Editing Lockheed YF-12 (section)

==Variants==
;YF-12A: Pre-production version. Three were built.<ref>Landis and Jenkins 2005, p. 40.</ref>
;F-12B: Production version of the YF-12A with various improvements such as an increased combat radius from 1,200 to 1,350 nautical miles and an improved fire control system with increased bomber detection range from 100 to 125 miles;<ref>{{cite report |author= Robert P. Lyons |date= 30 April 1986 |title=THE SEARCH FOR AN ADVANCED FIGHTER: A HISTORY FROM THE XF-108 TO THE ADVANCED TACTICAL FIGHTER |url=https://apps.dtic.mil/dtic/tr/fulltext/u2/a166724.pdf |archive-url=https://web.archive.org/web/20190121174102/https://apps.dtic.mil/dtic/tr/fulltext/u2/a166724.pdf |url-status=live |archive-date=21 January 2019 |publisher=Defense Technical Information Center |page=10}}</ref> canceled before production could begin.<ref>Landis and Jenkins 2005, p. 46.</ref>
;YF-12C: Fictitious designation for an SR-71 provided to NASA for flight testing. The YF-12 designation was used to keep SR-71 information out of the public domain.<ref name=Land_Jenk_p49-0>Landis and Jenkins 2005, pp. 49–50.</ref> From 1971 to 1978, 61-7951 was temporarily loaned to NASA from the Air Force as "YF-12C #06937".<ref>{{cite web |title=61-7951 |url=http://www.habu.org/sr-71/17951.html |website= habu.org}}</ref>