The S.23 was of very advanced design with a deep hull, single fin and rudder, cantilever wing with camber-changing flaps, and fixed wingtip floats. The four fully-cowled 920 hp Bristol Pegasus XC engines were mounted on the leading edge and drove three-blade propellers. The lower deck contained four passenger cabins with an initial total of 24 seats and the flight-deck and mail hold were on the upper deck.
Canopus, the first S.23, flew on July 4, 1936 and the order was changed to provide a total of 31 of which six were for Qantas Empire Airways while two of Imperial Airways' aircraft, the Caledonia and Cambria, were to be built as long-range aircraft for North Atlantic trials. Canopus made the first scheduled flight, from Alexandria (Egypt) to Brindisi (Italy), on October 30, 1936 and the same aircraft flew the first through service from Southampton (UK) to Durban (South Africa) in June 1937. View the Canopus wireless room and kitchen. On June 26, 1938, Camilla and Cordelia left Southampton to inaugurate flying-boat services to Australia, Challenger taking over at Singapore on July 2. The type maintained essential services during the war, undertook some military duties in Europe and the Mediterranean and played a major role in the Pacific war.
Nine heavier Perseus-engined S.30s were built, and four were equipped to enable flight refueling for North Atlantic operation. In 1938 three high-weigh S.33s were ordered to replace aircraft lost in accidents. Two were launched at the end of April 1940 but the third was not completed.
Span: 114 ft 0 in (34.70 m)
Length: 88 ft 0 in (26.80 m)
Height: 31 ft 9.75 in (9.70 m)
Wing area: 1,500 sq.ft (139.40 sq.m)
Empty weight: 23,500 lb (10,660 kg)
Loaded weight: 40,500 lb (18,371 kg)
Cruise speed: 165 mph (266 kmh)
Range: 1,500 mls (2,414 km)."