Kirkham started engineering by building motorcycle engines. In 1903, Kirkham and Curtiss delivered an engine to Thomas C. Benbow for future use in a dirigible.^[2] In 1905 he founded the Kirkham Motor and Manufacturing Company in Bath, New York with two others and $25,000 in capital.^[3] His father John Kirkham cast engine blocks for Glen Curtiss up until 1905.^[4] Kirkham worked in Senaca Falls, becoming sick and returning home. Kirkham enrolled in a mechanical engineering correspondence course while recuperating. In 1910 Kirkham built his first aircraft engine of his own design.^[5] The Kirkham B-6 was used on the 1910 Burgess Company Model F.^[6] In 1913 Kirkham started another company, the Kirkham Aeroplane and Motor Company with $100,000 in capital.^[7] Kirkham joined Glenn Curtiss and went to work for Curtiss Aeroplane in 1915 as Chief motor engineer^[8] for the popular Curtiss OX and sole VX engine that powered the speedboat "Miss Miami".^[9]

Later Kirkham would top rival Hispano Suiza with the Curtiss AB, a 300 hp aluminum blocked, twelve-cylinder engine for fighter use. This engine would evolve into the K-12.^[10] Kirkham designed a Curtiss Triplane in 1919 to take full advantage of the K-12 engine. A Seaplane variant became the world's fastest seaplane in 1920 at 138 mph. A biplane variant for the U.S. Army label the Curtiss P-86, was dropped after the crash of a prototype.^[11]

In 1919 Kirkham left Curtiss to form Kirkham Products.

• Kirkham 1911 Biplane
• Curtiss K-12
• Curtiss 18
• Kirkham Air yacht
• Kirkham-Williams Racer
• Kirkham Racer
• Kirkham Gull

• Harold E. Morehouse Flying Pioneers Biographies Collection - Kirkham, Charles B. – Smithsonian