The C3s fuselage and wing struts were built up from welded chromium-molybdenum alloy steel tubes, faired with wood battens.

[3] Ribs were built up from spruce and plywood, while on the C3-225, duraluminium sheet covered the leading edge of the wing to improve the aerodynamic form.

[4] The prototype had a conventional undercarriage similar to those used on most World War One aircraft, with a pair of vees braced from the lower longerons, connected with a spreader bar and suspension provided by bungee cords.

While the Walter was fitted to a significant number of the earlier airframes, as an import, it was never a popular engine in the United States and eventually the Wright Whirlwind supplanted it.

The ultimate variant was the C3-225, which was fitted with a much more powerful 225 hp (168 kW) Wright J-6-7 Whirlwind seven-cylinder radial engine, and it was given a larger fin and a greatly enlarged fuel tank in the wing center section.

[10] Other firms used the aircraft's ability to carry two passengers for barnstorming flights, the type was popular for shuttling crews around the oil fields, while some were used as air taxis.

[5] A C3-2 fitted with a large fuel tank in the front cockpit demonstrated its reliability by being flown nonstop from Walkersville, Ontario, in Canada to Key West, Florida, a distance of (1,220 miles (1,960 km)) in 17.5 hours in November 1928.

The Fuerza Aerea Mexicana purchased four C3-120s in 1933 along with six of the later Spartan C2-175 monoplanes,[12] and 5 other examples were exported to Mexico for commercial and private use,[13] and at least one was operated by Aeronautica del Sur.