B-2 Spirit HistoryFormal work on the development of "low-observable" or "stealth' aircraft in the US began in late 1974, when DARPA, a Pentagon organization that works on "blue sky" advanced technologies, began "Project Harvey" as an effort to build a stealthy aircraft.
Before Project Harvey, there were other attempts to incorporated stealth features into aircraft. In the early 1960s, Firebee target drones had been modified for the reconnaissance role as "Lightning Bugs" or "Fireflies". They had been fitted with stealth features, including pads of RAM on the sides of the fuselage. The drones also had a wire mesh over the air intake to mask the blades of the engine compressor, this technique was later used on the F-117 stealth fighter.
The high-flying Lockheed SR-71 Blackbird reconnaissance aircraft was designed to be stealthy as well, though it also used high altitude and speed for protection.
The goals of Project Harvey were much more ambitious: to create an aircraft that could survive on stealth alone. DARPA awarded study contracts to McDonnell Douglas and Northrop in January 1975. Lockheed found out about Harvey through the grapevine and insisted on participating, paying for their design effort out of company funds. That was a gamble, but it paid off: Northrop and Lockheed were selected by DARPA to design a stealth demonstrator, the "Experimental Survivable Testbed (XST)", while McDonnell Douglas was eliminated from the competition. The XST program's goals did not include building a flight demonstrator; Northrop and Lockheed were to build large-scale mockups, which would then be mounted on a pole at Holloman AFB in New Mexico and subjected to tests to determine their RCS.
Iin December 1976 DARPA officials called up Northrop to discuss a stealth aircraft as part of the Pentagon's "Assault Breaker" effort. DARPA wanted Northrop to study a stealthy "Battlefield Surveillance Aircraft -- Experimental (BSAX)" that would spot targets for Assault Breaker weapons. In April 1978, DARPA awarded Northrop a contract for a single flying prototype of the design, which was given the codename "Tacit Blue".
Tacit Blue performed its initial flight in February 1982, followed by 134 more flights over a three-year evaluation. Tacit Blue was put in storage in 1985 and was finally announced to the public in 1996.
While Northrop was beginning work on Tactic Blue, back at the Pentagon the top brass was becoming very interested in stealth. A group studying the military potential of stealth concluded that improvements in adversary air defenses were threatening to make the current "non-stealthy" US bomber force obsolete. In addition, stealth would allow a single aircraft to make a precision attack on a target, instead of requiring a full "strike package" of multiple bombers, with fighter escorts, jamming platforms, and defense-suppression ("Wild Weasel") aircraft.
The group recommended that two stealthy strike aircraft should be built, an "A Airplane", a fast-track development of the Lockheed Have Blue demonstrator, which would emerge as the F-117; and a "B Airplane" that would be bigger and more capable but would take more time to deliver.
The B Airplane concept grew over time into a full-blown, long-range heavy bomber. Lockheed had proposals, one apparently being a machine something like a scaled-up F-117 and codenamed "Senior Peg", but the Pentagon also asked Northrop to investigate. Northrop came up with two proposals, one of which, cooked up by designer Hal Markarian, took its inspiration from the YB-49, a flying wing design build by Northop three decades earlier. Incidentally, there is a story, possibly true, that the YB-49 had shown a surprising ability to disappear from radar at certain viewing angles.
The Northrop concept, codenamed "Senior Ice", was judged superior to the Lockheed proposal, codenamed "Senior Peg", and Northrop won the ATB contract in October 1981. The contract covered delivery of two static-test airframes, one flying prototype, and five evaluation machines. While the Carter Administration had pushed stealth there had been some ambivalence about production, but the new, hawkish Reagan Administration wanted to go full speed ahead on the ATB. The initial plan envisioned production of 127 ATBs, in addition to the five evaluation machines, which would be brought up to operational specification.
The first "B-2" prototype, "Air Vehicle One (AV-1)", was rolled out at the Northrop plant in Palmdale, California, on 22 November 1988. The rollout was public, but observers were restricted to stands that kept them well away from the aircraft and limited their view of it to the front. AV-1 performed its first flight on 17 July 1989, flying from Palmdale to Edwards AFB in California. Northrop Test pilot Bruce Hinds and USAF Colonel Richard Couch were at the controls. AV-2, the first of the five evaluation machines, performed its initial flight on 19 October 1990. The first production B-2A was accepted by the US Air Force Air Combat Command (USAF ACC) at Whiteman AFB in Missouri on 17 December 1993. Due to the merger of Northrop and Grumman in the 1990s, the aircraft is now the "Northrop Grumman B-2".