Sounds good, @struth It is a fascinating story. Not just the heroism of the boys of 617sqn, but the determination of Wallis to get the project done. Read about it myself in Paul Brickhill’s The Dambusters decades ago. A related read, if you want, would be J E Morpurgo’s Barnes Wallis biography. It examines the man’s other projects, “earthquake” bombs and his “aerodyne” swing-wing, lifting-body ideas.