward into the engine nacelles, while the nose wheel folded back into the forward fuselage. The tail wheel remained fixed but was partially concealed by a protective "bumper" design. According to Tapper, this aircraft was notable as the first British-built type with a retractable nose wheel produced in quantity for the Royal Air Force. Propulsion came from two Bristol Hercules XI air-cooled radial engines, each delivering 1,590 hp and turning three-blade de Havilland Hydromatic propellers. Fuel storage typically comprised four tanks—two located in the central fuselage and two within the wing center section—with provisions for auxiliary tanks in the bomb bay to extend range when necessary. This large bomb bay extended from just behind the cockpit to approximately midway between the wings and tail and featured hydraulically operated doors.

The cockpit accommodated two pilots seated side by side at the front, with the radio operator positioned directly behind them. The navigator was stationed in the nose ahead of the cockpit. Incorporated into the crew hatch on the underside of the nose was a bomb aimer’s sighting panel. Several glazed panels were installed along the rear fuselage to enable a "fire controller" to coordinate defensive turret operations against enemy aircraft. The dorsal turret was an electrically powered Boulton-Paul design initially armed with four Browning machine guns. A fairing located ahead of this turret automatically retracted as it rotated forward to engage targets. The original bomber layout required a six-person crew including two gunners—one manning the four-gun dorsal turret and another operating a manually controlled twin-gun ventral turret; however, only the first 32 aircraft (the Mk I Series I) were built with this configuration.

In its role as a bomber, the Albemarle was generally regarded as less capable compared to other RAF aircraft like the Vickers Wellington; aviation historian Ray Williams noted that it saw bombing missions on only two occasions. Consequently, subsequent production models were adapted for transport duties and designated either "General Transport" (GT) or "Special Transport" (ST). Modifications included removal of the ventral turret and reduction of the dorsal turret to a manually operated twin-gun setup; internally, bomb-aiming equipment and rear fuselage fuel tanks were eliminated. Additionally, a quick-release towing hook was installed at the aft fuselage for glider towing purposes. When configured as a paratroop carrier, it could accommodate up to ten fully equipped soldiers. These troops accessed their positions through a rear fuselage dropping hatch and a large loading door on the starboard side.

Operational history

Plans to employ the Albemarle as a bomber were abandoned shortly after it entered service, primarily because it did not offer any advantages over existing medium bombers like the Vickers Wellington, and its performance lagged behind the emerging four-engine heavy bombers that were soon to be introduced to the RAF. Instead, the aircraft found its niche in roles such as general reconnaissance and transport, leading to a shift in its operational focus.

In October 1942, the Soviet Air Force contracted for 200 Albemarles. To facilitate Soviet crews' training on ferrying the aircraft, No. 305 FTU was established at RAF Errol, near Dundee. Unfortunately, one aircraft was lost during training with no survivors. The Albemarle’s first operational RAF squadron was No. 295, based at RAF Harwell in January 1943. Additional squadrons equipped with the type included No. 296, No. 297, and No. 570. The initial combat sortie took place on 9 February 1943, when an Albemarle of 296 Squadron dropped leaflets over Lisieux in Normandy.Template:CN

A Soviet-manned Albemarle completed a flight from Scotland to Vnukovo airfield near Moscow on 3 March 1943, followed shortly by eleven additional aircraft. Two Albemarles were lost over the North Sea—one due to enemy fighter action and another from unknown causes. Evaluations of the remaining Albemarles highlighted their shortcomings as transports, particularly their cramped interiors and numerous mechanical issues; consequently, in May 1943, the Soviets halted deliveries and ultimately cancelled them in favor of plentiful American Douglas C-47 Skytrains. The Soviet presence at Errol Field persisted until April 1944, reportedly due to hopes of acquiring de Havilland Mosquito aircraft. Tapper suggested that a significant factor behind Soviet interest in the Albemarle was its Bristol Hercules engines, which were reverse-engineered and replicated by Soviet industry.

File:IWM-CH12962 Albemarle 205210548.jpg

Armstrong Whitworth Albemarle from No. 296 or No. 297 Squadron RAF departing RAF Brize Norton, Oxfordshire, towing an Airspeed Horsa Mark I glider.

Starting mid-1943, RAF Albemarles actively participated in numerous British airborne missions, beginning with the invasion of Sicily. The aircraft reached the height of its service during the D-Day operations on the night of June 5–6, 1944: squadrons 295 and 296 deployed Albemarles carrying pathfinder forces into Normandy, with No. 295 Squadron reportedly being the first to drop Allied airborne troops over the area. On June 6, during Operation Tonga, four Albemarle squadrons plus an operational training unit contributed aircraft; No. 296 Squadron used nineteen planes to tow Airspeed Horsa gliders; No. 295 Squadron towed twenty-one Horsas but lost six en route; No. 570 Squadron dispatched twenty-two aircraft towing ten gliders; while No. 42 OTU provided four aircraft for the mission. The following day’s Operation Mallard involved these squadrons towing a total of 220 Horsas and thirty Hamilcar gliders to Normandy. Later, on September 17, during Operation Market Garden at Arnhem, twenty-eight Albemarles from squadrons 296 and 297 towed fifty-four Horsas and two Waco Hadrian gliders into the Netherlands; forty-five more aircraft conducted similar missions on the subsequent day. Out of the total delivery of 602 units, seventeen were lost during combat operations while eighty-one succumbed to accidents.Template:CN

The Heavy Glider Conversion Unit was the last RAF formation to operate the Albemarle before replacing it with Handley Page Halifax aircraft in February 1946; this marked the formal retirement of the type from active service within all operational units.Template:CN

Variants

Throughout its manufacturing period, several versions of the Albemarle were produced:

• ST Mk I – 99 units
• GT Mk I – 69 units
• ST Mk II – 99 units
• Mk III – Single prototype
• Mk IV – Single prototype
• ST Mk V – 49 units
• ST Mk VI – 133 units
• GT Mk VI – 117 units

Various Marks were further categorized into "Series" to highlight equipment variations. For instance, the ST Mk I Series 1 (eight planes) replaced the four-gun turret with manually operated twin guns beneath a sliding canopy. A specialized transport version included a loading door on the starboard side after removing the rear fuel tank. The ST Mk I Series 2 comprised 14 aircraft outfitted for glider towing. The Mk II model could accommodate ten paratroops, while the Mk V shared this capacity but featured a fuel jettison mechanism. All Albemarle variants in production utilized two 1,590 hp (1,190 kW) Bristol Hercules XI radial engines. The Mk III and Mk IV were experimental platforms for alternative engines; the former was powered by the Rolls-Royce Merlin III, and the latter employed the 1,600 hp (1,200 kW) Wright Double Cyclone.

Operators

Template:USSR

• Twelve Albemarles were supplied to the Soviet Union (with two additional aircraft lost during shipment).
• These served in the transport division of the 1st Air Division and later in the 10th Guards Air Division until 1944; they were also used by naval aviation units until their phase-out in 1945.Template:CN

Template:UK

Royal Air Force

• No. 161 Squadron RAF operated Albemarle I aircraft from October 1942 through April 1943 at RAF Tempsford.
• No. 271 Squadron RAF maintained a single aircraft at Doncaster between October 1942 and April 1943.
• No. 295 Squadron RAF flew Albemarle I models from November 1943 to July 1944 at RAF Hurn and later RAF Harwell. The squadron also operated Albemarle II from October 1943 to July 1944 at these locations, and Albemarle V from April to July 1944 at RAF Harwell.
• No. 296 Squadron RAF utilized Albemarle I from January 1943 to October 1944 at RAF Hurn and RAF Stoney Cross, including missions in North Africa. They also flew Albemarle II from November 1943 to October 1944 at RAF Hurn and subsequently RAF Brize Norton, Albemarle V from April to October 1944 at RAF Brize Norton, and Albemarle VI between August and October 1944 at RAF Brize Norton.
• No. 297 Squadron RAF operated Albemarle I from July 1943 to December 1944 across RAF Thruxton, RAF Stoney Cross, and RAF Brize Norton; Albemarle II from February 1943 to December 1944 at RAF Stoney Cross and then RAF Brize Norton; Albemarle V from April to December 1944 at RAF Brize Norton; and Albemarle VI from July to December 1944 at RAF Brize Norton.
• No. 511 Squadron RAF flew Albemarle I between November 1942 and March 1944 based at RAF Lyneham.
• No. 570 Squadron RAF operated Albemarle I from November 1943 to August 1944 at RAF Hurn and then RAF Harwell, alongside Albemarle II during the same timeframe and locations, as well as Albemarle V from May to August 1944 at RAF Harwell.
• No. 1404 Flight RAF employed three aircraft at RAF St Eval between September 1942 and March 1943.
• No. 1406 Flight RAF used two planes stationed at RAF Wick from September to October of 1942.
• No. 13 Operational Training Unit RAF based at RAF Finmere operated two aircraft from October 1942 until April 1943.
• No. 42 Operational Training Unit RAF conducted operations with Albemarles at RAF Ashbourne between September 1943 and February 1945.
• Heavy Glider Conversion Unit functioned at both RAF Brize Norton and RAF North Luffenham during January–April 1943 and again August–October 1944 before transitioning into No. 21 Heavy Glider Conversion Unit.
• No. 21 Heavy Glider Conversion Unit operated out of RAF Brize Norton starting in 1944, relocated to RAF Elsham Wolds in December of that year, retiring the final operational Albemarles by February 1946.
• No. 22 Heavy Glider Conversion Unit was active at both RAF Keevil and RAF Blakehill from October 1944 through November 1945.
• No. 23 Heavy Glider Conversion Unit was stationed at RAF Peplow between October and December of 1944.
• No.3 Glider Training School managed eight Albemarles at RAF Exeter between January and August of the year 1945.
• No.301 Ferry Training Unit operated four aircraft based at RAF Lyneham from November of 1942 until April of the following year.
• No.305 Ferry Training Unit was located at RAF Errol beginning January of 1943 for training Soviet aircrews until its disbandment in April of the next year.
• Torpedo Development Unit utilized one aircraft in Gosport between April and September of the year 1942.
• Telecommunications Flying Unit employed a single plane during May of the year 1943 based out of RAF Defford.
• The Airborne Forces Experimental Establishment operated between May 1942 and October 1944 across bases including RAF Ringway and RAF Sherburn-in-Elmet.
• Coastal Command Development Unit flew two aircraft out of RAF Tain during September through December of the year 1942.
• Central Gunnery School used one aircraft between September and November of the year 1942 stationed at RAF Sutton Bridge.
• Bomber Development Unit had three aircraft operating out of RAF Gransden Lodge from August through November of the year 1942.
• Operation Refresher Training Unit was active at RAF Hampstead Norris between May of the year 1944 through February of the following year.

Additional use included testing and evaluation by various aviation companies, the Royal Aircraft Establishment, as well as the Aeroplane and Armament Experimental Establishment. De Havilland Propellers also operated an Albemarle for investigations into reversible propeller technology.Template:CN

Specifications (ST Mk I)

File:Armstrong Whitworth Albemarle ExCC.svg

Orthographic view of the Albemarle.

• Air Transport Auxiliary Ferry Pilots Notes. Elvington, Yorkshire, UK: Yorkshire Air Museum, Reprint edition, 1996. ISBN 0-9512379-8-5.
• Bowyer, Michael J.F. Aircraft for the Royal Air Force: The "Griffon" Spitfire, The Albemarle Bomber and the Shetland Flying-Boat. London, UK: Faber & Faber, 1980. ISBN 0-571-11515-2.
• Buttler, Tony. British Secret Projects: Fighters and Bombers 1935–1950. Hinckley, UK: Midland Publishing, 2004. ISBN 1-85780-179-2.
• Mason, Francis K. The British Bomber since 1914. London, UK: Putnam Aeronautical Books, 1994. ISBN 0-85177-861-5.
• Morgan, Eric B. "Albemarle". Twentyfirst Profile, Vol. 1, No. 11. New Milton, Hants, UK: 21st Profile Ltd. ISSN 0961-8120.
• Tapper, Oliver. Armstrong Whitworth Aircraft since 1913. London: Putnam, 1988. ISBN 0-85177-826-7.
• Williams, Ray. "The Unloved Albemarle". Air Enthusiast, No. 39, May–August 1989, pp. 29–42. ISSN 0143-5450.
• "Armstrong Whitworth Albemarle", Flight, 27 January 1944, pp. 87–91.
• Neil, Tom. "The Silver Spitfire", 2013. Wing Commander Neil shares his experiences with the Albemarle and recounts his daring efforts to pilot one without any formal guidance or manual.

External links

• "Whitley and Albemarle", Flight, 4 April 1946