Glide bomb
A glide bomb is an aerial bomb
A bomb is any of a range of explosive weapons that only rely on the exothermic reaction of an explosive material to provide an extremely sudden and violent release of energy...

 modified with aerodynamic surfaces to modify its flight path from a purely ballistic
Ballistics is the science of mechanics that deals with the flight, behavior, and effects of projectiles, especially bullets, gravity bombs, rockets, or the like; the science or art of designing and accelerating projectiles so as to achieve a desired performance.A ballistic body is a body which is...

 one to a flatter, gliding, one. This extends the range between the launch aircraft and the target. Glide bombs are often fitted with control systems, allowing the controlling aircraft to direct the bomb to a pinpoint target.

World War I

During October 1914, Dr. Wilhelm von Siemens suggested what became known as the Siemens torpedo glider, a wire-guided flying missile which would essentially have comprised a naval torpedo with attached airframe. It was not intended to be flown into a target but rather at a suitable altitude and position a signal would be transmitted causing the airframe components to detach from the torpedo which would then enter the water and continue towards its target. Guidance signals were to be transmitted through a thin copper wire, and guide flares were to be carried to help control.

Siemens-Schuckertwerke was already occupied with remote controlled boats (the FL-boat
The FL-boat was a weapon used by the Imperial German Navy during World War I. It was a remote-controlled motorboat, 17 m long, carrying 700 kg of explosives, which was intended to be steered directly at its targets - initially the Royal Navy monitors operating off the coast of Flanders.FL-boats...

s or Fernlenkboote), and had some experience in this area. Flight testing was performed under the supervision of Dipl. Ing. Dorner from January 1915 onwards, using airships as carriers and different types of biplane and monoplane gliders airframes to which a torpedo was fitted. The last test flight was performed on 1918-08-02.

It was planned to use the R VIII bomber as a carrier craft, but the Armistice stopped the project.

World War II

During World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

 the first operational glide bombs were developed by the Germans
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 as an anti-shipping weapon. Ships are typically very difficult to attack: a direct hit is needed to do any serious damage, and hitting a target as small as a ship was difficult during WWII. At first they used dive bomber
Dive bomber
A dive bomber is a bomber aircraft that dives directly at its targets in order to provide greater accuracy for the bomb it drops. Diving towards the target reduces the distance the bomb has to fall, which is the primary factor in determining the accuracy of the drop...

s with some success in this role, but their successes were countered by ever increasing anti-aircraft defenses placed on the Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 ships they were attacking. By 1941 such attacks were still just as difficult as ever, but the added defenses made such attacks almost suicidal.

The German solution was the development of a number of glide bombs employing radio control
Radio control
Radio control is the use of radio signals to remotely control a device. The term is used frequently to refer to the control of model vehicles from a hand-held radio transmitter...

 guidance. One was created by fitting a control package on the rear of an otherwise standard bomb, starting with their 100 kg armor-piercing bomb to create the Ruhrstahl SD 1400, commonly referred to as Fritz-X
Fritz X
Fritz X was the most common name for a German guided anti-ship glide bomb used during World War II. Fritz X was a nickname used both by Allied and Luftwaffe personnel. Alternate names include Ruhrstahl SD 1400 X, Kramer X-1, PC 1400X or FX 1400...

. This bomb was designed specifically to pierce the heavy deck armor of heavy cruisers and battleships. The bomb aimer dropped the bomb from high altitude while the aircraft was still approaching the ship, and guided it into an impact with the target by sending commands to spoilers attached to the rear of the bomb. This proved to be difficult to do, because as the bomb dropped toward the target it fell further behind the launch aircraft, eventually becoming difficult to see. This problem was solved by having the launch aircraft slow down and enter a climb to avoid overtaking the bomb as it fell.

In addition it proved difficult to properly guide the bomb to impact as the angle of descent changed, and if the bombardier didn't "get it right" and end up with the bomb roughly right over the target, there was little they could do at late stages to fix the problem. Nevertheless the Fritz X proved useful once crews were trained on its use. In test drops from 8000 m (26,246.7 ft), experienced bomb aimers could place half the bombs within a 15 metre radius and 90% within 30 metre.

Following the capitulation of Italy in 1943, Germany damaged the Italian battleship Italia
Italian battleship Littorio
|-External links:...

 and sank the Roma
Italian battleship Roma
Roma was the name of three battleships of the Regia Marina , and may refer to:, a broadside ironclad, the lead ship of the Roma class, completed in 1869 and stricken in 1895, a predreadnought battleship of the Regina Elena class completed in 1908 and stricken in 1927, a dreadnought battleship of...

 with Fritz-X bombs. Attacks were also made on the USS Savannah
USS Savannah (CL-42)
USS Savannah was a light cruiser of the Brooklyn-class. She was laid down on 31 May 1934 by the New York Shipbuilding Association in Camden, New Jersey; launched on 8 May 1937; sponsored by Miss Jayne Maye Bowden, the niece of Senator Richard B. Russell, Jr., of Georgia; and commissioned in the...

, causing heavy damage and extensive loss of life. HMS Warspite was hit by three Fritz-X, and although casualties were few, had to be towed to Malta
Malta , officially known as the Republic of Malta , is a Southern European country consisting of an archipelago situated in the centre of the Mediterranean, south of Sicily, east of Tunisia and north of Libya, with Gibraltar to the west and Alexandria to the east.Malta covers just over in...

 for repair and was out of action for six months. The cruiser USS Philadelphia
USS Philadelphia (CL-41)
USS Philadelphia , a Brooklyn class light cruiser of the United States Navy. She was the fifth ship named for Philadelphia, Pennsylvania. In the 1950s, she was commissioned into the Brazilian Navy as Almirante Barroso....

 was very slightly damaged by several near misses of Fritz-X bombs. The light cruiser HMS Uganda was also hit and put out of action for almost the entire war as a result.

A more widely employed weapon was the Henschel Hs 293
Henschel Hs 293
The Henschel Hs 293 was a World War II German anti-ship guided missile: a radio-controlled glide bomb with a rocket engine slung underneath it. It was designed by Herbert A. Wagner.- History :...

, which included wings and a rocket motor to allow the bomb to glide some distance away from the launching aircraft. This weapon was designed for use against thinly armored but highly defended targets such as convoy merchantmen or their escorting light warships. On release a small liquid fueled rocket fired to speed up the weapon and get it out in front of the bomber, which was flown to approach the target just off to one side. The bomb then dropped close to the water and glided in parallel to the launch aircraft, with the bomb aimer adjusting the flight left or right. As long as the bomb was dropped at roughly the right range so it didn't run out of altitude while gliding in, the system was easy to use, at least against slow-moving targets.

Design work started as early as 1939, and a version of the guidance package mounted to standard 500 kg bombs was tested in September 1940. It was found that the bomb was unable to penetrate a ship's armor, so changes were made to fit an armor-piercing warhead before the system finally entered service in 1943. The basic A-1 model was the only one to be produced in any number, but developments included the B model with a custom armor-piercing warhead, and the C model with the conical warhead that was designed to hit the water short of the ship and then travel a short distance underwater to hit the ship under the waterline.

The Hs 293 was first used operationally in the Bay of Biscay
Bay of Biscay
The Bay of Biscay is a gulf of the northeast Atlantic Ocean located south of the Celtic Sea. It lies along the western coast of France from Brest south to the Spanish border, and the northern coast of Spain west to Cape Ortegal, and is named in English after the province of Biscay, in the Spanish...

 against RN and RCN destroyers, sloops and frigates. Its combat appearance was made on August 25, 1943 when the sloop HMS Bideford
Shoreham class sloop
The Shoreham-class sloops were a class of eight small British warships built in the early 1930s.Developed from the Bridgewater-class sloops, with a longer hull, the Shoreham-class sloops were laid down between 1929 and 1931 at Chatham and Devonport Naval Dockyards.-Ships:*HMS Shoreham was launched...

 was slightly damaged by a missile which failed to fully detonate, killing one crewman in the process. Another sloop HMS Landguard
Banff class sloop
The Banff-class sloops were a group of ten ships of the Royal Navy. Built as United States Coast Guard Lake-class cutters, in 1941 these ships were loaned to the Royal Navy as anti-submarine warfare escorts. The transfers took place at the Brooklyn Navy Yard, where HMS Malaya was under repair after...

 survived a near miss with slight damage. The Germans attacked again two days later, sinking HMS Egret
HMS Egret (L75)
HMS Egret was a sloop of the British Royal Navy, the lead ship of her class. She was built by J. Samuel White at Cowes, Isle of Wight and was launched on 31 May 1938....

 on August 27, 1943 and seriously damaging HMCS Athabaskan
HMCS Athabaskan (G07)
HMCS Athabaskan was the first of three destroyers of the Royal Canadian Navy to bear this name. It was a destroyer of the Tribal-class, built in 1940-1941 in the United Kingdom by Vickers Armstrong of Newcastle upon Tyne with Parsons engine works....


Several defensive measures were implemented right away. Ships capable of maneuvering at high speed were instructed to make tight turns across the missile's flight path in order to complicate the missile operator's efforts. Attacking aircraft were interdicted with air patrols and heavy-caliber anti-aircraft weapons, disrupting either the visual or radio links to the guided weapons. Smoke was used to hide ships at anchor. Allied aircraft also attacked the home bases of the special German units equipped with these weapons, primarily (Gruppen II and III of Kampfgeschwader 100 and Gruppe II of Kampfgeschwader 40).

American, British and Canadian scientists also developed sophisticated radio jammers
Radio jamming
Radio jamming is the transmission of radio signals that disrupt communications by decreasing the signal to noise ratio. Unintentional jamming occurs when an operator transmits on a busy frequency without first checking whether it is in use, or without being able to hear stations using the frequency...

 to disrupt the radio guidance signal. Ultimately nine different jamming systems were deployed in the European theater
European Theatre of World War II
The European Theatre of World War II was a huge area of heavy fighting across Europe from Germany's invasion of Poland on September 1, 1939 until the end of the war with the German unconditional surrender on May 8, 1945...

 against these weapons. While early models proved inadequate, by the time the Allies were preparing for the invasion of France, more capable systems were deployed and the success rate of guided weapons declined considerably. Even more important to the defeat of the weapons was Allied command of the airspace and the interception of incoming bombers by Allied fighter aircraft.

The Hs 293 was also used in August 1944 to attack bridges over the River See and River Selume at the southern end of the Cherbourg peninsula in an attempt to break Patton's advance, but this mission was unsuccessful. A similar mission against bridges on the Oder River, designed to slow the Soviet advance into Germany, was made in April 1945 but failed.

The Germans also experimented with television
Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...

 guidance systems on the Hs 293D models. The use was problematic - as the bomb approaches the target, even tiny amounts of control input would cause the target to jump around the TV display, so much of the difficulty was in developing control systems that would become progressively less sensitive as the pilot required. A wire-guided version was also developed, but this Hs 293B variant was never deployed.


In 1939 Sir Dennistoun Burney and Nevil Shute
Nevil Shute
Nevil Shute Norway was a popular British-Australian novelist and a successful aeronautical engineer. He used his full name in his engineering career, and 'Nevil Shute' as his pen name, in order to protect his engineering career from any potential negative publicity in connection with his novels.-...

 worked together on an air-launched gliding torpedo, the "Toraplane", and a gliding bomb, "Doravane". Despite much work and many trials the Toraplane could not be launched with repeatable accuracy and the Toraplane project was finally abandoned in 1942

US designs

The GB-1 by Aeronca Aircraft
Aeronca Aircraft
Aeronca, contracted from Aeronautical Corporation of America, located in Middletown, Ohio, is a US manufacturer of engine components and airframe structures for commercial aviation and the defense industry...

 was the first US glide bomb used in WWII. On May 28, 1944, 42 of 113 glide bombs hit Cologne (killing 82, injuring 1500) after being released at 195 mph and 18 miles from the Eifeltor marshalling yard in Cologne
Bombing of Cologne in World War II
The City of Cologne was bombed in 262 separate air raids by the Allies during World War II, including 31 times by the Royal Air Force . Air raid alarms went off in the winter/spring of 1940 as enemy bombers passed overhead. However, the first actual bombing took place on 12 May 1940...

 (most "spun in and exploded 15 miles from the target ... many of the batteries failed to hold charge"). More advanced models in the GB series included the TV guided GB-4
GB-4 was a precision guided munition developed by the United States during World War II . It was one of the precursors of modern anti-ship missiles.Following German success with the Hs-293 and Fritz-X, the U.S...

, GB-5, GB-12, and GB-13, which used contrast-seekers for anti-ship use, and the command-guided GB-8
GB-8 was a precision guided munition developed by the United States during World War II . It was one of the precursors of modern anti-ship missiles.Following German success with the Hs-293 and Fritz-X, the U.S...

, Azon
AZON was one of the world's first smart bombs, deployed by the Allies and contemporary with the German Fritz X.Officially designated VB-1 , it was invented by Major Henry J. Rand and Thomas J...

, Razon, as well as the infrared-guided
Infrared homing
Infrared homing refers to a passive missile guidance system which uses the emission from a target of electromagnetic radiation in the infrared part of the spectrum to track and follow it. Missiles which use infrared seeking are often referred to as "heat-seekers", since infrared is just below the...

VB-6 Felix
The VB-6 Felix was a precision guided munition developed by the United States during World War II. It was one of the precursors of modern anti-ship missiles....

. US Navy glide bombs included the Bat
Bat (guided bomb)
-External links:*...

 and its variant Pelican. The longer-range Bat used an active radar seeker and was used in the Pacific on August 13, 1944, but could not distinguish between targets in a cluttered environment and could be easily spoofed by even simple radar countermeasures. Only four examples of an experimental glide bomb, the Pratt-Read LBE
Pratt-Read LBE
-See also:-References:CitationsBibliography...

, were produced.

Post-war developments

After the war the increasing sophistication of electronics allowed for these systems to be developed as a practical device, and starting in the 1960s air forces deployed a number of such systems, including the USAF's AGM-62 Walleye
AGM-62 Walleye
The AGM-62 Walleye is a television-guided glide bomb which was produced by Martin Marietta and used by the United States armed forces during the 1960s. Most had a 250 lb high-explosive warhead, some had a nuclear warhead...

. Contrast seekers were also steadily improved, culminating in the widely used AGM-65 Maverick
AGM-65 Maverick
The AGM-65 Maverick is an air-to-ground tactical missile designed for close-air support. It is effective against a wide range of tactical targets, including armor, air defenses, ships, ground transportation and fuel storage facilities....

 missile. Both were standard systems until the 1980s when the development of laser guidance
Laser guidance
Laser guidance is a technique of guiding a missile or other projectile or vehicle to a target by means of a laser beam. Some laser guided systems utilise beam riding guidance, but most operate more similarly to semi-active radar homing . This technique is sometimes called SALH, for Semi-Active...

 and GPS based systems made them unnecessary for all but the most accurate of roles. Various TV based systems remain in limited service for super-accurate uses, but have otherwise been removed.

In the anti-shipping role, direct attack from an aircraft even at long range became more dangerous due to the deployment of anti-aircraft missiles on ships. Weapons like the Bat had ranges too short to keep the attacking aircraft out of range, especially in a force provided by air cover. This was addressed with the introduction of small jet engines that greatly extended the range, producing the anti-shipping missile class that remains widely used today.

Similarly, the need to attack highly defended targets such as airbases and military command posts has led to the development of newer generations of glide bombs. European air forces use a glide package with a cluster bomb
Cluster bomb
A cluster munition is a form of air-dropped or ground-launched explosive weapon that releases or ejects smaller sub-munitions. Commonly, this is a cluster bomb that ejects explosive bomblets that are designed to kill enemy personnel and destroy vehicles...

 warhead for remotely attacking airbases, and the US is in the process of deploying their own similar system based around the GPS guidance system. It appears likely that the falling cost of such systems will eventually lead to almost all bombs being fitted with some sort of guidance package (such as the Paveway
Paveway is a generic term for Laser Guided Bombs .Pave or PAVE is sometimes used as an acronym for precision avionics vectoring equipment; literally, electronics for controlling the speed and direction of aircraft...

 and JDAM systems).

See also

  • Bigeye bomb
    Bigeye bomb
    The Bigeye bomb was a proposed U.S. binary chemical weapon. The Bigeye was a glide bomb designed under the auspices of the U.S. Navy. Initially approved by the Carter administration, the program persisted into the early 1990s.-Background:...

  • H-2 MUPSOW
  • H-4 MUPSOW
    HOPE and HOSBO are a new family of precision-guided munitions, currently under development by Diehl BGT Defence for the German Luftwaffe...

  • JDAM
  • Paveway
    Paveway is a generic term for Laser Guided Bombs .Pave or PAVE is sometimes used as an acronym for precision avionics vectoring equipment; literally, electronics for controlling the speed and direction of aircraft...

External links

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