Origins
The history of the B-1 is long and tortuous. It really started at the time that the North American B-70 was halted as a weapons system in 1960. The B-70 was a high-altitude Mach 3 penetrator, but after Gary Powers' U-2 was shot down, it became obvious that high altitude was no defence against missiles, and penetrating at low level seemed to be the only survivable option.
Various paper studies like AMPSS (advanced manned precision strike system) and SLAB (supersonic low-altitude bomber) were produced, but these didn't seem likely to result in any useful hardware. In 1962 the Air Force took a different approach. Instead of concentrating on hardware, it thought about the sort of situations in which a new bomber would be useful, and concluded that things like short field length, rapid reaction time and lots of clever offensive and defensive electronics were more important than supersonic speed over the target.
All these studies culminated in AMSA, or Advanced Manned Strategic Aircraft. In late 1966 the Air Force presented SecDef McNamara with its AMSA proposal. This called for a versatile aircraft capable of carrying 25 SRAMs or a heavy load of other ordnance over an unrefuelled range of 9500 km on a typical hi-low mission, with the ability to fly at high subsonic speed at low altitude and Mach 2.5 at altitude.
On November 3rd 1969 Requests for Proposals were sent out to Boeing, Rockwell International and General Dynamics for the aircraft, and Pratt and Whitney and General Electric for the engine. In June 1970 the winners were announced as Rockwell and General Electric.
The contract awarded to Rockwell was for five flight test and one static test aircraft. There was, however, a problem: there simply wasn't enough money available, so the design started to be downgraded. To begin with, avionics development was halted. Existing systems were to be used, although provision was made for more advanced equipment to be fitted at a later date. The amount of titanium in the airframe was reduced to about 21%. Although light and strong, titanium is relatively expensive, and 21% is roughly the point at which weight savings become increasingly more expensive. In addition, some of the operational requirements were reduced slightly.
These changes led to a B-1 that was heavier but smaller than AMSA, but costs continued to rise. Two of the original five aircraft ordered were cancelled, and the number of developmental engines was reduced from 40 to 27. The date of the first flight was put back, and the date for the production decision was deferred.
In April 1972 Boeing was selected to integrate the offensive avionics system, and in January 1974 the AIL Division of Cutler-Hammer secured the contract to do the same with the defensive avionics.
In mid-1973 an independent review of the program was critical of a number of areas in the development program, particularly the austere funding environment. This led to the funding of a fourth prototype.
One major change was the elimination of the crew escape capsule, which was found to be unstable at speeds above about 300 knots. This change came too late for the first three aircraft, but Number 4 and all subsequent aircraft were fitted with ejection seats instead.
The first B-1, 74-0158, was rolled out at Palmdale, California on October 26th 1974. After extensive ground tests it made its first flight on December 23rd 1974. After 78 minutes in the air it landed at Edwards AFB.
Development proceeded quite smoothly. On April 10th 1975 the aircraft reached supersonic speed for the first time (Mach 1.05), and also refuelled in the air for the first time. On November 11th it reached a speed of 560 knots at an altitude of 200ft at Edwards AFB.
In mid-1975 Rockwell was awarded a contract to build a fourth prototype. This was to have ejection seats, revised engine nacelles and an aft bay for defensive avionics.
The next aircraft to fly was Number 3, 74-0160, which made its first flight on April 1st 1976. It was scheduled to carried out offensive avionics, terrain-following and weapons delivery trials. It was followed by aircraft Number 2, 74-0159, which flew on June 14th 1976.
With three B-1s flying, development proceeded apace. On December 1st 1976 the production decision was taken; 244 B-1 bombers were to be procured. In April 1977 the B-1 team was awarded the Collier Trophy, presented annually for the "greatest achievement in aeronautics or astronautics in America". At this point 100 missions had been flown, for 542 hours.
On June 30th 1977, everything appeared to have been for naught: President Carter cancelled production of the B-1. The ostensible reasons were that aircraft carrying cruise missiles would be cheaper to build and operate, and that cruise missiles themselves would be more accurate and better able to penetrate Soviet air defences than a manned bomber.
Although production was stopped and 8000 workers laid off, construction of the 4th prototype was not affected, and the first three aircraft were retained for an R&D program. This took the form of the Bomber Penetration Evaluation, which began in late 1977, lasted for three and a half years and involved over 1350 flying hours.
The results of the BPE were remarkable. At 520 knots, 250 ft above the ground, following a winding track around and over the Nevada mountains, and jamming or confusing any radar close enough to be a problem, the B-1 proved very hard to track. The control centres frequently had no idea where the bomber was until it began its final attack run. The BPE essentially proved that the B-1 would be able to survive in hostile airspace.
On October 5th 1978, aircraft number 2 attained its highest-ever speed of Mach 2.22 at 50000ft.
On February 14th 1979 the fourth B-1, 76-0174, made its first flight. This aircraft carried the full avionics system, allowing testing to begin in earnest. Externally, it differed from its precessors in having a dorsal spine housing an experimental monopulse radar jamming system called Cross Eye (this was never fitted to a service aircraft). 76-0174 flew a lot of sorties in an operation called Giant Mask to evaluate how well it stood up to simulated Soviet defences.
The final BPE flight was made by the fourth aircraft on April 29th 1981. The four prototypes had flown a total of 347 missions for 1895 flight hours. In addition more than 25000 hours had been accumulated in the wind tunnel, the engines had accumulated nearly 7600 flight hours, the structural test airframe had been subjected to fatigue testing designed to simulate 3 aircraft lifetimes, 45 inert B-61 nuclear weapons had been dropped and 2 SRAMS launched.
By now it was obvious that the US really did need a new long-range multi-role aircraft, and an upgraded B-1 was the only serious contender. The proposed B-1B would have an extra 37 tonnes of payload, longer range and a smaller radar signature.
On October 20th 1981 President Reagan announced that 100 B-1Bs were to be built, with IOC some time in 1986. This would coincide with the B-52 being relegated to a stand-off cruise missile carrier, and also allow the Advanced Technology Bomber to be developed in a less urgent atmosphere. The total cost of the B-1B program was fixed at $20.5 billion at 1981 rates.
Differences between the B-1B and the B-1A are subtle, yet significant. Externally, only a simplified engine inlet, modified over-wing fairing and relocated pitot tubes are noticeable. Other less-evident changes include a window for the offensive and defensive systems officers' station and engine housing modifications that reduces radar exposure (and also makes the aircraft effectively subsonic). The B-1B was structurally redesigned to increase its gross takeoff weight by 20%, but only increasing its empty weight by 3%. This added takeoff weight capacity allows the B-1B to carry a wide variety of nuclear and conventional munitions. In addition, the avionics were significantly changed.
On January 20th 1982 Rockwell was awarded the full-scale development and the Lot 1 production contracts. On April 1st the first batch of F101 engines was ordered from GE. On June 8th the AIL Division of Eaton Corp. received the defensive avionics contract for Lot 1, and on June 11th Boeing received the same for the offensive avionics.
At this point the B-1B was still a paper aeroplane. A 1100-hour flying program based on the upgraded second and fourth B-1A prototypes was planned, with production B-1Bs joining the program later. Meanwhile the fourth B-1A flew the Atlantic and appeared at the Farnborough Air Show in September 1982. On its return to Edwards it was grounded for avionics modifications and was not to fly again until summer 1984.
In July 1982 work started on the second B-1A to modify it for the B-1B program. It flew again on March 23rd 1983. The fourth B-1A flew again on July 30th 1984. The former carried out stability and control, flutter and weapons release trials, and the latter tested the avionics. By March 1985 it had flown for 120 hours in 24 sorties.
On August 29th 1984 the program suffered its first mishap, when the second prototype crashed at Edwards AFB after CG limits were exceeded. Although the aircraft's escape module separated successfully, it made a hard landing which killed Rockwell CTP Doug Benefield and seriously injured pilot Maj Dick Reynolds and flight test engineer Capt Otto Waniczek.
The first B-1B, 82-0001, was rolled out at Palmdale on September 4th 1984. The new bomber took to the air on October 18th, 1984. It was flown and tested by M. L. Evenson, pilot; Lt. Col. L. B. Schroeder, copilot; Capt. D. E. Hamilton, defensive systems officer and Maj. S. A. Henry, offensive systems officer. The first flight originated from Palmdale and lasted three hours and 20 minutes before landing at Edwards Air Force Base. There the aircraft joined B-1A number 4 in the flight test program.
The first operational aircraft, 83-0065, was handed over to the Air Force at Offutt AFB, Nebraska, on July 27th 1985. After more than 20 years of trying, SAC at last had a modern bomber in its inventory.
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