XB-70
One of several abortive attempts in the 1960s to produce a new strategic bomber was the XB-70 Valkyrie, a six-engined behemoth and the largest bomber ever built. The B-70 was intended to fly for long periods at Mach 3 at high altitude, but its extraordinary performance was paralleled by its enormous costs, and after a spectacular crash in which one of the two prototypes was destroyed the whole project was cancelled.
B-1
The US air force’s final Cold War bomber was the B-1, which had a very protracted gestation, its official designation of AMSA (Advanced Manned
Strategic
Aircraft) being misinterpreted by cynics as ‘America’s Most Studied Aircraft’. One particularly strong argument in the early 1960s against the project was simply to question the need for a new manned bomber at all, since vast sums were already being spent on ICBMs, on upgrading B-52s for the air force, and on building new SSBNs and SLBMs for the navy. Even those who supported the need for a new bomber could not agree on what sort of aircraft was needed, but in 1971 the air force placed an order for an initial quantity of four B-1As, a four-engined, swing-wing aircraft, capable of Mach 2 at high altitudes. The first prototype flew in 1974, but when the Carter administration assumed power in January 1977 it gave high priority to an antagonistic examination of the project, which led to its cancellation, virtually in its entirety, that June. When the Reagan administration took over in 1981, however, the air force proposed a new version of the aircraft, optimized for low-level, stealthy penetration, which emerged as the B-1B. An order for 100 was placed, and they entered service from 1985 onwards.
In the low-level penetration role the B-1B flew at Mach 0.85 at a height of about 60 m. The B-1B defended itself partly through very sophisticated electronic-warfare equipment, but also through ‘stealth’ design, it being claimed that the B-1A had a radar cross-section (RCS) one-tenth that of a B-52, while the B-1B had an RCS one-tenth that of the B-1A. Payload comprised various combinations of Air-Launched Cruise Missiles, Short-Range Attack Missiles and nuclear gravity bombs.
SOVIET AIRCRAFT
Tu-4
At the start of the Cold War the Soviet Union saw itself as threatened by the long-range bombers of the USA but without any effective means of retaliation. For some years the Soviet air force depended upon a copy of the B-29, which had been reverse-engineered (i.e. copied) from three USAAF aircraft which had landed and been interned at Soviet airbases during the Second World War. Designated the Tupolev Tu-4 (NATO = ‘Bull’), large numbers served with the Soviet air force and thirteen were passed to the Chinese air force, which also used them for a time as nuclear bombers. The Tupolev bureau designed improved and larger versions of the Tu-4, but the Soviet leadership decided not to develop piston-engined bombers any further and to concentrate on the development of turboprop and turbojet designs.
Tu-16
The first Soviet design to enter service, in 1954, was the Tupolev Tu-16 (NATO = ‘Badger’), which was similar in capability to the US B-47 and the
British
Valiant (
see Chapter 12
), but with only two engines. Unlike those American and British designs, however, the Tu-16 remained in service for many years, with over 2,000 being built, of which the majority were still in service at the end of the Cold War. There were numerous versions, but the nuclear version carried two nuclear bombs in an internal bomb bay, and 287 of this strategic-bomber version remained in service as late as 1987. The Tu-16 was capable of carrying its maximum load of two nuclear weapons over a range of some 4,800 km at a speed of 780 km/h, which enabled it to threaten targets in Europe, Alaska and Japan, but not in the continental USA.
Tu-22
As the US progressed to the Convair B-58, so too did the Soviet air force develop supersonic bombers: the Myasishchev M-4 (NATO = ‘Bounder’), which progressed no further than the prototype stage, and the Tupolev Tu-22 (NATO = ‘Blinder’). The Tu-22 was a large and sophisticated aircraft, with highly swept wings and two massive turbojets in the tail, giving it a dash speed of Mach 1.4 at 12,000 m. Payload was either two nuclear gravity bombs carried internally or a ‘Kitchen’ cruise missile. Combat radius at high altitude was 2,250 km, with a 400 km supersonic dash over the target (or less at low level).
Tu-20/Tu-95
The Tupolev design bureau also produced the Tupolev Tu-20 (NATO = ‘Bear’) – a remarkable design, which first flew in 1955 and entered service in 1956. To the astonishment of Western observers, this aircraft combined swept wings with turboprop engines, and, despite its undoubted success, it remains the only aircraft to combine these two features. The Tu-20 had the immense range, without air-to-air refuelling, of 14,800 km with a payload of at least four nuclear bombs. It was regularly underrated by Western observers, especially in the Pentagon, despite regular non-stop flights by both military and civil versions from the USSR to Cuba. A variety of versions were still in wide-scale service at the end of the Cold War.
Strategic versions were the Bear-A bomber, carrying two nuclear gravity bombs, the missile-carrying Tu-95 Bear-B, carrying a huge AS-3 (NATO = ‘Kangaroo’) cruise missile with an 800 kT nuclear warhead and a range of some 680 km, and the Bear-H attack version, which carried four AS-15 ‘Kent’ cruise missiles, with a range of 3,000 km. All types of Bear regularly carried out training missions against NATO countries, approaching to within some 80 km of the US and British coasts. On an operational sortie against the USA, however, it would have had to fly at medium and high altitudes to obtain maximum range, which would have made it vulnerable to US and allied fighters.
M-6
Contemporary with the US B-52 was the Myasishchev M-6 (NATO = ‘Bison’), a large swept-wing strategic bomber, powered by four turbojets, rather than the Tu-20’s turboprops. The large number of M-6s dreaded by the West never materialized, as their performance – particularly the range and the size of the bomb bay – never quite met the operational requirement, and the M-6 was then used for reconnaissance and electronic-intelligence tasks; however, it was symptomatic of the atmosphere of the time that its appearance in 1955 caused much excitement in the United States and led to a great increase in the production rate of the B-52. Like the Bear, the M-6 would have had to approach the USA at medium to high altitudes.
Tu-22M/Tu-26
In 1969 US satellites began to return photographs of a new Soviet bomber on the apron at the new aircraft factory at Kazan. This turned out to be a swing-wing version of the Tupolev Tu-22, designated Tu-22M (NATO = ‘Backfire’). Subsequently, a virtually new aircraft with some external similarities to the Tu-22M appeared and was put into production as the Tu-26 (NATO = ‘Backfire-B’). (The relationship between the Tu-22M and the Tu-26 was probably similar to that between the American B-1A and B-1B.)
Three versions of the Tu-26 entered service, one of which carried nuclear weapons for use in the land-attack role. There were, however, repeated arguments between the United States and the Soviet Union over the role of this bomber, with the former stating and the latter denying that it was a strategic bomber. This became a major issue in the SALT II negotiations, and President Brezhnev eventually ordered that the aircraft’s flight-refuelling probes be removed to prove that it did not have the ability to reach the USA, although since these could have been replaced in less than thirty minutes this was only a token gesture. The Tu-26 entered service in the mid-1970s and was produced at the rate agreed under SALT II – thirty per year – with service numbers peaking at about 220.
Tu-160
Finally came the Tupolev Tu-160 (NATO = ‘Blackjack’), which flew for the first time in 1981 and just eighteen entered service from 1987 onwards. With a maximum take-off weight of 275,000 kg this was the heaviest combat aircraft ever built, and it carried a payload of 16,330 kg. The Tu-160 was fitted with swing wings and powered by four very powerful turbojets, giving it a range of 14,000 km at a height of 18,300 m, with a cruising speed of 850 km/h and a dash speed of Mach 1.9. The Tu-160 was also capable of low-level attack. Two large bomb bays could house nuclear gravity bombs, short-range missiles, or air-launched cruise missiles. Ironically, this remarkable aircraft – one of the finest bombers ever built, which at long last gave the
Soviet
Union the strategic bombing capability it had always sought – appeared just as the Cold War came to an end.
STAND-OFF MISSILES
Bomber designers and the tacticians fought an unending war against the potential defenders in an effort to ensure that the bomber would get through to its targets. In the late 1940s the major threat came from radar-directed anti-aircraft guns, which had reached a considerable degree of sophistication, and the bombers’ first response was simply to fly higher than the effective ceiling of the guns. The next threat was air-defence fighters, and here again the bombers responded by flying higher and faster – there were numerous reports of British and US reconnaissance flights over the USSR in the early 1950s in which the Soviet fighters simply could not reach the same altitude as the intruder.
Second World War bombers were fitted with machine-guns in a variety of positions – including the nose, the waist, above and below the fuselage, and the tail – but these were rapidly reduced to just the tail, the elimination of the others saving considerable weight and enabling the aircraft to fly higher and faster. Also in the Second World War, bombers had been escorted by fighters, particularly on the USAAF’s daylight raids; but the strategic ranges now being flown were far in excess of anything a fighter could undertake. So in the 1950s the US air force trialled the idea of the B-36 bomber taking a fighter with it, with the latter being carried on a retractable cradle from which it could be launched in mid-air to deal with enemy fighters, then being recovered for the return to base. A special miniature fighter, the McDonnell XF-85 Goblin, was tested, as was the RF-84K, a modified version of the full-size F-84 Thunderjet fighter, but, although launching proved feasible, recovery did not, and the idea was not pursued.
Electronic countermeasures (ECM) were always used, becoming increasingly sophisticated as time passed. Thus electronic jamming was used to confuse enemy radars, as was ‘chaff’ (strips of metal foil cut to the wavelength of the radar), which was dropped in large quantities, either by the bomber or by specialized escorting aircraft.
One of the earliest devices to help the bomber get through was the US air force’s ADM-20 Quail, which resembled a miniature unmanned aircraft and was dropped over enemy territory, where it flew for some 400 km, using its on-board ECM devices to confuse the enemy as to the strength, direction and probable targets of the incoming bomber force. A maximum of three Quails could be carried by a B-52, and the device was in service from 1962 to 1979.
The main emphasis then turned to stand-off missiles – a concept which,
like
so many others, had its genesis in Germany, where V-1 missiles had been launched from Heinkel He-111 bombers in 1944–5. The Cold War missiles carried a nuclear warhead and were designed to be launched from the bomber while still outside the range of the enemy air defences. One of the first was the US Hound Dog – a slim missile with small delta wings, and powered by a turbojet – which entered service in 1961. Two Hound Dogs, each with a 1 MT nuclear warhead, were carried beneath the wings of a B-52. The missile could be set to fly at any height between about 50 m and 16,000 m, and had a range at high level of 1,140 km, less at low level. The guidance system was capable of high- or low-level approach, with dog-legs and jinxes to confuse the defence.
Next came the unhappy saga of Skybolt, which was an attempt to use a bomber to launch a ballistic missile, which would have given longer range and, of greater importance, a much shorter flight time. The UK air force joined the project, but the incoming Kennedy administration unilaterally cancelled it in December 1961 – greatly to the indignation of the British, who used the issue as a lever to obtain Polaris missiles and SSBN technology to replace its V-force bombers (
see Chapter 12
).
The Short-Range Attack Missile (SRAM), which entered service in 1972, was a rocket-propelled missile with a 170 kT nuclear warhead and a speed of Mach 3. SRAMs could fly either a semi-ballistic, a terrain-following or an ‘under-the-radar’ flight profile, the latter terminating in a pull-up and high-angle dive on to the target. The range depended on the height, and was from 56 km at low level to 170 km at high level. B-52s normally carried twenty SRAMs, while the FB-111A carried six and the B-1B twenty-four.
The Air-Launched Cruise Missile (ALCM) entered service with the US air force in 1982. This weapon had folding wings which extended when it was dropped from the carrier aircraft, and was powered by a small turbojet engine. Designed exclusively for low-level flight, the ALCM used a radar altimeter to maintain height and a map-matching process known as terrain comparison (TerCom) to give very precise navigation. The nuclear-armed version (AGM-96B) had a 200 kT warhead, a CEP of 30 m and a range of some 2,500 km. The AGM-96C was conventionally armed, with a high-explosive warhead, and this version demonstrated its effectiveness and accuracy when thirty-five were launched by B-52s during the Gulf War. B-52s could carry up to twelve and B-1Bs twenty-four.
Soviet stand-off missile development followed a similar pattern and time-scale, although in the early stages of the Cold War the missiles tended to be much larger and less effective than their US counterparts. Indeed, the first missile designed for use by strategic bombers, the AS-3 (NATO = ‘Kangaroo’) remains the largest air-launched missile to go into service, with a length of some 15 m, a wingspan of 9 m and a weight of 11,000 kg; only one could be carried by a Tu-95 (Bear-B). It did, however, have a useful
range
(650 km) and a high speed (Mach 2), and with an 800 kT warhead it was targeted against large area targets such as cities and ports.