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.
Content ©MilitaryFactory.com; No Reproduction Permitted.