It’s a bird? It’s a plane? It’s a moth? No,
no, no! It is a Northrop Grumman B-2 Spirit bomber! For the Weapon of The
Fortnight, I will blog about a bomber with some information from Wikipedia. I read about it from the
2011 Military Intervention in Libya.
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A USAF B-2 Spirit in flight
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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 the
reasons for his cancellation of the 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).
Total procurement costs averaged $929 million per aircraft, which includes
spare parts, equipment, retrofitting, and software support. The total program
cost including development, engineering and testing, averaged $2.1 billion per
aircraft in 1997.
Because of its
considerable capital and operational 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 initial 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. A
total of 20 B-2s remain in service with the United States Air Force.
Though originally
designed primarily as a nuclear bomber, the B-2 was first used in combat to drop
conventional bombs on Serbia during the Kosovo War in 1998, and saw continued
use during the wars in Iraq and Afghanistan. B-2s were also used during the
2011 Libyan civil war.
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The
B-2's first public display in 1988
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Development
Origins:
In the mid-1970s
the search for a new US strategic bomber to replace the Boeing B-52
Stratofortress was underway, to no avail. First the B-70 and then the B-1A were
canceled after only a few of each aircraft were built. The B-70 was intended to
fly above and beyond defensive interceptor aircraft, only to find these same
attributes made it especially vulnerable to surface-to-air missiles (SAMs). The
B-1 attempted to avoid SAMs by flying close to the ground to use terrain to
mask its radar signature, only to face a new generation of interceptors with
look-down/shoot-down capabilities that could attack them from above.
By the mid-1970s,
it was becoming clear that there was a different way to avoid missiles and intercepts;
known today as "stealth"; the concept was to build an aircraft with
an airframe that deflected or absorbed radar signals so that little was
reflected back to the radar unit. An aircraft having stealth characteristics
would be able to fly nearly undetected and could be attacked only by weapons
and systems not relying on radar. Although such possibilities existed such as
human observation, their relatively short detection range allowed most aircraft
to fly undetected by defenses, especially at night.
In 1974, DARPA
requested information from US aviation firms about the largest radar
cross-section of an aircraft that would remain effectively invisible to radars.
Initially, Northrop and McDonnell Douglas were selected for further
development. Lockheed had experience in this field due to developing the
Lockheed A-12 and SR-71, which included a number of stealthy features, notably
its canted vertical stabilizers, the use of composite materials in key
locations, and the overall surface finish in radar-absorbing paint. A key
improvement was the introduction of computer models used to predict the radar
reflections from flat surfaces where collected data drove the design of a
"faceted" aircraft. Development of the first such designs started in
1975 with "the hopeless diamond", a model Lockheed built to test the
concept.
Plans were well
advanced by the summer of 1975, when DARPA started the Experimental
Survivability Testbed (XST) project. Northrop and Lockheed were awarded
contracts in the first round of testing. Lockheed received the sole award for
the second test round in April 1976 leading to the Have Blue program.
ATB program:
By 1976 these
programs progressed to where a long-range strategic stealth bomber appeared
viable. Whereas the B-1 relied on flying around known defense sites and could
only change its mission within a limited selection of pre-determined routes, a
stealth bomber could fly over the Soviet Union undetected, allowing it to
linger and hunt for targets rather than repeatedly entering and leaving the
target zone as quickly as possible. In a nuclear exchange, this strategy
permits the aircraft to wait out the initial attacks and find targets that
escaped destruction by eliminating the "overkill" that was built into
existing war planning. Also, stealth characteristics negated prior requirements
for high speed dash capabilities and extensive electronic warfare suites for
protection.
Carter was aware
of these developments during 1977, and it appears to have been one of the major
reasons the B-1 was cancelled. Further studies were ordered in early 1978, by
which point the Have Blue platform had flown and proven the concepts. During
the 1980 presidential election in 1979, Ronald Reagan repeatedly stated that
Carter was weak on defense, and used the B-1 as a prime example. In return, on
22 August 1980, the Carter administration publicly disclosed that the United
States Department of Defense (DoD) was working to develop stealth aircraft, including a
bomber.
The Advanced
Technology Bomber (ATB) began in 1979. Full development of the black project
followed, and was funded under the code name "Aurora". After the
evaluations of the companies' proposals, the ATB competition was narrowed to
the Northrop/Boeing and Lockheed/Rockwell teams with each receiving a study
contract for further work. Both teams used flying wing designs. Northrop had
prior experience developing the YB-35 and YB-49 flying wing aircraft. The
Northrop design was larger while the Lockheed design included a small tail.
The
Northrop/Boeing team's ATB design was selected over the Lockheed/Rockwell
design on 20 October 1981. The Northrop design received the designation B-2 and
the name "Spirit". The bomber's design was changed in the mid-1980s
when the mission profile was changed from high-altitude to low-altitude, terrain-following.
The redesign delayed the B-2's first flight by two years and added about US$1
billion to the program's cost. An estimated US$23 billion was secretly spent
for research and development on the B-2 by 1989. MIT scientists helped assess
the mission effectiveness of the aircraft under a five-year classified contract
during the 1980s.
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The B-2's
first public flight in 1989
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Secrecy and espionage:
The B-2's first
public flight in 1989 Both during development and in service, there has been
considerable importance placed to the security of the B-2 and its technologies.
Staff working on the B-2 in most, if not all, capacities have to achieve a level
of special-access clearance, and undergo extensive background checks carried
out by a special branch of the Air Force.
For the
manufacturing, a former car plant in Pico Rivera, California was acquired and
heavily rebuilt; the plant's employees were sworn to complete secrecy regarding
their work. To avoid the possibility of suspicion, components were typically
purchased through front companies, military officials would visit out of
uniform, and staff members were routinely subjected to polygraph examinations.
The secrecy extended so far that access to nearly all information on the
program by both Government Accountability Office (GAO) and virtually all
members of Congress itself was severely limited until mid-1980s.
In 1984, a
Northrop employee, Thomas Cavanaugh was arrested for attempting to sell
classified information to the Soviet Union; the information was taken from
Northrop's Pico Rivera, California factory. Cavanaugh was eventually sentenced
to life in prison and released on parole in 2001.
The B-2 was first
publicly displayed on 22 November 1988 at Air Force Plant 42, Palmdale,
California, where it was assembled. This viewing was heavily restricted, guests
were not allowed to see the rear of the B-2. However, Aviation Week editors
found that there were no airspace restrictions over the presentation area and
took photographs of the aircraft's then-secret planform and suppressed engine
exhausts from above, to the USAF's disappointment. The B-2's first public
flight was on 17 July 1989 from Palmdale.
In October 2005
Noshir Gowadia, a design engineer who worked on the B-2's propulsion system,
was arrested for selling B-2 related classified information to foreign
countries. On 9 August 2010 Gowadia was convicted in the United States District
Court for the District of Hawaii on 14 of 17 charges against him. On 24 January
2011, Gowadia was sentenced to 32 years in prison.
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B-2
from below
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Further developments:
A number of
upgrade packages have been applied to the B-2. In July 2008, the B-2's onboard
computing architecture was extensively redesigned, it now incorporates a new
integrated processing unit (IPU) that communicates with systems throughout the
aircraft via a newly-installed fibre optic network; a new version of the
operational flight program software was also developed, legacy code was
converted from the JOVIAL programming language used beforehand to C. Updates
were also made to the weapon control systems to enable strikes upon non-static targets,
such as moving ground vehicles.
On 29 December 2008, Air Force officials
awarded a US$468 million contract to Northrop Grumman to modernize the B-2
fleet's radars. Changing the radar's frequency was required as the US
Department of Commerce has sold that radio spectrum to another operator. In
July 2009, it was reported that the B-2 had successfully passed a major USAF
audit. In 2010, it was made public that the Air Force Research Laboratory had
developed a new material to be used on the part of the wing trailing edge
subject to engine exhaust, replacing existing material that quickly degraded.
In July 2010,
political analyst Rebecca Grant speculated that when the B-2 becomes unable to
reliably penetrate enemy defenses, the Lockheed Martin F-35 Lightning II may
take on its strike/interdiction mission, carrying B61 nuclear bomb as a
tactical bomber. However, in March 2012, the Pentagon announced a $2 billion,
10 year-long modernization of the B-2 fleet was to begin, these upgrades would
be mainly focused on replacing outdated avionics and equipment.
It was reported in
2011 that the Pentagon was evaluating an unmanned stealth bomber, characterized
as a "mini-B-2", as a potential replacement in the near future. In
2012, Air Force Chief of Staff General Norton Schwartz stated the B-2's
1980s-era stealth would make it less survivable in future contested airspaces,
so the USAF is to proceed with the Next-Generation Bomber despite overall
budget cuts. The Next-Generation Bomber was estimated, in 2012, to have an
projected overall cost of $55 billion.
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Side
view of a B-2 Spirit
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Design
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. The B-2 is a flying wing aircraft, meaning it has no fuselage or tail.
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).
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. Northrop Grumman is the B-2's prime contractor; other
contributing subcontractors include Boeing, Raytheon (formerly Hughes
Aircraft), G.E. and Vought Aircraft. The B-2 bears a resemblance to earlier
Northrop aircraft, the YB-35 and YB-49 were both flying wing bombers that had
been cancelled in development in the early 1950s; allegedly for political
reasons.
The B-2 has a crew of two: a pilot in the left seat, and mission
commander in the right; the B-2 has provisions for a third crew member if
needed. For comparison, the B-1B has a crew of four and the B-52 has a crew of
five. The B-2 is highly automated and, unlike most two-seat aircraft, one crew
member can sleep, 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.
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A
2000 lb BDU-56 bomb is being loaded onto a bomb bay's rotary launcher, 2004
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Armaments and equipment:
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.
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. Nuclear
ordnance includes the B61 and B83 nuclear bombs; the AGM-129 ACM cruise missile
was also intended for use on the B-2 platform.
It was decided, in light of the dissolution
of the Soviet Union, to equip the B-2 for convention precision attacks as well
as for the strategic role of nuclear-strike. The B-2 features a sophisticated
GPS-Aided Targeting System (GATS) that uses the aircraft's APQ-181 synthetic
aperture radar to map out targets prior to deployment of GPS-aided bombs (GAMs),
later superseded by the Joint Direct Attack Munition (JDAM). In the B-2's
original configuration, up to 16 GAMs or JDAMs could be deployed; an upgrade
program in 2004 raised the maximum carriable capacity to 80 JDAMs.
The B-2 has various conventional weapons in
its arsenal, able to equip Mark 82 and Mark 84 bombs, CBU-87 Combined Effects
Munitions, GATOR mines, and the CBU-97 Sensor Fuzed Weapon. In July 2009,
Northrop Grumman reported the B-2 was compatible with the equipment necessary
to deploy the 30,000 lb (14,000 kg) Massive Ordnance Penetrator
(MOP), which is intended to attack reinforced bunkers; up to two MOPs could be
equipped in the B-2's bomb bays, the B-2 is the only platform compatible with
the MOP as of 2012. As of 2011, the AGM-158 JASSM cruise missile is an upcoming
standoff munition to be deployed on the B-2 and other platforms.
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An
Air Force maintenance crew services a B-2 at Andersen AFB, Guam, 2004
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Avionics and systems:
In order to make the B-2 more effective than
any previous bomber, it has integrated many advanced and modern avionics
systems into its design, these have been modified and improved in light of the
switch to conventional warfare missions. The B-2 features the low probability
of intercept AN/APQ-181 multi-mode radar, a fully digital navigation system
that is integrated with terrain-following radar and Global Positioning System
(GPS) guidance, and a Defensive Management System (DMS) to inform the flight
crew against possible threats. The onboard DMS is capable of automatically
assessing the detection capabilities of identified threats and indicated
targets.
For safety and fault-detection purposes, an
on-board test system is interlinked with the majority of avionics on the B-2 to
continuously monitor the performance and status of thousands of components and
consumables; it also provides post-mission servicing instructions for ground
crews. In 2008, many of the standalone distributed computers on board the B-2,
including the primary flight management computer, were being replaced by a
single integrated system.
In addition to periodic software upgrades and
the introduction of new radar-absorbent materials across the fleet, the B-2 has
had several major upgrades to its avionics and combat systems. For battlefield
communications, both Link-16 and a high frequency satellite link have been
installed, compatibility with various new munitions has been undertaken, and
the AN/APQ-181 radar's operational frequency was shifted in order to avoid
interference with other operator's equipment. The upgraded radar features
entirely replaced arrays by those of a newer design, the AN/APQ-181 is now an Active
Electronically Scanned Array (AESA) radar.
Flight controls:
In order to address the inherent flight
instability of a flying wing aircraft, the B-2 uses a complex quadruplex
computer-controlled fly-by-wire flight control system, that can automatically
manipulate flight surfaces and settings without direct pilot inputs in order to
maintain aircraft stability. The flight computer receives information on
external conditions such as the aircraft's current air speed and angle of
attack via pitot-static sensing plates, as opposed to traditional pitot tubes
which would negatively affect the aircraft's stealth capabilities. The flight
actuation system incorporates both hydraulic and electrical servoactuated
components, it was designed with a high level of redundancy and
fault-diagnostic capabilities.
Northrop had investigated several means of
applying directional control that would least infringe on the aircraft's radar
profile, eventually settling on a combination of split brake-rudders and
differential thrust. Engine thrust became a key element of the B-2's
aerodynamic design process early on; thrust not only affects drag and lift but
pitching and rolling motions as well. Four pairs of control surfaces are
located along the wing's trailing edge; while most surfaces are used throughout
the aircraft's flight envelope, the inner elevons are normally only in use at
slow speeds, such as landing. To avoid potential contact damage during takeoff
and to provide a nose-down pitching attitude, all of the elevons remain drooped
during takeoff until a high enough airspeed has been attained.
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The B-2's engines are buried within its wing
to conceal the engines' fans and minimize their exhaust signature.
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Stealth:
The B-2's low-observable, or
"stealth", characteristics enable the safe penetration of
sophisticated anti-aircraft defenses and to attack even heavily defended
targets. This stealth comes from a combination of reduced acoustic, infrared,
visual and radar signatures to evade the various detection systems that could
be used to detect and be used to direct attacks against an aircraft. The
majority of the B-2 is made out of a carbon-graphite composite material that is
stronger than steel and lighter than aluminium, perhaps most crucially it also
absorbs a significant amount of radar energy. Reportedly, the B-2 Spirit has a
radar signature of about 0.1 m2
In contrast to the flat surfaces of the
earlier F-117 Nighthawk, the B-2 is composed of many curved and rounded
surfaces across its exposed airframe to deflect radar beams, additional
reduction in its radar signature was achieved by the use of various radar-absorbent
materials (RAM) to absorb and neutralise radar beams. The B-2's clean, low-drag
flying wing configuration not only gave it exceptional range, but was also
beneficial to reducing its radar profile as well.
Another design feature is the placement of
the engines, which are buried within the wing to conceal the engines' fans and
minimize thermal visibility of the exhaust. The original design had tanks for a
contrail-inhibiting chemical, but this was replaced in production aircraft by a
contrail sensor that alerts the crew as to when they should change altitude. To
reduce optical visibility during daylight operations, the B-2 is painted in an
anti-reflective paint.
Innovations such as alternate high-frequency
material (AHFM) and automated material application methods were also
incorporated into the aircraft to enhance its radar-absorbent properties and
lower maintenance requirements. In early 2004, Northrop Grumman began applying
a newly-developed AHFM to operational B-2s. In order to protect the operational
integrity of its sophisticated radar absorbent material and coatings, each B-2
is kept inside a climate-controlled hangar large enough to accommodate its
172-foot (52 m) wingspan.
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| A B-2 during aerial refueling which extends its range past 6,000 nautical miles (6,900 mi; 11,000 km) for intercontinental sorties |
Operational history
The first
operational aircraft, christened Spirit of Missouri, was delivered to Whiteman
Air Force Base, Missouri, where the fleet is based, on 17 December 1993. The
B-2 reached initial operational capability (IOC) on 1 January 1997. Depot
maintenance for the B-2 is accomplished by U.S. Air Force contractor support
and managed at Oklahoma City Air Logistics Center at Tinker Air Force Base.
Originally designed to deliver nuclear weapons, modern usage has shifted towards
a flexible role with conventional and nuclear capability.
The B-2's combat debut was in 1999, during
the Kosovo War. It was responsible for destroying 33% of selected Serbian
bombing targets in the first eight weeks of U.S. involvement in the War. During
this war, B-2s flew non-stop to Kosovo from their home base in Missouri and
back. The B-2 was the first aircraft to deploy GPS satellite-guided JDAM
"smart bombs" in combat use in Kosovo. The use of JDAMs and
precision-guided munitions effectively replaced the controversial tactic of
carpet-bombing, which had been harshly criticised due to it causing
indiscriminate civilian casualties in prior conflicts, such as the 1991 Gulf War.
On 7 May 1999, a B-2 accidentally deployed five JDAMs in a target building that
was actually the Chinese Embassy, killing several staff.
The B-2 saw service in Afghanistan, striking
ground targets in support of Operation Enduring Freedom. With aerial refueling
support, the B-2 flew one of its longest missions to date from Whiteman Air
Force Base, Missouri to Afghanistan and back.
The B-2's combat use preceded a U.S. Air
Force declaration of "full operational capability" in December 2003.
The Pentagon's Operational Test and Evaluation 2003 Annual Report noted that
the B-2's serviceability for Fiscal Year 2003 was still inadequate, mainly due
to the maintainability of the B-2's low observable coatings. The evaluation
also noted that the Defensive Avionics suite also had shortcomings with
"pop-up threats".
During the Iraq War (Operation Iraqi
Freedom), B-2s operated from Diego Garcia and an undisclosed "forward
operating location". Other sorties in Iraq have launched from Whiteman AFB.
This resulted in missions lasting over 30 hours and one mission of over 50
hours. "Forward operating locations" have been previously designated
as Andersen Air Force Base in Guam and RAF Fairford in the UK, where new
climate controlled hangars have been constructed. B-2s have conducted 27 sorties
from Whiteman AFB and 22 sorties from a forward operating location, releasing
more than 1.5 million pounds of munitions, including 583 JDAM "smart
bombs" in 2003.
In response to organisational issues and
high-profile mistakes made within the Air Force; all of the B-2s, along with
the nuclear-capable B-52s, and the Air Force's intercontinental ballistic
missiles (ICBMs) were transferred to the newly-formed Air Force Global Strike
Command on 1 February 2010.
In March 2011, B-2s were the first US
aircraft into action in Operation Odyssey Dawn, the UN mandated enforcement of
the Libyan no-fly zone. Three B-2s dropped 40 bombs on a Libyan airfield in
support of the UN no-fly zone. The B-2s flew directly from the US mainland,
being refuelled by allied tanker aircraft twice on the inbound journey and
twice again on the way back across the Atlantic.
In August 2011, The New Yorker reported that
prior to the May 2011 US special forces raid into Abbottabad, Pakistan that
resulted in the Death of Osama bin Laden, US officials had considered an
airstrike by one or more B-2s as an alternative; an airstrike was rejected due
to concerns of damage to surrounding civilian buildings.
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In a 1994 live fire exercise near Point Mugu,
California, a B-2 drops 47 500 lb (230 kg) class Mark 82 bombs, which
is more than half of a B-2's total ordnance payload
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Operators
B-2s are operated exclusively by the United States Air Force active units. It has 20 B-2s in service.- United States Air Force
- 509th Bomb Wing, Whiteman Air Force Base (currently has 19 B-2s)
- 13th Bomb Squadron
- 393d Bomb Squadron
- 394th Combat Training Squadron
- 131st Bomb Wing, Whiteman Air Force Base (Missouri Air National Guard)
- 110th Bomb Squadron
- 412th Test Wing, Edwards Air Force Base (currently has one B-2)
- 419th Flight Test Squadron
- 53d Wing, Eglin Air Force Base (former)
- 72d Test and Evaluation Squadron, Whiteman Air Force Base
- 57th Wing, Nellis Air Force Base (former)
- 325th Weapons Squadron, Whiteman Air Force Base
- 715th Weapons Squadron (inactivated)
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Specifications (B-2A Block 30)
Data
from USAF Fact Sheet,
Pace, Spick
General characteristics- Crew: 2
- Length: 69 ft (21.0 m)
- Wingspan: 172 ft (52.4 m)
- Height: 17 ft (5.18 m)
- Wing area: 5,140 ft² (478 m²)
- Empty weight: 158,000 lb (71,700 kg)
- Loaded weight: 336,500 lb (152,200 kg)
- Max. takeoff weight: 376,000 lb (170,600 kg)
- Powerplant: 4 × General Electric F118-GE-100 non-afterburning turbofans, 17,300 lbf (77 kN) each
- Fuel Capacity: 167,000 pounds (75,750 kg)
- Maximum speed: Mach 0.95 (550 knots, 630 mph, 1,010 km/h) at 40,000 ft altitude / Mach 0.95 at sea level
- Cruise speed: Mach 0.85 (487 knots, 560 mph, 900 km/h) at 40,000 ft altitude
- Range: 6,000 nmi (11,100 km (6,900 mi))
- Service ceiling: 50,000 ft (15,200 m)
- Wing loading: 67.3 lb/ft² (329 kg/m²)
- Thrust/weight: 0.205
- 2 internal bays for 50,000 lb (23,000 kg) of ordnance.
- 80× 500 lb class bombs (Mk-82) mounted on Bomb Rack Assembly (BRA)
- 36× 750 lb CBU class bombs on BRA
- 16× 2000 lb class weapons (Mk-84, JDAM-84, JDAM-109) mounted on Rotary Launcher Assembly (RLA)
- 16× B61 or B83 nuclear weapons on RLA
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A
B-2 in formation flight with 8 US Navy McDonnell Douglas F/A-18 Hornets
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