On this day in aviation history, 88 years ago (October 16, 1937), the Short S.25 Sunderland flew for the first time. Developed by Short Brothers for the Royal Air Force, the S.25 was a long-range flying boat designed for maritime patrol and bomber duties. The aircraft was named after the port city of Sunderland in North East England. The Sunderland was developed alongside the civilian S.23 Empire, sharing many design features, but with enhancements tailored to military operations, including a more aerodynamic hull and armament. The S.25 originated from British Air Ministry Specification R.2/33, which called for a dual-role patrol-reconnaissance flying boat capable of extended-range operations. Its design emphasized durability, range, and the ability to deliver offensive and defensive firepower in maritime environments.
The Sunderland typically carried a crew of nine to eleven: pilot, co-pilot, navigator, radio operator, flight engineer, bombardier, and three to five gunners. Four Bristol Pegasus XVIII 9-cylinder radial engines, each producing 1,065 horsepower, powered the aircraft. The Sunderland had a maximum speed of 210 mph, a cruising speed of 178 mph, a range of 1,550 nautical miles, and an endurance of up to 13 hours. The service ceiling reached 17,200 feet. Defensive armament included up to twelve .303-inch Browning machine guns in various turrets, with forward-firing guns later upgraded to twin .50-caliber weapons. The aircraft could carry up to 2,000 pounds of bombs, mines, or depth charges internally or underwing.
During World War II, the Sunderland earned a reputation as one of the most aggressive and effective flying boats. It was heavily employed during the Battle of the Atlantic, where Royal Australian Air Force Sunderlands—such as those of No. 10 Squadron—achieved the type’s first unassisted U-boat kill. The aircraft also saw action in the Mediterranean Theater, performing patrol and reconnaissance missions, as well as logistical support operations. Between 1938 and 1946, Short Brothers built 749 Sunderlands. Only a few survive today. One notable example is ML814, preserved at Kermit Weeks’ Fantasy of Flight museum. Originally a Mark III, this aircraft was later converted to a Mark V and used as a passenger hauler. ML814 holds the distinction of being the last four-engine passenger flying boat to cross a major ocean. While it has not flown since 1996, it remains an important and historic exhibit at the museum.
