Editing Lockheed YF-12 (section)

===Air Force testing===
[[File:Lockheed YF-12.jpg|thumb|YF-12A over mountainous terrain.|alt=Sideview of black jet aircraft overflying mountain towards right of photo.]]

During flight tests the YF-12As set a speed record of {{convert|2070.101|mph|km/h}}<ref>{{Citation |title=Could This Change Air Travel Forever? | date=5 January 2024 |url=https://www.youtube.com/watch?v=C_dNt4UEVZQ |access-date=2024-01-05 |language=en}}</ref> and altitude record of {{convert|80257.86|ft|m}}, both on 1 May 1965,<ref name=museum/> and demonstrated promising results with its unique weapon system. Six successful firings of the [[AIM-47]] missiles were completed, and a seventh failed due to a gyro failure on one of the missiles. The last one was launched from the YF-12 at Mach&nbsp;3.2 at an altitude of {{convert|74000|ft|m}} to a [[Boeing B-47 Stratojet#Variants|JQB-47E target drone]] {{convert|500|ft|m}} off the ground.<ref name=Land_Jenk_p44>Landis and Jenkins 2005, p. 44.</ref> The missile did not have a warhead but still managed to hit the B-47 directly and take a {{convert|4|ft|cm|adj=on}} section off its tail. The Air Force considered it a success and ordered 96 aircraft and had an initial budget of $90 million to further testing, but this was withheld by Secretary of Defense McNamara, who on 23 November 1967<ref name=knaack>Knaack, 1978.</ref> put it towards the much less successful [[Convair F-106 Delta Dart#Variants|F-106X]] program that nearly failed.<ref>SR-71 Blackbird By Paul F Crickmore. Bloomsbury. {{ISBN|9781472813176}}</ref>

The successful AIM-47 Falcon missile was increased in size and performance and became the [[AIM-54 Phoenix]] missile for the [[Grumman F-14 Tomcat|F-14 Tomcat]]. The AN/ASG 18 radar was upgraded to become the [[AN/AWG-9]] and APG-71, which added the ability to track multiple targets.

One of the Air Force test pilots, [[James Irwin|Jim Irwin]], would go on to become a NASA astronaut and [[List of Apollo astronauts#People who have walked on the Moon|walk on the Moon]].

The program was abandoned following the cancellation of the production F-12B, but the YF-12s continued flying for many years with the USAF and with NASA as research aircraft.