In 1976 Ben Rich of the Lockheed Skunk Works delivered a paper that briefly described the `Bx’, a straightforward modification of the existing SR-71 Blackbird into a supercruising strike aircraft.
The SR-71, unofficially known as the “Blackbird,” is a long-range, advanced, strategic reconnaissance aircraft developed from the Lockheed A-12 and YF-12A aircraft. The first flight of an SR-71 took place on Dec. 22, 1964, and the first SR-71 to enter service was delivered to the 4200th (later 9th) Strategic Reconnaissance Wing at Beale Air Force Base, Calif., in January 1966. The US Air Force (USAF) retired its fleet of SR-71s on Jan. 26, 1990.
Throughout its nearly 24-year career, the SR-71 remained the world’s fastest and highest-flying operational aircraft. From 80,000 feet, it could survey 100,000 square miles of Earth’s surface per hour.
As told by Scott Lowther in the book Origins and Evolution Lockheed SR-71 Blackbird, in 1976 Ben Rich of the Lockheed Skunk Works delivered a paper that briefly described the `Bx’, a straightforward modification of the existing SR-71 into a supercruising strike aircraft. This would be pe accomplished by putting AGM-69A SRAM missiles into the chines… not quite into the existing equipment bays, but rather into new longer bays in approximately the same positions.
The available diagram of the SR-71(Bx) is distressingly low resolution and has a few internal contradictions, but it appears that the forward fuselage of the aircraft would be ‘bent’ upwards along with having the blunter chines and the rounded underside to provide sufficient clearance for the missiles. The aircraft would have been fitted with a dedicated radar, though it’s difficult to make out the details; the nose would be recontoured and slightly lengthened to accommodate.
Further data on the SR-71(Bx) is lean; how rigorous the design effort for the SR-71(Bx) was is unclear. But by launching at Mach 3.2 and at an altitude of 80,000ft, the range of the SRAM could be notably increased to around 500 nautical miles. As the SRAM was not a guided missile, accuracy was not spectacular… Circular error probability (CEP) at 300 nautical miles was 3600ft. Rich suggested that CEP could be cut in half with terminal guidance, but details on that were not given.
Origins and Evolution Lockheed SR-71 Blackbird is published by Mortons Books and is available to order here.
Photo credit: U.S. Air Force and Scott Lowther via Mortons Books