The Lycoming R-680 is a nine-cylinder air-cooled radial engine, the first aero engine produced by Lycoming. The engine was produced in two types, the E and B series; both are essentially the same. The B4E was available in a trainer version with a front exhaust collector "ring" for use without cylinder air baffles. R-680 received Approved Type Certificate No. 42 on 4 Feb 1930.