Even though the USAF ordered 93 YF-12 aircraft and had an initial budget of $90 million to further testing, this was withheld by Sec. of Defense McNamara who put it towards the F-106X program.
The YF-12 Blackbird was developed in the 1960s as a high-altitude, Mach 3 interceptor to defend against supersonic bombers. Based on the A-12 reconnaissance aircraft, the YF-12A became the forerunner of the highly-sophisticated SR-71 strategic reconnaissance aircraft.
The first of three YF-12s flew in August 1963. In May 1965, the first and third YF-12s set several records, including a speed record of 2,070.101 mph and an altitude record of 80,257.65 feet. For their speed record flight, Col. Robert L. “Fox” Stephens (pilot) and Lt. Col. Daniel Andre (fire control officer) received the 1965 Thompson Trophy.
The YF-12 did not have any reconnaissance cameras: unlike the A-12, it was furnished with the Hughes AN/ASG-18 fire-control radar and could be armed with AIM-47 Falcon (GAR-9) air-to-air missiles.
It was because of Secretary of Defense Robert McNamara decisions that the YF-12 program was canceled.
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 74,000 feet (23,000 m) to a JQB-47E target drone 500 feet (150 m) off the ground.
The missile did not have a warhead but still managed to hit the KQB-47E directly and take a 4-foot section off its tail. The US Air Force (USAF) considered it a success, but McNamara decided to cancel the YF-12 program.
He decided to terminate the program because of the program high costs, the ongoing war in Southeast Asia, and a lower priority on air defense of the US.
So, even though the USAF ordered 93 aircraft and had an initial budget of $90 million to further testing, this was withheld by McNamara, who put it towards the F-106X program.
The F-106X was a design study for a Delta Dart follow-on. According to F-106 Delta Dart.com, “With the XF-108 effectively dead, Convair attempted to modernize the F-106 design. This study envisaged an interceptor with a canard layout that was powered by a JT4B-22 turbojet fed by rectangular air intakes. It was envisaged as an alternative to the Lockheed YF-12, and was to have had a fire control system with “look-down, shoot-down” capability fed by a 40-inch radar dish.
“The F-106X was extremely advanced for its time with Mach 5 performance envisaged by Convair. Carried over from the F-106, the only thing would have been the basic delta design. A more powerful engine was to be mounted with redesigned intakes to account for the new engine. Canards were added on the intakes and the cockpit was raised to improve visibility. The fire control systems were to be given a complete overhaul with the AN/ASG-18 previously developed for the XF-108.
“Under the F-106X development project were the designated F-106C/D aircraft, with “C” being the single-seat version, the “D” being the two-seat version.”
At one time the USAF had considered acquiring 350 of these advanced interceptors with several attempts initiated to upgrade the entire current F-106 fleet, but none were approved by McNamara and the F-106X program was cancelled too. Later Sec. McNamara pushed through the F-4 program instead.
Moreover, he also ordered the tooling of all of the YF-12s to be destroyed. Noteworthy, the tooling was harder to destroy than you would think because it was made of titanium. (After the SR-71 Blackbird program was terminated, when they were destroying the pieces after the retirement of the SR-71, they did find some un destroyed tooling pieces).
One journalist reported criticism of McNamara as a “‘human IBM machine’ who cares more for computerized statistical logic than for human judgments.”
The YF-12 program officially ended in early 1968 and soon after this McNamara resigned as Secretary of Defense.
One YF-12 remained at NASA for testing until the early 70s. An SR-71 was at NASA masquerading as an YF-12C. You can see the last YF-12 at the Museum of the US Air Force at Dayton, Ohio.
Be sure to check out Linda Sheffield Miller (Col Richard (Butch) Sheffield’s daughter, Col. Sheffield was an SR-71 Reconnaissance Systems Officer) Facebook Pages Habubrats and Born into the Wilde Blue Yonder for awesome Blackbird’s photos and stories.
Photo credit: U.S. Air Force and Convair