In 1994 I bought a handsome collection of short biographies of aviation pioneers, from which I quote:
“The Wing Man: David R. Davis – 1894(?) – 1972 
“David Davis grew up as a sickly child who was advised to spend as much time outdoors as possible. While a young man, he was sent on an educational camping trip with a tutor, during which they retraced the route of Lewis and Clark.  When he was fifteen he moved to California with his mother. Their home was near Los Angeles where [aviation pioneer] Glenn Martin was experimenting and Davis would often help Martin ground-handle his plane.
“In 1911 Davis made his first flight and four years later he bought his first aeroplane. During World War I he served in the Army. After the war he became a barnstormer before joining with Donald Douglas in 1920 to start the Davis-Douglas Airplane Company [Davis put up $40,000.] This venture failed and Davis was completely wiped out with the Stock Market crash in 1929.”
About the period with Douglas, Oliver E. Allen writes in “The Airline Builders“:
“…In 1920 Douglas was ready to start his own firm. He went to Southern California with less than $1000 because he felt at home there and one could fly there all year. It was however a bad time to start an aircraft factory anywhere. Douglas tried to borrow money everywhere, until a friend introduced him to David R. Davis, a well to do young man from California who wanted to have an airplane built for a non-stop transcontinental flight.”
“The two men founded the Davis-Douglas Co. and rented an office. Afterwards they moved to a loft over a lumberyard in Los Angeles. There they constructed the Cloudster. This airplane had one unique property: it was the first plane that could transport a load greater than its own weight. During the first [attempt of the] transcontinental flight the [Liberty] engine broke down and Davis had to crash land at Fort Bliss (Texas). In 1923, when he was ready for a second attempt, two army officers had already completed the non-stop flight with a Fokker T2. Davis lost interest and withdrew from the company…”
Quoting again from Longyard:
“…Davis took an everyday job to support his family but he never gave up his penchant for airplanes. He tried to develop a variable pitch propeller, but lack of funds hampered his efforts. By the late 1930s, he had developed a theory of aerofoils that he thought could greatly increase the efficiency of wings. He tested model sections mounted on a borrowed car.
Through Walter Brookins, he was able to convince Reuben Fleet [of Consolidated Aircraft] of the possibilities inherent in his new wing. Fleet had a wing section tested at the California Institute of Technology where the scientists said the wing was an impossible 102 percent efficient. They disassembled their windtunnel to see what was wrong! Fleet ordered that his next flying boat be built with a ‘Davis Wing’ – a million dollar gamble. In 1939 this plane [the Corregidor] was flown by an amazed test pilot who said it handled like a fighter.”
Altogether not a very complete picture of what exactly went on with the Davis-wing. Remember this was the time before Google, Internet and Wiki. In those days one had to search in libraries and magazines. So imagine what a surprise it was when one day in 1996 I found a letter in the mail from my old friend of Canadian days John Galipeau, whom I had not seen for thirty years. He had heard of my interest in the Davis wing and he had visited the San Diego Air & Space Museum, where he had found fresh information for me, such as the photograph of two of the principal actors shown above: Donald Douglas and David R. Davis.
to be continued…
 Picture of Cloudster is shown at the top of the article. Note the big belly needed to store all the fuel. Pic credit: Wiki
 The collection of short biographies is from: William H. Longyard, “Who’s Who in Aviation History“, Shrewsbury, Airlife, 1994.
 Two famous explorers, who were sent out by Thomas Jefferson in 1803 to find a route from St.Louis to the Pacific Coast.
 Chicago, Time/Life, 1981, here translated from the Dutch edition.