The Kinner C-5 was an American five cylinder radial engine for small general and sport aircraft of the 1930s.
The C-5 was a development of the earlier R-5 with greater power and dimensions. The main change was the increase in cylinder bore from 128 mm (5.0 in) to 143 mm (5.625 in) and an increase in cylinder stroke from 140 mm (5.5 in) to 145 mm (5.75 in). This led to a corresponding increase in displacement from 8.85 liters (540 cu in) to 11.71 liters (715 cu in).
The U.S. military designation was R-720.