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
Wing commander (rank) French Canadian usage, a wing commander's rank title was "lieutenant-colonel d'aviation". The rank of wing commander continues to be used as a cadet rank at the Royal Military College of Canada. In the 1990s, the Canadian Forces Air Command (the post-1968 RCAF) altered the structure of those bases under its control, redesignating them as wings. The commander of such an establishment was re-designated as the "wing commander" (or "Wg Comd"). Like the United States Air Force usage, the term "wing commander" (as used in the modern Canadian Forces) is an appointment, not a rank. A wing commander usually holds the