Butterfly Bomb
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A Butterfly Bomb, or (Sprengbombe Dickwandig 2 kg or SD2, also known as Splitterbombe) was a German 2 kg anti-personnel bomb dropped by the German Luftwaffe during the Second World War. It was so named because the thin cylindrical metal outer shell hinged open when it was dropped and gave a superficial appearance of a large butterfly.
The bomb was an 8 cm long cylinder which was slightly smaller in diameter before its vanes deployed. A steel cable 15 cm long was attached via a spindle to the fuze screwed into the fuze pocket in the side of the bomb. The outer shell would hinge open as two half-cylinders when it was dropped and spring-loaded vanes at the ends would flip out. These rotated the spindle as the bomb fell and armed the fuze.
The bomb could be fitted with one of three fuzes - the 41 fuze which detonated on impact, the 67 fuze which had a settable time delay of between 5 and 30 minutes, and the 70 fuze which detonated if the bomb was moved. It contained .225 Kg of TNT. It was generally lethal to anyone standing unprotected within about 25 metres of it and could injure people as far away as 150 metres. Defusing ones which had failed to detonate or equipped with the anti-handling fuze was not practical and they were usually destroyed where they fell.
Butterfly bombs were generally painted green, sometimes with a yellow stripe.
On October 28, 1940, a butterfly bomb that was incompletely armed was discovered by British ordnance technicians Sgt. Cann and 2nd Lt. Taylor. By returning the arming rods they were able to recover the unit and dismantle it to learn more about how it functioned. The SD2 was disarmed by making a clay wall around the weapon and pouring liquid nitrogen over it, thus freezing the mercury spirit gauge that would activate the bomb once disturbed. The bomb was loaded onto a vehicle and safely disposed of.
They were packed into canisters containing between 6 and 108 of the bombs, depending upon the canister type, and were released as the canister fell. This bomb type was the first cluster bomb ever used operationally.
It was first used in June 1942 against Grimsby and Cleethorpes in Great Britain, and subsequently used in the Middle East. The British kept secret all the damage and disruption caused by these bombs so as not to encourage Germany to use them elsewhere. The United States manufactured a copy of the bomb for use during the Korean War and Vietnam War, designating it the M83 Butterfly Bomb.
