Bomb designer. Personally Signed bySir Barnes Wallis. As assistant Chief designer at Vickers – Armstrongs Aviation Section his many contributions included the bouncing bombs used by 617 Squadron to breach the Mohne and Eder Dams in 1923,the 12,000 lb tallboy penetration bomb and 10 ton grand slam bomb as well as the mine - detonating electric coil fitted below Wellingtons.RAF Museum Reference Number SC36c Official Signed Cover ( Blue Cachet) numbered 0089.
