The A-12CB (Carrier Based) was a minor study for a major change in operations for the Oxcart: flight to and from aircraft carriers
Project Oxcart, a secret military program to develop a high-speed, high-altitude reconnaissance aircraft, produced the A-12. The A-12 was constructed by Lockheed’s Advanced Development Projects office, which is now known as Skunk Works, and made its first flight in 1962. The A-12 could fly over Mach 3, or three times the speed of sound, and could perform delicate intelligence-gathering missions. Up to 1968, A-12s were employed by the CIA for surveillance missions. Through the 1990s, variants that followed, referred to as the SR-71 Blackbird, were used by NASA and the US Air Force (USAF) for test and reconnaissance missions.
The A-12CB was a minor study for a major change in operations for the A-12: flight to and from aircraft carriers. As told by Scott Lowther in his book Origins and Evolution Lockheed SR-71 Blackbird, the A-12 certainly seems an unlikely aircraft to operate at sea… big, finicky, fragile, and with blistering takeoff and landing speeds. Numerous changes would have been required.
Known so far from only two similar but not identical diagrams, the A-12CB (carrier-based) would have had sizable solid rocket motors attached to the underside. The motors were Rocketdyne RS B-202s, used for the F-104G zero-length launch system.
With a total thrust of 130,000lb and a burn time of 7.9 seconds, these jettisonable take-off units would, with the aircraft carriers’ catapult system, have done a good job of lofting the A-12 forwards into the air. The A-12 would have required substantial internal modification both to the underside of the wings and the forward fuselage to tie these new sources of thrust into the aircraft structure. For landing, an arrester hook was fitted, which also would have required a tie-in to the main structure. Presumably, the landing gear would also need reinforcement.
The available diagrams show that the A-12CB was to be catapult-launched using the now-obsolete system of a bridle cable attached to two hooks located on the underside of the fuselage, straddling the centerline just aft of the inlets. The bridle cable attached to a very large catapult shuttle seemed to serve as a support for the forward fuselage, perhaps intended to hold the nose of the aircraft down during the catapult launch. With the large booster rockets firing, substantial forces would likely have been in play that could have thrown the aircraft all over the deck until aerodynamic flow held it on course.
Nothing is known about what aircraft carrier or carriers the A-12CB was meant to operate from. Here it has been provisionally shown on the deck of the CVAN-65 USS Enterprise. It can be seen that it would have been a very large aircraft for the deck of that ship, though it appears that with some effort it could have been made to fit on the ship’s elevators. Whether it could have been shoved through the hangar doorway is unclear; it may have had to be partly disassembled to fit. Additionally, the deck of the carrier would likely need reinforcement, or at the very least protective coatings, to shield it from the booster rocket exhaust.
Operations would have been complex and difficult, and their purpose is unclear. Presumably, the A-12 would have remained a reconnaissance platform, but it is possible that the A-12 was to be a strike variant. One diagram of the A-12CB shows a crudely sketched something penciled in above the fuselage, but it’s impossible to determine what was intended.
In any event, nothing came of the design. Dimensions, weights, and performance are not available but would presumably have been much the same as for the standard A-12.
Origins and Evolution Lockheed SR-71 Blackbird is published by Mortons Books and is available to order here.
Photo by Gunnar Klack’s own work via Wikipedia and Scott Lowther via Mortons Books
