Editing Avro Vulcan (section)

====Vulcan B.1 and B1A====
The first 15 production B.1s were powered by the Olympus 101. Many of these early examples in a metallic finish remained the property of the Ministry of Supply, being retained for trials and development purposes. Those entering RAF service were delivered to [[No. 230 Operational Conversion Unit RAF|No 230 Operational Conversion Unit]] (OCU), the first in July 1956.<ref>Laming 2002, pp. 217–219.</ref> Later aircraft, painted in [[anti-flash white]] and powered by the Olympus 102 with {{convert|12000|lbf|kN|abbr=on}} thrust, began to enter squadron service in July 1957.<ref>Wynn 1997, p. 145.</ref> The Olympus 102s were modified during overhaul to the Olympus 104 standard, ultimately rated at {{convert|13500|lbf|kN|abbr=on}} thrust.<ref>Baxter 1990, p. 46.</ref>

Rebuilding B.1s as B.2s was considered but rejected over cost. Nevertheless, to extend the B.1's service life, 28 (the surviving B1 aircraft fitted with Olympus 102/104 engines) were upgraded by [[Armstrong Whitworth]] between 1959 and 1963 to the B.1A standard, including features of the B.2 such as ECM equipment,<ref>Brookes and Davey, 2009, p. 12.</ref> in-flight refuelling receiving equipment,<ref>''Pilot's Notes'' intro. Para. 1.</ref> and UHF radio.<ref name="PilotNotes">''Pilot's Notes'' pt. 1, ch. 16, para. 5.</ref>  However, the B.1As were not strengthened for low-level operations and all were withdrawn by 1968.<ref>Laming 2002, pp. 217–220.</ref>