Proximity fuze
Overview
 
A proximity fuze is a fuze that is designed to detonate an explosive
Explosive material
An explosive material, also called an explosive, is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure...

 device automatically when the distance to target becomes smaller than a predetermined value or when the target passes through a given plane. The proximity fuze should not be confused with the common contact fuse
Contact fuse
A contact fuze, percussion fuze or direct-action fuze is the fuze that is placed in the nose of a bomb or shell so that it will detonate on contact with a hard surface....

.

One of the first practical proximity fuzes was codenamed the VT fuze, an acronym of “Variable Time fuze”, as deliberate camouflage for its operating principle.
Encyclopedia
A proximity fuze is a fuze that is designed to detonate an explosive
Explosive material
An explosive material, also called an explosive, is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure...

 device automatically when the distance to target becomes smaller than a predetermined value or when the target passes through a given plane. The proximity fuze should not be confused with the common contact fuse
Contact fuse
A contact fuze, percussion fuze or direct-action fuze is the fuze that is placed in the nose of a bomb or shell so that it will detonate on contact with a hard surface....

.

One of the first practical proximity fuzes was codenamed the VT fuze, an acronym of “Variable Time fuze”, as deliberate camouflage for its operating principle. The VT fuze concept in the context of artillery shells originated in the UK with British researchers (particularly Sir Samuel Curran
Samuel Curran
Sir Samuel Crowe Curran , FRS, FRSE, was a physicist and the first Principal and Vice-Chancellor of the University of Strathclyde - the first of the new technical universities in Britain....

) and W. A. S. Butement
W. A. S. Butement
William Alan Stewart Butement , was a defence scientist and public servant. A native of New Zealand, he made extensive contributions to radar development in Great Britain during World War II, served as the first chief scientist for the Australian Defence Scientific Service, then ended his...

, whose schematic design for a radar proximity fuze was used with only minor variations and was developed under the direction of physicist Merle A. Tuve
Merle Tuve
Merle Anthony Tuve, PhD was an American scientist and geophysicist who was the founding director of the Johns Hopkins University Applied Physics Laboratory. He was a pioneer in the use of pulsed radio waves whose discoveries opened the way to the development of radar and nuclear...

 at The Johns Hopkins University Applied Physics Lab (APL). The fuze is considered one of the most important technological innovations of 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 Germans were supposedly also working on proximity fuses in the 1930s, research and prototype work at Rheinmetal being halted in 1940 to devote available resources to projects deemed more necessary.

History

Before the fuze's invention, detonation had to be induced either by direct contact, or a timer set at launch, or an altimeter. All of these have disadvantages. The probability of a direct hit with a relatively small moving target is low; to set a time- or height-triggered fuze one must measure the height of the target (or even predict the height of the target at the time one will be able to get a shell or missile
Missile
Though a missile may be any thrown or launched object, it colloquially almost always refers to a self-propelled guided weapon system.-Etymology:The word missile comes from the Latin verb mittere, meaning "to send"...

 in its neighbourhood). With a proximity fuze, all one has to worry about is getting a shell
Shell (projectile)
A shell is a payload-carrying projectile, which, as opposed to shot, contains an explosive or other filling, though modern usage sometimes includes large solid projectiles properly termed shot . Solid shot may contain a pyrotechnic compound if a tracer or spotting charge is used...

 or missile on a trajectory that, at some time, will pass close by the target. This is still not a trivial task, but it is much easier to execute than previous methods.

Use of timing to produce air burst
Air burst
An air burst is the detonation of an explosive device such as an anti-personnel artillery shell or a nuclear weapon in the air instead of on contact with the ground or target or a delayed armor piercing explosion....

s against ground targets requires observers to provide information for adjusting the timing. This is not practical in many situations and is slow in any event. Proximity fuzes fitted to such weapons as artillery and mortar shells solve this problem by having a range of pre-set burst heights (e.g. 2, 4 or 10 metres, or about 7, 13, or 33 feet) above ground, which can be selected by gun crews prior to firing.

Design

In the late 1930s the UK was working on a variety of developments to increase air defence efficiency "...Into this stepped W. A. S. Butement
W. A. S. Butement
William Alan Stewart Butement , was a defence scientist and public servant. A native of New Zealand, he made extensive contributions to radar development in Great Britain during World War II, served as the first chief scientist for the Australian Defence Scientific Service, then ended his...

, designer of radar sets CD/CHL and GL, with a proposal on 30 October 1939 for two kinds of radio fuze: (1) a radar set would track the projectile, and the operator would transmit a signal to a radio receiver in the fuze when the range, the difficult quantity for the gunners to determine, was the same as that of the target and (2) a fuze would emit high-frequency radio waves that would interact with the target and produce, as a consequence of the high relative speed of target and projectile, a Doppler-frequency signal sensed in the oscillator". Coincidently, a German vacuum tube and a design of a German prototype proximity fuze was received by British Intelligence in mid November 1939. Butement, Edward S. Shire, and Amherst F.H. Thompson proposed the radio frequency proximity fuze concept in a memo to the British Air Defence Establishment in May 1940. A breadboard
Breadboard
A breadboard is a construction base for prototyping of electronics. The term is commonly used to refer to solderless breadboard ....

 circuit was constructed by the inventors and the concept was tested in the laboratory by moving a sheet of tin at various distances. Early field testing connected the circuit to a thyratron
Thyratron
A thyratron is a type of gas filled tube used as a high energy electrical switch and controlled rectifier. Triode, tetrode and pentode variations of the thyratron have been manufactured in the past, though most are of the triode design...

 trigger operating a tower-mounted camera which photographed passing aircraft to determine distance of fuze function. Prototype fuzes were then constructed in June 1940, and installed in unrotated projectile
Unrotated Projectile
The Unrotated Projectile, or UP, was a short range rocket-firing anti-aircraft weapon developed for the Royal Navy to supplement the 2 pounder Pom-Pom gun due to a critical lack of close-range anti-aircraft weapons. It was used extensively by British ships during the early days of World War II...

s (the British cover name for solid fuelled rocket
Rocket
A rocket is a missile, spacecraft, aircraft or other vehicle which obtains thrust from a rocket engine. In all rockets, the exhaust is formed entirely from propellants carried within the rocket before use. Rocket engines work by action and reaction...

s) fired at targets supported by balloons. During 1940-42 a private venture initiative by Pye Ltd., a leading British wireless manufacturer, worked on the development of a radio proximity fuze. Pye's research was transferred to the United States as part of the technology package delivered by the Tizard Mission
Tizard Mission
The Tizard Mission officially the British Technical and Scientific Mission was a British delegation that visited the United States during the Second World War in order to obtain the industrial resources to exploit the military potential of the research and development work completed by the UK up...

 when the United States entered the war. It is unclear how this work relates to other British developments. The details of these experiments were passed to the United States Naval Research Laboratory
United States Naval Research Laboratory
The United States Naval Research Laboratory is the corporate research laboratory for the United States Navy and the United States Marine Corps and conducts a program of scientific research and development. NRL opened in 1923 at the instigation of Thomas Edison...

 and National Defense Research Committee
National Defense Research Committee
The National Defense Research Committee was an organization created "to coordinate, supervise, and conduct scientific research on the problems underlying the development, production, and use of mechanisms and devices of warfare" in the United States from June 27, 1940 until June 28, 1941...

 (NDRC) by the Tizard Mission in September 1940, in accordance with an informal agreement between Winston Churchill
Winston Churchill
Sir Winston Leonard Spencer-Churchill, was a predominantly Conservative British politician and statesman known for his leadership of the United Kingdom during the Second World War. He is widely regarded as one of the greatest wartime leaders of the century and served as Prime Minister twice...

 and Franklin D. Roosevelt
Franklin D. Roosevelt
Franklin Delano Roosevelt , also known by his initials, FDR, was the 32nd President of the United States and a central figure in world events during the mid-20th century, leading the United States during a time of worldwide economic crisis and world war...

 to exchange scientific information of potential military value.

Following receipt of details from the British, the experiments were successfully duplicated by Richard B. Roberts, Henry H. Porter, and Robert B. Brode under the direction of NDRC section T chairman Merle Tuve
Merle Tuve
Merle Anthony Tuve, PhD was an American scientist and geophysicist who was the founding director of the Johns Hopkins University Applied Physics Laboratory. He was a pioneer in the use of pulsed radio waves whose discoveries opened the way to the development of radar and nuclear...

. Lloyd Berkner
Lloyd Berkner
Lloyd Viel Berkner was an American physicist and engineer. He is notable as the first person to measure the height and density of the ionosphere. This permitted the first complete theory of short wave radio propagation.Later he investigated the development of the Earth's atmosphere...

 of Tuve's staff devised an improved fuze using separate tubes
Vacuum tube
In electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...

 (British English: thermionic valves or just "valves") for transmission and reception. In December 1940, Tuve invited Harry Diamond and Wilbur S. Hinman, Jr, of the United States National Bureau of Standards (NBS) to investigate Berkner's improved fuze. The NBS team built six fuzes which were placed in air-dropped bomb
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...

s and successfully tested over water on 6 May 1941.

While working for a defense contractor in the mid-1940's, Soviet spy Julius Rosenberg stole a working model of an American proximity fuze and delivered it to the KGB.

Parallel NDRC work focused on anti-aircraft fuzes. Major problems included microphonic difficulties and tube failures attributed to vibration and acceleration in gun projectiles. The T-3 fuze had a 52% success against a water target when tested in January, 1942. The United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

 accepted that failure rate and batteries aboard cruiser tested proximity-fuzed ammunition against drone aircraft targets over Chesapeake Bay
Chesapeake Bay
The Chesapeake Bay is the largest estuary in the United States. It lies off the Atlantic Ocean, surrounded by Maryland and Virginia. The Chesapeake Bay's drainage basin covers in the District of Columbia and parts of six states: New York, Pennsylvania, Delaware, Maryland, Virginia, and West...

 in August 1942. The tests were so successful that all target drones were destroyed before testing was complete.

The German proximity fuze in development by Rheinmetall Borsig A.G. had the following characteristics:
  • The fuze was based on electrostatic principles. It is known that the nose of the shell was electrically insulated and isolated from the rest of the shell. The program was halted in 1940, restarted in early 1944 and then terminated again due to being overrun by the Allies at the point that it was ready for production.

  • Initial fuze testing demonstrated a sensitivity of 1–2 meters and a reliability of 80% when fired against a metal cable target. A circuit adjustment yielded an increase to 3–4 meters and a reliability of close to 95%. Further work showed a 10-15 meter sensitivity. This was with 88mm cannon shells. The shell to all intents and purposes was ready for production.

The shell probably could not have been easily degraded by jamming or chaff, unlike the Allied shell.

In contrast, the Allied fuze workings:
  • Technically, the Allied fuze used constructive and destructive interference to detect its target. The design had four tubes. One tube was an oscillator connected to an antenna that would both transmit and receive. When there was no target nearby, the received signal would be small and have little effect on the circuit. When a target was nearby, it would reflect a portion of the oscillator's signal back to the fuze. This reflected signal would affect the oscillator depending on the round trip distance from the fuze to the target. If the reflected signal were in phase, the oscillator amplitude would increase and the oscillator's plate current would also increase. If the reflected signal were out of phase, then the plate current would decrease. When the distance between the fuze and the target changed rapidly, the phase relationship also changed. A low frequency signal developed at the oscillator's plate. Two additional amplifiers detected this low frequency and triggered the 4th tube (a gas-filled thyratron
    Thyratron
    A thyratron is a type of gas filled tube used as a high energy electrical switch and controlled rectifier. Triode, tetrode and pentode variations of the thyratron have been manufactured in the past, though most are of the triode design...

    ) to set off the detonator. There were many shock hardening techniques including planar electrodes and packing the components in wax and oil to equalize the stresses.

Production

First large scale production of tubes for the new fuzes was at a General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...

 plant in Cleveland, Ohio
Cleveland, Ohio
Cleveland is a city in the U.S. state of Ohio and is the county seat of Cuyahoga County, the most populous county in the state. The city is located in northeastern Ohio on the southern shore of Lake Erie, approximately west of the Pennsylvania border...

 formerly used for manufacture of Christmas-tree lamps. Fuze assembly was completed at General Electric plants in Schenectady, New York
Schenectady, New York
Schenectady is a city in Schenectady County, New York, United States, of which it is the county seat. As of the 2010 census, the city had a population of 66,135...

 and Bridgeport, Connecticut
Bridgeport, Connecticut
Bridgeport is the most populous city in the U.S. state of Connecticut. Located in Fairfield County, the city had an estimated population of 144,229 at the 2010 United States Census and is the core of the Greater Bridgeport area...

.

By 1944 a large proportion of the American electronics industry concentrated on making the fuzes. Procurement contracts increased from $60 million in 1942, to $200 million in 1943, to $300 million in 1944 and were topped by $450 million in 1945. As volume increased, efficiency came into play and the cost per fuze fell from $732 in 1942 to $18 in 1945. This permitted the purchase of over 22 million fuzes for approximately $1,010 million. The main suppliers were Crosley, RCA, Eastman Kodak, McQuay-Norris and Sylvania.

Deployment

Vannevar Bush
Vannevar Bush
Vannevar Bush was an American engineer and science administrator known for his work on analog computing, his political role in the development of the atomic bomb as a primary organizer of the Manhattan Project, the founding of Raytheon, and the idea of the memex, an adjustable microfilm viewer...

, head of the U.S. Office of Scientific Research and Development
Office of Scientific Research and Development
The Office of Scientific Research and Development was an agency of the United States federal government created to coordinate scientific research for military purposes during World War II. Arrangements were made for its creation during May 1941, and it was created formally by on June 28, 1941...

 (OSRD) during this war, credited the proximity fuze with three significant effects:
  • First, it was important in defense from Japanese Kamikaze
    Kamikaze
    The were suicide attacks by military aviators from the Empire of Japan against Allied naval vessels in the closing stages of the Pacific campaign of World War II, designed to destroy as many warships as possible....

     attacks in the Pacific. Bush estimated a sevenfold increase in the effectiveness of 5-inch antiaircraft artillery with this innovation.
  • It was an important part of the radar-controlled antiaircraft batteries that finally neutralized the German V-1
    V-1 flying bomb
    The V-1 flying bomb, also known as the Buzz Bomb or Doodlebug, was an early pulse-jet-powered predecessor of the cruise missile....

     bomb attacks on England.
  • Third, it was released for use in Europe just before the Battle of the Bulge
    Battle of the Bulge
    The Battle of the Bulge was a major German offensive , launched toward the end of World War II through the densely forested Ardennes mountain region of Wallonia in Belgium, hence its French name , and France and...

    . At first the fuzes were only used in situations where they could not be captured by the Germans. They were used in land-based artillery in the South Pacific in 1944. They were incorporated into bombs dropped by the U.S. Air Force on Japan in 1945, and they were used to defend Britain against the V-1 attacks of 1944, achieving a kill ratio of about 79%. (They were ineffective against the much faster V-2 missiles.) There was no risk of a dud falling into enemy hands. The Pentagon decided it was too dangerous to have a fuze fall into German hands because they might reverse engineer it and create a weapon that would destroy the Allied bombers, or at least find a way to jam the radio signals. Therefore they refused to allow the Allied artillery use of the fuzes in 1944.
  • General Dwight D. Eisenhower
    Dwight D. Eisenhower
    Dwight David "Ike" Eisenhower was the 34th President of the United States, from 1953 until 1961. He was a five-star general in the United States Army...

     protested vehemently and demanded he be allowed to use the fuzes. He prevailed and the VT fuzes were first used in the Battle of the Bulge
    Battle of the Bulge
    The Battle of the Bulge was a major German offensive , launched toward the end of World War II through the densely forested Ardennes mountain region of Wallonia in Belgium, hence its French name , and France and...

     in December 1944, when they made the Allied artillery far more devastating, as all the shells now exploded just before hitting the ground. It decimated German divisions caught in the open. The Germans felt safe from timed fire because they thought that the bad weather would prevent accurate observation. The effectiveness of the new VT fused shells exploding in mid-air, on exposed personnel, caused a minor mutiny when German soldiers started refusing orders to move out of their bunkers during an artillery attack. U.S. General George S. Patton
    George S. Patton
    George Smith Patton, Jr. was a United States Army officer best known for his leadership while commanding corps and armies as a general during World War II. He was also well known for his eccentricity and controversial outspokenness.Patton was commissioned in the U.S. Army after his graduation from...

     said that the introduction of the proximity fuze required a full revision of the tactics of land warfare.
  • The Germans started their own independent research in the 1930s but the programme was cut in 1940 likely due to the 'fuhrer directive' (Führerbefehl) that, with few exceptions, stipulated all work that could not be put into production within 6 months was to be terminated to increase resources for those projects that could (in order to support operation Barbarossa
    Operation Barbarossa
    Operation Barbarossa was the code name for Germany's invasion of the Soviet Union during World War II that began on 22 June 1941. Over 4.5 million troops of the Axis powers invaded the USSR along a front., the largest invasion in the history of warfare...

    ). It was at this time that the Germans also abandoned their magnetron and microwave radar development teams and programs. Many other advanced and experimental programs also suffered. Upon resumption of research and testing by Rheinmetall
    Rheinmetall
    Rheinmetall AG is a German automotive and defence company with factories in Düsseldorf, Kassel and Unterlüß. The company has a long tradition of making guns and artillery pieces...

     in 1944 the Germans managed to develop and test fire several hundred working prototypes before the war ended.

Radio frequency sensing

Radio frequency sensing is the main sensing principle for artillery shells.

The device described in World War II patent works as follows: The shell contains a micro-transmitter
Transmitter
In electronics and telecommunications a transmitter or radio transmitter is an electronic device which, with the aid of an antenna, produces radio waves. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating...

 which uses the shell body as an antenna
Antenna (radio)
An antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...

 and emits a continuous wave of roughly 180–220 MHz. As the shell approaches a reflecting object, an interference pattern is created. This pattern changes with shrinking distance: every half wavelength in distance (a half wavelength at this frequency is about 0.7 meters), the transmitter is in or out of resonance. This causes a small oscillation of the radiated power and consequently the oscillator supply current of about 200–800 Hz, the Doppler
Doppler effect
The Doppler effect , named after Austrian physicist Christian Doppler who proposed it in 1842 in Prague, is the change in frequency of a wave for an observer moving relative to the source of the wave. It is commonly heard when a vehicle sounding a siren or horn approaches, passes, and recedes from...

 frequency. This signal is sent through a band pass filter, amplified, and triggers the detonation when it exceeds a given amplitude.

Optical sensing

Optical sensing was developed in 1935, and patented in Great Britain in 1936, by a Swedish inventor, probably Edward W. Brandt, using a petoscope
Petoscope
A Petoscope is an optoelectronic device for detecting small, distant objects such as flying aircraft. The design, as described in 1936 , consisted of an instrument with two parallel light paths...

. It was first tested as a part of a detonation device for bombs that were to be dropped on bombers, part of the UK's Air Ministry's "bombs on bombers" concept. It was considered (and later patented by Brandt) for use with anti-aircraft missiles. It used then a toroidal lens, that concentrated all light out of a plane perpendicular to the missile's main axis onto a photo cell. When the cell current changed a certain amount in a certain time interval, the detonation was triggered.

Some modern air-to-air missile
Air-to-air missile
An air-to-air missile is a missile fired from an aircraft for the purpose of destroying another aircraft. AAMs are typically powered by one or more rocket motors, usually solid fuelled but sometimes liquid fuelled...

s use laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...

s. They project narrow beams of laser light perpendicular to the flight of the missile. As the missile cruises towards the target the laser energy simply beams out into space. As the missile passes its target some of the energy strikes the target and is reflected back to the missile where detectors sense it and detonate the warhead.

Acoustic sensing

Acoustic sensing used a microphone in a missile. The characteristic frequency of an aircraft engine is filtered and triggers the detonation. This principle was applied in British experiments with bombs, anti-aircraft missiles, and airburst shells (circa 1939). Later it was applied in German anti-aircraft missiles, which were mostly still in development when the war ended.

The British used a Rochelle salt microphone and a piezoelectric device to trigger a relay to detonate the projectile or bomb's explosive.

Naval mine
Naval mine
A naval mine is a self-contained explosive device placed in water to destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, an enemy vessel...

s can also use acoustic sensing, with modern versions able to be programmed to "listen" for the signature of a specific ship.

Magnetic sensing

Magnetic sensing can only be applied to detect huge masses of iron such as ships. It is used in mines and torpedoes. Fuzes of this type can be defeated by degaussing
Degaussing
Degaussing is the process of decreasing or eliminating an unwanted magnetic field. It is named after Carl Friedrich Gauss, an early researcher in the field of magnetism...

, using non-metal hulls for ships (especially minesweepers
Minesweeper (ship)
A minesweeper is a small naval warship designed to counter the threat posed by naval mines. Minesweepers generally detect then neutralize mines in advance of other naval operations.-History:...

) or by magnetic induction
Electromagnetic induction
Electromagnetic induction is the production of an electric current across a conductor moving through a magnetic field. It underlies the operation of generators, transformers, induction motors, electric motors, synchronous motors, and solenoids....

 loops fitted to aircraft or towed buoy
Buoy
A buoy is a floating device that can have many different purposes. It can be anchored or allowed to drift. The word, of Old French or Middle Dutch origin, is now most commonly in UK English, although some orthoepists have traditionally prescribed the pronunciation...

s.

Pressure sensing

Some naval mines are able to detect the pressure wave of a ship passing overhead.

VT and "Variable Time"

The designation "VT" is often said to refer to "variable time". Fuzed munitions before this invention were set to explode at a given time after firing, and an incorrect estimation of the flight time would result in the munition exploding too soon or too late. The VT fuze could be relied upon to explode at the right time—which might vary from that estimated.

One theory is that "VT" was coined simply because Section "V" of the Bureau of Ordnance was in charge of the programme and they allocated it the code-letter "T". This would mean that the initials also standing for "variable time" was a happy coincidence that was supported as an intelligence smoke screen by the allies in World War II to hide its true mechanism.

An alternative is that it was deliberately coined from the existing "VD" (Variable Delay) terminology by one of the designers.

Developed by the US Navy, development and early production was outsourced to the Wurlitzer
Wurlitzer
The Rudolph Wurlitzer Company, usually referred to simply as Wurlitzer, was an American company that produced stringed instruments, woodwinds, brass instruments, theatre organs, band organs, orchestrions, electronic organs, electric pianos and jukeboxes....

 company, at their barrel organ factory
North Tonawanda Barrel Organ Factory
The North Tonawanda Barrel Organ Factory was a street organ organ manufacturing company and building, locted in North Tonawanda, New York. Started by expatriate German Eugene de Kleist with backing from Allan Herschell, the company was later purchased by the Wurlitzer company.-Foundations:In 1892,...

 in North Tonawanda, New York
North Tonawanda, New York
North Tonawanda is a city in Niagara County, New York, United States. The population was 31,568 at the 2000 census. It is part of the Buffalo–Niagara Falls Metropolitan Statistical Area. The city is named after Tonawanda Creek, its south border...

.

See also

  • Allied technological cooperation during World War II
    Allied technological cooperation during World War II
    The Second World War was not won by one nation; the Allies had to cooperate while fighting on the ground, as well as by sharing technological resources and innovations...

  • Contact fuse
    Contact fuse
    A contact fuze, percussion fuze or direct-action fuze is the fuze that is placed in the nose of a bomb or shell so that it will detonate on contact with a hard surface....

  • M734
    M734
    The M734 Multi-Option Fuze shown in Figure 1 is a rangefinder and collision detection system used on 60mm, 81mm, and 120mm mortar shells as a trigger to detonate the shells at the most damaging heights of burst when combating four types of battlefield threats:* The rangefinder electronics is a...

     proximity fuze

Further reading

. Baldwin
Ralph Belknap Baldwin
Ralph Belknap Baldwin was an American planetary scientist known for his work on lunar craters, beginning in the late 1940s...

 was a member of the (APL) team headed by Tuve that did most of the design work. Fulltext: Ebsco

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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