Vickers Windsor Heavy Bomber Prototype
Developed for the Royal Air Force as a heavy bomber during World War 2, the Vickers Windsor was no longer needed for its intended role - limiting the program to just three aircraft.
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Beyond the "Warwick" of 1939, the Vickers concern failed to net much interest from the Royal Air Force (RAF) in another heavy bomber design during World War 2 (1939-1945). In seeking a successor for its "Wellington" medium bomber series, company engineers went to work on an attempt to fulfill Air Ministry Specification B.11/41, this product intended as a twin-engine, high-speed medium bomber. However, this design did not live up to its proposed expectation so a four-engined form was drawn up in its place and the same "geodesic" construction practice used on earlier Vickers large aircraft was to be employed - the process incorporating a "basket-weave" type understructure covered over in fabric to produce a lightweight-yet-strong body.
As the same time, company engineers were attempting to develop a Wellington bomber with pressurized cabin spaces for the crew operating at high altitudes and Air Ministry authorities pushed for such a feature on the existing Warwick. Added to this was a new elliptical wing mainplane now carrying two engines apiece - for a total of 4 x Rolls-Royce "Merlins" - with the project goal becoming a heavy bomber exhibiting a 55,500lb Maximum Take-Off Weight (MTOW) and capable of a warload of 8 x 1,000lb conventional drop bombs, a service ceiling nearing 43,000 feet and a maximum speed of 350 miles per hour.
Two prototypes were covered by Specification B.5/41 and work on the airframes spanned into late-1942 by which point the original Wellington successor design was merged into the program under Specification B.3/42 and this commitment ultimately begat the "Windsor" (Type 447) high-altitude heavy bomber - the first-form of the aircraft recognized as "Windsor B.Mk I" before the end of 1943.
For the high-altitude role, pressurization of the crew cabin spaces was a must. The aircraft would be of considerable size for the operating altitudes, range and bombload required. The mainplanes were shoulder-mounted along the fuselage sides, the fuselage given a deep profile with stepped cockpit. The tail unit incorporated a sole vertical fin with low-mounted horizontal planes and each wing mainplane managed a pair of Rolls-Royce engines for the power needed. The internal geodetic construction was also carried to the wings resulting in no spars being needed for supporting the wide-spanning structures - though the process was a complex one and required fine tuning (a special composite fabric also had to be designed to contend with the speeds at play). These structures also carried noticeable anhedral when the aircraft was at rest, flexing upwards when the bomber was in flight which further complicated the construction and skinning process of the aircraft). The undercarriage was unique in that each engine nacelle was given a wheeled main leg, the tail of the aircraft supported by a conventional tailwheel. This presented a pilot's challenge during ground-running on narrower runways.
The original defensive armament suite of 1942 involved 2 x 7.7mm machine guns in fixed, forward firing mounts at the nose with 2 x 20mm cannons fitted to a rear turret. For 1943, the rear turret was dropped from contention and was succeeded by a pair of remote-controlled turret barbettes, each armed through 2 x 20mm cannons, now fitted to the aft-sections of the outboard engine nacelles. In April 1944, waist gun positions were added to further broaden the defensive network protecting the aircraft.
Three total Windsor prototypes were ultimately built and completed. The first to fly was the gun-less DW506 (Type 447) testbed on October 23rd, 1943 with Rolls-Royce Merlin 65 series engines of 1,315 horsepower each installed. Subsequent testing revealed a sound, large aircraft with good characteristics for a bomber though the design was far from finalized and ready for serial production as it flew underweight with little to no mission-equipment installed. DW506 was eventually written-off following a crash-landing on March 2nd, 1944 - the bomber sliding off the runway and the main part of the fuselage damaged beyond repair.
On February 10th, 1944, prototype DW512 (Type 457) first took to the air with some of its critical mission equipment in place though it still lacked its defensive gun suite. This model was powered by Rolls-Royce Merlin 85 series engines of 1,635 horsepower each (driving four-bladed propellers) and closer matched the intended production form than its predecessor. Testing of this article soon revealed a ballooning effect of the special fabric skin (a defect first witnessed on prototype DW506) so a new skin formula was drawn up and applied.
The third prototype became NK136 (Type 461) and this carried the same engine fit as DW512 but installed the intended armament suite of 4 x 20mm cannons in their remote-controlled, nacelle-mounted turret barbettes. A first-flight of this aircraft was had on July 11th, 1944 and firing trials spanned into June of 1945 by which point the war in Europe had ended.
With the war over in full by September 1945 (the Japanese surrender in the Pacific), the Windsor program was cancelled during November as its need was no longer apparent. The continued evolution of the Avro Lancaster heavy bomber also added to the notion that the Windsor would become a bloated, costly large aircraft for the long term and the war-proven Lancaster essentially was able to handle nearly any mission role given to it.
Over 130 total flights were completed by the trio of test aircraft for the Windsor program. Revisions and proposals occurred throughout its test life which included a reworked undercarriage, various engine fits, a proposed "combination" powerplant mix (jet / propeller) scheme, and reworked nose better mimicking that of the competing Lancaster though none of these came to fruition. None of it mattered much in the scope of the War and the post-World War 2 British RAF heavy bomber of choice became the Avro Lincoln (detailed elsewhere on this site). The surviving Windsor airframes were all scrapped before 1950.