Many engines sought to replace the ubiquitous Curtiss OX-5, many of which remained following World War I. Kinner 5-cylinder radials were rugged, durable, reliable, and economical, but not considered elegant at any time during this company’s existence, and apparently never cowled. First introduced in 1927, they were used in military biplane aircraft as well as Kinner’s own monoplane.
The Kinner R-5, Series 2 engine was certificated in December 1935. A principal R-5 design change from previous Kinner engines was a greatly increased cooling area resulting from longer and more closely spaced fins on the cylinder heads.
This military version of the engine, the R-540-1, powered the Ryan PT-22 and PT-22A primary trainer aircraft. Other R-540 series engine models powered aircraft such as the Stearman PT-9 and Verville PT-10 as well as the Sikorsky H-4 helicopter. The firm rapidly declined from 1945.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.