Editing Vickers Valiant (section)

===The Valiant B2===
One of the three prototypes was the B.2 version.<ref name="Jones p26">Jones 2007, p. 26.</ref> The B.2 was intended to serve as a [[Pathfinder (RAF)|Pathfinder]] aircraft, flying at low level to mark targets for the main bomber force. To cope with increased air turbulence at low level, the B.2 had a strengthened airframe. In particular, the wing was strengthened with the removal of the cut-outs in the wing structure into which the main wheels retracted, allowing the wing torsion box structure to be uninterrupted and giving more room for internal fuel storage. Instead, the main landing gear, which had four wheels instead of the two wheels of the B.1, retracted backwards into large [[Aircraft fairing|fairing]]s set into the rear of the wings.<ref name = "bomber 77 78">Gunston and Gilchrist 1993, pp. 77–78.</ref> The B.2 had a lengthened fuselage with a total length of {{convert|112|ft|9|in|m|abbr=on}}, in contrast to a length of {{convert|108|ft|3|in|abbr=on}} for the Valiant B.1, with the extra length giving room for more avionics.<ref name="Jones p32,6">Jones 2007, pp. 32, 36.</ref>

The prototype B.2, serial number WJ954 first flew on 4 September 1953.<ref name="AndrewsVickers p445">Andrews and Morgan 1988, p. 445.</ref> Finished in a gloss black night operations paint scheme, it became known as the "Black Bomber". Its performance at low level was superior to that of the B.1 (or any other V-bomber), particularly at [[sea level#Aviation|sea level]],<ref name = "bomber 77"/> with the aircraft being cleared for {{convert|580|mph|abbr=on}} at low level (with speeds of up to {{convert|640|mph|abbr=on}} being reached in testing). This was compared to the B.1 sea-level limit of {{convert|414|mph|abbr=on|round=5}}. The Air Ministry ordered 17 production B.2 aircraft, which were to be powered by [[Rolls-Royce Conway]] [[turbofan]]s. Although the Valiant B.2 low-level capabilities were significant, the programme was terminated because the World War 2 "Pathfinder concept" was considered obsolete in the nuclear era.<ref name = "bomber 78">Gunston and Gilchrist 1993, p. 78.</ref> The B.2 prototype was used for tests for a few years, including the clearance of rocket-assisted take-offs, for the Valiant B.1 at hot or high airfields, using two Super-Sprite rocket motors. It also did extensive taxiing tests to investigate the cause of brake judder which caused a fatigue failure of the landing gear. It was scrapped in 1958.<ref>Trubshaw and Edmondson 1998, p. 37.</ref><ref name="Jones p36-7">Jones 2007, pp. 36–37.</ref><ref name="Osprey p83-4">Brookes 2012, pp. 83–84.</ref><ref name = "black wright 20"/>