The project began in 1951 as a requirement by Charles Daubenberger for an inexpensive replacement for the corporate Ryan Navion operated by his Dauby Equipment Company, to achieve better reliability while crossing high mountain ranges.

He commissioned Roger Keeney of the Acme Aircraft Company to provide a solution, that evolved into a twin engine conversion of a Navion.

[1][3] A second aircraft was converted for Jack Riley, who specified 140 hp engines, and he purchased the production rights from Dauby.

In September 1954, the design was upgraded to include 170 hp Lycoming O-340 engines plus increased fuel capacity in wingtip tanks, officially named Temco D-16A but typically marketed as the Riley 55 for the 1955 model year.

[1][3][4][5][6] In 1957, after 45 conversions to D-16A specification, production ceased in the face of competition from more cost-effective new-build types such as the Piper PA-23 Apache.