Concrete-piercing bombs (BetAB) designed for efficient destruction of concrete covers and runways of airfields. Constructively presented with 2 main types of bombs: free fall and with jet boosters. Concrete-free-fall bombs designed for bombing huge heights and structurally very similar to the standard thick-walled high-explosive bombs. Concrete-piercing bombs parachute and jet accelerators used for bombing all heights (including small ones). Due to the angle of incidence of the parachute bomb rises to 60 degrees, then the parachute and started fires back booster jet.
In most cases, the mass of concrete-bombs is 500-1000 kg., With all this can occur bombs and larger caliber. Such kind of weapon created to destroy targets with a sturdy concrete or concrete protection or very armored targets. For example, fortifications (such as DOT), bunkers, shore batteries, runway or large warships.
Currently, more mainstream American concrete-bomb, which is known in the world, is the GBU-28 (BLU-113), which was created before the operation «Desert Storm» and was created to destroy Saddam Hussein’s bunkers. Task to develop similar bombs in October 1990 was issued design units ASD Development Planning group, located on the Eglin Air Force Base in Florida, USA. By working on this project were also connected companies spetsy Space Company and Lockheed Missile.
In order to successfully penetrate the ground, floors made of concrete and armor, the bomb must be quite weighty, also own a small cross section (in order not to «spread» its kinetic energy over a large area), other than that it should consist of solid alloy. It is necessary in order to contact with an obstacle warhead did not fire on a rigid surface, and penetrated her. In his time in the U.S. broke head over to find and make a suitable housing for concrete-bomb. Out of the situation gave a hint last army officer who worked in the company Lockheed. He remembered that artillery depots stored huge number of trunks from 203 mm howitzer M201 SP.
These trunks were made of suitable alloy and found in sufficient quantities to artillery arsenals, namely arsenal Watervliet, in the State of New-york. Specifically, in the workshops of this arsenal artillery guns were brought to the desired size. For production of cut bomb under these dimensions, then removed all of the protruding elements located on the outer side. Inside trunks were specially reamed, their diameter was brought up to 10 inches (245 mm). It was made in order to newcomer to «body» bomb could apply a tip from an old BetAB BLU-109.
With terrain Watervliet Arsenal collected body for bombs were delivered to Eglin base, where they had to fill with explosives. With all this, special equipment for bomb of this size at the airbase was not simple, and operate military had actually artisanal methods. So namely, an insulating layer, which was deposited on the inner surface of the bombs was to pass a function of heat treatment in a special oven, but instead of the engineers at the military base had to use makeshift outdoor electric heater. Dug into the ground body bombs, hand poured buckets in her hot molten tritonal. Guidance systems for bombs was applied laser sighting device of GBU-24. The result of all works was the warhead, which received the title of BLU-113, and all completely bomb was designated GBU-28.
Since time was running out to the creators, they did not carry out a series of 30 test launches laid, confining only with 2. February 24, 1991 the first bomb GBU-28 was dropped from the F-111 on the desert ground in the United States. Betonoboynymi bomb went off in the soil to a depth of 30 meters — from this depth it even decided not to dig. Even a day or two later broke up a bomb on the rail cart and reactive shot at standing upright pile of concrete slabs. Ultimately bomb broke all the plates and flew another 400 meters.
2 more body, which had been prepared Eglin AFB, were charged with explosives, equipped and sent to combat test in Iraq. The advantage of using the full in the air, February 23, 1991 2 tactical fighter F-111 without any problems reached its goal — 1st of underground bunkers belonging to the Iraqi army. While one of the F-111 backlit purpose other inputs on the bombing. Ultimately, one of the bombs went past, and the other hit the target, leaving the surface of any visible damage. Only 7 seconds from the ventilation shaft hopper went thick dark smoke that could only mean one thing — the bunker was struck and killed. From setting tasks to combat test the latest bombs GBU-28 has only been 4 months.
International developments in this area
Another first 90s defense ministries of NATO states series: United States, Germany, England and France were formed munitions requirements with high penetrating power. This kind of bomb would be used against perfectly protected underground enemy targets (thickness slabs up to 6 meters). In the current time in sufficient quantity are executed only bombs of type 1, which is able to damage such facilities. This South American bomb BLU-113, which comes in the guided air bombs (ASD) GBU-28 and GBU-37 (the total mass of 2300 kg). Such concrete-piercing bombs can be placed in strategic weapons bay bombers B-2A or a ventral suspension point tactical fighter F-15E. Proceeding from this, the military think about developing lighter ammunition of this type that would use them with other aircraft carriers, which have restrictions on the size and weight of bombs placed on the pylons.
South American and European experts at 2 pushed the concept of creating new concrete-piercing ammunition weighing less than 1000 kg. According made in Europe concept proposes the creation of tandem warheads betonoboynymi new type (TBBCH). Currently, the Air Force has made concrete-England submunitions with tandem cumulative and explosive charges — SG-357, which are part of the non-resettable aviation equipment JP-233 cassette and is intended to defeat airport runways.
But due to the small size and low power charges SG-357 is not able to destroy objects located deep underground. Proposed newcomer TBBCH consists of an optical non-contact detonation device (ONVU), also 1st or more shaped charges that are specifically before the main warhead bomb (OBCH). With all of this main body warhead bombs made from durable materials based on tungsten steel using other heavy metals possessing similar qualities. Located inside the explosive charge, and in the bottom of the bomb detonation programmable device.
According to the developers, the loss of kinetic energy OBCH eventually interaction with detonation products will not exceed 10% of the initial value. Undermining the cumulative charge is on a rational distance from the target to disk imaging coming from ONVU. As shown in the result of the interaction of cumulative jet bombs obstacle space OBCH directed that after the defeat of the remainder of the barriers already explodes inside the object. The laboratory studies have shown that the penetration depth of the concrete-piercing bombs in the main barrier depends on the speed of the collision, as the physical characteristics of the interacting bodies (such as hardness, density, tensile strength, etc.), as the ratio of the mass of warhead and cross-sectional area, and TBBCH for bombs besides the diameter of the shaped charge.
The defeat of the concrete bomb shelters for aircraft
During testing TBBCH bombs up to 500 kg (impact velocity with an object 260-335 m / s) it was found that they can seep into the ground at an average density of 6-9 meters in depth, then punching a concrete slab with a total width of 3 -6 meters. In addition, these munitions can successfully hit targets at the least, than ordinary concrete-piercing bombs, kinetic energies, at least as acute angles of attack and more than sharp corners approach to the target.
In turn, South American spetsy went towards improving the existing unitary betonoboynymi combat units (UBBCH). Feature of the implementation of such bombs is that they need to make before the collision with the aim of huge kinetic energy, resulting in significantly increasing demands on their body. When developing new ammunition Americans conducted a series of studies aimed at developing a particularly strong alloys for the production of housing, and finding good geometric dimensions (eg, nose bombs).
To increase the ratio of warhead mass and cross-sectional area that provides a tremendous penetrating power, it was proposed and same dimensions available ammunition to increase the thickness of their shell by reducing the amount of explosives in the warhead bombs. The advantages of the new UBBCH can confidently carry simplicity of their design and more than a low cost, especially in comparison with tandem ammunition. As a result, a series of tests it was found that a new type UBBCH (weighing up to 1000 kg. And speed of 300 m / s) can seep into the soil to a depth of an average density of 18 to 36 meters and fight with all this concrete floors 1,8 -3,6 meter. Work to improve these characteristics still last.
At the current time on the Russian army is type 2 betonoboynymi bomb weighing 500 kg. Betonoboynymi svobodnopadayuschie bomb BETAB-500U is designed for the destruction of underground warehouses of ammunition, fuel, nuclear weapons, communications centers, command and control Fri, concrete shelters (including aircraft), freeways, taxiways, etc. This bomb can penetrate concrete or 1.2 meters to 3 meters of soil. Can be used at altitudes from 150 meters to 20,000 meters at speeds of 500 to 2300 km / h To ensure that the angle of incidence of 90 degrees bomb equipped with a parachute.
Russian bomb betonoboynymi BetAB 500SHP sectional
Width: 450 mm.
Length: 2480 mm.
Weight bombs 510 kg.
Explosive weight: 45 kg. TNT
Second concrete-air bomb is BETAB-500SHP — assault with a jet accelerator. This bomb is designed for the destruction of airport runways and taxiways, concrete shelters airplanes, freeways. This ammunition can penetrate armor up to 550 mm width. At an average density of the soil is capable of forming a bomb crater with a diameter of 4.5 meters. When the bombs hit the runway in the concrete cover is damaged on an area of 50 square meters. meters. This bomb is applied from aircraft at speeds 700 — 1150 km / h and at altitudes from 170 to 1000 meters (horizontal flight). When you dive-bombing at an angle less than 30 degrees and at a height of over 500 meters.
Width: 325 mm.
Length: 2509 mm.
Weight bomb: 424 kg.
Explosive weight: 77 kg.