G.Swanborough, P.Bowers United States Military Aircraft Since 1909 (Putnam)

MARTIN MODELS T AND S
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   The Model S was a direct development of the T, the major changes being the use of the 125-h.p. Hall-Scott A-5 engine and the ailerons built into the upper wing instead of being between the wings. Appearance was distinctive due to the location of the fuselage above the lower wing instead of on it. The Army bought six as observation seaplanes late in 1915 and ordered eight more in June 1916.

G.Swanborough, P.Bowers United States Navy Aircraft Since 1911 (Putnam)

MARTIN S SEAPLANE

Glenn L. Martin was one of the first successful American aeroplane designers and manufacturers. In 1915 the Army bought six Model S seaplanes fitted with 125 hp Hall-Scott A-5 engines and the Navy bought one as AH-19 to replace the rejected Wright Aeroboat AH-19. When the Navy Martin was re-serialled A69, a second was bought as A70. Span, 46 ft 5 in; length, 29 ft 7 in; gross weight, 2,600 lb; max speed, 82 mph.