A-12 OXCART Blackbird - Service
As a consequence of the technical difficulties, the delivery date of the first aircraft began sliding and costs started rising. Originally promised for May 1961, delivery was moved to August and the first flight was moved to December 1961. Project officials decided to reduce production to 10 aircraft, at a total cost of over $161 million.
To prevent further scheduling setbacks, Johnson and CIA officials already had decided to use the less powerful J75 in early flights. The airframe had to be slightly altered to accommodate the substitute engine, which could power the craft only up to Mach 1.6 and 50,000 feet. Despite enormous development costs of the J58, the engines were not ready until January 1963, and the A-12 did not reach Mach 3 speed until the following July — more than a year after the first test flight.
The design feature that ultimately made it possible for the J58s to generate the power needed to fly at planned speed was a pair of retractable, spike-shaped cones that protruded from the engine inlets. The “spikes,” as they were known, served as regulators that would decelerate, compress, and superheat incoming air. The system’s mechanical controls did not respond quickly enough to shock-wave-induced variations in the incoming air flow to prevent engine “unstarts” caused violent buffeting and severe yawing. The unstarts and the “popped shocks” occurred at speeds between Mach 2.5 and 2.9 while the aircraft was on an accelerated climb to design speed. Ultimately the inlet system had to be redesigned. In the new configuration, the spike could be moved in or out as much as 26 inches at supersonic speeds to capture and contain the shock.
The A-12’s first flight — unofficial and unannounced in keeping with a Lockheed tradition — took place on 25 April 1962 and almost caused the loss of the only OXCART aircraft built so far. Lockheed test pilot Lou Schalk flew the plane less than two miles, at an altitude of about 20 feet, because serious wobbling was caused by improper hookup of some navigational controls. Thef trouble was determined to be an improper hookup between the rudder pedals and nose wheel steering, as the rudder and nose wheel turned in opposite directions from those desired.
Article 124, a trainer version nicknamed the “Titanium Goose,” was delivered in November. It was fitted with the less powerful J75 engines, could only reach Mach 1.6 and 40,000 feet, and was the only A-12 that Kelly Johnson ever flew in.
While the A-12 was being tested, US officials confronted two major issues. The first was whether to publicly disclose the OXCART program. The Department of Defense was concerned that it could not overtly explain the money the Air Force was spending on its versions of the A-12. And some CIA and Pentagon officials recognized that crashes or sightings of test flights could compromise the program.
Since the contracting and funding of the OXCART program had been accomplished through black channels, the ostensible purpose was to conduct research in the supersonic transport field. After a more careful examination of this story, it was realized that too many people would have to be telling the same story at the same time and that once this explaining scenario got out of phase that embarrassment would undoubtedly come to all concerned. It was, therefore, recommended that a simple "no comment" type cover story would be adopted adhering to the principle that the less said the better. All concurred in this approach; however, they all realized that a fall-back position would have to be available. Therefore, the classified research work on an Air Force interceptor-type aircraft would be the explanation.
Soon after the first flights in April 1962, everyone again looked at the cover story, and it was soon apparent that the Air Force interceptor story had obvious loopholes. b. What is the source of funds for the project? What were the reasons for such tight security? etc... It would be difficult to convince the technical press of an aircraft program with but a slight improvement in performance above the B-58 program. Military type aircraft would normally be tested at Edwards Air Force Base. To change this pattern would call attention to the program.
CIA and the Air Force changed the program’s cover story from involving an interceptor aircraft to a multipurpose satellite launch system. The cover story was that the OXCART vehicle was part of a satellite launch system being tested for future satellite programs. The story was that Lockheed Aircraft Corporation's unique experience in advanced aircraft (F-104) and space / satellite field made Lockheed especially qualified to do the job of developing a multi-purpose advanced aircraft with particular capability as a recoverable booster for a satellite launch system.
In April 1963 Lockheed was directed to rebuild the aircraft chines to change the optimum radar cross section at S-band to favor better performance against the Tall King. This was an expensive and as it finally turned out to be undesirable change.
In late 1962 and early 1963 the Department of Defense considered surfacing the YF-12A to provide a cover, reasoning that divulging the existence of a purely tactical aircraft would not reveal any clandestine collection capabilities. On 29 February 1964, the White House announced the successful development of an advanced experimental aircraft, the A-11, which has been tested in sustained flight at more than 2,000 miles per hour and at altitudes in excess of 70,000 feet. For security reasons, the Air Force’s YF-12A interceptor was surfaced, not the A-12, and it was referred to as the A-11. Then on 1 May 1965, a YF-12A set speed and altitude records of 2,070.1 mph and 80,257.65 feet — the first of many for OXCART aircraft.
The year 1964 also marked the debut of two more Blackbird variants, designated M-21 and SR-71. The M-21, a two-seat variant of the A-12, was built expressly as a launch aircraft for the secret D-21 reconnaissance drone as Project TAGBOARD. A fatal accident during the fourth launch resulted in the death of the launch control officer and destruction of both drone and M-21. The second new Blackbird, the SR-71, became the most familiar member of the family. Operated by the U.S. Air Force under Project SENIOR CROWN, the SR-71 served as an aerial reconnaissance workhorse around the world for more than 25 years.
The A-12 aircraft achieved a full operational capability in late 1965 by repeatedly demonstrating acceptable inflight reliability. The fleet ultimately consisted of nine aircraft. Six were operational, one was a test bed, and one was a two place trainer. One test aircraft was placed in storage in accordance with the OXCART phase—down.
On 15 May 1967 the OXCART detachment was ordered by Higher Authority to deploy to Kadena Air Base, Okinawa and conduct reconnaissance operations over North Vietnam. Deployment was executed successfully and the first, operational mission was conducted on 31 May 1967. Three more missions were flown in the period through 30 June 1967. As of 30 June 1967, 2470 flights had been completed for a total of 4013 flight hours. 757 flights had been completed (339 during the past year) which have reached or exceeded speeds of Mach 3.0 for a total of 455 flight hours (249 during the 12 months up to June 1967) at or above Mach 3.0. The maximum speed achieved was Mach 3.29. The maximum altitude achieved was 90,000 feet. The longest single flight was been 7 hours 40 minutes. On another flight 3 hours 50 minutes were spent at or above Mach 3.0. The longest single sustained flight time at Mach 3.2 and above was 1 hour 14 minutes. For these two years, Mach 3 flights have been made repeatedly, routinely, and successfully on a daily basis.
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