During flight tests the YF-12As set a speed record of and altitude record of , both on 1 May 1965, 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 3.2 at an altitude of to a JQB-47E target drone off the ground. The missile did not have a warhead but still managed to hit the B-47 directly and take a 4-foot section off of 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 put it towards the much less successful F-106X program that nearly failed.