Mary Stopes Roe, the daughter of Barnes Wallis, described in an exclusive interview with the RAF Benevolent Fund how her father taught her and her sister and brothers to skim stones on the Dorset coast before the war.
"I hate to say it but I never could make them go more than two," says Mary, "but his would go for seven or eight or nine."
The family went on camping trips to the Isle of Purbeck, between Swanage and Corfe Castle, where she says that Barnes Wallis ran a tight ship.
"All the guy ropes had to be exactly the right tension,’ says Mary, ‘and he taught us how to put in place proper sanitation. We were properly brought up."
However, Mary also suggests that the skimming stones analogy that has worked its way into the popular imagination as the origin of the idea for the bouncing bomb, is probably false.
"I'm not sure that it probably is the origin of the idea for the bouncing bomb, but it’s fun to think like that," she says.
"The navy had used ricochet for about two hundred years, I think, since the days of Nelson to make their mines go further when attacking other ships, but never inland on lakes and so on."
This blog is dedicated to the memory of Bill Astell, a pilot with 617 Squadron on the Dambusters raid, who died age 23, when his plane hit power lines.