Thomas-Morse S-4 Scout

Thomas-Morse Aircraft · United States · first flew 1917 · light aircraft

The Thomas-Morse S-4 Scout was the primary single-seat advanced trainer for US Army Air Service pilots in World War I, designed to bridge the gap between basic trainers and the demanding French and British fighters to which American pilots would transition.

Recognition (WEFT)

W — WingsHigh-mounted, straight
E — Engines1 × piston, nose-mounted
F — Fuselage5.97 m fuselage
T — TailConventional

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Spot it by:

A trim single-bay equal-span biplane with a circular-cowled rotary engine, single cockpit, and clean lines influenced by the Nieuport; the single-bay wing structure distinguishes it from earlier biplane trainers.

Specifications

Figures are for the representative variant described above; marks differ. See how AircraftIQ sources figures.

History

First flown in 1917, the S-4 was produced in large numbers — over 500 — to train the rapidly expanding USAS. It used a French Le Rhône rotary engine and was deliberately designed to mimic the handling qualities of the Nieuport fighters then in French service. The S-4B and S-4C were refined variants with aerodynamic improvements. Many postwar examples appeared in air races and films.

Variants

S-4A was the initial version; S-4B introduced a larger fin; S-4C was the main production model with further refinements; some were re-engined postwar.

Where you'll see it

Used solely by the US Army Air Service for pilot training during World War I; postwar examples became popular as sport and racing aircraft.

Related aircraft

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