Butterfly Bomb 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 . External links Description of the M83 , a US copy of this design See also Thermos Bomb Lists related to aviation Aircraft | Aircraft manufacturers | Aircraft engines | Aircraft engine manufacturers | Airports | Airlines Air forces | Aircraft weapons | Missiles | Timeline of aviation Categories : Air-dropped bombs | Anti-personnel weapons | German World War II weapons | Submunitions 