The Douglas World Cruiser (DWC) was conceived in response to a request from the United States Army Air Service for an aircraft that could be utilized for the first-ever circumnavigation of the globe.
The Douglas Aircraft Company, in turn, developed a modified version of their DT torpedo bomber, the DWC, to meet this requirement.
A total of five aircraft were commissioned for the round-the-world flight, with one being designated for testing and training purposes and the remaining four for the actual expedition.
The success of the World Cruiser proved to be a significant boon to the international standing of the Douglas Aircraft Company.
Subsequently, the design of the DWC was further adapted to create the O-5 observation aircraft, which was utilized by the Army Air Service.
In 1923, the U.S. Army Air Service expressed interest in embarking on a mission to become the first to circumnavigate the Earth by aircraft, which was named “World Flight”.
Donald Douglas proposed a modified version of the Douglas Aircraft Company DT to meet the Army’s requirements.
The DT biplane torpedo bomber, which had previously been supplied to the Navy, was a two-place, open-cockpit aircraft that shortened the production time for the new series.
The DTs that were to be modified were taken from the assembly lines at the company’s manufacturing plants in Rock Island, Illinois and Dayton, Ohio.
Douglas assured the Air Service that the design could be completed within 45 days of receiving a contract.
The Air Service agreed and assigned Lieutenant Erik Nelson, a member of the War Department planning group, to assist Douglas.
Nelson worked directly with Douglas at the Santa Monica, California factory to formulate the new proposal.
The modified aircraft, known as the Douglas World Cruiser (DWC), was powered by a 420 hp Liberty L-12 engine and was the first major project at Douglas for Jack Northrop.
Northrop designed the fuel system for the series, which involved incorporating a total of six fuel tanks in the wings and fuselage.
The total fuel capacity was increased from 115 gallons (435 litres) to 644 gallons (2,438 litres) for greater range.
Other modifications from the DT included increased cooling capacity, two separate tanks for oil and water, a tubular steel fuselage, strengthened bracing, a modified wing of 49 ft (15 m) wingspan, and a larger rudder for a more robust structure.
The dual cockpits for the pilot and copilot/crewman were also located closer together with a cutout in the upper wing to increase visibility.
Similar to the DT, the DWC could be fitted with either floats or conventional landing gear for water or ground landings.
Two different radiators were available, with a larger version for tropical climates.
After the prototype was delivered in November 1923 and successfully tested on 19 November, the Army commissioned Douglas to build four production series aircraft.
Due to the demanding expedition ahead, spare parts, including 15 extra Liberty engines, 14 extra sets of pontoons, and enough replacement airframe parts for two more aircraft were specified and sent to waypoints along the route.
The last aircraft was delivered on 11 March 1924.
Following the triumph of the World Cruiser, the Army Air Service proceeded to commission six comparable aircraft for use as observation planes.
These aircraft retained the interchangeable wheel/float undercarriage of their predecessor but were equipped with significantly less fuel and two machine guns on a flexible mounting in the rear cockpit.
Initially designated as DOS (Douglas Observation Seaplane), they were later redesignated as O-5 in May of 1924.
The success of the DWC propelled the Douglas Aircraft Company to the forefront of the global aircraft industry, prompting the adoption of the motto “First Around the World”.
Additionally, the company replaced its original winged heart logo with a new emblem depicting aircraft encircling a globe. Specifications DWC and DOS with wheels/floats Crew 2 Length 35 ft 6 in (10.82 m) (landplane) 39 ft (12 m) (floatplane) Wingspan 50 ft 0 in (15.24 m) Height 13 ft 7 in (4.14 m) (landplane) 15 ft 1 in (4.60 m) (floatplane) Wing area 707 sq ft (65.7 m2) Airfoil USA 27 Empty weight 4,380 lb (1,987 kg) (landplane) 5,180 lb (2,350 kg) (floatplane) Gross weight 6,995 lb (3,173 kg) (landplane) 7,795 lb (3,536 kg) (floatplane) Fuel capacity 644 US gal (536 imp gal; 2,440 L) in 6 tanks. DOS 110 US gal (92 imp gal; 420 L) Powerplant 1 × Liberty L-12 V-12 water-cooled piston engine, 420 hp (310 kW) Propellers 2-bladed fixed-pitch wooden propellers Performance Maximum speed 103 mph (166 km/h, 90 kn) at sea level (landplane) 100 mph (87 kn; 160 km/h) (floatplane) Ferry range 2,200 mi (3,500 km, 1,900 nmi) (landplane) 1,650 mi (1,430 nmi; 2,660 km) (floatplane) Service ceiling 10,000 ft (3,000 m) (landplane) 7,700 ft (2,300 m) (floatplane) Wing loading 9.9 lb/sq ft (48 kg/m2) (landplane) 11 lb/sq ft (54 kg/m2) (floatplane) Power/mass 0.06 hp/lb (0.099 kW/kg) (landplane) 0.054 hp/lb (0.089 kW/kg) (floatplane) Armament Guns DOS 2x 0.3 in (7.6 mm) machine-guns on a flexible mount in the rear cockpit. Sources McDonnell Douglas Aircraft Company 1st 75 Years Aviation Book-McDonnell Douglas. McDonnell Douglas Aircraft since 1920, Volume 1-René J Francillon. San Diego Air and Space Museum Archive. The National Museum of the U.S. Air Force.