Dambuster Raid On 26 Feb 1943, the new "Upkeep" bomb was approved for use against German dams. "Upkeep" was designed by Barnes Wallis. It was a drum-shaped bomb designed to be carried by aircraft. When released at a low altitude, they spun at the rate of over 500 RPM (revolutions per minute) backwards, which... http://ww2db.com/battle_spec.php?battle_id=211
See: http://www.dambusters.org.uk/ and: http://www.thedambusters.org.uk/ The Sorpe dam had a different bomb used against it. The 1957 draining of the Sorpe dam reservoir in West Germany revealed an unexploded, 12,000 pound bomb - a very special type with three fuses, dropped by the RAF's 617 Squadron. https://www.youtube.com/watch?v=B3D7sMiRrzA
