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AGM-86B ALCM Air-Launched Cruise Missile
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AGM-86B |
The
AGM-86B ALCM (Air-Launched Cruise Missile) is the major long-range
standoff attack missile of the U.S. Air Force's B-52H Stratofortress
strategic bombers. With the conversion of nuclear armed rounds to
conventional warheads, the AGM-86 will remain a very important weapon
for the foreseeable future.
Development of the ALCM can be traced back to January
1968, when the USAF drew up a requirement for a vehicle called SCAD
(Subsonic Cruise Aircraft Decoy). SCAD was to be a decoy missile
carried by B-52 and B-1A bombers, which was to simulate the bombers on
radar to disrupt enemy air-defense systems. As such, it was
essentially a follow-on to the ADM-20 Quail decoy. Early in the
concept phase it became clear that SCAD could also be fitted with a
small nuclear warhead, and the acronym was accordingly changed to
Subsonic Cruise Armed Decoy. Full scale development was approved in
July 1970, and the designation ZAGM-86A was assigned to SCAD. In the
early 1970s, however, the expected cost of SCAD's advanced electronic
systems rose dramatically. In June 1973, development was halted after
it had become clear that it was more cost effective to develop a pure
attack cruise missile without any decoy capability.
Following SCAD's cancellation, the USAF immediately
started a new program for a long-range nuclear-armed air-launched
cruise missile, using SCAD as a starting point. In September 1974,
Boeing was awarded a contract to develop the new missile. The
designation AGM-86A was retained, because the new ALCM was essentially
an armed SCAD. The AGM-86A was only 4.3 m (14 ft) long and could
therefore be used with the same launchers as the AGM-69 SRAM. The
first powered flight occured in March 1976, and the first fully guided
flight succeeded in September that year. The AGM-86A used an inertial
navigation system together with a TERCOM (Terrain Contour Matching)
system.
During AGM-86A development, the USAF had already
issued a requirement for an extended range (2400 km (1500 miles))
missile. There were two viable options to achieve this, either by
using external fuel tanks with an essentially unchanged AGM-86A, or
with a new lengthened missile called ERV (Extended Range Vehicle). The
ERV had the drawback that existing external AGM-69 SRAM launchers
could not be used, and that the missile would fit no longer into the
bomb bay of the B-1A. The Air Force therefore decided to field the
AGM-86A first, later to be followed by either the external tank
missile or the ERV. In January 1977, the AGM-86A was cleared for
full-scale production, but this was not to be, because 1977 saw
another drastic change in the direction of the ALCM program.
Under a program called JCMP (Joint Cruise Missile
Project), the USAF and the U.S. Navy were directed to develop their
cruise missiles using a common technology base. At that time the Navy
had just declared the BGM-109 Tomahawk as winner of its SLCM
(Sea-Launched Cruise Missile) competition. One consequence of JCMP was
that only one cruise missile propulsion system (the Williams F107
turbofan of the AGM-86) and TERCOM guidance system (the
McDonnell-Douglas AN/DPW-23 of the BGM-109) would be further
developed. Another one was the cancellation of the short-range
AGM-86A, together with a directive to select a long-range ALCM from a
competition between the ERV ALCM (now designated AGM-86B) and an
AGM-109 air-launched version of Tomahawk. The first flight of an
AGM-86B occurred in August 1979, and in March 1980 the AGM-86B was
declared winner of the fly-off with the AGM-109. Full-scale production
started soon after, and in August 1981, the ALCM was operational with
the B-52G/H Stratofortress.
The AGM-86B is powered by a single Williams
F107-WR-100 or -101 turbofan engine, and armed with a W-80-1
variable-yield thermonuclear warhead. It is equipped with a Litton
P-1000 inertial navigation system, which is updated until immediately
before launch by the B-52's INS. The wings and control surfaces are
folded to the fuselage, and are unfolded in about 2 seconds after
launch. Once at low-level, the AGM-86B uses its McDonnell-Douglas
AN/DPW-23 TERCOM system to find its way to the target. In a TERCOM
system, altitude information obtained by a radar altimeter is
continuously matched to a preprogrammed radar map of the area below
the missile, so that the ALCM can effectively follow a detailed
predetermined flight path. The accuracy of the whole guidance system
is probably between 30 m (100 ft) and 90 m (300 ft) CEP. B-52Hs
equipped with the new CSRL (Common Strategic Rotary Launcher) in the
bomb bay can carry up to 20 ALCMs, 8 on the CSRL and a further 12 on
two wing pylons.
When production ended in 1986, Boeing had delivered
more than 1700 AGM-86B ALCMs. Because the intended successor, the
AGM-129 ACM was built in much smaller numbers than anticipated, the
AGM-86 will remain in the USAF's arsenal for the quite some time,
although most of them will be converted to CALCMs.
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AGM-86C |
In 1986, Boeing
began converting some AGM-86Bs to AGM-86C standard. The main change is
the substitution of the nuclear warhead with a conventional 900 kg
(2000 lb) class blast-fragmentation warhead, and the AGM-86C is
therefore also known as CALCM (Conventional ALCM). It is rather
convenient that the C suffix of the designation can also be read as
"Conventional", but other than most press releases may suggest, this
is pure coincidence. The AGM-86C is also equipped with a GPS receiver
for significantly increased accuracy. The AGM-86C was used very
successfully during Operation Desert Storm in 1991, and in the NATO's
war against Serbia in 1999. Because the CALCM is heavier than the
nuclear ALCM, range is significantly reduced.
The original AGM-86C is known as CALCM Block 0. A new
Block I configuration, using improved avionics and GPS receiver and a
larger 1450 kg (3000 lb) blast-fragmentation warhead, was successfully
tested in 1996, and all existing Block 0 missiles were upgraded to
Block I configuration. Block IA is a further improvement to achieve
very high precision terminal guidance. It features an extremely
accurate optimized multi-channel GPS receiver, and also incorporates
enhanced shallow and steep terminal dive capability. The projected
accuracy is said to be 3 m (10 ft). Development of Block IA started in
1998, and the first missiles were delivered to the USAF in January
2001. More than 300 ALCMs have already been converted to AGM-86Cs, and
Boeing has contracts to convert several hundred more to CALCM Block
I/IA configuration. The DATM-86C is a handling and loading practice
variant of the CALCM with completely inert warhead and propulsion
sections.
The AGM-86D CALCM Block II is equipped with a new
Lockheed Martin 540 kg (1200 lb) AUP (Advanced Unitary Penetrator)
penetrating warhead for use against deeply buried and/or hardened
targets. The first flight test of an AGM-86D occurred in November
2001, and it is currently planned to produce almost 200 CALCMs as
AGM-86Ds.
Specifications: |
| Length |
6.32 m (20 ft 9 in) |
| Wingspan |
3.66 m (12 ft) |
| Diameter |
62 cm (24.5 in) |
| Weight |
1450 kg (3200 lb)
AGM-86C Block I: 1950 kg (4300 lb) |
| Speed |
800 km/h (500 mph) |
| Range |
2400 km (1500 miles)
AGM-86C Block I: 1200 km (750 miles) |
| Propulsion |
Williams F107-WR-101
turbofan; 2.7 kN (600 lb) |
| Warhead |
W-80-1 thermonuclear
(5-150 kT)
AGM-86C Block I: 1450 kg (3000 lb) HE blast-fragmentation
AGM-86D: 540 kg (1200 lb) hard-target penetrator |
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