The B-1 has a blended wing body configuration, with
variable-sweep wing, four turbofan engines, and triangular fin control
surfaces. The wings can sweep from 15 degrees to 67.5 degrees (full forward to
full sweep). Forward-swept wing settings are used for takeoff, landings and
high-altitude maximum cruise. Aft-swept wing settings are used in high subsonic
and supersonic flight. The wings of the B-1B originally were cleared for use at
settings of 15, 25, 55 and 67.5 degrees. The 45-degree setting was later
cleared in 1998–99 timeframe. The B-1's variable-sweep wings and
thrust-to-weight ratio provide it with better takeoff performance, allowing it
to use more runways than previous bombers. The length of the aircraft presented
a flexing problem due to air turbulence at low altitude. To alleviate this,
Rockwell included small triangular fin control surfaces or vanes near the nose
on the B-1. The B-1's Structural Mode Control System rotates the vanes
automatically to counteract turbulence and smooth out the ride.
Unlike the B-1A, the B-1B made no attempt at Mach 2+
speeds. Its maximum speed is Mach 1.25 (about 950 mph or 1,530 km/h at
altitude), but its low-level speed increased to Mach 0.92 (700 mph, 1,130
km/h). Technically, the current version of the aircraft can exceed its speed
restriction, but not without risking potential damage to its structure and air
intakes. To help lower its radar cross section (RCS), the B-1B uses serpentine
air intake ducts and fixed intake ramps, which limit its speed compared to the
B-1A. Vanes in the intake ducts serve to deflect and shield radar emissions
from the highly reflective engine compressor blades. The B-1A's engine was
modified slightly to produce the GE F101-102 for the B-1B, with an emphasis on
durability, and increased efficiency. The core of this engine has since been
re-used in several other engine designs, including the GE F110 which has seen
use in the F-14 Tomcat, F-15K/SG variants and most recent versions of the
General Dynamics F-16 Fighting Falcon. It is also the basis for the
non-afterburning GE F118 used in the B-2 Spirit and the U-2S. However its
greatest success was forming the core of the extremely popular CFM56 civil
engine, which can be found on some versions of practically every
small-to-medium sized airliner. The nose gear cover door has controls for the
auxiliary power units (APUs), which allow for quick starts of the APUs upon
order to scramble.
The B-1's main computer is the IBM AP-101, which is also
used on the Space Shuttle orbiter and the B-52 bomber. The computer is
programmed with the JOVIAL programming language. The Lancer's offensive
avionics include the Westinghouse (now Northrop Grumman) AN/APQ-164
forward-looking offensive passive electronically scanned array radar set with
electronic beam steering (and a fixed antenna pointed downward for reduced
radar observability), synthetic aperture radar, ground moving target indicator
(MTI), and terrain-following radar modes, Doppler navigation, radar altimeter,
and an inertial navigation suite. The B-1B Block D upgrade added a Global
Positioning System (GPS) receiver beginning in 1995. The B-1's defensive
electronics include the Eaton AN/ALQ-161A radar warning and defensive jamming
equipment, which has three sets of antennas; one at the front base of each wing
and the third rear-facing in the tail radome. The ALQ-161 is linked to a total
of eight AN/ALE-49 flare dispensers located on top behind the canopy, which are
handled by the AN/ASQ-184 avionics management system. Each AN/ALE-49 dispenser
has a capacity of 12 MJU-23A/B flares. The MJU-23A/B flare is one of the
world's largest infrared countermeasure flares at a weight of over 3.3 pounds
(1.5 kg). The B-1 has also been equipped to carry the ALE-50 Towed Decoy System.
Also aiding the B-1's survivability is its relatively low radar cross-section
(RCS). Although not technically a stealth aircraft in a comprehensive sense,
thanks to the aircraft's structure, serpentine intake paths and use of
radar-absorbent material its RCS is about 1/50th that of the B-52 (probably
about 26 ft² or 2.4 m²), although the Lancer is not substantially smaller in
mass than the Stratofortress.
Strategic Air Command
The second B-1B, "The Star of Abilene", was the
first B-1B delivered to the USAF Strategic Air Command (SAC) in June 1985.
Initial operational capability was reached on 1 October 1986 and the B-1B was
placed on nuclear alert status. The B-1 received the official name
"Lancer" on 15 March 1990. However, the bomber has been commonly
called the "Bone"; a nickname that appears to stem from an early
newspaper article on the aircraft wherein its name was phonetically spelled out
as "B-ONE" with the hyphen inadvertently omitted.
In late 1990 engine fires in two Lancers caused the
grounding of the fleet. The cause was traced back to problems in the
first-stage fan, the aircraft were placed on "limited alert"; in
other words, they were grounded unless a nuclear war broke out. Following
inspections and repairs they were returned to duty beginning on 6 February
1991. Due to the engine problems, the B-1B was effectively sidelined in the
First Gulf War. Originally designed strictly for nuclear war, the B-1's
development as an effective conventional bomber was delayed until the 1990s.
The collapse of the Soviet Union had brought the B-1's nuclear role into
question, leading to President George H. W. Bush ordering a $3 billion
conventional refit. By 1991, the B-1 had a fledgling conventional capability,
forty of them able to drop the 500 lb (230 kg) Mk-82 General Purpose (GP) bomb,
although mostly from low altitude. Despite being cleared for this role, the
problems with the engines precluded their use in Operation Desert Storm. B-1s
were primarily reserved for strategic nuclear strike missions at this time,
providing the role of airborne nuclear deterrent against the Soviet Union. The
B-52 was more suited to the role of conventional warfare and it was used by
coalition forces instead. After the de-activation of Strategic Air Command
(SAC) and the establishment of the Air Combat Command (ACC) in 1992, the B-1
developed a greater conventional weapons capability. Part of this development
was the start-up of the US Air Force Weapons School B-1 Division. In 1994, two
additional B-1 bomb wings were also created in the Air National Guard, with
former fighter wings in the Kansas Air National Guard and the Georgia Air
National Guard converting to the aircraft. By the mid-1990s, the B-1 could
employ GP weapons as well as various CBUs. By the end of the 1990s, with the
advent of the "Block D" upgrade, the B-1 boasted a full array of
guided and unguided munitions. The B-1B no longer carries nuclear weapons; its
nuclear capability was disabled by 1995 with the removal of nuclear arming and
fuzing hardware.
Conventional Role
Operationally, the B-1 was first used in combat in support
of operations against Iraq, during Operation Desert Fox in December 1998,
employing unguided GP weapons. B-1s have been subsequently used in Operation
Allied Force (Kosovo) and, most notably, in Operation Enduring Freedom in
Afghanistan and the 2003 invasion of Iraq. The B-1's role in Operation Allied
Force has been criticized as the aircraft was not used until after enemy
defenses had been suppressed by aircraft like the older B-52 it was intended to
replace. The B-1 has deployed an array of conventional weapons in war zones,
most notably the GBU-31, 2,000 lb (900 kg) Joint Direct Attack Munition (JDAM).
JDAM munitions were heavily used by the B-1 over Iraq, notably on 7 April 2003
in an unsuccessful attempt to kill Saddam Hussein and his two sons. At the
height of the Iraq War, a B-1 was permanently airborne to provide rapid
precision bombardment upon important targets as intelligence identified them.
During Operation Enduring Freedom, the B-1 was able to raise its mission
capable rate to 79%.
The B-1 has higher survivability and speed when compared to
the older B-52, which it was intended to replace. It also holds 61 FAI world
records for speed, payload, distance, and time-to-climb in different aircraft
weight classes. In November 1983, three B-1Bs set a long distance record for
the aircraft, which demonstrated its ability to conduct extended mission
lengths to strike anywhere in the world and return back to base without any
stops. The National Aeronautic Association recognized the B-1B for completing
one of the 10 most memorable record flights for 1994. Of the 100 B-1Bs built,
93 remained in 2000 after losses in accidents. In June 2001, the Pentagon
sought to place a third of its then fleet of 93 into reserve; this proposal
resulted in several Air National Guard officers and members of Congress
lobbying against the proposal, including the drafting of an amendment to
prevent such cuts. The 2001 proposal was intended to allow money to be diverted
to further upgrades to the remaining B-1Bs, such as computer modernization. In
2003, accompanied by the removal of B-1Bs from the two bomb wings in the Air
National Guard, the USAF decided to retire 33 aircraft to concentrate its budget
on maintaining availability of remaining B-1Bs. In 2004 a new appropriation
bill called for some of the retired aircraft to return to service, and the USAF
returned seven mothballed bombers to service to increase the fleet to 67
aircraft.
On 14 July 2007, the Associated Press reported on the
growing USAF presence in Iraq as a result of "surge" in forces. Also
mentioned is the reintroduction of B-1Bs to be a close-at-hand
"platform" to support Coalition ground forces. B-1s have been used in
Iraq and Afghanistan. Since 2008 B-1s have been used there in an "armed
overwatch" role. They loiter over the region maintaining surveillance,
ready to deliver guided bombs in support of ground troops if contacted. The
B-1B underwent a series of flight tests using a 50/50 mix of synthetic and
petroleum fuel; on 19 March 2008, a B-1B from Dyess Air Force Base, Texas,
became the first US Air Force aircraft to fly at supersonic speed using a
synthetic fuel during a flight over Texas and New Mexico. This was conducted as
part of an ongoing Air Force testing and certification program to reduce
reliance on traditional oil sources. On 4 August 2008, a B-1B flew the first
Sniper Advanced Targeting Pod equipped combat sortie where the crew
successfully targeted enemy ground forces and dropped a GBU-38 guided bomb in
Afghanistan. The USAF had 65 B-1Bs in service in September 2010, split between
four squadrons organized into two Bomb Wings: the 7th Bomb Wing at Dyess AFB,
Texas, and the 28th Bomb Wing at Ellsworth AFB, South Dakota. In March 2011,
B-1Bs from Ellsworth Air Force Base attacked undisclosed targets in Libya as
part of Operation Odyssey Dawn. With upgrades to keep the B-1 viable, the Air
Force may keep the bomber in service until approximately 2038. Despite
upgrades, the B-1 has repair and cost issues resulting from its age. For every
flight hour it needs 48.4 hours of repair. The fuel, repairs and other needs
for a 12-hour mission costs $720,000 as of 2010. The $63,000 cost per flight
hour is, however, less than the $72,000 for the B-52 and the $135,000 of the
B-2. In June 2010, senior US Air Force officials met to consider retiring the
entire fleet to meet budget cuts. It is expected to be supplemented by the Next
Generation Bombers in the 2020s. And in the meantime its "capabilities are
particularly well-suited to the vast distances and unique challenges of the
Pacific region, and we'll continue to invest in, and rely on, the B-1 in
support of the focus on the Pacific" as part of President Obama's
"Pivot to East Asia".
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