New hard-target munitions for the US Air Force.

New Hard-Target Munitions for the US Air Force

The progressive hardening of permanent military installations by the Warsaw Pact has led to the introduction of a new generation of hardened target munitions in the United States Air Force .

For attacking such installations as aircraft shelters, command posts, munitions depots, bunkers, logistic facilities, etc. sited on the surface, underground or else protected in caves and cliffs as well as major structures such as bridges and tunnels on the enemy's L of C, operational squadrons of the Tactical Air Command are being issued with the BLU-109/B, a conventional bomb nicknamed the "Mole". Also going by the name of Project I-2000 (Improved 2000, standing for lbs), this weapon is derived from the general-purpose Standard Mk. 84 bomb. Used as a free-fall bomb, as the core of a guided bomb or else as a guided dispenser payload, the BLU-109/B is 2.4 metres long and has a diameter of 0.37 metres, 240 kg of the total delivery weight of 874 kg being accounted for by the Tritonal charge. The bomb's casing is of one piece and made of forged gunbarrel steel with a wall one inch thick. Depending on the angle of impact it can penetrate between 1.8 and 2.4 metres of reinforced concrete. During tests it also succeeded in penetrating granite and ship's armour plating. The USAF has a requirement for a total of 64 000 BLU-109/Bs. At present in service are a free-fall version and a guided bomb based on the GBU-10 Paveway II. In various feasibility and development phases there are, in addition, the following air-to-ground weapons using the BLU-109/B. * GBU-15 glide bomb * GBU-24 LLLGB (Low-Level Laser-Guided Bomb) * AGM-130 rocket-assisted glide bomb * The thermal image - guided Autonomous Guided Weapon * The 1 000 lb I-1000 version * An advanced rocket motor-boosted 610 m/s version for higher penetration effect.

The BLU-109/B is launched at speeds between 556 km/h and Mach 1.4. Currently serving as carrier aircraft are the F-4 (two bombs) and F-111 (four). Other types due to be qualified to carry the bomb are the F-16, F-15E and A-7. There are certain indications that the BLU-109/B may be the main armament of the F-117A Nighthawk stealth combat aircraft, of which the USAF recently publicly confirmed the existence in a heavily touched-up photo. Known for some years in professional circles as the F-19, the F-117A is optimized for tactical strike missions and thus offers minimal radar, infrared, noise and exhaust signatures and is said to have been in service with the 4450th Tactical Group, Nellis AFB, Nevada since October 1983. Until recently it only flew at night from the Tonopah Test Range Airfield, although it is now also flying by day. The USAF has ordered a series of 59 units of this single-seater subsonic plane, of which 52 have so far been assigned to operational squadrons. The last of the F-117As will enter into service in the course of FY 1990. According to unconfirmed reports the F-117A was designed for the attack of high-value permanent installations in nap-of-the-earth profile carrying a number of BLU-109/Bs. To achieve maximum penetration the free-fall bomb is usually dropped by the Nighthawk in a steep dive. The F-117A's stealth technology allows it to fly this attack profile which would otherwise make normal strike aircraft highly vulnerable to anti-aircraft fire. Conventional aircraft would have to approach in a low-altitude flight profile followed by a steep climb to toss the bomb in a ballistic trajectory. The BLU-109/B was developed in record time by the Lockheed Missiles & Space Company, Sunnyvale, California. Development started in May 1984, and initial deliveries to the USAF began in December 1985. Apart from Lockheed, which acted as main contractor, a number of other firms had a share in the programme - Fairchild Weston of Syosset, New York (tail fuze), National Forge of Warren, Pennsylvania and Cameron Iron Works of Houston, Texas (forged bomb casing), McAlester Army Depot, Oklahoma (explosives) and the Lookheed Austin Division of Austin, Texas (final assembly).

As from 1993 the US Air Force wants to put into service the Direct Airfield Attack Combined Munition (DAACM) dispenser-type weapon for the cratering and mining of enemy airfield runways and aprons. The 907 kg DAACM uses the SUU-64/B cluster ammunition airframe and carries a mix of 8 BLU-106/B BKEP (Bomb Kinetic Energy Penetrator) bombs and 24 HB876 area denial mines. The idea behind the DAACM (the programme is now on "hold" as the USAF are having second thoughts) is first to destroy runways with the BLU-106/Bs and then with the HB876 to make it impossible to repair them. The BLU-106/V munition was developed by Massachusets-based Textron Defense Systems and is capable of blowing craters of about three metres in diameter in runways. Once ejected from the dispenser, the bomb is retarded by a parachute which also gives it a correct dive angle (almost vertical) relative to the runway. At a predetermined altitude, a rocket motor forces the round into the concrete, where it explodes. The HB786 on the other hand was developed by Hunting Engineering in conjunction with Ferranti for the JP233 dispenser and for the HADES cluster bomb. This munition, which will also be used in the Hunting SWAARM weapon system currently under development for the Royal Air Force, weighs just over one kilogramme. It contains a shaped charge surrounded by a pre-fragmented belt for effect against personnel and soft-skinned vehicles. The 24 HB786s also descend by parachute and land after the BLUs have finished their destructive work. On touchdown, spring legs deploy to turn the munition upright. Detonation occurs when the munition is moved or initiated by its sensors, but it can also be programmed to take place at any preset time or at random. On detonation, the steel warhead casing produces a high-velocity slug capable of penetrating the blade of a clearance vehicle and damaging its engine. Fragments will reach longer distance targets such as vehicles and parked aircraft.

The BLU 106/B runway penetrating bomb is also being trialled as a payload for the MSOW family of guided stand-off dispensers as well as for a cruise missile. The BLU/106/B is claimed to have three times the penetration effect of the Durandal. This French bomb operates on the same principle as the BLU106/B and was bought in large numbers by the USAF as a temporary stop-gap.

PHOTO : Rockwell's AGM-130 missile, basically a booster-powered and guided Mk. 84 bomb, has recently undergone a series of trials.

PHOTO : The F-117A, in service with the US Air Force since 1983, is believed to be carrying the BLU-109/B as its primary armament.

PHOTO : The DAACM is an SUU-64/B dispenser carrying a mix of eight Textron BLU-106/B runway cratering bombs and 24 HB876 Hunting Engineering area denial mines.