Butterfly Bomb
Encyclopedia
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...
2 kilogram anti-personnel submunition used by the Luftwaffe during the Second World War. It was so named because the thin cylindrical metal outer shell which hinged open when the bomblet deployed gave it the superficial appearance of a large butterfly
Butterfly
A butterfly is a mainly day-flying insect of the order Lepidoptera, which includes the butterflies and moths. Like other holometabolous insects, the butterfly's life cycle consists of four parts: egg, larva, pupa and adult. Most species are diurnal. Butterflies have large, often brightly coloured...
. The design was very distinctive and easy to recognise. SD2 bomblets were not dropped individually, but were packed into containers containing between 6 and 108 submunitions e.g. the AB 23 SD-2 and AB 250-3 submunitions dispensers. The SD2 submunitions were released after the container was released from the aircraft and had burst open. Because SD2s were always dropped in groups (never individually) the discovery of one unexploded SD2 was a reliable indication that others had been dropped nearby. This bomb type was one of the first 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...
s ever used in combat and it proved to be a highly effective weapon.
Description
The SD2 submunition was an 8 centimetres (3.1 in) long cylinderCylinder (geometry)
A cylinder is one of the most basic curvilinear geometric shapes, the surface formed by the points at a fixed distance from a given line segment, the axis of the cylinder. The solid enclosed by this surface and by two planes perpendicular to the axis is also called a cylinder...
of cast iron
Cast iron
Cast iron is derived from pig iron, and while it usually refers to gray iron, it also identifies a large group of ferrous alloys which solidify with a eutectic. The color of a fractured surface can be used to identify an alloy. White cast iron is named after its white surface when fractured, due...
, which was slightly smaller in diameter before its wings deployed. A 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...
cable 15 cm long was attached via a spindle to an aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
fuze
Fuze
Fuze Beverage, commercially referred to as just Fuze , is a manufacturer of teas and non-carbonated fruit drinks enriched with vitamins. Currently the brand consists of five vitamin-infused lines: Slenderize, Refresh, Tea, Defensify, and Vitalize...
screwed into the fuze pocket in the side of the bomblet. The outer shell was hinged and would flip open as two half-cylinders when it was dropped. Additionally, spring-loaded wings at the ends would flip out. The wings at the end were canted at an angle to the airflow, which turned the spindle (connected to the fuze) anti-clockwise as the bomblet fell. After the spindle had revolved approximately 10 times (partially unscrewing itself from the bomb) it released a spring-loaded pin inside the fuze, which fully armed the SD2 bomb. The wings and arming spindle remained attached to the bomb after the fuze had armed itself, as the bomb descended towards the ground. Butterfly bombs contained 225 grams of TNT. They were generally lethal to anyone within a radius of 10 metres (32.8 ft) and could inflict serious shrapnel injuries (e.g. penetrating eye wounds) as far away as 100 metres (328.1 ft). Butterfly bombs were usually painted dark green. A dull yellow colour scheme was sometimes used, either for use in the middle east
Middle East
The Middle East is a region that encompasses Western Asia and Northern Africa. It is often used as a synonym for Near East, in opposition to Far East...
, or when dropped on grain crops at harvest time to kill farm-workers.
Butterfly bombs could be fitted with any one of three fuze
Fuze
Fuze Beverage, commercially referred to as just Fuze , is a manufacturer of teas and non-carbonated fruit drinks enriched with vitamins. Currently the brand consists of five vitamin-infused lines: Slenderize, Refresh, Tea, Defensify, and Vitalize...
s, which were made of aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
and stamped with the model type surrounded by a circle:
- 41 fuze - has an external selector switch with two settings. The "Zeit" (time) setting will detonate the bomb in the air, approximately 5 seconds after being armed. The "AZ" (impact) setting triggers detonation when the bomb hits the ground. The fuze is armed if 4 screw threadScrew threadA screw thread, often shortened to thread, is a helical structure used to convert between rotational and linear movement or force. A screw thread is a ridge wrapped around a cylinder or cone in the form of a helix, with the former being called a straight thread and the latter called a tapered thread...
s at the base of the arming spindle are visible. This fuze is highly sensitive to disturbance if the selector switch is set to "Zeit" and the bomb is unexploded. The particular switch setting of any type 41 fuze is clearly visible on its exterior. - 67 fuze - clockworkClockworkA clockwork is the inner workings of either a mechanical clock or a device that operates in a similar fashion. Specifically, the term refers to a mechanical device utilizing a complex series of gears....
time delay, adjustable between 5 and 30 minutes after arming itself in the air. This fuzeFuzeFuze Beverage, commercially referred to as just Fuze , is a manufacturer of teas and non-carbonated fruit drinks enriched with vitamins. Currently the brand consists of five vitamin-infused lines: Slenderize, Refresh, Tea, Defensify, and Vitalize...
also has an external selector switch for impact detonation. The particular switch setting of any type 67 fuze is clearly visible on its exterior. - 70 fuze - anti-handling deviceAnti-handling deviceAn anti-handling device is an attachment to or integral part of a landmine or other munition e.g. some fuze types found in air-dropped bombs such as the M83, cluster bombs and sea mines. It is specifically designed to prevent tampering. When the protected device is disturbed it detonates, killing...
(i.e. boobytrap) will trigger detonationDetonationDetonation involves a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations are observed in both conventional solid and liquid explosives, as well as in reactive gases...
if the bomb is moved after impact with the ground. The fuze is armed if 3 screw threads at the base of the arming spindle are visible.
Butterfly bombs in a submunitions container could have a mixture of different fuzes fitted to increase disruption to the target. Additionally, when a single fuze type with two operating functions was fitted (e.g. type 41), bombs in a submunitions container could have either or both possible fuze settings selected. Fuze variants such as the 41A, 41B, 70B1, 70B2, etc., also existed. These variants were inserted into the fuze pocket via a bayonet fitting (the fuze was held in place via two steel clips) but otherwise functioned identically.
As with more modern cluster bombs, it was not considered practical to disarm butterfly bombs which had fully armed themselves but failed to detonate. This was because SD2 fuzes were deliberately designed to be extremely difficult and dangerous to render safe once they had armed themselves. Instead, the standard render safe procedure
Render safe procedure
The render safe procedure is the portion of the explosive ordnance disposal procedures involving the application of special explosive ordnance disposal procedures, methods and tools to provide the interruption of functions or separation of essential components of unexploded ordnance to prevent an...
for any unexploded SD2 butterfly bomb was to evacuate the area for at least 30 minutes (in case the bomblet was fitted with a type 67 time delay fuze), then surround it with a ring of sandbags (to cushion the explosion) and destroy it in situ by detonating a small explosive charge beside it. Other solutions were to attach a long string to the bomb and tug on it after taking cover, or for bombs in open countryside, shooting at them with a rifle from a safe distance.
Not all unexploded SD2 butterfly bombs still have their wings attached. In some cases the wings have rusted away and fallen off. The SD2 then resembles a rusty tin can with an aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
disc (the fuze) in its side, sometimes with a short stub projecting from it. Regardless of age and condition, all unexploded SD2s remain highly sensitive to disturbance and can easily detonate.
Use
Butterfly bombs were first used against IpswichIpswich
Ipswich is a large town and a non-metropolitan district. It is the county town of Suffolk, England. Ipswich is located on the estuary of the River Orwell...
in 1940, but were also dropped on Grimsby
Grimsby
Grimsby is a seaport on the Humber Estuary in Lincolnshire, England. It has been the administrative centre of the unitary authority area of North East Lincolnshire since 1996...
and Cleethorpes
Cleethorpes
Cleethorpes is a town and unparished area in North East Lincolnshire, England, situated on the estuary of the Humber. It has a population of 31,853 and is a seaside resort.- History :...
in June 1943, amongst various other targets in the UK. They were subsequently used against Allied forces in the Middle East
Middle East
The Middle East is a region that encompasses Western Asia and Northern Africa. It is often used as a synonym for Near East, in opposition to Far East...
. The British Government deliberately suppressed news of the damage and disruption caused by butterfly bombs in order not to encourage the Germans
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...
to keep using them.
On October 28, 1940 some butterfly bombs that had incompletely armed themselves were discovered in Ipswich
Ipswich
Ipswich is a large town and a non-metropolitan district. It is the county town of Suffolk, England. Ipswich is located on the estuary of the River Orwell...
by British ordnance
Bomb disposal
Bomb disposal is the process by which hazardous explosive devices are rendered safe. Bomb disposal is an all encompassing term to describe the separate, but interrelated functions in the following fields:*Military:...
technicians Sergeant Cann and 2nd Lieutenant Taylor. By screwing the arming rods back into the fuzes (i.e. the unarmed position) the two men were able to recover safe examples to reverse engineer
Reverse engineering
Reverse engineering is the process of discovering the technological principles of a device, object, or system through analysis of its structure, function, and operation...
.
The SD2 saw use in the opening stages of 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...
, the German invasion of the Soviet Union, which began on 22 June 1941. Twenty to thirty aircrews had been picked to drop SD2s and SD10s (10 kg submunitions) on key Soviet airfields, a flight of three aircraft being assigned to each field. The purpose of these early attacks was to cause disruption and confusion as well as to preclude dispersion of Soviet planes until the main attack was launched. It was reported that Kampfgeschwader 51
Kampfgeschwader 51
Kampfgeschwader 51 "Edelweiss" was a Luftwaffe bomber unit during World War II. The unit began forming in December 1939. The unit operated the Dornier Do 17, Heinkel He 111 and Junkers Ju 88 light and medium bombers...
had lost 15 aircraft due to accidents with the SD2s, nearly half of the total Luftwaffe losses that day.
The last recorded death from a German butterfly bomb in England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
took place on November 27, 1956, over 11 years after the Second World War ended: Flight Lieutenant Herbert Denning of the RAF was examining an SD2 at the Upminster bomb cemetery, East of RAF Hornchurch
RAF Hornchurch
RAF Hornchurch was an airfield in the south of Hornchurch in what is now the London Borough of Havering. Known as Sutton's Farm during the First World War, it occupied of the farm of the same name and was situated east north-east of Charing Cross...
, when it detonated. He died of shrapnel and blast injuries at Oldchurch Hospital
Oldchurch Hospital
Oldchurch Hospital was a hospital in London, United Kingdom, located in Romford, in the London Borough of Havering and part of the Barking, Havering and Redbridge Hospitals NHS Trust....
the same day.
Deaths have also been recorded on the Island of Malta as late as 1981 when Paul Gauci, a 41-year-old Maltese man, died after welding a butterfly bomb to a metal pipe and using it as a mallet, thinking it was a harmless can. The latest find of such a bomb was on 28 October 2009, by an 11 year old boy in a secluded valley close to a heavily bombarded airfield. This bomb was safely detonated on-site by the Armed Forces of Malta.
In the TV show "1000 Ways to die", Season 4, Ep. 8, in the last section references a young male "artist" who hung up a butterfly bomb as a sculpture, but apparently due to some frustration in failing to obtain relations with a woman, struck it in frustration and was killed when it detonated. The location and date are given by the show as NY, NY (USA), June 11, 2006. The show states names are changed to protect the identity of the deceased. If true, this is probably the most recent recorded death caused by this munition.
US copy
The United StatesUnited States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
manufactured a copy of the SD2 for use 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 Korean War
Korean War
The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union...
and 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...
, designating it the M83 submunition. The 4 lbs fragmentation bomblet was used in the US M28 and M29 cluster bomb
M29 cluster bomb
The M29 cluster bomb was a cluster bomb used by the United States Air Force during World War II against troops, unarmoured vehicles and artillery. The weapon contained ninety M83 fragmentation submunitions - a direct copy of the earlier German Butterfly Bomb - in 9 ten-bomb "wafers"...
s.