Editing Hawker Siddeley Nimrod (section)

===R1===
{{Main|Hawker Siddeley Nimrod R1}}
[[File:Hawker Siddeley Nimrod R1 (801), UK - Air Force AN1554801.jpg|thumb|Nimrod R1 XW665 landing during [[Waddington International Airshow]] in [[Lincolnshire]] in 2009]]
Three Nimrod aircraft were adapted for the [[signals intelligence]] role, replacing the Comet C2s and [[English Electric Canberra|Canberra]]s of No. 51 Squadron in May 1974.<ref name="AIJul01 p31">Lake ''Air International'' July 2001, p. 31.</ref><ref name = "Fricker 594">Fricker 1972, p. 594.</ref> The R1 was visually distinguished from the MR2 by the lack of a MAD boom.<ref>Haddon-Cave 2009, p. 17.</ref> It was fitted with an array of rotating dish aerials in the aircraft's bomb bay, with further dish aerials in the tailcone and at the front of the wing-mounted fuel tanks. It had a flight crew of four (two pilots, a flight engineer and one navigator) and up to 25 crew operating the SIGINT equipment.<ref name="AIJul01 p30-1">Lake ''Air International'' July 2001, pp. 30–31.</ref>

Only since the end of the [[Cold War]] has the role of the aircraft been officially acknowledged; they were once described as "radar calibration aircraft". The R1s have not suffered the same rate of fatigue and corrosion as the MR2s. One R1 was lost in a flying accident since the type's introduction; this occurred in May 1995 during a flight test after major servicing, at [[RAF Kinloss]]. To replace this aircraft an MR2 was selected for conversion to R1 standard, and entered service in December 1996.<ref name="AIJul01 p34">Lake ''Air International'' July 2001, p. 34.</ref>

The Nimrod R1 was based initially at [[RAF Wyton]], Cambridgeshire, and later at [[RAF Waddington]], Lincolnshire, and flown by [[No. 51 Squadron RAF|51 Sqn]]. The two remaining Nimrod R1s were originally planned to be retired at the end of March 2011, but operational requirements forced the RAF to deploy one to [[RAF Akrotiri]], Cyprus on 16 March in support of [[Operation Ellamy]]. The last flight of the type was on 28 June 2011 from RAF Waddington, in the presence of the Chief of the Air Staff, ACM Sir Stephen Dalton.<ref name=dmj-r1>[http://www.defencemanagement.com/news_story.asp?id=16738 "Nimrod R1 makes final flight"] {{webarchive|url=https://web.archive.org/web/20120325162031/http://www.defencemanagement.com/news_story.asp?id=16738 |date=25 March 2012 }} ''Defence Management Journal,'' 28 June 2011. Retrieved 28 June 2011.</ref><ref>[https://www.bbc.co.uk/news/uk-13942014 "Nimrod R1 aircraft in final flight for RAF."] ''BBC,'' 28 June 2011. Retrieved 13 July 2011.</ref> XV 249, the former MR2, is now on display at the RAF Museum Cosford, West Midlands. The R1 was replaced by three [[Boeing RC-135|Boeing RC-135W ''Rivet Joint'']] aircraft, acquired under the Airseeker project; the first aircraft was delivered in late 2013.<ref>[http://www.flightglobal.com/news/articles/pictures-first-raf-rivet-joint-aircraft-arrives-in-uk-392875/ "PICTURES: First RAF Rivet Joint aircraft arrives in UK."]''Flight Global.'' Retrieved: 18 December 2013</ref>