Despite the cancellation of the B-1A project, the test flight program continued. The greatest effort was concentrated on improving the avionics, particularly the defensive system. General Electric continued to work on improving the F101 engines, and many other contractors kept their engineering teams in place. Work continued on the task of reducing the radar cross section of the aircraft.
The USAF was still interested in an aircraft that would replace the B-52, and several lines of research were carried out. One of these was the pursuit of technologies that would dramatically reduce the radar cross section of the aircraft, making it more difficult to detect by the enemy. These efforts involved changing the shape of aircraft to minimize reflectivity in the direction of the hostile radar, the coating the aircraft with radar absorbent material, and achieving a smooth, unbroken surface without cracks or joints. This work eventually evolved into a highly-classified program known as the Advanced Technology Bomber (ATB). However, the ATB was at best a long-term project and did little to provide the need for a new strategic aircraft in the short term.
Other approaches involved modifications of existing aircraft to produce a new strategic aircraft. These aircraft would carry a battery of air-launched cruise missiles (ALCMs) which were being increasingly studied as a means of penetrating sophisticated Soviet air defenses. The cruise missiles would be launched from locations well outside the enemy's most effective defenses and would rely on sophisticated guidance systems that would make it possible for them to fly quite low to the ground, effectively hiding them from enemy radars. The ALCMs that were proposed were the Boeing AGM-86B and the General Dynamics AGM-109 Tomahawk, both with a range of about 1500 miles.
General Dynamics proposed the FB-111B/C, which could be created by modifying existing FB-111As. It would carry a battery of ALCMs mounted externally underneath the wings along with extra fuel tanks. In 1979, Rockwell proposed a modified B-1A that would have a fixed wing swept back at 25 degrees, fixed air intake inlets, and a huge gap along the underside between crew cabin and tail. This gap could accommodate a variety of large assemblies, including a penetration package that could launch SRAMs, could carry extra fuel as well as a comprehensive suite of electronic warfare equipment, plus a strategic package that could carry ALCMs or conventional bombs. In addition, the aircraft could be configured as an aerial tanker.
In November of 1979, the Air Force began to show some interest in these projects, and began to study them under the project name of Long-Range Combat Aircraft (LRCA). The FB-111B/C was thought to be too small to carry very many of these ALCMs, and in any case they would all have to be carried externally, adversely affecting range and performance. The Rockwell approach attracted more favorable attention. During 1980, Rockwell refined its LRCA approach, and proposed a minimal-change version of the B-1A that would be capable of launching stand-off ALCMs. One of the major changes was the elimination of the Mach 2.0-plus dash capability by simplifying the engine inlets and overwing fairings. It would be optimized for penetration of sophisticated defenses by flying nap-of-the-earth penetrations at near supersonic speeds, avoiding enemy radars, interceptors, and missiles. Maximum penetration speed would be increased from Mach 0.85 to Mach 0.92. The aircraft would be strengthened in order to raise the maximum takeoff weight from 395,000 to 477,000 pounds. Much of this extra weight would be taken up by additional fuel and weapons. In addition, the elimination of the Mach 2.0 dash capability made it possible to eliminate the variable air intakes, which had the additional benefit of making it possible to configure them for minimal radar cross section. These changes, along with the use of radar absorptive material covering critical areas of the surface, would, it was hoped, make it possible to build an aircraft with only a tenth of the radar cross section of the B-1A. Maximum unrefueled range was to be increased from 6011 to 7455 miles.
From 1979 to 1981, several agencies had collaborated in a Bomber Penetration Evaluation (BPE) to determine how effective these options would be in penetrating Soviet air defenses. It was concluded that the ALCM-capable LRCA should be able to defeat any conceivable Soviet defense until at least the end of the century. On January 20, 1981, President Ronald Reagan took office after having defeated Jimmy Carter for re-election, and he promised a massive defense buildup to counter the Soviet "Evil Empire", as he put it. Suddenly, proposals for a new strategic bomber began to have a much more favorable reception
On June 1, 1981, the USAF decided that it would select the Rockwell LRCA as its new multi-role strategic bomber. On October 2, 1981, President Reagan announced a Strategic Modernization Program (SMP), a key feature of which would be the procurement of 100 LRCAs. The LRCA would be designated B-1B. Another (as yet secret) key part of the SMP would be the commencement of R&D work on the ATB, which would eventually emerge as the Northrop B-2 Spirit. The general public was not made aware of the fact that two strategic bombers were being prepared rather than just one.
On January 20, 1982, Rockwell received a contract for FSD work. There would be no B-1B prototype as such,
B-1As numbers 74-0159 and 76-0174 would be modified to support the B-1B development program.
Also included was a contract for the production of the
first batch of B-1Bs. Other contracts were placed for avionics. An attempt was made to keep
costs down so that the aircraft would remain uncontroversial and would not unduly attract the attention
of the news media. The aircraft was to have 85 percent commonality with the B-1A, and the
offensive avionics were to have 90 percent commonality with those of the B-52H.
As in the B-1A, the structural heart of the aircraft is the wing carry-through assembly. It is made almost entirely of 6AI-4V titanium alloy The fixed inboard wing glove is smoothly faired into the central fuselage. The large fairings are made almost of entirely of fiberglas. The inboard wing does not have a recognized aerofoil profile, and its highly swept leading edge is very blunt in order to accommodate a variety of antennae that make up the electronic countermeasures system. The inboard wing glove does generate a significant fraction of the total lift, and is especially important in flight at extreme angles of attack.
In the B-1A the opening into which the outer wing slid was sealed by a complicated set of doors which were individually raised during wing sweep and then lowered tightly against the wing. In the B-1B, the system redesigned to make it much simpler, with a hinged upper and fixed lower edge, both provided with an inflatable seal.
The outer variable-sweep portion of the wing has a minimum sweep of 15 degrees and a maximum sweep of 67 degrees. The outer wing is a two-spar structure made of conventional aluminum alloy. The interior of the wing is sealed so that it can act as a fuel tank. The inboard trailing edge of the wing is cut away to reduce stowage problems at maximum sweep, so at minimum sweep it is readily noticeable. There is a series of six separate Fowler flaps that occupy almost the entire trailing edge of the outer wing, extending from the edge of the inboard wing trailing edge cutout all the way to within 13 feet of the tip. Although each flap section has its own hydraulic drive, they are all mechanically linked so that they operate and move together. The leading edge of the wing has a series of seven slats which cover the entire length of each leading edge. On the upper surface of the wing, just head of the four outer flap sections, are a set of four sections of spoiler. Each spoiler panel has the same span and approximately the same chord as the flap section behind it. The wing spoilers work with the differential tailplanes to control the aircraft in roll, the inboard pair of spoilers on each wing being mechanically linked and the outer pair being FBW. The inboard pair of spoilers on each wing can also be used to act as speed brakes. In addition, all four spoilers on each wing can be opened to kill lift and slow the aircraft while it is on its landing roll.
The tail was identical to that of the B-1A, and was comprised of a single fixed vertical fin and left and right all-flying tailplanes. The tailplanes can move together for control in pitch or differentially for control in roll. The rudder is in three sections, with the upper and intermediate rudders controlling the aircraft in yaw, but with the lower section being controlled by automatic systems to damp out yaw motions in turbulent air. The upper and intermediate rudders are above the tailplane/fin fairing, the lower section below.
There is a small steerable vane on each side of the lower nose, just ahead of the cockpit
windshield. These vanes are part of the Structural Mode Control System (SMCS), which acts
to dampen out the effects of turbulence in dense, low-altitude air. A series of accelerometers
near the center of gravity and near the nose sense lateral and vertical accelerations and
send signals to the vanes and lower rudder to counter them
The B-1B is powered by four afterburning General Electric F101-GE-102 turbofans, each rated at 17,000 lb.s.t. dry and 30,780 lb.s.t. with afterburning. The turbofans have a bypass ratio of about 2, and are installed in twin-engine packages underneath the wingroots, which are spaced far enough apart so that the landing gear could fit between them. The exhausts of each engine have 12-petal variable nozzles fitted. Initially, the actuators for these variable nozzles were covered by "turkey feather" fairings, but most of these fairings have now been removed to save weight and reduce complexity.
Since there was no longer any requirement that the aircraft be able to exceed Mach 2, the variable
air intake inlets were no longer needed and it was possible to simplify them and to redesign
them to reduce the radar cross section. The inlets are fixed and are also inclined in side view.
Inside the inlet, there is an array of baffles that deflect incoming
radar signals and prevent them from reaching the highly-reflective blades of the turbofan engines.
Superficially, the airframe of the B-1B was almost identical to that of the 4th B-1A, but with a significantly strengthened structure so that it could accommodate takeoff weights up to 82,000 pounds heavier.
The nose gear has twin wheels which are hydraulically steerable. The nose gear retracts forward into a well in the forward part of the nose. The main landing gears are attached to the undersides of the fixed inner wing glove, just inboard of the engine nacelles. Each main landing gear member has twin tandem wheels, and they retract upwards into wells in the lower fuselage between the engine nacelles.
There are seven separate airframe fuel tanks, four in the main fuselage, one inside the wing carry-through box, and one in each of the outboard wing panels. A total of 29,755 US gallons of fuel can be carried in these tanks. In addition, each of the three weapons bays can carry a cylindrical drum tank. The B-1B is capable of being refueled in midair via a receptacle located immediately in front of the windscreen.
Like the B-1A, the B-1B has three internal weapons stores bays, one in the rear fuselage behind the main landing gear adjacent to the rear engine nacelles, and two located forward of the main landing gear just ahead of the engine air intakes. In the B-1A, these bays were each 18 feet long, having been designed to carry the original ALCM, the Boeing AGM-86A. When the B-1A was cancelled, Boeing began working on an increased range AGM-86B. Since the AGM-86B was now 20 feet 9 inches long, this meant that the weapons bays of the B-1B would have to be redesigned if it were to carry this weapon. A compromise was reached in which the aft weapons bay was kept at a length of 18 feet, but the forward two weapons bays were redesigned so that they could be joined as one if this were required. Alternatively, a bulkhead can be placed between the two, providing three bays which are essentially identical.
In principle, the B-1B can be equipped to carry external weapons attachment pylons. One dual pylon can be attached
on the lower fuselage sides just outboard of each of the weapons bay. Two single external
pylons can also be attached (not sure where), allowing up to 14 weapons to be carried
externally. However, these have been
only rarely used. Under the previsions of the SALT/START treaties, no more than twelve nuclear weapons
can be carried externally, and external carriage of weapons is considered to degrade aircraft
performance unacceptably. Today, the B-1B is not believed to have any external weapons carriage
The B-1B is operated by a crew of four: pilot, co-pilot, defensive system operator, and offensive system operator. The pilot and copilot are seated side-by-side in the front, behind large, sharply-raked windscreens which are designed to meet severe birdstrike specifications. The pilot and copilot both have fighter-style stick and throttle controls. The offensive and defensive system operators are seated side-by-side to the rear. Unlike in the B-1A, the rear crew members are each provided with a small side window. The crew enters the cockpit via a ventral hatch and extendable stairway that are located immediately behind the nose gear bay. Each of the four crew members sits on a Weber ACES II ejection seat. These seats replace the escape capsule used on the first three B-1As. Each seat has a survival kit, including a life raft and a radio beacon.
On training missions, provision was made for the crew to be accompanied by two instructors who sat on fixed jumpseats. In an emergency, the two instructors would have to jettison the entry door and ladder and extend the nose gear and jump headfirst through the entry hatch. However, the system did not work very well, as was shown by the deaths of two instructors in a B-1B crash on September 28, 1987. After this accident, the decision was made to limit the total crew to four on any mission involving low-level flight, even though this means that each instructor would have to replace a regular crew member.
The B-1B has a complex avionics system consisting of automatic flight control systems, an Offensive Avionics System (OAS) which handles navigation, stores management and weapons delivery and the Defensive Avionics System (DAS).
As its name implies, the Offensive Avionic System manages the delivery of offensive weapons. The offensive digital avionics system is reprogrammable, to allow inflight changes to be made in the mission. The OAS can aim gravity bombs accurately without using any optical or laser sighting system. The key component of the OAS is the radar system. There is no separate terrain-following radar, instead it is a separate mode of the main offensive radar system using the same antenna.
The B-1B has a single Westinghouse
APQ-164 radar with a single antenna. It was developed from the APG-66 used in the F-16. It has a fixed phased array which is mounted at an
angle to reflect enemy radar emissions downward. The radar can operate in any of eleven
During the terrain following mode, the radar automatically switches rapidly between scanning ahead to build a profile of the approaching terrain in its memory and scanning to each side. In terrain following mode, the radar scans directly ahead to a distance of about 10 miles to build a profile of the terrain to be flown over. The Terrain Following Avionics Control Unit draws a line parallel to the terrain profile seen by the radar, and the aircraft automatically flies this route. The pilot can select the terrain clearance between values as high as 2000 feet to as low as 200 feet. The better the enemy radars, the lower the terrain clearance that will be selected. Low-altitude air can be quite turbulent, making this a very bumpy ride indeed
The navigation system includes the Singer-Kearfott SKN2440 inertial navigation system, a Teledyne Ryan APN-230 Doppler velocity sensor, a gyro-stabilization system, a dead reckoning system, and a radar altimeter. Before each mission, the system is aligned on a surveyed spot, but in an emergency the aircraft can takeoff on stored alignment modes.
The ARN-118 tactical air navigation system (or TACAN) provides bearing and distance to a TACAN ground beacon up to 300 miles away. The system has two UHF antennae, one between the roof hatches of the DSO and OSO positions, and the other underneath the right engine nacelle. The ARN-108 instrument landing system (ILS) has a flush antenna system above the nose. There is an APX-105 beacon with an antenna inside the front of the vertical fin cap which can be used to enhance the B-1B's radar cross section during rendezvous with a tanker aircraft.
The ARC-190 HF radio has a flush antenna in the fin leading edge, with the coupler at the junction with the dorsal spine. The ARC-171 UHF radio has a small blade antenna above the fuselage and two others underneath the front of each engine nacelle. There is a King KY-58 secure voice line-of-sight radio that is operated by the copilot. Added at a later time was an ASC-19 satellite receiver, with an antenna located on the upper centerline just behind the crew component. The APX-101A IFF (Identification Friend or Foe) shares the UHF-2 antennae located above the fuselage and under the left nacelle.
The Defensive Avionics System (DAS) system is a comprehensive electronic countermeasures package that is designed to detect enemy radar threats or missiles, and to defend the aircraft by applying the appropriate countermeasures, which could be electronic jamming or expendable chaff and or flares. It has four subsystems: a radio frequency surveillance/electronic countermeasures system, a tail warning system, a defensive management system, and an expendable countermeasures system that uses chaff cartridges and flares to deflect enemy missiles. There is no defensive armament.
The DAS system is comprised of the Eaton ALQ-161A system, plus a management system designated ASQ-184. It acts to detect enemy radar emissions, especially those coming from air defense or missile guidance radars. It stores these signals in a threat library, assigns a priority to each one of them, and then emits high-power signals to jam or confuse them. The system also manages the passive defensive system that fires cartridges containing chaff to blind enemy radars or bright flares to distract enemy infrared-homing missiles. Most of this electronic equipment is mounted in the avionics bay immediately behind the crew compartment. The remainder are in the left and right fuselage side fairings. and in the rear end of the fuselage. The receiver antennae are located inside the blunt tail dome, sending signals to the electronic equipment in the mail wheel wells. there are some large blade antennae that are located high on each side of the fuselage behind the crew compartment and one each side of the rear fuselage. Other antennae are located inside electronically-transparent regions of the airframe.
The DAS also includes an automatic pulse-Doppler radar in the end of the tailcone that is designed to detect enemy missiles or aircraft approaching from the rear. If a threat is detected, a signal is sent to the DSO's station, and a warning tone is sent to each crew member. Multiple threats can be prioritized, and the DSO decides what action to take. This can include the launching of chaff cartridges or decoy flares, or the initiation of evasive action.
The trailing edge of the fin cap houses AN/ALQ-161A receivers for bands 6, 7, and 8 and has a high-intensity strobe light immediatelly below that. The tail warning function antennas are housed lower down on the trailing edge of the vertical fin/horizontal stabilizer intersection fairing.
100 production B-1Bs were ordered. New manufacturing facilities had to be constructed at Palmdale. In general, the production program was on time and within budget
The development of the B-1A was supported by two modified B-1A prototypes, Nos 2 and 4. Number 2 (74-0159) was intended for airloads testing and engine/inlet deveooment and number 4 (76-0174) for use as an offensive and defensive avionics testbed. These two planes did not have B-1B engine inlets, but they were extensively reworked internally. B-1A number 2 was modified by having B-1B flight control system features installed. It began flying on March 23, 1983. Unfortunately, it crashed on August 29, 1984 when the aircraft lost control when the center of gravity got unbalanced during fuel transfer management. The escape capsule deployed successfully, but the parachute risers did not deploy properly. The capsule hit the ground at a steep angle, so steep that the inflatable cushions could not shield the impact. Chief test pilot Doug Benefield was killed, and two other crew members were seriously injured.
B-1A number 4 resumed flying on July 30, 1984. Externally, the main change was the removal of the long dorsal spine but many of the B-1B avionics systems were installed internally.
The first B-1B (82-0001) was assembled largely by hand and incorporated several sub-assemblies of the No 5 B-1A, which has been under construction when the B-1A program was cancelled. It was rolled out on September 4, 1984. It flew for the first time on October 18, 1984, crewed by Rockwell test pilot M. L. Evenson, Lt Col L. B. Schroeder, Capt D. E. Hamilton, and Maj. S. A. Henry It was a 3 hour 20 minute flight which ended with a landing at Edwards AFB in California. The second aircraft was delivered on July 7, 1985. The B-1B was declared ready for delivery to the Strategic Air Command barely eight months after its first flight.
Initial B-1B assignment was to the 4018th Combat Crew Training Squadron at Dyess AFB, Texas., which was activated on March 15, 1985 as a replacement training unit. The first operational squadron was the the 337th Bombardment Squadron (Heavy), which had previously been equipped with the B-52H. IOC was achieved on October 1, 1986, even though the crews had not yet flown any terrain-following sorties and had not launched any cruise missiles. and the first B-1B unit achieved on October 1, 1986. The 100th and last aircraft was delivered on May 2, 1988.
Unfortunately, numerous shortcomings surfaced during the introduction of the B-1B into service. First, the unit cost of a B-1B was quite high, over $283 million. In addition, the B-1B could not safely fly at high speeds at low altitude with nearly the amount of payload that had been promised. The reason for this was that it was difficult to fly a heavily-loaded aircraft in terrain-following mode and have enough margin of safety to be able to fly around or over obstacles. These sudden maneuvers cost fuel, and the heavier the aircraft the more the fuel that was consumed. With a typical load of 8 B61 nuclear weapons and 8 SRAMs, only enough fuel could be carried to to achieve a low-level range of 1300 miles. This would limit the plane to a combat radius of only about 700 miles. In addition, the aircraft could not always fly in a straight line but would have to maneuver around mountains and other objects and may even have to use its afterburners to avoid enemy aircraft, limiting the range even further. This was far short of the advertised maximum unrefueled range of 7455 miles. The media immediately began to pounce on the B-1B, denouncing it as incredibly costly and nearly useless.
These low-altitude range problems were addressed by a series of modifications. First, the pilot feel was improved while enabling the B-1B to approach much closer to the limiting angle of attack and even to exceeding it without suffering an aerodynamic stall. This would make it possible to increase the weights at which a low-level flight could be safely carried out. This was handled by changing the computer software which controlled the fly-by-wire system. The new software was installed in the first 17 aircraft between March 1988 and June 1988. The second stage involved an improved stability system that was installed in the remaining 83 aircraft between March 1988 and June 1990. The third stage was a more comprehensive system that added additional sensors to measure the actual angle of attack plus a major upgrade in the software that established the safe limits more precisely. These were retrofetted into all existing B-1Bs between March 1988 and January 1992. These changes made it possible to significantly increase the amount of fuel that could be carried, raising the mission range from 1300 nm to over 3000 nm.
The terrain following radar system encountered considerable difficulties in the early years of B-1B operations. The software had some difficulty in handling low-level overflights of hilly country. The software was pre-programmed to guide the aircraft over small obstructions but around larger ones. The software had difficulty in handling situations when the aircraft suddenly changed course and would turn toward a previously-unseen obstacle. This was especially hard to handle when the aircraft had just passed over a smaller objection and was in the process of pitching down. This was addressed by software upgrades that limited the rate and magnitude of pitch-downs and improved the ability to detect obstructions in turning flight.
Another difficulty was software problems which generated unnecessary fly-ups when no obstruction was actually there. Not only did these unnecessarily upset the crew members, they adversely affected the fatigue life of the aircraft. Naturally, the system was deliberately designed to err on the side of caution, but it would sometimes happen that an error signal would be sent that would cause the aircraft to suddenly zoom upwards at 2.4g for 10 seconds for no reason. On some missions, this would happen as often as once every three minutes. Software fixes were introduced to correct this problem, but the problem was never entirely cured.
The defensive avionics system also did not initially perform as well as expected. Its reliablity was somewhat less that what was desired, and in some situations, it was found possible for the aircraft actually to jam itself. The system could not detect, locate, or identify some of the newer Soviet air defense radars that had been introduced in the 1980s, and had trouble with some of the newer Soviet interceptors and missiles. Continual upgrades were added throughout the 1980s, but during the upgrade process it often proved true during this period that no two B-1Bs ever had precisely the same equipment aboard.
In 1986/87, the Air Force started the introduction of an upgraded defensive avionics system. The first phase was a rationalization process in which all of the B-1Bs in the fleet were brought up to the same standard. The second phase introduced some new features such as the option of selecting either manual or automatic jamming. It included several hardware changes, but most of the changes were in the software. The installation was first flight tested in mid 1988. The system still had problems with processing a large number of radar signals simultaneously. This was a fundamental issue with the architecture of the ALQ-161A system that covered eight radar bands. The problems with the defensive avionics system are still being worked, although the collapse of the Soviet Union and the end of the Cold War probably means that the B-1B will never be called upon to carry out such a risky, low-altitude penetration.
In a contract awarded to Boeing for the Defensive System Upgrade Program (DSUP), the unreliable AN/ALQ-161 is to be replaced by the Lockheed Martin AN/ALQ-56 radar warning receiver and the Sanders Integrated Defensive Electronic Countermeasures (DECM) radio frequency subsystem. Testing is scheduled to begin in 2003.
The B-1B suffered from fuel leaks throughout the early years of its career. At the height of the problem, it was necessary to frequently wash down the aircraft while it was sitting on the ramp. Today, the problem is much less severe, and leaks are a lot less frequent.
There were problems with the Central Integrated Test System which was intended to facilitate maintenance by automatically drawing attention to problems and pinpoint their source. However, the system was so complex that it issued far too many false alarms that complained about aircraft problems that did not exist. These were traced to faulty sensor, wiring, plus software bugs. These have been addressed by repeated upgrades, and the number of false alarms had been drastically reduced.
B-1B 84-0052 apparently collided with a large bird on September 28, 1987, causing an uncontrolled fire to break out and forcing the crew to abandon the aircraft. Unfortunately, three of the six people aboard were killed (two of them were instructors). This accident initiated an investigation of means by which the aircraft could be "hardened" against birdstrikes, with critical areas being identified that were vulnerable. These included the wing/nacelle junctions and support structures, the base of the fin, and the leading edge inboard of the wing pivot. Kits were hastily designed with protective shields of hardened steel to be attached to the aircraft.
On March 1, 1990, the B-1B was officially given the name Lancer. However, the plane is almost universally known as the "Bone" (for B-One).
On December 20, 1990, all B-1Bs were grounded (except those on alert status). There had been a rash of F101 turbofan blade failures. As an interim fix, the first stage retaining ring was replaced by a thicker ring made of armored steel, and a stiffer regimen of inspection of fan blades was instituted.
The B-1Bs were all initially assigned to the Strategic Air Command. On September 1, 1991, all SAC B-1B wings were renamed from "Bombardment Wing, Heavy", to simply "Wing", reflecting the fact that the Wing was equipped with both bombers and aerial refueling aircraft. All of the B-1B squadrons were relabeled from "Bombardment Squadron, Heavy" to "Bomb Squadron".
Reflecting the end of the Cold War, all USAF bombers stood down from nuclear alert on September 27, 1991. The Strategic Air Command was disestablished on June 1, 1992, and the bomber force was transferred to the Air Combat Command. The ACC was created by the merger of SAC and TAC, and is responsible for all USAF bombers along with all Continental United States (CONUS)-based fighter, attack, reconnaissance, and combat rescue aircraft. The aerial refuelling tankers went to the Air Mobility Command.
With the perceived nuclear threat no longer present, USAF B-1Bs went through a multi-phased Conventional Mission Upgrade Program (CMUP) that was designed to increase the B-1B's conventional capabilities and survivability. Prior to the CMUP, all B-1Bs were designated "Block A", and were optimized for the nuclear warfare role. The first stage of the program (termed Block B) was the introuction of an improved synthetic aperture radar and an improved AN/ALQ-161A DAS, which reduced the false alarm rate and improved the overall reliablility of the system. The next stage was termed Block C, which gave the B-1B the ability to carry various cluster bomb units (CBUs). The bomb modules of 50 B-1Bs were modified to carry a ten-station bomb rack capable of holding 10 1000-lb Cluster Bomb Units (CBUs), with one rack in each weapons bay. The B-1Bs were given the ability to deliver CBU-87, CBU-89, and CBU-97 cluster munitions by altering the software. Some CBU-certified aircraft received modified conventional weapons modules (CWMs) that can be loaded outside the aircraft and then placed inside the bomb bay. Block C upgrades also included the use of Mk 82 GP bombs with conical fins to provide for a more accurate delivery. Later changes (termed Block D) included the ability to carry the 2000-lb GBU-32 Joint Direct Attack Munitions (JDAM) and also added the Communications/Navigation Management System (CNMS) that includes jam-resistant AN/ARC-210 radios and a global positioning system and a Mil-Std 1760 data bus which provided a smart weapons interface that enables the bomber to communicate with the JDAM. The first test of a JDAM-equipped B-1B took place on February 11, 1998. Further upgrades (named Block E) will include replacement of the current mission computer with a more modern system. In addition, the AGM-158 Joint Air-to-Surface Standoff Missile (JASSM), the AGM-154 Joint Stand-Off Weapon (JSOW), and the WCMD will be added to the aircraft's arsenal. Block F preliminary plans include the AN/ALR-56 integrated defensive electronic countermeasures system and a new fiber optic towed decoy which will replace the interim AN/ALE-50. All of these modifications should be completed by 2005. The B-1B could in principle be modified to carry CALCMs, but his would require bomb bay reconfiguration, which would not be allowed under the provisions of START II.
The B-1B was not used in Desert Storm, the official reason being that the B-1Bs were all needed to stand nuclear alert in the USA. However, at that time the B-1B had been encountering a rash of turbofan blade failures and was experiencing all sorts of problems with its DAS, and the real reason might have been that the plane really wasn't yet combat ready. Nevertheless, at that time the B-1B had not yet undergone the conversions that would have made it capable of delivering conventional weapons.
The B-1B received its combat debut in an attack on Iraq on December 16, 1998, in Operation Desert Fox, an expedition to punish Iraq's lack of cooperation with UN weapons inspectors. The B-1Bs were from the 7th Bomb Wing (9th Bomb Squadron) and the 28th Bomb Wing (37th Bomb Squadron). The missions were staged out of Oman in the Persian Gulf. Two aircraft hit separate targets in the Al Kut barracks complex in northwest Iraq. Two more missions were carried out the next day. For these sorties, each B-1B carried 66 500 lb Mk 82GP bombs, which were carred in 28-bomb modules in the forward and intermediate bays, and a 20-bomb module in the aft bay.
Five B-1Bs from the 28th Bomb Wing (4 from the 77th BS, one from the 37th BS) based at Ellsworth AFB, South Dakota were deployed to RAF Fairford in support of Operation Allied Force, the NATO intervention in Kosovo. These planes had received the latest Conventional Munitions Upgrade Program, with Raytheon AN/ALE-50 fiber-optic towed jammers and decoys. They were also capable of carrying up to 24 JDAMs, but these were used only by the B-2A Spirit. They flew their first missions on April 1, 1999. By May 17, the 28th BW had flown over 60 combat missions, and they achieved 100 percent availability rates. A typical mission lasted between 7 and 8 hours, and the usual load was 84 500-lb Mk 82 bombs per aircraft.
82-0001 Rockwell B-1B Lancer 82-0002 Cancelled contract for Rockwell B-1B Lancer 83-0065/0071 Rockwell B-1B Lancer 84-0049/0058 Rockwell B-1B Lancer 85-0059/0092 Rockwell B-1B Lancer 86-0093/0140 Rockwell B-1B Lancer
Engines: Four General Electric F101-GE-102 turbofans, 14,600 lb.s.t. dry, 30,780 lb.s.t. with afterburning. Performance: Maximum speed at 50,000 feet Mach 1.25 (823 mph), maximum speed at low altitude (500 feet) Mach 0.92 (699 mph). Maximum unrefueled range 7455 miles, 3444 miles with normal weapons load Service ceiling 60,000 feet. Weights: 182,360 pounds empty, 477,000 pounds maximum takeoff. Dimensions: Length 147 feet. Wingspan at minimum sweep 136 feet 8 1/2 inches, wingspan at maximum sweep 78 feet 2.5 inches. Wing area 1950 square feet at maximum sweep. Height 33 feet 7 1/4 inches. Maximum fuel: 29,755 US gallons. Maximum weapons load 75,000 pounds in three internal weapons bays.