Translated by BabelFish
The hang-glider Northrop B-2 was developed during the Cold war and in the greatest secrecy like strategic, furtive or undetectable bomber by radar, with for mission of attacking the Soviet strategic targets with bombs and nuclear weapons drawn remotely from safety. B-2 began its existence in a "black" program, initially known under the name "Project Senior C J" then under the name "Bomber ATB" ("Advanced Technology Bomber"). In the beginning, the persons in charge for the US Air Force believed that the bomber B1 B was the priority number one, whereas only one handle of them knew the existence of the B-2 project. For the latter, B-1 B was a "temporary" weapon, while waiting for B-2. At the height of the Cold war, USAF had envisaged to acquire some not less than 132.
Being based largely on designs of preceding hang-gliders, Northrop profited from the powerful support from Boeing, Vought and General Electric, using a system of design and manufacture 3d computer-assisted to conceive the single shape of the wing in ' W' of B-2. More than 100 000 images of equivalent surfaces radar of models of B-2 and their components were analyzed to evaluate their characteristics of furtivity, followed by 550 000 hours of wind tunnel tests. The program required the development of nine hundred new methods of design-manufacture, including new composite materials high temperature and high strength, ultrasonic cutting tools, tools with numerical control controlled by 3d and system laser data base of detection of splits. Northrop is responsible for the construction of the nose sections and of the cockpit, Boeing of the part power station-before and of the external sections, and Vought produced the median sections of the fuselage and the composite material and titanium, aluminium parts.
B-2 makes an intensive use of composite materials graphite/époxy in its structure in honeycomb intended to absorb, the waves radar. To reduce the infra-red signature, the exhaust fumes of the four turbojets General Electric F118-GE110 are evacuated by conduits in form of ' V' assembled above and in withdrawal of the trailing edges to mask these thermal sources with the terrestrial detectors. Acid chlorinated-fluorosulphonique is injected into the wake of exhaust to prevent the formation of trails of condensation. The leading edge out of arrow (331 and the trailing edge in teeth of saw trap the waves radar. Other passive countermeasures of detection include intakes air curved in form of ' and furtive dielectric panels covering the radar of bands-J AN/APQ-181 and preventing its antenna from reflecting the enemy waves radar while allowing a normal operation. The cockpit is equipped for two pilots, with ejector seats upwards evacuating Douglas/Weber ACES II, and has sufficient space for a third member crew. The pilot controls the computer of mission which manages the designation of the targets (or their redesignation in flight). The navigation and the shooting of the armament are responsibility for the officer system of weapons (WSO), sitted on the right seat. The two principal flight compartments have four multifunction screens color. The aircraft is equipped with a quadruple system of numerical electric controls of flight controlling the control surfaces of trailing edge of the wings, combining the functions of aileron, of shutter and elevator which accounts for 15% of the surface of the wing. An embryo of horizontal stabilizer is used as pitch trim as well as shock absorber of gusts in co-operation with the elevons.
to readjust the position of the objective at the last minute, B-2 briefly activates its lighting radar AN/APQ-181 a minimal zone right before launching its attack. Since 1987, this system was tested in C-135 de I' LISAF especially modified. Although this radar is installed on certain prototypes of B-2, all its tests were carried out on C-135. B-2 will be equipped with an electronic system of war, integrating the detector of emissions radar AN/APR50 (ZSR-63) of Federal IBM Systems and the secret system of defensive assistances ZSR-62.
B-2 was initially considered like an apparatus of penetration at high altitude but, when its final design was fixed in 1983, one allotted to him an operational mission at low altitude. The integration of this new mission to initial design ATB involved the displacement of the cockpit and the air intake of the engines, the addition of inboard elevons (which gave him its distinctive profile in ' W'), the modification of the leading edges and the internal changes important such that new partitions. With the general surprise, USAF published, in April 1988, a sight of artist of the apparatus which until had been kept there in the greatest secrecy. Six prototypes (five for USAF) were financed in 1982. November 22, 1988, the first apparatus (82-1066) left workshop 42 of USAF in Palmdale. Northrop had organized an inaugural ceremony and had taken great care to dissimulate the principal characteristics of the design of the wing, being arranged so that the 500 guests * only see the apparatus before and since the ground. An astute photographer discovered that Northrop had not prohibited the overflight of the factory and could obtain the first complete photographs of the plane thanks to a fast overflight in Cessna.
the inaugural flight of B-2 took place on July 17, 1990 (initially envisaged in 1987), when this apparatus (also indicated AV-1/Air Vehicle One) was delivered to USAF with Edwards AFB, to begin the test routine. Envisaged the 15, this event was delayed two days by a failure of the fuel system. It was preceded by a series by tests wheelers at high speed the 13, with a short lift-off of the caster of nose. October 19, 1990, the 82-1067 joined the AV-1. A test routine 3600 hours was fixed, initial with 16 flights (67 hours) of certification and tests of handiness. Finished in mid-June 1990, these flights also included/understood the first in-flight refueling with a KC-10A, November 8, 1989. A second series of tests began in October 1990, relating mainly to the furtive characteristics in real size. One could thus discover for the first time that furtive B-2 did not answer exactly its promises, the following flights were stopped to carry out modifications on 82-1066. The tests of furtivity continued in 1993, while the 82-1067 carried out bearing tests and performances. The third apparatus (82-1068) accomplished its first flight on June 18, 1991 and was the first model with being completely equipped with the new system avionics, including the radar Hughes AN/APQ-181 LPI (with weak probability of interception). The first dropping of weapons by B-2 was carried out by the fourth apparatus (821069), which had taken the air for the first time on April 17, 1992. September 4, 1992, it released only one inert bomb Mk84 of 908 kg. Intended to receive others weapons and to carry out climatic tests and of furtivity, fifth B-2 (821070) took its take-off on 5 October 1992, followed by the 82-1071, February 2, 1993. With the end of 1993, the program had accumulated 1500 hours of flight.
In July 1991, the defects of furtivity of B2 were revealed, and it was admitted that it could be detected by radars on the ground of detection advanced with high power. On the other hand, no comment came to confirm or contradict the Russian assertions according to which this bomber would be vulnerable to the systems of missiles SAM news generation, such as the S-300PMU (SA-10/A ' Grumble') and S-300V-9M83/82 (SA-12A/B ' Gladiator'/' Giant'). USAF implemented a whole of "treatments" on the leading edges and the airfoils to reduce the signature of the apparatus in certain frequency bands.
the problems of performances of B-2 did not help it in its fight for the financing in front of the American Congress. The initial budget counted a fleet of 133 units, including the prototypes, but in 1991, this figure had been tiny room with 76. After the first six apparatuses, ordered in 1982, three others were financed when B-2 was still a "black" project. In 1989, funds were resolved for three other units, then two in 1990, and finally two others in 1991. The Congress blocked then acquisitions with 16 (15 for USAF). USAF affirmed whereas it could not guarantee an effective operational capacity with less than 20 apparatuses, thus in 1993, the financing of five B-2 additional was approved. This authorization of financing was matched condition which the problems of furtivity are solved so that the production can begin. The costs by plane (ready with the flight) of the program had then reached 2220 million $. In 1987, the initial estimates of the program of 75 apparatuses rose with a total of 64700 million $, but it is not impossible that certain parts of the colossal budget of B-2 were devoted to other secret projects. Budget FY1995 included 793 million $ for the equipment of support and the provisions for the closing of the chains of production.
the first apparatus of USAF (88-0329/ ' WM', ' Spirit of Missouri') was delivered to 509ème BW in Whiteman AFB, Missouri, December 17, 1993, exactly 90 years day for day after the first flight of the Wright brothers. Eighth B-2 of series (AV-8), it is the first standard standard appliance to have preceded the AV-7 in the airs. The AV-7 had then not finished its of the electromagnetic properties and intensive control test routine of the emissions, and like the other apparatus taking part in the test routine in flight, it will be delivered to USAF in 1997. The AV-9 accomplished its first flight on January 24, 1994. 509ème BW will be divided into two squadrons, the 393ème and 750ème BS. Each one of them will be operational with eight B-2 into 1996/97. The two AV-8 and AV-9 are approved apparatuses Block 10, including/understanding many improvements of furtivity resulting from the test routine. They will be then modified to be definitively approved Block 30 (see the Options of armament, below), when the fleet supplements is operational in 1997.
B-2 misses vertical surfaces for the marks of identification. Consequently, the trap doors of the principal train now carry the code of the base, the job number FY and at least 88-0329 the legends ' Spirit of Missouri' (Spirit of Missouri) and ' Follow Us' (Follow us).
Options of armament
B-2 is built around two large compartments of armament placed coast at coast in the lower part of its centre section. In front of each bay, small spoilers drop to produce swirls guaranteeing a good separation of the weapons during the dropping. Rotary launchers in the two compartments can receive a theoretical load of 34 020 kg, but according to the American regulation of the war (STOP, ' Individual Integrated Operational Plan'), no nuclear load must exceed 9072 kg. If B-2 is able to carry 80 Mk82 bombs of 227 kg, it is too invaluable to be used as truck with bombs. In a conventional role, its capacity to fire 16 weapons from precision on a zone extended on the only one way with an accuracy of 10 m remains its principal advantage. The five prototypes intended for I' USAF and the AV-7, -8 and -9 were put at the standard Block 10. They can thus transport 16 nuclear bombs "smooth" B83, or 16 conventional bombs Mk84 908 kg. For the strategic missions with armament drawn remotely from safety, B-2 can carry 16 cruise missiles AGM-69 SRAM II or AGM-129A. The intermediate standard Block 20 will add to him a nuclear capacity with B61 (16 to the maximum) or to 36 conventional weapons CBU-87, -89, -97 and -98 as well as a capacity limited in guided armaments of precision (PGM) conventional since 1997. This still implies the addition of two new weapons under development. The first of them is the furtive cruise missile and subsonic AGM-137 TSSAM (missile of remote attack tri-service), having of a range of 600 km and a payload of submunitions for infra-red and acoustic guidance. Eight missiles AGM-137 could be taken along, that is to say four per rotary launcher. The second new weapon is consisted of the kit with guidance GPS (JDAM). Gone up on bombs Mk82, Mk84 or BLU-109, kit JDAM allow a guidance of high precision of the weapon thanks to the system of navigation of the plane and a system of inertial navigation (SNI) embarked. Finally, it will be an autonomous weapon, any time, equipped with a programmable detonator. The two B-2 last of series will be completely put at the standard Block 30. They will have the capacity with the guided armaments of precision (PGM), in more than one load of 80 Mk82 bombs of 227 kg, or 36 bombs with guidance of Mk117 precision of 340 kg or 80 air mines Mk62. B-2 Block 30 will be equipped with the operational and offensive systems complete and a radar with synthetic opening sophisticated.