Lockheed A-12

Design

With the failure of the CIA’s Project Rainbow to reduce the radar cross-section (RCS) of the  U-2, preliminary work began inside Lockheed in late 1957 to develop a follow-on aircraft to overfly the Soviet Union.

Under Project Gusto the designs were nicknamed “Archangel“, after the U-2 program, which had been known as “Angel”.

As the aircraft designs evolved and configuration changes occurred, the internal Lockheed designation changed from Archangel-1 to Archangel-2, and so on. These names for the evolving designs soon simply became known as “A-1”, “A-2”, etc. The CIA program to develop the follow-on aircraft to the U-2 was code-named Oxcart.

At the A-11 stage the aircraft was completing with the kingfish by Convair and they added several RCS fetures which were seen as favourable by the panel members so Lockheed responded with

Adding twin canted fins instead of a single right-angle one, and adding a number of areas of non-metallic materials.

This became the A-12 design. On 26 January 1960, the CIA ordered 12 A-12 aircrafts.

Because the A-12 was well ahead of its time, many new technologies had to be invented specifically for the Oxcart project with some remaining in use in present day. One of the biggest problems that engineers faced at that time was working with titanium.

In his book Skunk Works: A Personal Memoir of My Years at Lockheed  Ben Rich stated

“Our supplier, Titanium Metals Corporation, had only limited reserves of the precious alloy, so the CIA conducted a worldwide search and using third parties and dummy companies, managed to unobtrusively purchase the base metal from one of the world’s leading exporters – the Soviet Union The Russians never had an inkling of how they were actually contributing to the creation of the airplane being rushed into construction to spy on their homeland.“

Test stage

After development and production at the Skunk Works, in Burbank, California, the first A-12 was transferred to Groom Lake test facility (Area 51). On 25 April 1962 it was taken on its first (unofficial and unannounced) flight with Lockheed test pilot Louis Schalk at the controls. The first official flight took place on 30 April and subsequent supersonic flight on 4 May 1962, reaching speeds of Mach 1.1 at 40,000 ft (12,000 m).

Although originally designed to succeed the U-2 overflying the Soviet Union and Cuba , the A-12 was never used for either objective. After a U-2 was shot down in May 1960 , the Soviet Union was considered too dangerous to overfly except in an emergency (and overflights were no longer necessary, thanks to reconnaissance satellites) and, although crews trained for flights over Cuba, U-2s continued to be adequate there.

Mission Details

• SAM evasion over North Vietnam
  • The Soviet Union’s increasingly sophisticated surface-to-air missile (SAM) sites, which the A-12 had to reckon with while planning mission routes, was one of many factors that led to its retirement. The vehicle was detected by acquisition radar over North Vietnam in 1967, however the SAM site’s use of the Fan Song guide radar to home the missile on the target was unsuccessful. On October 28, a single, but failed missile was fired from a North Vietnamese SAM position. This mission’s photography captured the event, including images of the missile and its contrail as well as images of the missile’s smoke over the SAM firing location. Equipment for electronic countermeasures seemed to work effectively against the missile fire.
  • During a flight on 30 October 1967, pilot Dennis Sullivan detected radar tracking on his first pass over North Vietnam. Two sites prepared to launch missiles but neither did. During the second pass, at least six missiles were fired, each confirmed by missile vapor trails on mission photography. Looking through his rear-view periscope, Sullivan saw six missile contrails climb to about 90,000 ft. (27,000 m) before converging on his aircraft. He noted the approach of four missiles, and although they all detonated behind him, One approached his aircraft at a distance of 100 to 200 meters or 300 to 700 feet. A metal fragment had entered the lower right wing fillet area and been lodged against the wing tank’s support structure, according to a post-flight inspection. The fragment, which was not a warhead pellet, might have been a piece of the missile detonation debris that the pilot had seen.
  • Early missiles like the SA-2 “Guideline” were made to fight slower, lower-flying aircraft like the B-52 and B-58. The Soviet Union had started developing significantly upgraded missile systems, most notably the SA-5 “Gammon,” in response to faster, higher-flying designs like the B-70. The SA-5 was approved for service by the Soviet Air Defense Forces (Protivo-Vozdushnaya Oborona, PVO) in 1967; if sent to Vietnam, it would have posed a further threat to the A-12.
  • On March 8, 1968, the last Black Shield mission over North Vietnam and the Demilitarized Zone (DMZ) was carried out. Khe Sanh and the border regions with Laos, Cambodia, and South Vietnam were captured on high-quality photos. Due to unfavourable weather, no suitable photographs of North Vietnam could be taken. No signs of a hostile weapon response were present, and no ECM systems were turned on.
• Missions over North Korea
  • On March 8, 1968, the last Black Shield mission over North Vietnam and the Demilitarized Zone (DMZ) was carried out. Khe Sanh and the border regions with Laos, Cambodia, and South Vietnam were captured on high-quality photos. Due to unfavourable weather, no suitable photographs of North Vietnam could be taken. No signs of a hostile weapon response were present, and no ECM systems were turned on.
  • The first two-pass mission over North Korea took place on the second mission, which took place on February 19, 1968. 84 core targets and 89 secondary targets were captured by the Oxcart vehicle. Twenty percent of the region was obscured by scattered clouds, including the spot where the USS Pueblo was photographed during the previous mission. Near Wonsan, one new SA-2 site was found.

Retirement

Even before the A-12 was put into service, it was less likely to accomplish its original goal of taking the place of the U-2 on flights over the Soviet Union. The Soviet Union’s radar systems boosted their blip-to-scan ratios, making the A-12 more susceptible.

The A-12 program ended on 28 December 1966 – even before Black Shield began in 1967 – due to budget concerns and because of the SR-71, which began to arrive at Kadena in March 1968. The twin-seat SR-71 was heavier and flew slightly lower and slower than the A-12.

General characteristics

• Crew: 1
• Capacity: 2,500 lb (1,100 kg) payload
• Length: 101 ft 7 in (30.96 m)
• Wingspan: 55 ft 7 in (16.94 m)
• Height: 18 ft 6 in (5.64 m)
• Wing area: 1,795 sq ft (166.8 m)
• Max takeoff weight: 117,000 lb (53,070 kg) *Max landing weight: 52,000 lb (24,000 kg)
• Fuel capacity: 10,590 US gal (8,818 imp gal; 40,088 L) / 68,300 lb (30,980 kg) of JP-7 at 6.45 lb/US gal (7.75 lb/imp gal; 0.773 kg/L)
• Powerplant: 2 × Pratt & Whitney JT11D-20B (J58-1) Afterburning turbojet, 20,500 lbf (91 kN) thrust each dry, 32,500 lbf (145 kN) with afterburner.

Performance

• Maximum speed: Mach 3.35
• Supersonic cruise: Mach 3.1
• Range: 2,500 nmi (2,900 mi, 4,600 km)
• Service ceiling: 85,000 ft (26,000 m) or higher
• Rate of climb: 11,800 ft/min (60 m/s)
• Wing loading: 65 lb/sq ft (320 kg/m)
• Thrust/weight: 0.56

References

Lockheed A-12 – Wikipedia

The Oxcart Story

A-12 Blackbird

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