Armstrong Whitworth Albemarle

For “BARNOWL”

The Albemarle was designed as a light bomber built from non-strategic materials. It was built from wood and steel instead of aluminium alloys, and suitable for construction in dispersed factories. Not very good as a bomber, so used mainly as glider tug and paratrooper transport.

Albemarle Mk I: In 1938 the Air Ministry issued its P9/38 requirement for a twin engine medium bomber. Bristol responded with its Type 155 design powered by two Bristol Taurus radial engines and a defensive armament of a single power operated dorsal and ventral turrets each carrying a pair of 20mm cannon. The P9/38 specification was then amended to B17/38 standard demanding an airframe based on maximum use of non-strategic materials and responsibility of further development of the Type 155 concept was then passed on to Armstrong Whitworth, who revised the basic design to accord with the requirements of yet another specification – B18/38 calling for a reconnaissance bomber.

The Albemarle was of mixed steel and wood construction and was a cantilever mid-wing monoplane that was the first type to enter production with the RAF with retractable tricycle landing gear. The fuselage was built in three sections based on a bolted steel tube primary structure and covered in plywood. Built integrally with the central fuselage section, the wing center section was a one piece structure extending as far as the outer sides of the engine nacelles. The center section was of steel tube construction covered entirely with plywood except on the leading edges that had light alloy skinning. The two outer wing panels were of steel tube braced wooden construction covered entirely with plywood. Provision was made for four fuel tanks – two in the center section and two in the wings. The plane was powered by two 1,590 hp Bristol Hercules XI radial engines driving three bladed constant speed propellers. The airframe was completed with tricycle landing gear.

Designed as a reconnaissance bomber, the Albemarle was planned with a defensive armament of four 7.7mm machine guns in a power operated dorsal Boulton Paul turret and two 7.7mm machine guns in a manually operated ventral turret. The dorsal turret was offset to port allowing the incorporation of a passage linking the central and rear fuselage section where provision was made for a fire control coordinator in an extensively glazed compartment just forward of the tailplane’s leading edge. The ventral turret was soon dropped from the specification.

As the design process was continuing and arrangements were being made for construction of the assemblies by a team of just about 1,000 subcontractors, it was realized that the Albemarle had been rendered obsolete as a reconnaissance bomber by the advent of the first four engine bombers offering higher performance and higher bomb loads. It was therefore decided that the Albemarle should be operated as a special transport for delivery of paratroopers and as a glider tug. This change resulted in the addition of a quick release hook at the extreme rear of the fuselage, replacement of the power operated dorsal turret by a manually operated twin gun installation, incorporation of a door on the starboard side of the rear fuselage, removal of all bombing capability and removal of the rear fuselage tank that reduced the fuel capability by 198.2 US gallons. The maiden flight was made in 3/40 and revealed disastrous handling as a result of its weight and small wing area. Wingspan was increased by 10 feet that corrected the problem, but only made the plane an indifferent one for performance. The first 42 were completed as the B. Mk I, but never used in the bomber role and were soon converted to the airborne force’s role. Initial deliveries were made in 1/43 to No. 295 Squadron as glider tugs and 12 more Mk Is were delivered as ST marks (paratroop planes) and 66 as GT (glider tug) planes.

Albemarle Mk II: This variant differed only in internal equipment and 99 ST and 1 GT marks were produced.

Albemarle Mk V: Again, only internal differences were made and 49 ST marks were produced.

Albemarle Mk VI: Differing only in internal details, 133 ST and 17 GT marks were produced. The Albemarle was never a notably successful airplane, buts its availability meant that more capable warplanes could be used for their intended roles rather than having to be diverted to airborne special forces roles.

Construction ceased with the 600th example in 12/44 when orders for a further 478 were cancelled. 10 Albemarles were allocated to the Soviets, but it is unknown how many made the actual flights from Scotland to the USSR. Four British and Two North African squadrons operated the Albemarles, which disappeared from service when the war ended.

Specifications – Mk II:
Powerplant: Two 1,590 hp Bristol Hercules XII radial piston engines.
Maximum speed: 265 mph at 10,500 ft.
Cruising speed: 170 mph.
Fuel: 726.6 US gallons internally and up to 756.6 US gallons of auxiliary fuel in three drop tanks.
Typical range: 1,300 miles with internal fuel.
Service ceiling: 18,000 ft.
Armament: Two Vickers K .303 machine guns in dorsal turret.
Crew: 3 (Pilot, navigator and gunner)