T-12 Cloudmaker

• Name — T-12 Cloudmaker General Purpose bomb • Origin — United States • Type — Earthquake bomb • Is Explosive — Yes • Service — 1949 - 1958 • Used By — United States Air Force • Wars — None • Design Date — 1944 • Production Date — 1944–1948 • Filling — Tritonal • Yield — TNT equivalent

The T-12 was a further development of the concept initiated with the United Kingdom's Tallboy and Grand Slam weapons developed by British aeronautical engineer Barnes Wallis during the Second World War: a hardened, highly aerodynamic bomb of the greatest possible weight designed to be dropped from the highest possible altitude. Penetrating deeply in the earth before exploding, the resulting shock wave was transmitted through the earth into targets. The resulting underground cavity and ground motion could also undermine structures. The bomb could also be used against hardened targets. These types of bombs can reach supersonic speeds and have tail fins designed to spin the bomb for greater accuracy. Originally designed to meet a 42000 lb target weight (one half of the maximum payload for the Convair B-36 "Peacemaker" bomber), with its hardened case the bomb weighed slightly less than 43000 lb. The final T-12 weighed 43600 lb. This was twice the size of the United States' previous largest bomb, the 22000 lb M110 (T-14), the American-built version of the British Grand Slam. The T-12 was not a simple scale up of the M110, but incorporated modifications based on testing and calculations. The B-36 was redesigned so it could carry the T-12, although a converted B-29 Superfortress was used for testing.