23-class airship

The 23 class were four British rigid airships built during the First World War, designed by H. B. Pratt and Barnes Wallis of Vickers as a lengthened development of the No. 9r. Vickers built the first and last of the four, and William Beardmore and Armstrong-Whitworth built the other two. Power came from four 250 hp Rolls-Royce Eagle engines in three gondolas, and the keel carried a bomb bay, crew quarters and a radio room. The first, 23r, made its trial flight at Barrow on 19 September 1917 and was lightened because it lifted less than rated. None was used in combat, but the ships gave British crews and designers many hours of valuable training and experimental data. Seventeen were once contemplated, but the class was found to be overweight and was cancelled in favour of the R23X class.