By the early 1980s, computer power had reached the point where it was finally possible to take the mathematical calculations that had been done on the flat-faceted surfaces of the F-117 stealth fighter and do them for a smooth curved surface. The result was the B-2 bomber.
"Icons of Aviation History" is a diary series that explores significant and historic aircraft.
In 1975, the Air Force began “Project Harvey”, a crash program intended to produce aircraft designs that would be undetectable by enemy radars, allowing attack planes to easily penetrate Soviet airspace. (The name came from a giant invisible rabbit named “Harvey” in a contemporary Broadway play.) The first design to result from this was the F-117 Nighthawk stealth fighter.
By 1978, computers were beginning to reach the level where they were capable of doing the complicated calculations for producing a radar-reflective curved surface, and this was confirmed on the TACIT BLUE test aircraft. President Carter authorized work on an “Advanced Technology Bomber (ATB)”, and this was soon codenamed as part of “Project Aurora” and became highly classified.
Two designs were selected for potential development: Northrop and Boeing joined together to submit a concept called SENIOR ICE, and Lockheed and Rockwell teamed up for the SENIOR PEG submission. Both concepts were similar, as they were constrained by the mathematics required for stealth: they were both “flying wing” designs, with the PEG plans having a small tail and the ICE being tailless. In 1980, the SENIOR ICE concept was selected and began development under the designation “B-2”. The contract called for two prototypes and six production planes, with an option to produce 127 more as required. The new bomber was planned to enter service in 1987.
During the 1980 election campaign, politics entered the picture. President Carter, knowing that the ATB project was already in the works, had canceled the proposed B-1 bomber, prompting candidate Ronald Reagan to accuse him of being “soft on national defense”. Carter then made the decision to defend himself from the unfair charge by publicly disclosing the existence of the ATB bomber project.
The B-2 was 69 feet long and had a wingspan of 172 feet. Its “flying wing” design was loosely based on an old concept that Northrop had worked on before. The new bomber was powered by four General Electric F118-GE-100 jet engines which were buried deep inside the fuselage to minimize their heat signature. The engines lacked afterburners and the B-2 was not capable of supersonic flight, having a maximum speed of around Mach 0.8. There were two bomb bays, each of which would hold up to eight B61 or B83 nuclear bombs.
The entire airframe was made of lightweight reinforced carbon-fiber panels, which had been specially-molded to minimize the amount of radar energy which they would reflect. The entire airframe was also coated with a spray-on rubberlike “radar absorbent material”. There was a special laser sensor at the rear which detected any visible contrails which the bomber may have produced, allowing the pilot to adjust his altitude to remove it.
The rear edges of the wings were designed in a “double-W” configuration both to minimize radar reflections and to use a complex system of baffles to mix the engine exhaust with cool air coming over the wings, which further reduced the plane's heat signature. The control surfaces were built into the rear edge of the wings. In normal flight, they acted as elevators and ailerons. In stealth mode, they were not used, and the plane was maneuvered by adjusting the thrust of each engine. The plane was inherently aerodynamically unstable, and it only flew at all because the inbuilt “fly-by-wire” computer system made constant adjustments and responded to pilot inputs to actually fly the plane.
In the mid-80s, the Reagan Administration changed the planned mission profile for the B-2. It had originally been intended to deliver nuclear weapons at an altitude of around 50,000 feet. But new Soviet AA missiles and radars had made this hazardous, so it was decided to alter the mission profile to a low-altitude penetration, and this led to a two-year delay as new avionics and terrain-following radars, adapted from those used in the F-15, were added. For preferred night missions, the plane had an additional navigation system which fixed the exact position using measurements of known stars in the sky.
The B-2 was finally publicly revealed in a carefully stage-managed roll-out in November 1988. Actual test flights, however, did not start until the next year. Now named the “Spirit”, the B-2 proved to be effective against radar, thermal sensors, sound detectors, and visual detection.
Original plans called for a total production run of 132 combat aircraft. But just as the factories were gearing up, the Soviet Union collapsed and the Cold War came to an end. The B-2 found itself without a mission, and planned production was cut first to 75, then to just the already-existing 21 planes. The program had cost some $40 billion in total.
Reassigned to the conventional bombing role, the B-2 saw its combat debut during the 1991 Iraq War, when it took off from American bases in the Indian Ocean to strike air-defense targets in Baghdad. Since then, the B-2 has undergone several updates to its avionics and computer systems.
In December 2022, the US publicly rolled out a prototype for the new B-21 Raider nuclear bomber. A highly-modified successor to the similar-looking B-2, the Raider is “crew optional” and can be remotely flown to its target by an operator on the ground. The B-21 is scheduled to begin replacing the B-2 and B-1 in 2027.
As of 2023 there is only one B-2 bomber on public display, in the Museum of the US Air Force in Dayton OH. This is an engineering test model that was built without engines or avionics: it was rigged up to stress-test the flight control surfaces. Since the baffle system used to hide the engine exhaust is still classified, the plane is displayed in such a way that visitors cannot see the rear portion of the engines.
NOTE: As some of you already know, all of my diaries here are draft chapters for a number of books I am working on. So I welcome any corrections you may have, whether it's typos or places that are unclear or factual errors. I think of y'all as my pre-publication editors and proofreaders. ;)