First aerial circumnavigation

The first aerial circumnavigation of the world was conducted in 1924 by a team of aviators of the United States Army Air Service, the precursor of the United States Air Force. The trip took 175 days, covering over 27,553 miles (44,342 km).

In 1929 Australian Charles Kingsford Smith completed the second circumnavigation of the world by flight, and the first within both hemispheres, including the first trans-Pacific flight to Australia in 1928.

In the early 1920s several countries were vying to be the first to fly around the world. The British had made one unsuccessful around-the-world air flight attempt in 1922. The following year, a French team had tried; the Italians, Portuguese, and British also announced plans for a world-circling flight. In the spring of 1923, the U.S. Army Air Service became interested in having a squadron of military aircraft undertake a round-the-world flight. It assigned a group of officers in the War Department planning group, the job of finding a suitable aircraft and planning the mission.

The War Department instructed the Air Service to look at both the Fokker T-2 transport and the Davis-Douglas Cloudster to see if either would be suitable and to acquire examples for testing. Although deemed satisfactory, the planning group considered other U.S. Air Service military aircraft both in service and production, with a view that a dedicated design that could be fitted with interchangeable landing gear, wheeled and pontoons for water landings, would be preferable.

When the head of Davis-Douglas, Donald Douglas, was asked for information on the Davis-Douglas Cloudster, he instead submitted data on a modified DT-2, a torpedo bomber that Douglas had built for the U.S. Navy in 1921 and 1922. The DT-2 had proven to be a sturdy aircraft that could accommodate interchangeable wheeled and pontoon landing gear. Since the aircraft was an existing model, Douglas stated that a new aircraft, which he named the Douglas World Cruiser (DWC), could be delivered within 45 days after a contract was awarded. The Air Service agreed and sent Lieutenant Erik Henning Nelson (1888 - 1970), a member of the planning group, to California to work out the details with Douglas.

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Wikipedia