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Douglas C-1

The Douglas Aircraft Corporation manufactured the Douglas C-1, a cargo and transport aircraft, for the United States Army Air Service, commencing production in 1925.

In 1925, Douglas was commissioned to produce nine single-engine transport aircraft, with the inaugural flight taking place on 2 May of that year from the company’s factory in Santa Monica, California.

The C-1 was the first aircraft to be designated under the new C-category.

Drawing on earlier designs from the early 1920s, including the Douglas World Cruisers used in the first round-the-world flight in 1924, the C-1 boasted an enclosed passenger compartment capable of accommodating six passengers or approximately 2,500 lb (1,100 kg) of cargo.

To facilitate the loading of large and/or heavy cargo, such as aircraft engines, a trap door was installed in the lower fuselage, while an auxiliary door for passengers and light cargo was situated on the right side of the centre fuselage.

The C-1 biplane was equipped with the Liberty L-12 engine and accommodated a crew of two in an exposed cockpit.

A C-1 was successfully flown in the 1926 Ford National Reliability Air Tour.

Subsequently, seventeen additional aircraft were procured between 1926 and 1927 by the United States Army Air Corps, designated as C-1Cs, which were marginally larger than the original C-1s.

Several C-1s were employed in experimental programs, serving as an engine test platform, a prototype air ambulance, and as refuelling aircraft for early air-to-air refuelling trials.

Notably, two of these aircraft were utilized as “tankers” in the 1929 record endurance flight of the Fokker C-2 Question Mark Aircraft.
Single-engined cargo/passenger transport aircraft, powered by a 435 hp (324 kW) Liberty V-1650-1 piston engine, accommodation for two crew and six to eight passengers.
One C-1 was used to test a variety of engines and cowlings, it was also used for several experiments with ski landing gear.
Single-engined cargo/passenger transport aircraft, fitted with a metal cabin floor, and modified landing gear, it had a higher gross landing weight and increased dimensions, plus a new balanced rudder; 17 built.
Douglas C-1
6 or 8 pax / 2,500 lb (1,100 kg) payload
35 ft 4 in (10.77 m)
56 ft 7 in (17.25 m)
14 ft (4.3 m)
Wing area
805 sq ft (74.8 m2)
Clark Y
Empty weight
3,836 lb (1,740 kg)
Gross weight
6,443 lb (2,922 kg)
1 × Liberty V-1650-1 V-12 water-cooled piston engine,
435 hp (324 kW)
2-bladed fixed-pitch propeller
Maximum speed
116 mph (187 km/h, 101 kn) at sea level
Cruise speed
85 mph (137 km/h, 74 kn)
385 mi (620 km, 335 nmi)
Service ceiling
14,850 ft (4,530 m)
Rate of climb
645 ft/min (3.28 m/s)
Wing loading
8 lb/sq ft (39 kg/m2)
0.0676 hp/lb (0.1111 kW/kg).
The National Museum of the U.S. Air Force,

McDonnell Douglas aircraft since 1920: Volume I-René J Francillon,

San Diego Air and Space Museum Archive.

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