A daisy cutter is a type of fuse

Fuse (explosives)

In an explosive, pyrotechnic device or military munition, a fuse is the part of the device that initiates function. In common usage, the word fuse is used indiscriminately...

 designed to detonate

Detonator

A detonator is a device used to trigger an explosive device. Detonators can be chemically, mechanically, or electrically initiated, the latter two being the most common....

 an aerial bomb

Aerial bomb

An aerial bomb is a type of explosive weapon intended to travel through the air with predictable trajectories, usually designed to be dropped from an aircraft...

 at or above ground level. The fuse itself is a long probe affixed to the weapon's nose, which detonates the bomb if it touches the ground or any solid object.

The purpose for a daisy-cutter fuse is primarily to maximize blast damage on the surface of a target. A bomb with a conventional fuse will often be driven deeply into the ground by the force of its impact, limiting the range of its blast. A bomb with a daisy-cutter fuse will detonate before it has a chance to penetrate the ground, allowing its energy to spread over a larger area. For this reason daisy-cutter fuses are often used to clear foliage and vegetation, such as for the purpose of creating Landing Zone

Landing Zone

A Landing Zone or "LZ" is a military term for any area where an aircraft can land.In the United States military, a landing zone is the actual point where aircraft land...

s for helicopter

Helicopter

A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...

s.

The first reference to a "daisy-cutter type of bomb" is found in the memoir of Lieutenant Jack Wilkinson in describing the 1918 attack on the Royal Air Force

Royal Air Force

The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...

 airfield at Bertangles

Bertangles

Bertangles is a commune in the Somme department in Picardie in northern France.-Geography:Bertangles is situated on the D97 road, just off the N25, north of Amiens...

. Wilkinson describes it as a "bomb that seemed to explode before it buried itself in the ground so that bits and pieces flew horizontally in all directions."

Oskar Dinort

Oskar Dinort

Oskar Dinort was a German World War II Luftwaffe Stuka pilot and first Stuka pilot to be awarded the coveted Knight's Cross with Oak Leaves...

 invented an extended-nose fuse device known as the Dinort-Stab device. These were placed on the noses of German

Nazi Germany

Nazi Germany , also known as the Third Reich , but officially called German Reich from 1933 to 1943 and Greater German Reich from 26 June 1943 onward, is the name commonly used to refer to the state of Germany from 1933 to 1945, when it was a totalitarian dictatorship ruled by...

 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...

-era bombs up to 250 kg (551.2 lb) in mass, such as the SC 50 and 250 bombs dropped from Junkers Ju 87

Junkers Ju 87

The Junkers Ju 87 or Stuka was a two-man German ground-attack aircraft...

 (Stuka) 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.

"Daisy cutter" fuses, when known under that exact name, were first used by the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 during the Vietnam War

Vietnam War

The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...

. The concept for the fuse is attributed to an Air America employee who grasped the idea during a night of drinking. Shortly thereafter, his drinking buddy, a Royal Lao Air Force

Royal Lao Air Force

The Royal Lao Air Force was the air force branch of the Military of the Royal Lao Government in the Kingdom of Laos. The RLAF, along with the Royal Lao Navy, and the Royal Lao Army, were placed under the control of the Ministry of Defense in Vientiane....

 airman at Louang Phrabang, gathered the needed materials for the prototype and started welding

Welding

Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material that cools to become a strong joint, with pressure sometimes...

 used aircraft gun barrel

Gun barrel

A gun barrel is the tube, usually metal, through which a controlled explosion or rapid expansion of gases are released in order to propel a projectile out of the end at a high velocity....

s directly into the nose fuse cavity of bombs. After the concept proved itself useful was made famous by being used for the largest conventional bomb in the U.S. military's arsenal at the time, the BLU-82

BLU-82

The BLU-82B/C-130 weapon system, known under program "Commando Vault" and nicknamed "daisy cutter" in Vietnam and in Afghanistan for its ability to flatten a forest into a helicopter landing zone, is a 15,000 pound conventional bomb, delivered from either a C-130 or an MC-130 transport aircraft....

. When used gun barrels were in short supply, water pipes were requisitioned for the task. The welded pipe versions had several adverse effects, such as vibration, pipe weld separation or breakage while in flight, and wind drag

Drag (physics)

In fluid dynamics, drag refers to forces which act on a solid object in the direction of the relative fluid flow velocity...

, due to impossibility of aligning the pipes correctly with the nose of the weapon, so that phase of development eventually gave way to threaded steel

Steel

Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

 water pipes screwed into the nose cavity of the bombs, leaving only the tail fuse for detonation. After the war more precise fuses were created for this purpose. These weapons were used in the "shock and awe" phase of the Iraq War.