Aircraft stealth us air force The Northrop Grumman B-2 Spirit, also known as the Stealth Bomber, is an American strategic bomber, featuring low observable stealth technology designed for penetrating dense anti-aircraft defenses; it is able to deploy both conventional and nuclear weapons. The bomber has a crew of two and can drop up to eighty 500 lb (230 kg)-class JDAM GPS-guided bombs, or sixteen 2,400 lb (1,100 kg) B83 nuclear bombs. The B-2 is the only aircraft that can carry large air-to-surface standoff weapons in a stealth configuration. Development originally started under the "Advanced Technology Bomber" (ATB) project during the Carter administration, and its performance was one of his reasons for the cancellation of the supersonic Rockwell B-1 Lancer. ATB continued during the Reagan administration, but worries about delays in its introduction led to the reinstatement of the B-1 program as well. Program costs rose throughout development. Designed and manufactured by Northrop Grumman with assistance from Boeing, the cost of each aircraft averaged US$737 million (in 1997 dollars).[3] Total procurement costs averaged $929 million per aircraft, which includes spare parts, equipment, retrofitting, and software support.[3] The total program cost including development, engineering and testing, averaged $2.1 billion per aircraft in 1997.[3] Because of its considerable capital and operating costs, the project was controversial in the U.S. Congress and among the Joint Chiefs of Staff. The winding-down of the Cold War in the latter portion of the 1980s dramatically reduced the need for the aircraft, which was designed with the intention of penetrating Soviet airspace and attacking high-value targets. During the late 1980s and 1990s, Congress slashed plans to purchase 132 bombers to 21. In 2008, a B-2 was destroyed in a crash shortly after takeoff, and the crew ejected safely.[4] A total of 20 B-2s remain in service with the United States Air Force, who plan to operate the B-2 until 2058.[5] The B-2 is capable of all-altitude attack missions up to 50,000 feet (15,000 m), with a range of more than 6,000 nautical miles (11,000 km) unrefuelled and over 10,000 nautical miles (19,000 km) with one refueling. Though originally designed primarily as a nuclear bomber, it was first used in combat to drop conventional bombs on Serbia during the Kosovo War in 1999, and saw continued use during the war in Iraq and in Afghanistan.[6] Overview The B-2 Spirit was developed to take over the USAF's vital penetration missions, able to travel deep into enemy territory to deploy their ordnance, which could include nuclear weapons.[59] The B-2 is a flying wing aircraft, meaning it has no fuselage or tail.[59] The blending of low-observable technologies with high aerodynamic efficiency and large payload gives the B-2 significant advantages over previous bombers. Low observability provides a greater freedom of action at high altitudes, thus increasing both range and field of view for onboard sensors. The U.S. Air Force reports its range as approximately 6,000 nautical miles (6,900 mi; 11,000 km).[6][60] At cruising altitude the B-2 refuels every six hours, taking on up to 50 short tons (45 t) of fuel at a time.[61] Due to the aircraft's complex flight characteristics and design requirements to maintain very-low visibility to multiple means of detection, both the development and construction of the B-2 required pioneering use of computer-aided design and manufacturing technologies.[59][62] Northrop Grumman is the B-2's prime contractor; other contributing subcontractors include Boeing, Raytheon (formerly Hughes Aircraft), G.E. and Vought Aircraft.[6] The B-2 bears a resemblance to earlier Northrop aircraft: the YB-35 and YB-49 were both flying wing bombers that had been canceled in development in the early 1950s,[63] allegedly for political reasons.[64] As of September 2013 about 80 pilots fly the B-2.[61] Each aircraft has a crew of two, a pilot in the left seat and mission commander in the right,[6] and has provisions for a third crew member if needed.[65] For comparison, the B-1B has a crew of four and the B-52 has a crew of five.[6] The B-2 is highly automated and, unlike most two-seat aircraft, one crew member can sleep in a camp bed, use a toilet, or prepare a hot meal while the other monitors the aircraft; extensive sleep cycle and fatigue research was conducted to improve crew performance on long sorties.[66][67][61] The B-2, in the envisaged Cold War scenario, was to perform deep-penetrating nuclear strike missions, making use of its stealthy capabilities to avoid detection and interception throughout missions.[68] There are two internal bomb bays in which munitions are stored either on a rotary launcher or two bomb-racks; the carriage of the weapons loadouts internally results in less radar visibility than externally mounting of munitions.[69][70] Nuclear ordnance includes the B61 and B83 nuclear bombs

• published: 24 Mar 2014
• views: 156