NORTHROP GRUMMAN B-2 'Spirit'

TYPE:

• Low-observable "stealth" strategic penetration bomber and missle-launch platform

PROGRAMME:

• Development of high-level bomber started in 1978 with contract placed by the USAF Aeronautical Systems Division in October 1981.
• This new aircraft evolved into a medium/high-altitude penetration at subsonic speed, relying on stealth design and composite structure to evade detection until it has closed to within a few miles of its target
• The KC-135 was a testbed for B-2 avionics flying at Edwards AFB since January 1987.
• Six B-2s were assigned to trials, all but the first were be refurbished for operational service.
• Two static airframes were also funded and during the structural test, the airframe exceeded ultimate (150 per cent) load test before fracturing at 161 per cent in December 1992.
• By 1995, durability test on the airframe had completed its second simulated lifetime of 20,000 hours/30 years.
• Overall, 4,000 hours of test programme was planned, of which 26 per cent was concerned with low observables (LO). Testing ended in 1997.
• The B-2 is the most expensive aircraft ever, costing $865 million (US) per aircraft.
• USAF originally wanted 133, but only 20 was funded.

DESIGN FEATURES:

• The whole aircraft is the design of the relaxed-stability type, a flying wing with straight leading-edges swept at 40° with a W-shaped trailing edges.
• Emphasis was placed on smooth surfaces with blended flight deck and nacelle bulges.
• Use of radiation-absorbant materials to minimize reflectivity.
• 'Double-W' trailing-edge incorporating elevons and drag rudders outboard of engines.
• Two side by side weapons bays in lower centrebody each have small, drop-down spoiler panels ahead of doors to generate vortexes, ensuring a clean weapons release.
• Engines are fed by S-shaped air ducts, with 3-pointed splitter plates ahead of inlets which remove boundary layer and provide secondary air flow for cooling and IR emissions control.
• These 2D nozzles reduce thermal and acoustic signatures.
• Two V-shaped overwing exhausts set well forward of trailing-edge.
• Titanium on wing surface behind engine outlet, wingtips and leading-edges have dielectric covering of aerofoil section to mask radar-dissipating with a sawtooth construction.
• The main APQ-181 radar, similar to the APG-10 in F-15C/D/E, is a synthetic-aperture type and has 21 operational modes, including coherent mapping.
• A total of 80,000 hours of testing was done on the B-2's components.
• These include 24,000 hours in the wind tunnel, 44,000 hours of avionics testing and 6,000 hours of full-scale 'plastic bird' control system tests.
• Flight testing of the B-2 to total 4,000 hours with six aircraft.
• The prototype is built on production tooling to an accuracy of +/-6.3 mm from tip to tip.
• Developement of the B-2 required nearly 900 new materials and processes to be invented, including over 4,000 subcontractors throughout the USA.

POWER PLANT:

• Four 8618 kg (17,300 lb) General Electric F118-GE-100 non-afterburning, dry thrust turbofans mounted in pairs within wing structure.
• Total thrust of 34,472 kg (76 000 lb, 169 kN)
• In-flight refuelling receptacle in centrebody spine.

ACCOMMODATION:

• Two crew members, with upward-firing ejection seats: pilot to port, mission commander/instructor pilot to starboard.
• Provision for third member behind commander.
• Both forward positions have conventional control columns.
• Flight, engine, sensor and systems information presented on nine-tube EFIS display.

ARMAMENT:

• Boeing rotary launcher assembly (RLA) in each of two side by side weapons bays in lower centrebody, each detachable for loading at weapons dump with up to eight large stores each.
• The total capacity of of the RLA include 16 AGM-129 ACMs.
• Alternative weapons include:
• 16 B61 tactical/strategic or 16 B83 strategic free-fall nuclear bombs
• 80 Mk 82 500 lb bombs
• 16 Joint Direct Attack Munitions
• 16 Mk 84 2,000 lb bombs
• 36 M117 750 lb fire bombs
• 36 CBU-87/89/97/98 cluster bombs
• 80 Mk 36 560 lb or Mk 62 sea mines
• Stores of 1,000 lb and below held in four (two per weapons bay) bomb rack assemblies (BRA)