SST-class blimp

The SST (Sea Scout Twin) class blimps were developed in Great Britain during World War I from the earlier SS class blimp. The main role of these craft was to escort convoys and scout or search for German U-Boats.

Designs were submitted in 1917 for a twin-engined SS class airship, the idea being that should there be an engine failure, the craft would not be rendered helpless and therefore less likely to be lost. The first submission was a failure, but the second showed promise and was put into production. Designated the SST class, the first of 13 examples entered service in June 1918, and the last in May 1919, three of which, S.S.T.9, 11 and 12 were purchased by the US Navy.

The SST used a larger 100000 ft3 envelope than any of the other SS class types, and was equipped with a streamlined and waterproofed car that could accommodate a crew of five. Two 100 hp Sunbeam or 75 hp Rolls-Royce Hawk engines were each mounted on a gantry either side of the car, and drove 9 ft diameter four-bladed propellers in pusher configuration. At 57 mph, the SSTs had a greater top speed than all other SS class types, had the highest useful lift, and could stay airborne for up to two days. They were also cheaper to produce and easier to handle than the successful C-Star class blimp.

Experiments involving SSTs were carried out at the end of the war; one notable example being SSE.3 (SS Experimental) that had an envelope design known as shape "U.271", the shape from which the hulls of both R100 and R101 were derived.

Operators

 * Royal Naval Air Service / Royal Air Force
 * US Navy
 * US Navy
 * US Navy