The Douglas C-1C was an improved version of the Douglas C-1. The wingspan of the -C was increased by nearly 3.5 feet and was slightly longer than the C-1. The same engine, the Liberty 12, powered both the C-1 and C-1C; however, the C-1C had a slightly faster maximum speed. The balanced rudder tested on the C-1A was used on all C models. The aircraft also had a metal floor in the cargo compartment for increased durability and provided strengthened mount points for the installation of litters.
The C-1C could be rapidly converted into an air ambulance for medical evacuation of battle casualties or flying injured crewmen out of remote crash sites. The plane could be configured for carrying four litters or two litters, a medical officer and a medical supply cabinet.
Seven C-1Cs were ordered in 1926 and ten more in 1927. All aircraft were delivered by the end of 1927 and some remained in service until the mid-1930s. Because so few aircraft were ordered, most were assigned singly to various units throughout the United States. Large cargo/transport units would not become common until the early World War II era.
First plane using C designation
C-1 with engine change
Design study only
Improved, larger C-1
TECHNICAL NOTES: Engine:Liberty V-1650-1 of 435 hp Maximum speed: 121 mph Cruising speed: 85 mph Range: 385 miles Service ceiling: 15,950 ft. Span: 60 ft. 0 in. Length: 36 ft. 0 in. Height: 14 ft. 0 in. Weight: 7,410 lbs. loaded Cargo/passenger capacity: 7-8 passengers, or 4 litter patients, or approx. 3,000 lbs. of cargo Crew: Two (pilot and flight mechanic) Serial numbers: 26-421 to 26-427; 27-203 to 27-212