Armstrong Whitworth A.W.41

Armstrong Whitworth Aircraft

Industry	Aerospace
Predecessor	Armstrong Whitworth
Founded	1912
Headquarters	Coventry , United Kingdom
Parent	Hawker Siddeley Group

The Armstrong Whitworth A.W.41 Albemarle was a British twin-engine transport aircraft developed by Armstrong Whitworth and mainly manufactured by A.W. Hawksley Ltd, a division of the Gloster Aircraft Company. It was among the numerous aircraft types deployed by the Royal Air Force (RAF) during Second World War operations.

Initially conceived as a medium bomber to meet Specification B.9/38, the Albemarle was designed to be constructed using wood and metal without relying on light alloys. However, it was ultimately rejected for bombing missions and repurposed for roles including aerial reconnaissance and transport, necessitating significant redesign during development. The aircraft completed its first flight on 20 March 1940, but entry into RAF service was postponed until January 1943 when 295 Squadron at RAF Harwell received it in operational numbers. Given that more capable bombers like the Vickers Wellington were already widely available, the Albemarle’s intended bomber function was discontinued.

Throughout its service, the Albemarle primarily fulfilled general and specialised transport tasks, including paratroop deployment and glider towing. It saw active participation in major operations such as the Normandy landings (Operation Overlord) and the assault on Arnhem during Operation Market Garden. Although it remained operational for the duration of the war, the RAF retired its last Albemarles less than twelve months after hostilities ended. In October 1942, the Soviet Air Force placed an order for 200 units; however, only a limited number were delivered before the Soviets halted further shipments in May 1943 and subsequently cancelled the contract in favour of acquiring American Douglas C-47 Skytrain aircraft instead.

Background

The Albemarle's inception dates back to the mid-1930s with the issuance 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 the use of light alloys. The aim was to enable manufacturers lacking extensive aircraft industry experience to build the plane efficiently. Additionally, the design required segmentation into relatively compact sections, all sized to fit on a standard Queen Mary trailer, supporting a dispersed manufacturing approach. At that time, the Air Ministry was particularly wary that any large-scale conflict might result in shortages of essential materials, potentially obstructing mass production.

Several aircraft manufacturers, including Armstrong Whitworth, Bristol, and de Havilland, were invited to submit designs meeting this specification. Bristol proposed two variants: one with a conventional undercarriage and an 80 ft (24 m) wingspan capable of reaching 300 mph, and another featuring a tricycle undercarriage with a 70 ft (21 m) wingspan and a top speed of 320 mph (510 km/h). Both versions, designated Type 155, were powered by two Bristol Hercules engines. The competing Armstrong Whitworth AW.41 featured a tricycle landing gear and was designed in modular subsections to facilitate production by companies without prior aircraft manufacturing expertise. The AW.41 was primarily intended to be equipped with Rolls-Royce Merlin engines but also included provisions to accommodate Bristol Hercules engines as an alternative.

By June 1938, mock-ups of both the AW.41 and Bristol 155 had been reviewed, leading to updated specifications B.17/38 and B.18/38 tailored for each design; de Havilland chose not to submit a proposal. The requirements called for an economical cruising speed of 250 mph (400 km/h) at 15,000 ft (4,600 m) altitude while carrying a bomb load of 4,000 lb (1,800 kg). Bristol, already committed to other projects, ceased development on the Type 155. Shifts in strategic priorities led the Air Staff to reclassify the Albemarle primarily as a reconnaissance platform with bombing capability. This adjustment necessitated increased fuel capacity to achieve a range of approximately 4,000 mi (6,400 km). Additional defensive features such as an upper dorsal turret and a retractable ventral turret for downward firing were incorporated.

Into production

In October 1938, an order for 200 aircraft was placed directly from the design stage without constructing prototypes first. The aircraft initially garnered a favorable reputation with high expectations for its capabilities; however, it ultimately did not fulfill those anticipations. Aviation historian Oliver Tapper noted that the specification posed significant challenges for any manufacturer. Early efforts focused on building two lead aircraft intended for flight testing before commencing full-scale production. 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 unintentionally when the test pilot accelerated excessively during taxiing and barely lifted off after using the entire runway length. Several months later, P1360 sustained damage due to a forced landing during testing but was swiftly repaired. Test pilots generally described early flights as unremarkable yet free from major defects. During this final development phase, numerous alterations were implemented, including a comprehensive structural redesign by Lloyd at Coventry. Measures aimed at enhancing take-off performance included increasing the wingspan to 77 ft (23 m) and thickening the rudder's trailing edge to address over-balance tendencies. Persistent issues with engine overheating remained unresolved; however, the maximum allowable operating temperature was raised from 280°C to 300°C.

The primary manufacturing responsibility for the Albemarle was assigned to A.W. Hawksley Ltd in Gloucester, a subsidiary established specifically for this project under the aegis of the Gloster Aircraft Company. Initially, Gloster had planned to produce the aircraft at its Brockworth plant. Both Gloster and Armstrong Whitworth belonged to the Hawker Siddeley group, one of Britain's largest aviation conglomerates. More than 1,000 subcontractors supplied parts and sub-assemblies for the Albemarle. Notable subcontractors included MG Motor, responsible for producing the forward fuselage; Rover Company, which manufactured the wing center section; and Harris Lebus, tasked with building tailplane components. Production ceased in December 1944 after a total of 602 units had been completed.

Design

The Armstrong Whitworth Albemarle was designed as a mid-wing cantilever monoplane featuring twin vertical stabilizers and rudders. Its fuselage was constructed in three main segments, utilizing unstressed plywood over a steel tube framework that incorporated four circular steel longerons; the majority of components were connected using gusset plates. This segmented construction allowed for rapid removal and replacement of damaged sections in combat situations. The wing's center section was a single integral piece passing through the fuselage, built around a steel tube girder. This section supported the central and nose fuselage assemblies, engines, main landing gear legs, and the outer wing panels. Except for part of the leading edge made from light alloys, most of the wing surface was plywood-covered. The outer wing extensions were predominantly wooden, with steel tubing reinforcing the two spars; similarly, the Frise-type ailerons and tailplane were crafted from wood. Stainless steel tubing was employed in the forward fuselage to minimize interference with the aircraft's magnetic compasses.

A distinctive feature of the Albemarle was its Lockheed-engineered hydraulically operated retractable tricycle undercarriage. The main wheels retracted rearward into the engine nacelles, while the nose wheel folded backward into the front fuselage. The tail wheel remained fixed but was partially shielded by a "bumper" design. According to Tapper, this aircraft marked a milestone as the first British-built model with a retractable nose wheel produced in substantial numbers for the Royal Air Force. Propulsion came from two Bristol Hercules XI air-cooled radial engines, each delivering 1,590 hp and driving three-blade de Havilland Hydromatic propellers. Fuel storage typically comprised four tanks: two positioned in the central fuselage and two within the wing center section. For missions demanding extended range, auxiliary tanks could be installed inside the spacious bomb bay. This 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 near the front, with the radio operator positioned directly behind them. The navigator occupied a station in the aircraft's nose, ahead of the cockpit area. The bomb aimer's sighting panel was integrated into a hatch on the underside of the nose section. Towards the rear fuselage, multiple glazed panels allowed a "fire controller" to coordinate defensive turret operations against enemy threats. The dorsal turret was an electrically powered Boulton-Paul design originally armed with four Browning machine guns. A forward fairing automatically retracted as this turret rotated forward to engage targets. Initially, the bomber variant required a crew of six, including two gunners—one manning the four-gun dorsal turret and another operating a manually controlled twin-gun ventral turret; however, this configuration applied only to the first 32 production units known as Mk I Series I.

When deployed as a bomber, the Albemarle was generally regarded as less capable than other RAF aircraft such as the Vickers Wellington. Aviation historian Ray Williams noted that it saw action as a bomber on merely two occasions. Consequently, subsequent production models were adapted for transport roles under designations like "General Transport" (GT) or "Special Transport" (ST). Modifications for these versions included removing the ventral turret and downgrading the dorsal turret to a manually operated twin-gun setup. Internally, bomb-aiming mechanisms and rear fuselage fuel tanks were eliminated to create more usable space. Additionally, a quick-release towing hook was installed at the aft fuselage to facilitate glider towing operations. As a paratroop carrier, it could accommodate up to ten fully equipped soldiers; these troops accessed dropping hatches located in the rear fuselage along with a large loading door on the starboard side.

Operational history

Plans to utilize the Albemarle as a bomber were quickly abandoned once it entered service. This decision stemmed from the aircraft offering no significant advantage over existing medium bombers like the Vickers Wellington, while also falling short in performance compared to the emerging four-engine heavy bombers soon to be introduced by the RAF. Instead, the Albemarle found a more fitting role in general reconnaissance and transport missions, leading to its reassignment to these duties.

In October 1942, the Soviet Air Force placed an order for 200 Albemarles. To prepare Soviet crews for ferrying these aircraft, the RAF established No. 305 FTU at RAF Errol, near Dundee. Unfortunately, training accidents occurred, including one fatal crash with no survivors. The first RAF squadron to operate Albemarles was No. 295, which began flying them from RAF Harwell in January 1943. Other units equipped with the type included No. 296, No. 297, and No. 570. The Albemarle's inaugural operational sortie took place on 9 February 1943, when a No. 296 Squadron aircraft dropped propaganda leaflets over Lisieux in Normandy.

On 3 March 1943, an Albemarle crewed by Soviet personnel flew from Scotland to the Vnukovo airfield near Moscow, soon followed by eleven additional deliveries. However, two Albemarles were lost over the North Sea—one due to enemy fighter attack and another from unknown causes. Evaluations of the remaining aircraft highlighted several shortcomings as transports, including a cramped cabin and various technical issues. Consequently, in May 1943, the Soviet government halted further deliveries and ultimately canceled the order in favor of plentiful American Douglas C-47 Skytrains. Despite this, the Soviet presence at Errol Field persisted until April 1944, reportedly because of continued hopes to acquire de Havilland Mosquito aircraft. It has been suggested that a key factor behind Soviet interest in the Albemarle was its Bristol Hercules engines, which were reverse-engineered and replicated by Soviet industry.

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

Beginning in mid-1943, RAF Albemarles took part in numerous British airborne missions, starting with the invasion of Sicily. The aircraft’s most notable contribution came during D-Day on the night of 5/6 June 1944: squadrons 295 and 296 deployed Albemarles carrying pathfinder units to Normandy, with No. 295 Squadron reportedly being the first to drop Allied airborne troops over the region. On D-Day itself, four squadrons plus an operational training unit participated in Operation Tonga; No. 296 Squadron used nineteen Albemarles to tow Airspeed Horsa gliders, while No. 295 Squadron towed twenty-one Horsas but suffered six losses en route; No. 570 Squadron dispatched twenty-two aircraft towing ten gliders; and 42 OTU contributed four planes. During Operation Mallard on 7 June, these units collectively transported 220 Horsas and thirty Hamilcar gliders into Normandy. Later, during Operation Market Garden at Arnhem on 17 September 1944, twenty-eight Albemarles from Nos. 296 and 297 Squadrons towed fifty-four Horsas and two Waco Hadrian gliders into the Netherlands; an additional forty-five aircraft followed on the next day with more gliders. Of all 602 Albemarles produced, seventeen were lost during missions and eighty-one were destroyed in accidents.

The last RAF unit operating the Albemarle was the Heavy Glider Conversion Unit, which phased out its remaining examples in favor of Handley Page Halifaxes by February 1946, marking the official retirement of the type from active service.

Variants

Throughout its manufacturing period, several different 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

Most model designations were further categorized into "Series" to indicate variations in equipment. For example, the ST Mk I Series 1 (comprising eight aircraft) replaced the four-gun turret with manually operated twin guns housed under a sliding canopy. In this special transport variant, a cargo door was installed on the starboard side, and the rear fuel tank was removed. The ST Mk I Series 2 consisted of 14 aircraft fitted with glider towing apparatus. The Mk II variant was capable of carrying ten paratroops, while the Mk V shared this capacity but included a fuel jettison system. Every Albemarle produced was powered by two 1,590 hp (1,190 kW) Bristol Hercules XI radial engines. The Mk III and Mk IV were experimental models designed to test alternative engines; the former featured the Rolls-Royce Merlin III, and the latter was equipped with the 1,600 hp (1,200 kW) Wright Double Cyclone.

Operators

Template:USSR

• A total of twelve Albemarles were delivered to the Soviet Union (with two additional aircraft lost during transit).
• These served within the transport division of the 1st Air Division, later transitioning to the 10th Guards Air Division until 1944; naval aviation units continued use until their retirement in 1945.Template:CN

Template:UK

Royal Air Force

• No. 161 Squadron RAF operated Albemarle I aircraft from October 1942 through April 1943 based at RAF Tempsford.
• No. 271 Squadron RAF flew a single Albemarle at Doncaster between October 1942 and April 1943.
• No. 295 Squadron RAF utilized Albemarle I from November 1943 to July 1944 at RAF Hurn and later at RAF Harwell. They also operated Albemarle II during the same period at these bases, along with Albemarle V from April to July 1944 at RAF Harwell.
• No. 296 Squadron RAF flew Albemarle I between January 1943 and October 1944 at RAF Hurn and RAF Stoney Cross, including missions in North Africa. Albemarle II was used from November 1943 to October 1944 at RAF Hurn and subsequently at RAF Brize Norton. Albemarle V served from April to October 1944 at RAF Brize Norton, with Albemarle VI operating there from August to October 1944.
• No. 297 Squadron RAF employed Albemarle I from July 1943 to December 1944 across RAF Thruxton, RAF Stoney Cross, and RAF Brize Norton. They also used Albemarle II from February 1943 through December 1944 at RAF Stoney Cross and then RAF Brize Norton. Albemarle V was active from April to December 1944 at RAF Brize Norton alongside Albemarle VI from July to December of that year.
• No. 511 Squadron RAF operated Albemarle I aircraft between November 1942 and March 1944 at RAF Lyneham.
• No. 570 Squadron RAF flew Albemarle I from November 1943 until August 1944 at RAF Hurn followed by RAF Harwell; similarly, they used Albemarle II during this timeframe at these locations as well as Albemarle V from May to August 1944 at RAF Harwell.
• No. 1404 Flight RAF operated three Albemarles at RAF St Eval between September 1942 and March 1943.
• No. 1406 Flight RAF flew two aircraft at RAF Wick during September and October of 1942.
• No. 13 Operational Training Unit RAF had two Albemarles stationed at RAF Finmere between October 1942 and April 1943.
• No. 42 Operational Training Unit RAF operated from RAF Ashbourne between September 1943 and February 1945.
• Heavy Glider Conversion Unit utilized Albemarles at both RAF Brize Norton and RAF North Luffenham during January–April and August–October of 1943 before becoming No. 21 Heavy Glider Conversion Unit.
• No. 21 Heavy Glider Conversion Unit continued operations with Albemarles at RAF Brize Norton starting in 1944, relocating to RAF Elsham Wolds in December of 1945, retiring its last operational aircraft in February of the following year.
• No. 22 Heavy Glider Conversion Unit was active at RAF Keevil and RAF Blakehill from October 1944 through November of the next year.
• No. 23 Heavy Glider Conversion Unit operated out of RAF Peplow between October and December of 1944.
• No.3 Glider Training School managed eight Albemarles based at RAF Exeter between January and August of 1945.
• No.301 Ferry Training Unit flew four aircraft out of RAF Lyneham from November ’42 until April ’43.
• No.305 Ferry Training Unit was stationed at RAF Errol beginning January ’43 to train Soviet Air Force personnel before disbanding in April ’44.
• Torpedo Development Unit employed one Albemarle for testing purposes at Gosport between April and September of ’42.
• Telecommunications Flying Unit operated a single aircraft during May ’43 out of RAF Defford.
• The Airborne Forces Experimental Establishment utilized these aircraft across locations such as RAF Ringway and RAF Sherburn-in-Elmet spanning May ’42 through October ’44.
• Coastal Command Development Unit flew two aircraft out of RAF Tain between September and December ’42.
• Central Gunnery School employed one unit between September and November ’42 based at RAF Sutton Bridge.
• Bomber Development Unit made use of three aircraft stationed at RAF Gransden Lodge during August to November ’42.
• Operation Refresher Training Unit functioned out of RAF Hampstead Norris from May ’44 until February ’45.

In addition to military use, various organizations including aircraft manufacturers, the Royal Aircraft Establishment, and the Aeroplane and Armament Experimental Establishment conducted tests with these planes. One example includes De Havilland Propellers using an Albemarle for research involving reversing propellers.Template:CN

Specifications (ST Mk I)

Orthographic view of the Albemarle.

See also

Bibliography

• Air Transport Auxiliary Ferry Pilots Notes. Yorkshire Air Museum, Elvington, Yorkshire, UK, Reproduction 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, Volume 1, Number 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, Issue Thirty-nine, 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 flying the Albemarle and his daring attempts to pilot one without prior instruction or a manual.

External links

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