Waco Standard Cabin series

The Waco Standard Cabin series is a range of American single-engine 4–5 seat fabric covered cabin biplanes produced by the Waco Aircraft Company beginning in 1931 with the QDC and continuing until 1942 when production ended for the VKS-7F. They were used as light passenger and utility transports, navigational trainers, bushplanes and briefly as maritime reconnaissance aircraft during World War II. == Design == All of the Waco Standard Cabins were powered by cowled radial engines and Waco tried to accommodate their customers preferences for many of the more common commercially available engines of the period, hence the profusion of designations, as the first letter indicates the engine installed. Individual models were each certified with various available engines but not all variations found customers.

Source: Wikipedia — Waco Standard Cabin series (CC BY-SA 4.0)