World War). In the 1940s, the brilliant and eccentric American engineer Jack Northrop designed the XB-35 heavy bomber, a propeller-driven flying wing, and later the YB-49, a promising eight-engined turbojet bomber (which compromised the purity of the design by adding four small vertical fins). Unfortunately, the manual flight controls of the time were inadequate to solve the inherent stability problems of pure flying wing designs, and the Air Force canceled the project. Despite the problems inherent in the flying wing design, it does have one undeniable characteristic: It is tough to see on radar. Thus, the stage was set for the development of the B-2.
Originally called the Advanced Technology Bomber (ATB), the B-2 began development in 1978 as a black program, which means that it was not published in the Air Force budget and its existence was revealed only to a limited circle of legislators. In 1981 the Northrop/Boeing team's proposal was selected, and full-scale development of the new bomber followed. It took seven years, including a major redesign in the mid-1980s, when the USAF changed the original B-2 specification to include a low-level penetration capability. (Shortly before his death, under a special security dispensation, Jack Northrop was allowed to see a model of the B-2—the vindication of the idea he had championed four decades earlier.)
The first B-2 pre-production aircraft (known as Air Vehicle #1) was rolled out at Palmdale, California, on November 22nd, 1988, and the first flight was on July 17th, 1989. The first B-2A squadron (of eight aircraft) of the 509th Bombardment Wing at Whiteman AFB, Missouri, are scheduled to reach IOC (initial operation capability) in 1996. Given the official Air Force designation of Spirit, each aircraft will be named for a state; the first five are 'Spirit of California,' 'Spirit of Missouri,' 'Spirit of Texas,' 'Spirit of Washington,' and 'Spirit of South Carolina.' General Mike Loh, the ACC commander, likes the designation because, like a ghost, the B-2 will be able to come and go without being seen.
A combination of several advanced technologies made the B-2 possible. Foremost among these was computer-aided design/computer-aided manufacturing, known as CAD/CAM in the aircraft industry. The F-117A had to employ awkwardly faceted flat surfaces, because this was the only solution available in the mid-1970s to the earlier-generation computer hardware and software on which it was designed (millions of radar cross section calculations were necessary to validate the design). The B-2, designed on vastly more powerful computer systems, could have smoothly contoured aerodynamic surfaces because, by that time, the billions of necessary calculations could be performed relatively quickly.
Moreover, the B-2 was the first modern aircraft to go into production without requiring a prototype, or even a development fixture. Designed with advanced three-dimensional CAD/CAM systems, which are used to fix parts, the B-2's virtual development fixture allowed every component to be fit-checked before it was manufactured. As a result, when the first B-2s were assembled, something happened that was unprecedented in aviation history, possibly in the entire history of engineering development and manufacturing. Every part fit perfectly the first time, and the finished aircraft precisely matched its designed dimensions within a few millimeters over a span of 172 feet/52.4 meters.
The B-2's flight-control surfaces are unique. The outboard trailing edge of each wing tip consists of a pair of hinged 'drag rudders,' moved by hydraulic actuators, with another set called 'elevons' inboard of those. These surfaces take the place of the rudder, elevators, and ailerons on a conventional aircraft.
The B-2's crew consists of a mission commander and pilot, who sit side by side on conventional ejection seats beneath blow-out panels overhead. The commander is in the right-hand (starboard) position, with the pilot on the left (port). Each crew station has four color multi-function displays and fighter-type control sticks, rather than the control yokes commonly used on large multi-engined aircraft. These controls feed into the quad-redundant fly- by-wire flight control system, which makes the Spirit very stable, but highly agile. (According to the test pilots, the B-2 flies 'like a fighter' thanks to the agility of the fly-by-wire system.) The communications systems consist of a full array of HF/UHF/VHF radios, as well as a satellite communications terminal, all of which are controlled from a single data entry panel. Eventually, this will be fully compatible with the new MILSTAR communications satellites that are now coming online. The wraparound windows are very large, but there is no visibility aft, so the crew must rely on sophisticated tail-warning sensors to 'check six.' The crew enters through a floor hatch with a retractable ladder that is just aft of the nose landing gear well. The traditional 'alert' button is on the nose gear, though most experts agree that it will probably never be used by a B-2 crew.
The four General Electric F118-100 turbofan engines buried inside the wing are non-afterburning versions of the F101 used in the B-1B. Each engine is rated at 19,000 lb./8,600 kg. of thrust. To dissipate heat and hide the hot section from hostile IR tracking systems, the complex air intakes receive incoming air through an S-shaped turn, which shields the fan sections from the view of any hostile radar; then the unique V-shaped exhaust slots pass the exhaust gases across a long, wide, trough-shaped section of the upper wing.
While many details of the structure and materials of the B-2 will remain closely guarded secrets for years to come, published sources suggest that graphite-epoxy composites are used extensively. Even the paint requires unique new technology. Antennas are mounted flush with the skin; even the air-data sensors which stick out prominently on most fly-by-wire aircraft are flush-mounted on the leading edge of the B-2. The most conventional equipment is the main landing gear, derived from the Boeing 767 airliner, and the nose gear, from the Boeing 757.
With only one air-to-air refueling, a range of more than 10,000 nm./ 18,280 km. is possible. Endurance is thus limited only by crew fatigue, which is exceptionally low due to the high degree of onboard automation. In effect, with a minimum of tanker support, the B-2 can strike any target in the world and return to a base in the continental United States. The in-flight refueling receptacle on top of the crew compartment is concealed behind a retractable door of radar-absorbing material, and according to pilot reports, the B-2 is quite stable and has very pleasant flying qualities around tankers.
All weapons will be carried internally — an absolute requirement for any stealthy aircraft, since ordnance dangling on pylons increases the radar cross section dramatically. The two bomb bays, aft of the crew compartment, are designed to each accommodate an eight-round rotary launcher, or a conventional munitions module similar to those on the B-1B.
The Air Force plans to buy twenty B-2s by 1998 for $44 billion from Northrop Grumman Corp. of Los Angeles. Originally the service wanted 132 B-2s, but because of the plane's high purchase price and the end of the Cold War, Congress limited the program. Though Northrop Grumman has proposed constructing an additional twenty aircraft by 2008 at a guaranteed fixed price of about $570 million each, the future of the program is highly uncertain. Nevertheless, the B-2A Spirit is the state of the art in strike aircraft, and probably will be well into the middle of the next century.
Lockheed Martin-Boeing F-22
It has been over twenty years since the current USAF air superiority fighter, the F-15 Eagle, first took wing in 1972. Those two decades have seen massive changes, both in the political makeup of the world and the nature of aviation technology. Thus, it is in that context that the Air Force is betting billions of dollars and the future of manned fighter aircraft on the Lockheed Martin-Boeing F-22 and its new Pratt & Whitney F119 engines. In 1984, the ATF specification called for a 50,000 lb./22,700 kg., $35 million aircraft (that's in 1985 U.S. dollars) incorporating the latest advances in low-observable technologies and able to cruise at supersonic speed (the YF- 22A demonstrated the ability to cruise at Mach 1.58 during the competitive fly-off, and to do so at altitudes in excess of 50,000 feet) to a combat radius of more than 800 nm./ 1,200 km. By 1986 the competition narrowed down to two teams, each of which would build and fly a pair of prototypes: the Lockheed-Boeing-General Dynamics YF-22 and the Northrop-McDonnell Douglas YF-23. Although the YF-23 had excellent performance, the Air Force decided in April 1991 to go with the superior agility of the YF-22. Under current plans, the Air Force will now buy 442 aircraft, with a first production aircraft flight scheduled early in 1997 and initial operational capability by 2004. Planned production will continue through 2011, with follow-on versions such as strike, SEAD (Suppression of Enemy Air Defenses), and reconnaissance coming afterwards as required.
