Heavy bomber version of the bouncing bomb, was used to destroy the Mohne and Eder dams by Lancasters from the specially recruited and trained 617 Squadron, often known as the Dambusters, under Wing Commander Guy Gibson. In March and April 1945, as the war in Europe was ending, Lancasters dropped Grand Slams and Tallboys on U-boat pens and railway viaducts across north Germany. At Bielefeld more than of railway viaduct was destroyed by Grand Slams creating an earthquake effect, which shook the foundations. The Boeing B-29 Superfortress was a development of the Fortress, but a larger design with four Wright R-3350 Duplex-Cyclone
Charles Elworthy, Baron Elworthy responsible for operations at Headquarters RAF Bomber Command in October 1941 and became Group Captain responsible for operations there in May 1942. Promoted to wing commander on a war substantive basis on 9 November 1942, he was mentioned in despatches again on 1 January 1943. He became Station Commander at RAF Waddington in April 1943 and was mentioned in despatches yet again on 14 January 1944. In April 1944 he was made Bomber Command's Representative to Air Chief Marshal Sir Arthur Tedder, who was then serving as Deputy Supreme Allied Commander, Supreme Headquarters Allied Expeditionary Force. He was, in this