Curtiss S-1 Speed Scout

Also called Baby Scout, the original Model S-1 was the smallest aeroplane that Curtiss could build around the 90hp OX engine. Construction was thoroughly conventional for the time, but the 6.09m span of the single-bay wings was inadequate. The upper wing was lengthened and the strut arrangement was altered to two spanwise Vs. The S-1 did not sell, and Curtiss kept the modified prototype for its own use.

Peter M. Bowers "Curtiss Aircraft 1907-1947", 1979