The Lockheed A-12 was designed to replace the U-2. The work was ordered and financed by the US Central Intelligence Agency. The main reason for the start of work was the improvement of the air defense systems of a potential enemy - the U-2, despite the flight altitude, was rather slow, which means it was vulnerable to air defense. The A-12 was produced in 1962-1964 and operated in 1963-1968 (the last flight was in May 1968). The design of the single-seat aircraft served as the basis for the SR-71 Blackbird high-altitude high-speed reconnaissance aircraft.
Lockheed was already working on possible solutions when Prospect Development Manager Clarence L. (Kelly) Johnson, who served as director of Lockheed's Advanced Development Projects office (also known as the Skunk Works), was summoned to Washington in 1958.
A-12 (serial # 06932) in flight, 1960s
A competition was announced for the best car to replace the U-2. At the same time, not a cent was allocated for the design of new machines - the companies developed the machines at their own expense, hoping that all costs would be compensated in the future. Among those presented were a Navy project and a Boeing project. Lockheed presented several projects for consideration: G2A - subsonic tailless with low RCS, CL-400 - supersonic with hydrogen engines, A-1 and A-2 - supersonic aircraft with ramjet or turbojet-ramjet. The designation of the latter was deciphered as "Archangel-1 (2)". In September 1958, the FISH project proposed by the Convair division of General Dymanics Corporation received the greatest approval. The vehicle was an unmanned reconnaissance aircraft launched from the projected high-speed version of the Hustler bomber, the B-58B. However, after 2 months, Lockheed proposes a new high-speed reconnaissance project under the designation A-3. At the end of November, Convair and Lockheed are offered to create supersonic strategic reconnaissance aircraft using two powerful Pratt & Whitney J58 engines. The project was codenamed GUSTO.
Preference was given to the Lockheed project. In addition to the lower cost and better tactical and technical characteristics, the fact that the previous U-2 was created on time and without exceeding the budget also played an important role. In addition, the verification of the Skunk Works personnel ensured complete secrecy. In total, the Skunk Works developed 12 prototypes before the layout of the aircraft was approved - it was the last prototype that received the designation A-12. On September 14, 1958, the CIA signed a contract with Lockheed to continue work on the A-12. For expenses in the period from 1959-01-09 to 1960-01-01, 4.5 million dollars were allocated. The project was given the code designation OXCART ("Bovine cart"). On January 26, 1960, the CIA issued an order for 12 A-12 aircraft. The contract was worth almost $ 100 million.
An interesting fact is that the CIA began recruiting pilots even before the first flight of the plane took place. In total, 11 people were selected from the air force units. All pilots have passed CIA checks and rigorous medical screening.
The program had a very high level of secrecy, comparable to the Manhattan Project. The American president, several people from the Air Force and several congressmen knew about the development of the Lockheed A-12, in addition to people conducting research and development work. It was strictly forbidden to link work with Lockheed, all drawings, units and assemblies were labeled "C&J Engineering". The necessary calculations, carried out on a NASA computer, were performed by Skunk Works employees at night to maintain secrecy.
The A-12 project was carried out according to a modified tailless scheme with a wing that smoothly mated with the fuselage (later this scheme was called integral). When designing, the designers faced various problems "creeping out" from everywhere. "Tailless" with delta wing were available, but they had only one engine. Two engines of the Mirage IV were located in the fuselage, and in the new car they were spaced apart. The designers feared that if one of the engines failed, the rudders on the keels would not be able to compensate for a significant turning moment.
The high temperature of the structure at high speeds was also a problem. Expansion of the metal upon heating could cause unacceptable temperature stresses, deformation and fractures. High temperatures have led to the use of special kerosene. Titanium alloys used for A-12 caused a headache. Titanium was not only difficult to handle, but there was also an acute shortage of this material in the United States. For aircraft, titanium was ordered from the USSR. The electrical contacts were electroplated, and in some places they were additionally lined with asbestos to increase their reliability at high temperatures.
According to the contract, the EPR A-12 had to be minimized. In November 1959, electromagnetic tests of the model began at a specially designed Groom Lake test site (Nevada). In the course of modifications, the Lockheed A-12 received a characteristic "cobra" shape - a curving contour and sagging on the sides of the fuselage. The sagging did not worsen the aerodynamics, but even increased the stability of the aircraft and the lift, and reduced the bending moment on the fuselage. Small keels mounted on the ends of the engine nacelles were tilted towards the center of the aircraft 15 degrees from vertical. The firm has developed a radio-absorbing spike-like structure with a plastic honeycomb filler. It was used to make side beads, elevons and wing tips. About 20% of the wing area is made using such a design, which made it possible to withstand heating up to 275 ° C. Ferrite-based black paint dissipated heat and reduced the vehicle's radar signature.
The fuselage, wing (sweep along the leading edge - 60 °) and other elements of the aircraft had a complex shape, which made it possible to achieve high aerodynamic characteristics in various flight modes. All-turning keels in different flight modes turned asynchronously or synchronously within ± 20 degrees. To save weight, the single cab was not equipped with heat protection. All life support systems were connected to the pilot's spacesuit.
The first five A-12s, built in 1962, were powered by Pratt & Whitney J75 engines (76 kN thrust). However, the engines used for the first machines made it possible to develop a dive speed of M = 2. To increase the speed in October, specially designed J58 engines began to be installed on the aircraft, which made it possible to develop a speed of M = 3, 2 in 1963.
Since the main purpose of the Lockheed A-12 was to carry out reconnaissance flights over the territory of a potential enemy, special cameras were ordered to equip the machines. To create them, Hycon, Eastman Kodak and Perkin-Elmer were attracted. All cameras developed by these companies (Type I, II and IV) were purchased for the OXCART software. In addition, the FFD-4 infrared stereo camera, developed by Texas Instruments Corporation in 1964 for the U-2 under the TACKLE project, was used. To protect the chambers from heating, a special quartz glass window was created. Glass was fused with a metal frame using ultrasound.
In mid-January 1962, the first prototype of the aircraft was assembled in the hangar of the Watertown Strip Air Force flight test base. Flight tests began in the spring. During the same period, equipment was installed. The prototype Lockheed A-12, piloted by test pilot Lou Schalk, took to the air for the first time on April 25, 1962, during one of the runs the car took off from the ground. The first "official" flight of the A-12 took place on April 30, 1962. A-12 broke the sound barrier on May 2, 1962 during its second test flight.
All this time, Lockheed A-12 aircraft were equipped with J75 engines. On October 5, 1962, a car with J75 and J58 engines took off, and on January 15, 1963, the A-12 flew with two J58s. During the tests, a constant fuel leak was detected. Leakage and overheating of the wiring insulation remained a problem throughout the entire period of operation of the A-12.
The plane had a lot of flaws. The main one is the enormous psychophysical load on the pilot of a one-seater car. On May 24, 1963, the first A-12 crash occurred near Wendover, UT. During flights over American territory for various reasons in 1963-1968, 4 A-12s crashed.
The speed M = 3 was reached on July 20, 1963. In November of the same year, the design speed and altitude were reached. On February 3, 1964, the scout at an altitude of 25290 meters picks up speed M = 3, 2 and maintains it for 10 minutes. On January 27, 1965, A-12 flew for 1 hour 40 minutes at a speed of M = 3, 1 having covered a distance of 4, 8 thousand km.
As of October 1966, there were about 40 flights per month during the tests. Another impressive demonstration of the capabilities of the Lockheed A-12 was Bill Perk's six-hour flight on December 21, 1966. The vehicle covered 10,198 miles (16,412 km). 1967 began with a tragedy - Walter Ray crashed on the fourth prototype on a routine training flight on January 5. Immediately after takeoff, the flow meter failed, which caused an increased fuel supply and engine fire.
Despite the fact that the aircraft was originally designed for reconnaissance flights over the territory of the USSR and Cuba, the A-12 was never used for these tasks. Despite the successes demonstrated by the A-12 during test flights, the car remained "raw" and extremely difficult to pilot and maintain. Despite this, the customer demanded by November 5, 1964, to provide 4 aircraft for reconnaissance flights over Cuba. Since civilian pilots were not trained, Kelly Johnson allowed the testers to voluntarily take part in this operation. By November 10, the A-12s were ready for the operation, but the CIA leadership had already refused to use the new intelligence officer. One of the reasons for the abandonment of the A-12 was the unavailability of onboard electronic warfare equipment.
The Lockheed A-12 was to be baptized by fire in Asia. On March 18, 1965, a meeting was held between McConn, Director of the CIA and McNamara, Secretary of Defense. The issue of strengthening China's air defense and the increased threat from it to American U-2 aircraft and reconnaissance UAVs was discussed. It was decided that the Lockheed A-12 was an alternative to the UAV and the U-2, which needed to be airlifted to Asia. The program was given the name Black Shield. The base was the Kadena airfield on the island of Okinawa. During the first phase of the program, three scouts were to be deployed at Cadena for a period of 60 days twice a year.
In 1965, interest in the A-12 from high-ranking officials declined sharply. The requests of the CIA leadership to allow flights over North Vietnam and China under the Black Shield program met with opposition from the State Department and McNamara.
The reluctance of the management to use the A-12 for its intended purpose was the reason for raising the question of their necessity. The decision to put the already built Lockheed A-12s on storage was made at the end of 1966. Their place was to be taken by spy satellites and the SR-71 double reconnaissance aircraft - a direct descendant of the A-12. The deadline for conservation was set in February 1968. However, instead of mothballing the scouts, they began to prepare them for combat missions. The appearance of the S-75 air defense system in North Vietnam forced the decision to change. A request to use the A-12 for flights over the DRV came from US President Johnson. The scouts were supposed to monitor the North Vietnamese air defense, tracking changes in the deployment of missile systems. The use of the A-12 over Vietnam was authorized by the American President on May 16, 1967. On May 22-27, three unmarked A-12s, completely painted black, were deployed to Okinawa.
On May 29, the commander of the expeditionary unit, Colonel Slater, reported on the readiness for the first reconnaissance flight, which took place two days later - on May 31, 1967. The flight duration is 3 hours 39 minutes, the speed is M = 3, 1, the altitude is 80 thousand feet (24 383 km). The scout recorded 70 positions of the air defense missile system. In the period from May 31 to August 15, seven sorties were made. Radar radiation was recorded in four of them, but no missile launches were noted.
August 16 - December 31, scouts made fifteen more flights over the DRV. In flight, on September 17, one missile of the S-75 complex was launched at the plane, on September 23, another launch was made. On October 30, six missiles were fired at the A-12 piloted by Dennis Sullivan, which caused minor damage to the aircraft - this is considered the only case of a reconnaissance defeat.
In the period from January 1 to March 31, 1968, the aircraft flew over Vietnam four times, over North Korea - twice. The first flight over Korea was made by CIA pilot Frank Murray on January 26. Pilot Jack Layton's flight over the DPRK on May 8, 1968 was the last for the Lockheed A-12. After that, the scouts began to be mothballed.
Back in July 1966, the budget committee prepared a memorandum proposing two options for the fate of Lockheed A-12 and SR-71:
- to maintain the status quo, A-12 - remained in the CIA, SR-71 - in the air force;
- to cancel the A-12, transferring all functions to the SR-71 reconnaissance officers.
The only two-seat training A-12 built, on display at the California Science Center in Los Angeles
On December 16, 1966, the last option was chosen: the curtailment of the A-12 program began on January 1, 1968. They tried to keep the A-12 for the CIA in the first half of 1968 - various options for creating a "rapid response squadron" were proposed. However, on May 16, the American president confirmed his earlier decision. In May-June 1968, the scouts left Kadena, on June 4, work began on the conservation of the scouts in Palmdale. Not all planes returned from Okinawa, on June 4, during a training flight, an A-12 piloted by Jack Wick (Jack Weeks) disappeared. It was officially reported that the SR-71 was missing.
A-12 took to the skies for the last time on June 21, 1968.
In total, 18 aircraft of the following modifications were built under the A-12 program:
A-12 - supersonic single-seat strategic reconnaissance aircraft for the CIA;
A-12 "Titanium Goose" - two-seater combat training aircraft;
YF-12A - fighter-interceptor, two-seater;
SR-71A - supersonic strategic two-seat reconnaissance aircraft for the Air Force;
SR-71B - combat training aircraft, two-seater;
SR-71C - combat training aircraft, two-seater;
M-21 is a double carrier for the D-21 unmanned aerial vehicle.
Flight performance of Lockheed A-12:
Length - 31, 26 m;
Height - 5, 64 m;
Wing area - 170 m²;
Wingspan - 16, 97 m;
Empty aircraft weight - 30,600 kg;
Normal takeoff weight - 53,000 kg;
Engine - 2 × Pratt & Whitney J58-P4;
Engine weight - 3200 kg;
Maximum thrust - 2x10630 kgf;
Afterburner thrust - 2x14460 kgf;
Fuel - 46180 l;
Maximum speed - 3300 km / h;
Cruising speed - 2125 km / h;
Climb rate - 60 m / s;
Practical range - 4023 km;
Tactical range - 2000 km;
Service ceiling - 28956 m;
Flight duration - 5 hours;
Wing loading - 311 kg / m²;
Thrust-to-weight ratio - 0, 54;
Crew - 1 person.
Prepared based on materials:
