GBU-28

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GBU-28


The GBU-28 / B

General Information
Designation: Guided Bomb Unit 28 Deep Throat
Type: Bunker-breaking laser-guided free-fall weapon
Country of origin: United States
Manufacturer: Texas Instruments , now Raytheon
Development: 1991
Commissioning: 1991
Unit price: $ 145,600
Technical specifications
Combat weight: 2268 kg
Length: 3886 mm
Diameter: 368 mm
Range: about 9 kilometers
Furnishing
Warhead: 545 kg Tritonal (BLU-113 / B)
Steering: Laser beam steering
Detonator: FMU-143 series (delay detonator)
Weapon platforms: McDonnell Douglas F-15 E
General Dynamics F-111 F.
List of bombs by country of origin

The laser-guided bomb GBU-28 / B (Guided Bomb Unit 28; nickname "Deep Throat") is a heavy, bunker-breaking, free-falling bomb weighing 2268 kg and belongs to the Paveway -III series . Their basic model was developed in 1991 during the Second Gulf War (Operation "Desert Storm") for the US Air Force . It took less than 12 weeks from conception to test maturity; After just one test drop, it was sent to the US Air Force for use in the Gulf War and successfully used against a massive Iraqi command bunker on the night of February 27-28, 1991 .

Development history

Beginning as a temporary measure in a crash program

When, after the start of the air offensive against Iraq (January 17, 1991), it was determined by the US Air Force that the available BLU-109 / B bunker-breaking bombs were unsuitable for the destruction of the largest Iraqi bunker facilities, one was earlier Study prepared during Operation Desert Shield (1990) was used as the basis for an urgent program to develop a suitable weapon for this purpose. The previously used BLU-109 / B bombs had proven to be fundamentally suitable for attacks on bunkers, but a weapon with considerably increased capabilities had to be developed for the largest and most heavily fortified Iraqi bunkers. The concept would have corresponded to the Tallboy type bombs developed by Barnes Wallis , which were successfully used by the RAF against German submarine bunkers during World War II . In order to keep the required time to be ready for use short, it was obvious that any development would have to make use of components already on the market.

Since increasing the bomb diameter due to the standardized suspension points under the wings of the US American bombers F-111 “Aardvark” and F-15E “Strike Eagle” was out of the question, as was the new weapon with the standard steering unit of the Paveway-III Row should be equipped, only an extended and heavier version with a diameter of the BLU-109 / B (around 37 centimeters) came into question.

Disused gun barrel as bomb cover

The program was under considerable time pressure from the start. Developing and building a suitable bomb cover would have taken weeks or even months. Tubes from the 203 mm self-propelled howitzer M110 , which had been decommissioned by the US Army and had been stored for some time in the Letterkenny Arsenal, a depot in the US state of Pennsylvania , were selected as the casing material for the new heavy bunker crusher version . By February 1, 1991, some of these pipes were hastily reworked in the Watervliet Army Arsenal in New York State . The further equipment was taken over by a cooperation of the armaments companies Lockheed Corporation and the "Texas Instruments Defense Systems and Electronic Group" (now part of the Raytheon group ), a part of the Texas Instruments group . These bombs were given the designation BLU-113 / B "Super Penetrator". On the " Tonopah Test Range " in the US state of Nevada , several of these bombs were subjected to a series of tests to prove their operational suitability. In a test with a rocket-propelled high-speed sled near Holloman Air Force Base in New Mexico , a test bomb filled with concrete achieved a penetration capacity of 6.7 meters of reinforced concrete, only to come to a rest after another 800 meters without major damage to the shell. The new development was almost complete. The new bomb - still without a steering unit - weighed around 545 kg Tritonal as an explosive filling 2136 kg and was nicknamed " Deep Throat " due to its enormous length of 7.6 meters based on the well-known film . A total of 33 of these bombs were made during the crash program.

In the meantime, the start of the land offensive of the US-led coalition forces was approaching, and the fight against the last, still intact, heavily bunkered command centers in Iraq became the focus of strategic planning in the Allied air force staff. After Texas Instruments had carried out the wind tunnel tests in record time on the weekend of February 16 and 17, 1991 and Lockheed had completed the development of new steering computer software, the US Air Force requested the construction of two more bombs to be carried out by test drops on Nellis Air Force Base , Nevada, to confirm the weapon’s readiness for use. In the meantime, the US Air Force had chosen the F-111F as a weapon carrier.

Drop test

The only test drop of the new weapon that could be carried out under the tight time conditions took place on February 24, 1991. The fully integrated bomb - now with its final designation GBU-28 / B (BLU-113 / B with Paveway III steering unit) - was dropped with a concrete filling from an F-111F onto a target bunker. The gun hit the bunker as expected and penetrated it. It was registered with astonishment that the bomb body had drilled its way through the bunker almost 31 meters deep into the clay-like desert floor. A recovery that was actually planned was not carried out for cost reasons.

After this test, two GBU-28 / B steering bombs (disassembled into their component parts: two steering computers WGU-36A / B, two steering units BSG-92 / B and two BLU-113 / B bomb bodies) were carried with a transport machine of the Lockheed C-141 “Starlifter” type to the Saudi Arabian air base “Taif RSAFB”, where the 48th Tactical Fighter Wing of the US Air Force was stationed. Immediately after unloading, the three-and-a-half hour assembly of the bombs began, and it took another 90 minutes to hang them under the wings of the two fighter-bombers. After a total of five hours of preparation, the weapons were ready for use. The two F-111F each carried a GBU-28 / B (with an operating weight of 2268 kg) under a wing; A laser-guided glide bomb GBU-24A / B weighing 909 kg was installed under the second wing to compensate for the weight, which nevertheless could not prevent the aircraft from hanging clearly to the side.

Use against the Iraqi bunker Taji # 2

Target selection

The goal of the planners on the coalition forces' staff was a bunker on a military airfield about 27 kilometers northwest of Baghdad. According to information from the secret services, this bunker with the code name "Taji # 2" was used by the Iraqi leadership as a command center. Until this 27./28. In February 1991, he had survived three attacks by “stealth” bombers of the Lockheed F-117A “Nighthawk” type with laser-guided GBU-27 / B glide bombs without significant damage.

attack

The attack on the "Taji # 2" bunker was ordered less than 12 hours before the armistice came into force (February 28 at 8:00 am Iraqi time). The operation of the two F-111Fs flown during the night was successful; at least one impact from the two GBU-28 / B bombs was observed. The effect at the target was enormous: it is reported that the bunker's six armored gates were torn from their anchorages in the explosion and an enormous fireball with a subsequent cloud of debris and debris rose from the destroyed bunker. Although official reports were not released, there were statements that the attack had killed numerous high-ranking members of the Iraqi political and military leadership.

Further development

A GBU-28 / B was dropped by a US Air Force F-15E fighter-bomber

After the end of the Gulf War in 1991, the successful crash program, which since its inception had been carried out without an official procurement order and without written contracts between government agencies and companies, continued under regular conditions. Necessary design changes, improvements and modifications (including a new bomb cover) have been made. In order to complete a regular series of tests, another 28 weapons were produced; additional units were put in stock to secure the capabilities of the GBU-28 / B for possible further missions. Today the GBU-28 / B is an important part of the US bombing arsenal. As a “bunker breaker” in the US Air Force's arsenal, it offers the US a non-nuclear option to combat underground and hardened bunkers.

The current laser search head of the GBU-28 / B is being replaced in the latest versions by a GBU-28 / B system with GPS support developed by Raytheon. The previous BLU-113 penetrator will be replaced by the BLU-122 / B warhead from the BLU-113 PPI program (Preplanned Product Improvement) . The further development runs under the designation EGBU-28C / B and is intended for use with the strategic stealth bomber Northrop B-2A "Spirit" and the fighter-bomber F-15E "Strike Eagle" (status: December 2008).

Export to Israel

The first foreign buyer of the GBU-28 / B was Israel , which ordered 100 units from the United States in 2005. In July 2006, at the urging of the Israeli government, the contracted extradition rate was increased after the Israeli secret service found that the Lebanese organization Hezbollah was carrying out its rocket attacks on Israel from underground bunkers and fortifications. In 2009, 55 units were delivered.

Web links

Individual evidence

  1. ↑ Globalsecurity.org: Guided Bomb Unit-28 (GBU-28) BLU-113 Penetrator Specifications ( English ) Retrieved November 20, 2009.
  2. ^ Report to the US Congress on the Implementation of the War on Iraq (Poli378), section on GBU-28 / B on the Rice University website
  3. ↑ a b "The GBU-28 Bunker Buster" Detailed article on the GBU-28 / B at www.ausairpower.com (English)
  4. ↑ a b c d e f Tom Clancy - Fighter Wing - A Guided Tour of an Air Force Combat Wing . Berkley Books, New York, 1995, pp. 154-157, ISBN 0-425-14957-9
  5. ↑ Guided Bomb Unit-28 (GBU-28) Bunker Buster - Smart Weapons
  6. ↑ Raytheon (Texas Instruments) Paveway III - Designation Systems Description of the Paveway III systems (English)
  7. ↑ US Wants to Sell Israel 'Bunker-Buster' Bombs . ( Memento of June 29, 2011 in the Internet Archive ) Article in the Financial Times of April 27, 2005 about the sale to Israel.
  8. ↑ Without the US Air Force, Israel can do little . In: Zeit Online , March 7, 2012.

Remarks

  1. ↑ The statement in Tom Clancy's book differs from the observations made in the article "The GBU-28 Bunker Buster" on [1] about the effect in the target. There it is written that it was not until about seven seconds after the impact of the bomb that smoke could be detected from one of the ventilation shafts of the bunker, which was interpreted as a successful penetration of the bomb into the interior of the bunker. Further observations are not mentioned there. These differences may be due to the various sources used by the authors, such as eyewitnesses, target camera recordings, and battle damage assessments .