[1] The C3 was a rugged biplane with simple straight wings, a tough undercarriage with oleo shock absorbers and two open cockpits with the pilot in the rear and two side-by-side passenger seats in the front.

Changes included an increased volume oil tank and larger sized baggage compartment.

[1]: 59, 198–199 The C3 was built with light commercial applications in mind, including passenger flying and business flights.

The C3MB was a special mail-carrying aircraft based on the C3 with the forward cockpit enclosed as a dedicated cargo compartment.

This version was operated in 1928 by National Parks Airways on airmail route CAM 26 from Salt Lake City, Utah to Pocatello, Idaho and Great Falls, Montana.