Editing Avro Vulcan (section)

===Engine test beds===
* The first prototype VX770 had its Sapphire engines replaced with four {{convert|15000|lbf|kN|abbr=on}} Rolls-Royce Conway RCo.7 turbofans in 1957. It was transferred to Rolls-Royce as the Conway test bed.<ref name="Vul" >Jackson 1990, pp. 409–411.</ref> It flew with the Conways, the first [[turbofan]]s in the world, until its [[#Accidents_and_incidents|fatal crash]] in September 1958.<ref name="Vul2" >Jackson 1990, p. 411.</ref>
* The first Vulcan B.1 XA889 was used for the flight clearances of the Olympus 102 and 104.<ref>Baxter 1989, p. 44.</ref>
* Vulcan B.1 XA891 was fitted with four Olympus 200 engines in the spring of 1958 for intensive flying trials. The aircraft [[#Accidents_and_incidents|crashed]] in July 1958 during a routine test flight.<ref>Baxter 1989, p. 50.</ref>
* Vulcan B.1 XA894 flew with five Olympus engines, the standard four Mk.101s, plus a reheated Olympus 320 destined for the BAC TSR-2 in an underslung nacelle. This aircraft was destroyed in a ground fire at Filton on 3 December 1962.<ref name="Vul2"/>
* Vulcan B.1 XA896 was withdrawn from RAF service in June 1964 and transferred to be converted to the test bed for the [[Bristol Siddeley BS100]] vectored thrust turbofan for the [[Hawker Siddeley P.1154]]. The P.1154 was cancelled in February 1965 and XA896 was scrapped before being converted.<ref name="brookes15">Brookes and Davey 2009, p. 15.</ref>
* Vulcan B.1 XA902 was withdrawn from RAF service after a landing accident in 1958. After rebuilding, it replaced VX770 as the Conway test bed, fitted with four RCo.11s. The two inner Conways were replaced with [[Rolls-Royce Spey]]s, flying for the first time in this configuration on 12 October 1961.<ref name="Vul2" />
* Vulcan B.1 XA903, surplus to Blue Steel trials, was converted to a similar layout to XA894 to flight test the Olympus 593 Concorde installation. The first flight was on 1 October 1966 and testing continued through to June 1971.<ref>Austin 2009, pp. 111–113.</ref> In April 1973, XA903 started flying with an underslung [[Rolls-Royce RB.199]] turbofan destined for the Panavia Tornado. XA903 was the last B.1 to fly, being retired in February 1979.<ref>Austin 2009, p. 113.</ref>
* Vulcan B.2 XH557 was used by BSEL for developing the Olympus 301 and first flew with the larger engine in May 1961. It was returned to [[Woodford Aerodrome|Woodford]] in 1964 to be refurbished for the RAF.<ref>Baxter 1989, pp. 60, 64.</ref>