Vickers Windsor

Vickers-Armstrongs

Industry	Aerospace, Defence
Headquarters	Brooklands , United Kingdom
Products	Aircraft (including Vickers Windsor)

The Vickers Windsor was a British four-engine heavy bomber developed during the Second World War, engineered specifically for operations at high altitude. Its design was the work of Barnes Wallis and Rex Pierson at the Vickers-Armstrongs facility located in Brooklands.

Although three prototypes were constructed, production plans were ultimately abandoned following the conclusion of the war.

Design and development

Vickers initially proposed several designs as potential successors to the pre-war Vickers Wellington medium bomber. The first concept aimed to satisfy the same criteria as the Bristol Buckingham under Air Ministry Specification B.11/41 and featured a high-speed twin-engine medium bomber equipped with remotely controlled turrets housed within the engine nacelles and forward-facing nose guns. However, this design fell short, lacking sufficient speed to qualify as a fast bomber and inadequate armament for a conventional medium bomber role. Subsequently, a four-engine variant of this model was also drafted. Officially, the Wellington was deemed outdated, yet since Vickers’ manufacturing processes were specialised in geodetic construction, any new design had to incorporate this technique. Vickers was simultaneously developing a pressurised cabin version of the Wellington for high-altitude missions, while the Ministry showed interest in a pressurised variant of the Vickers Warwick, an initiative supported by Lord Beaverbrook. This concept involved replacing the Warwick’s twin-engine wing with an elliptical wing fitted with four Merlin engines. The aircraft was projected to operate at altitudes up to 43,000 ft (13,000 m) while delivering an 8,000-pound (3,600 kg) bomb load. Two Warwick prototypes were contracted under Specification B.5/41, with development proceeding until September 1942. By mid-1942, efforts to replace the Wellington and developments under B.5/41 were combined into a new specification, B.3/42, targeting a Lancaster replacement without high-altitude capabilities. Vickers adapted previous work by integrating the four-engine wing onto a newly designed fuselage, resulting in a contract for what became known as the Windsor. The initial prototypes’ wings adhered to earlier specifications imposing lower weight limits.

The Windsor was developed in response to Air Ministry Specification B.5/41 (later revised as B.3/42), specifying a high-altitude heavy bomber featuring a pressurised crew cabin and capable of reaching speeds of 345 miles per hour (555 km/h) at 31,000 feet (9,400 m) altitude. Key characteristics included its pressurised crew compartment and main landing gear consisting of four single-wheel oleo struts positioned within each engine nacelle. Defensive armament comprised remotely operated gun barbette turrets located at the rear of each outboard nacelle; these were controlled by a gunner stationed in a pressurised compartment situated at the extreme tail.

The Windsor employed Wallis’s geodetic structural approach for both fuselage and wings—a technique previously utilized in the Wellesley, Wellington, and Warwick bombers. In these earlier aircraft, bending strength of the wing structure was primarily managed by a single spar, while torsional stiffness was provided by the geodetic lattice framework. However, wing testing revealed that geodetic construction also contributed significantly to bending resistance. Consequently, Wallis redesigned the Windsor’s wing so that its geodetic lattice would carry all bending and torsional stresses without reliance on a spar. This was achieved by gradually decreasing the lattice angle from 45 degrees near the tips to approximately 15 degrees at the root. Eliminating the spar freed additional internal space for fuel storage but increased wing flexibility; concerns arose about excessive wing tip deflections during emergency landings with fully fuelled wings. To mitigate this risk, Wallis incorporated an additional landing gear leg into each outboard engine nacelle. This modification also resulted in more compact undercarriage assemblies compared to the dual large struts used on other British heavy bombers.

Unlike earlier geodetic aircraft that utilized doped Irish linen fabric covering, the Windsor featured a lightweight yet rigid skin made from woven steel wires combined with extremely thin (approximately 1⁄1000 inch (0.025 mm)) stainless steel ribbons coated with PVC or similar plastics designed to prevent ballooning effects. Fitting this skin precisely required use of a tuning fork tool.

The cockpit accommodated only a single pilot seat.

Operational history

Only three units were constructed: the initial model along with two subsequent prototypes designated Type 457 and Type 461. This limited production resulted from improvements made to the existing Lancaster bomber, which ultimately fulfilled the role intended for the Windsor. The maiden flight of the first prototype, serial number DW506, occurred on 23 October 1943. The second prototype, DW512, took to the air on either 10 or 15 February 1944, followed by the third, NK136, which flew on 11 July 1944. All three aircraft were assembled at Vickers' confidential Foxwarren Experimental Department, located between Brooklands and nearby Cobham. Specifically, DW506 was put together at Farnborough, while DW512 operated out of Wisley. The latter two prototypes underwent testing until the conclusion of World War II, after which further development and mass production were halted.

Following 40 sorties, DW506 was involved in a crash on 2 March 1944. During testing of engine feathering procedures, one engine failed to restart, forcing the pilot into an emergency landing. The aircraft veered off the runway into a ditch and broke apart. However, its rudder was salvaged and installed on DW512. Compared to DW506, DW512 featured additional equipment including some armor but lacked armament. This prototype was grounded in November 1945 when the project ended and was slated for disposal by June 1946. Armament for NK136 was not available until January 1945 and was partially developed using the Vickers Warwick prototype L9704. Ground testing of its weaponry occurred in April, with live firing commencing at the end of May; during these tests, DW512 served as a camera aircraft. After concluding its flight operations in November 1945, NK136 was repurposed as a training airframe at RAF Manby until it was scrapped in 1948.

Two pre-production airframes were also in progress: Type 471 (later redesignated Type 483) NN670, equipped with Merlin 85 engines and anticipated to have a range of approximately 4,000 miles, was nearly finished and preparing for its first flight. Meanwhile, NN673, intended to be powered by Merlin 100 engines, had reached about half completion.

A production order for 300 Type 483 Windsors was placed in 1943, with delivery initially projected to start in July 1946. During the period when it appeared that hostilities in the Pacific theater against Japan would continue, plans envisioned equipping up to 30 squadrons with this aircraft. However, by November 1944 the order had been reduced to 100 units, then further cut to 40 before being completely canceled following the end of combat against Japan.

Variants

Type 447

The initial prototype, identified by serial DW506, was equipped with four Rolls-Royce Merlin 65 engines, each delivering 1,315 horsepower (981 kW).

Type 457

The second prototype, bearing the serial number DW512, featured four Rolls-Royce Merlin 85 engines, each producing 1,635 horsepower (1,219 kW).

Type 461

The third prototype, serial NK136, utilized four Merlin 85 engines rated at 1,635 horsepower (1,219 kW) each. It was armed with two 20mm cannons housed in remote-controlled barbettes situated behind the outer engine nacelles, with targeting controlled from the unarmed tail turret.

A proposed Type 601, also referred to as the "Clyde Windsor," would have represented the Windsor B.II variant in operational service. This model was designed to incorporate the Rolls-Royce Clyde turboprop engine, potentially featuring contra-rotating propellers if available, aiming for a maximum velocity exceeding 400 mph. One pre-production Windsor unit (serial NN673) was slated for conversion to this engine type as a trial. However, following the cancellation of production, Vickers requested that a Windsor prototype be fitted with Clyde engines for experimental purposes, but this plan was also terminated in early 1946.

The Type 482 designation encompassed four civilian airliner configurations derived from the Windsor airframe. In November 1943, designs included an unpressurized model for continental routes accommodating 40 passengers and an Empire route version with seating for 24 passengers plus 18 sleepers. A transatlantic variant with similar accommodation was also proposed. By January 1944, pressurized versions were introduced: one featuring a stressed skin fuselage and another utilizing Geosteel construction, where the pressure cabin consisted of a rubberized bag enclosed within the structure.

Operators

Template:UK

• Royal Air Force

See also

Bibliography

• Bridgman, Leonard, editor. Jane’s All The World’s Aircraft 1945-1946. London: Samson Low, Marston & Company, Ltd., 1946.
• Buttler, Tony. British Secret Projects: Fighters & Bombers 1935-1950. Hinckley: Midland Publishing, 2004. ISBN 1-85780-179-2
• Goulding, James and Philip Moyes. RAF Bomber Command and its Aircraft, 1941-1945. Shepperton, Surrey, UK: Ian Allan Ltd., 1978. ISBN 0-7110-0788-8.
• Mason, Francis K. The British Bomber since 1914. London: Putnam Aeronautical Books, 1994. ISBN 0-85177-861-5.
• Murray, Dr. Iain. Bouncing-Bomb Man: The Science of Sir Barnes Wallis. Haynes Publishing. ISBN 978-1-84425-588-7.
• Swanborough, Gordon. British Aircraft at War, 1939-1945. Saint Leonards-on-Sea, East Sussex, UK: HPC Publishing, 1997. ISBN 0-9531421-0-8.