The R985 features a built-in centrifugal supercharger and direct-drive propeller. The R-985 was in production from 1930 through 1953. Over 39,000 were produced.

The Wasp Junior was used on the Vultee BT-13 Valiant, Beechcraft -18 Expeditor (and its AT-7 and AT-11 variants), and the DeHavilland L-20A Beaver.