NAMING a MILITARY aircraft is an unofficial seal of approval; the withholding of it betrays uncertainty. When in June 1990 the name Lancer was officially adopted for the Rockwell B-1B, some four years after initial operational capability was achieved and more than two years after the 100th and final aircraft was accepted by the USAF, it looked suspiciously like belated remorse. Prior to this, the unofficial soubriquet of Excalibur had been applied, but as this is also a brand name for an unmentionable rubber product, it failed to catch on. After a long and chequered history, it now seems that the B-1 B has finally been accepted in service as the spearhead of Strategic Air Command.
The main problem of strategic bombing is how to penetrate the defences without unacceptable losses. The historical answer was to fly too high and/or too fast for defending fighters to reliably intercept. This trend peaked with Convair’s B-58 Hustler, which was designed to penetrate at over 50,000ft (15,200m) at supersonic speed, culminating with a Mach 2 dash over the target area, and was to have been perpetuated by North American’s B-70 Valkyrie, capable of Mach 3 sustained for long periods at 80,000ft (24,400m).
Advent of the missile age brought the ever faster and higher trend grinding to a halt. Strategic nuclear weapons could be more swiftly and reliably delivered by global ranged missiles, while the air defence variety made the manned bomber look distinctly vulnerable. Valkyrie was cancelled in 1960, and Hustler was phased out in 1970 after only ten years service. The subsonic Boeing B-52 Stratofortress was retained to provide a retaliatory strike capability in the event of a pre-emptive attack on the strategic missile bases. To ensure credibilty, a handful of bombers were kept in the air around the clock, for several years. To aid survivability they were equipped with comprehensive ECM suites and decoys such as Quail, and trained in low level (1,500ft/450m) penetration techniques.
The idea of the manned strategic bomber had not been abandoned, and studies for a new aircraft were initiated in 1961. These showed that high subsonic speed at very low altitudes gave the greatest survivability in heavily defended areas, while high altitude supersonic performance was needed to reduce transit time and to give greater operational flexibility. The USAF issued Requests for Proposals in 1969, and in 1970 Rockwell International was selected to develop what was to become the B-1.
One of the primary design considerations was the ability to survive a pre-emptive nuclear strike against airfields. Submarine-launched ballistic missiles, with their short time of flight, gave only seven minutes warning, and could target every military airfield in the continental USA. To counter this threat, the new bomber had to be able to disperse in times of tension to some of the many hundreds of smaller civil airfields. This called for good short field performance, rapid reaction, and independence from sophisticated support facilities. VSTOL was considered, but the technical risks were adjudged too great, and a variable sweep wing, adjustable in flight to give short field performance, economical cruising, high speed dash, or low gust response, was adopted. High wing loading helped to alleviate gust response, but the length of the aircraft was such that the fuselage would tend to flex as it rode the bumps at low level. Over an extended period, this could cause an unacceptably high level of crew fatigue. Beefing up the structure to give extra rigidity was the obvious answer, but this would incur a prohibitive weight penalty. The solution adopted was to use small sensor-driven vanes at the front of the nose, which would counter the bumps and smooth out the ride.
In October 1974, the first prototype was rolled out at Palmdale. It was a very sleek bird, an impression aided by the blending of the fuselage and wing gloves. While this did much to hold down the radar cross-section, it was adopted primarily to provide extra structural strength and volume. Four General Electric F101-100 augmented turbofan engines rated at 17,000lb/75.6kN static thrust dry, and 30,000lb/133kN wet, were set in pairs beneath each wing glove. The horizontal tail surfaces were located one third of the way up the fin. Originally to have been made of titanium and set low, cost savings demanded that they be manufactured in aluminium, and the high location was chosen to keep them away from the hot engine effluxes. The four man crew was housed in an escape module similar to that of the F-111, which allowed them to fly in shirtsleeve comfort. Apart from some fancy paintwork and a black radome, the finish was anti-flash white.
First flight of the B-1A took place on December 23, 1974, when the first prototype was delivered from Rockwell’s facility at Palmdale, to Edwards AFB. Joined after an extended period by the second and third prototypes, a highly successful trials programme was flown over the next 30 months, during which time a fourth prototype was ordered. This had ejection seats in place of the escape capsule; revised engine nacelles, and a defensive avionics bay in the rear fuselage.
B-1A was an extremely expensive project, and it had attracted much criticism, often unjustified, from the politicians and the media. The Carter Administration then discovered a new and cheap wonder weapon, the cruise missile (hadn’t they ever heard of the Doodlebug?). This could be carried in quantity by the elderly B-52, and flying a low level pre-programmed course, would eliminate the need to penetrate hostile territory. With governmental cries of «whoopee, we’ve saved money», all B-1 production contracts were terminated on July 6, 1977.
Shortly after, a new Bomber Penetration Evaluation commenced, which lasted until June 1981. The B-1 A was pressed into service as a research vehicle, clocking up some 1,350 hours over the next 42 months, when the second prototype reached a speed of Mach 2.22 at 50,000ft (15,240m). The fourth prototype joined the fleet on February 14, 1979. This bird differed from the first three in external appearance in that it carried a dorsal spine housing a waveguide for the Crosseye monopulse jamming system. This was the first ‘full up’ aircraft, and testing of the avionics suites now began in earnest.
By now it was becoming obvious that stealth technology was of prime importance to any manned penetrator, although at this stage, the Advanced Technology Bomber, later to emerge as the Northrop B-2, was just a dream on the horizon. It was equally obvious that the antediluvian B-52 could not maintain credibility as a penetrator until 1995, when the ATB was schduled to enter service.
Tweaked to give a lower radar signature, beefed up to take off at an 82,0001b (37,195kg) higher maximum gross weight, and capable of flying iron bomb, maritime reconnaissance and minelaying missions in addition to nuclear strike, the B-1 became the front runner to fill the gap. This was confirmed on October 2, 1981, when the Reagan administration announced that an order was to be placed for 100 B-1 s. Contracts were placed in 1982, including the offensive and defensive avionics suites by Boeing and AIL respectively.
A new flight test programme was scheduled for the B-1 B. as the redesigned aircraft had now become. This was flown by the low time second and fourth prototypes, using the two high time aircraft as hangar queens. No 2 B-1 A was modified for the programme, and returned to the air in March 1983, followed by the fourth aircraft in July.
The test programme, although generally successful, was marred by an accident. The centre of gravity moves aft as the wings sweep back, and this has to be compensated by pumping the fuel around to achieve balance. On August 24, 1984, the big bomber was allowed to slow down and the wings to sweep forward while the eg was still aft. As the speed decayed through 145kt (269km/hr) it pitched up to an angle of 70deg. Recovery was impossible, and ejection initiated. A malfunction caused the crews module to make a hard, nose-down landing, killing Rockwell’s chief test pilot. Doug Benefield, and injuring the other three crew members.
While this mishap was tragic, it had little impact on the test programme. B-1 A No 2 was close to completing its schedule, and less than a fortnight later, the first production B-1B. 82-0001, was rolled out to join B-1 A No 4.
In appearance, the B-1B was almost identical to the B-1 A, with external differences being limited to a blunter tailcone, a rounded acorn behind the horizontal tail surfaces, modified engine inlets, a small transparency to the rear crew compartment, and wing fairing, seals of sliding ‘feathers’ over an inflatable bag; a scheme pioneered by Tornado. But under the skin it was quite a different bird. The B-1 A had been weight limited, and with a full weapons load could take off only at half fuel capacity, relying on inflight tanking to complete the mission.
With the B-1B not only was the maximum range increased, requiring an extra 24.0001b (10,886kg) fuel, but external weapons were to be carried, increasing the warload by a massive 50.000lb (22,680kg). Unlike the B-1 A. the ‘B’ had to be able to take off with a full fuel and weapons load. Naturally a penalty in terms of structural weight had to be paid, but Rockwell managed to hold this down to about 8,000lb (3,630kg), an increase of just four and a half percent.
A further problem was that the Air Launched Cruise Missile (ALCM) had grown in length during development, and no longer fitted the three weapon bays. The fix was to make the bulkhead between the first two bays removable, a solution requiring extra structural stiffening.
Low observable technology was also used to improve penetrability. The B-1 A had a much smaller radar cross-section (RCS) than the B-52. This was largely fortuitous, but great efforts were made to reduce the RCS of the B-1 B even more. Radar-absorbent material (RAM) was used in critical areas of the fuselage; composite bomb bay doors replaced metal ones; the antenna of the terrain-following radar was angled downwards so as not to reflect radar emissions straight back, and serpentine inlets with curved baffles and RAM shielded the engine compressor faces.
So important was this last judged that the Mach 2 requirement was dropped so that fixed inlets (with a considerable weight saving) could be used. The actual RCS of the B-1 B is highly classified although various figures, typically 1m!, have been widely touted. It is however safe enough to say that it is significantly less than that of many much smaller aircraft. The B-1B retains a residual supersonic capability. V™. now being about 1.4 Mach.
One apparently surprising thing about the B-1B is that its engines have the same thrust ratings as those of the B-1 A, yet it is able to take off at far higher weights without using much extra concrete. The B-1 A was powered by the F101-GE-100, while the B-1B mounts the F101 -GE-102, and the official figures for static thrust of both are identical. In practice, under dynamic conditions, the -102 runs appreciably hotter than the -100, with about five percent more thrust. While this may not sound much, the take-off run of the B-1B takes a full five seconds less and is appreciably shorter than that of the B-1 A at comparable weights.
B-1 B Avionics
State-of-the-art avionics were central to the B-1 mission from its inception, and so complex were these that they were split into three distinct areas. Of these, the flight control and allied systems remained with Rockwell, while the offensive and defensive systems were the subject of separate contracts as previously noted.
B-1 A carried two radars in the nose; one for navigation and target location, the other for terrain following. They were replaced in the B-1 B by a single Westinghouse APQ-164 multimode radar with a fixed phased array antenna with electronic scanning. The full list of radar modes has not been released, but it is known to include terrain following and terrain avoidance, ground mapping, ground moving target detection and tracking, including synthetic aperture techniques, weather detection, and more than half a dozen others. Terrain following mode can be preset to three different grades of ride: hard, medium or soft, and any one of eleven ground clearance altitudes can be selected.
Problems were experienced in terrain following mode in the early days; this was due to a software fault which has since been corrected. Also part of the offensive avionics kit are the usual navigation and communications items, including TACAN and secure voice. As is standard practice, nuclear weapons can only be released by joint action from two widely spaced crew stations, one being the specialist OAS operator, the other is one of the pilots.
The B-1 A was to have relied heavily on electronic countermeasures (ECM) to ensure penetration. This has one basic fault. However effective the jamming, the other side know that something is out there causing it, and the obvious course when all else fails is to get defending fighters into the area to search visually. The B-1B concept took this a stage further with its concentration on low observables, working on the principle that if you can evade detection in the first place, you do not need to reveal your presence by using jamming. The really clever bit is in knowing when to rely on what!
ALQ-161 is the B-1B’s defensive avionics system. This consists of a comprehensive antenna array to give a full 360° coverage around the aircraft, linked to a battery of 108 black boxes and assorted jamming transmitters. Hostile radar emissions are detected, sorted, and then automatically assigned priorities. Jamming is initiated according to preprogrammed priorities, or the electrons can be overruled by the specialist defensive systems ope,c;*’y It hardly needs saying that extremely fine judgement is needed.
A feature of the B-1B which did not appear on the B-1 A is the Westinghouse ALQ-1 53 tail warning radar. It seems obvious that this will be used sparingly, with intermittent sweeps, in high risk fighter and SAM areas only, as constant use would betray the position, course, and speed of the bomber, making it much easier to intercept. While missiles can be jammed or decoyed, counter-measures give no protection against a fighter coming in astern for a visual or IRST guns attack. Only evasive action remains, and with virtually no rearward visibility from the B-1B cockpit, tail warning radar is needed to make last ditch defensive manoeuvres possible.
Since its early days, the B-1 B has caught a tremendous amount of flack and in no area has this been worse than the defensive avionics system. Indeed, it has been castigated as the world’s first self jamming bomber. While it is correct that ALQ-161 has failed to meet its original specifications, this is hardly surprising.
Major General Elbert Harbour of USAF Systems Command, covered this point in some detail at a Royal Aeronautical Society lecture in 1988. When specifying something like the B-1B defensive avionics system, it must be aimed, not at the current threat, but at a projection of that threat ten or fifteen years in the future. This immediately causes problems, as there is no certainty of knowing what technology will be available to a potential aggressor, or even what technology will be available to counter it that far in the future. One wrong guess will provide a target for all those who have that most powerful aid to decision-making, hindsight, available to them. It just needs their fellow on the other side of the hill to go a different way, or a bit of confidently predicted homebrew technology to foul up, to make a nonsense of a new system.
This is in fact what has happened. The system works perfectly well against all except the newer threats which can easily be detected and classified, but not so easily jammed. Finally General Harbour pointed out that the defensive system specified was at least twice as capable as anything that had gone before, and that while only about 90% of expected capability had been achieved, this still represented a massive advance of 180% over previous capability, which was well worth having. But having said that, reliability is less than desired, and the automated part of the system is not performing as advertised, throwing a greater workload on.to the specialist operator. More work on the software is expected to provide the eventual solutions.
Other problems have been encountered with the flight control system, but these have largely been overcome. At high all-up weights, both g and alpha limits restricted fast pull-ups in terrain following mode, while a Department of Defence official stated in 1986 that the B-1 B could not fly higher than 20,000ft (6,100m) at maximum weight. It was not pointed out that this was almost 50% better than the F-111 at maximum weight, nor that maximum weights are rarely achieved under operational conditions.
Part of the trouble was that at the stall, the B-1 B pitches up, and to prevent this point being reached, a stall inhibitor system prevented the pilot from exceeding the alpha limit. But this limit simply did not give enough lift in certain flight regimes, and the answer was to provide a stability enhancement function which allowed this to be exceeded, permitting controlled flight in what were previously unstable regions of the envelope. The B-1 B has a mixed fly-by-wire and mechanical system with a reversionary link to cover against failure of one or the other.
Other problems encountered with the B-1B have, with two major exceptions, been one-offs. The second production aircraft got its wings stuck at 55° sweep in March 1986. Despite this, it landed safely, if rather fast. Then in March 1989, the wing sweep mechanism got out of synch on a Dyess-based aircraft, the port wing swept too far forward and ruptured a fuel tank. Fortunately this happened on the ground. Probably the most comic incident of all happened to the first production aircraft during assembly. In accordance with Murphy’s First Law, a wing bearing fitting was wrongly stamped «This Side Up». Only when the wing was on and the final clearances were being checked was the error discovered. Fortunately Rockwell had to provide the USAF with a training manual and video film of a wing change, and correcting this error gave them the perfect opportunity. Years later I asked General Harbour whether he had been informed of the error before or after the event. His reply was, to say the least, rather dusty!
Two major problems encountered concerned external weapons carriage and fuel. In the first case it was found that cruise missiles could not be carried on the outside hardpoint of the wing glove. As the Strategic Arms Limitation Treaty, restricting the number of nuclear weapons came into force shortly after, this hardly mattered. Much more serious was persistent fuel leakage.
Fuel tanks of the B-1 B were an integral part of the structure with mastic sealant to metal joints and fasteners. The mastic used proved inadequate, with the result that fuel seeped through. The scale of the problem was enormous; each bomber has 290,000 fasteners and 3,100m of joints to be sealed. The USAF tried to make light of it, saying that the sweating (they wouldn’t use the word «leak») did not affect operational capability in the event of a national emergency.
Be that as it may, it was sufficiently serious to cause a significant number of training sorties to be cancelled. Anything to do with fuel being where it didn’t oughter is a potential hazard when the fumes build up. The cure was to reseal the lot with a different mastic at Rockwell’s expense. The only difficulty was access. Apparently General Harbour press ganged a team of the smallest men in the Air Force to crawl about inside the tanks and do the work. I only hope they checked that nobody was left behind!
An original buy of 244 had been envisaged for the B-1 A, but this was reduced to 100 for the B-1 B, which was increasingly regarded as a stopgap between the B-52 and the future Advanced Technology Bomber under development by Northrop. This was enough to equip four Bombardment Wings; the 96th at Dyess, Texas; the 28th at Ellsworth, South Dakota; the 319th at Grand Forks, North Dakota; and the 384th at McConnell, Kansas.
Strategic Air Command officially took over its first B-1 B (the second production article, serial no. 83-0065 at SAC HQ. Offutt AFB in Nebraska, on July 27, 1985). Unfortunately, as it came in to land at Offutt, the doors to the environmental control system intake came off and damaged both engines on one side, which put it out of action for a few days. As it was due at Dyess two days later to attend a further ceremony attended by both high ranking USAF officers and the general public, this was embarrassing, but the first production machine was taken off the test programme and flown to Dyess to substitute.
The B-1B carries a tremendous amount of hitting power. Its warload falls into three categories: nuclear free fall bombs; nuclear guided weapons, and conventional iron bombs.
In the first category, the maximum load consists of 24 B-61 or B-83 special weapons carried internally, eight in each weapons bay, and a further 14 externally. The B-61 has a yield of one megaton, while the smaller B-83 has a yield varying between 10 and 500 kilotons. Parachute retarded, they can be released at altitudes as low as 150ft (46m). It would, of course, be very unlikely that the B-1B would carry beasties externally on a penetration mission, or come to that, any other external weapon, as the RCS would increase considerably, thus defeating the bomber’s chances of remaining undetected.
In the second category come the AGM-69 Short Range Attack Missile (SRAM) and the AGM-86B Air Launched Cruise Missile (ALCM). SRAM has a warhead yield of 200kT, and 24 SRAMs can be carried internally on three rotary launchers. A further 14 can be hung on the outside. SRAM can be programmed to attack targets ahead of the bomber, or well off to one side. It could be used to suppress the defences on the ingress, or to attack the main targets. Depending on launch speed and altitude. SRAM’s speed varies between Mach 2.8 and 3.2, and its range between 30 and 90nm (56 and 170km).
ALCM is much slower but longer ranged, flying a terrain-hugging profile at 435kt (805km/hr) for a distance of up to 1,300nm (2,500km). It carries a 200kT warhead. The B-1 B can carry eight ALCMs in the forward double bay (in which case an extra fuel tank can be fitted), and a further four externally. Armed with this sort of weaponry, there are few targets for which the B-1 B would need to penetrate the defences to any great depth.
The conventional bomb load is also very destructive. Typically 84 MK 82 500lb (227kg) or 24 MK 84 2,000lb (907kg) bombs can be carried internally, with a further 14 of either externally. For the maritime role, MK 36 and MK 60 sea mines can be carried.
«Stand-alone» capabilities of the B-1B are quite exceptional. While the continental USA holds at least 100 airfields capable of supporting it, there are another 250 Grade III fields that can be used for dispersal, thus reducing the risk of elimination posed by a pre-emptive missile strike. The B-1 B was designed to be dispersed at these lesser fields, with no maintenance facilities, for up to four weeks at a time, then be able to get away fast enough to be outside the effect of a nuclear strike within four minutes. When the alert is given, the crew run to the boarding ladder. The first man to reach it hits a switch on the nosegear which starts the auxiliary power unit, and by the time the crew are settled in the cockpit, all electrical systems are up. All four engines can be started simultaneously.
B-1B is easy to fly, and remarkably manoeuvrable for such a big aircraft. Unusually it has a fighter-type control column rather than a wheel, and certain accounts in the technical press have described it as handling more like a fighter than a bomber. When it appeared at Le Bourget in 1987, the writer asked Rockwell’s chief test pilot Merv Evinson, about this. Merv assured me that while it handled very nicely, it was still very definitely a bomber.
The final B-1B was rolled out at Palmdale in January 1988, and accepted by the USAF on April 30. Remarkably it was two months ahead of schedule, and the entire programme was within budget.
While work on the defensive avionics system continues, the fleet is gathering flight time and experience. The Air Force likes it; the crews like it. Recent changes in international relations mean that it will probably never fly its primary mission, but its whole raison d’etre was to deter, not to destroy. It can now be regarded as a mature system, and the spearhead of SAC. Perhaps we all should start calling it by its given name: Lancer.