Waco YMF-5Waco YMF 5 biplane airplane model. The YMF 5 is an open cockpit., light biplane produced by the WACO Aircraft Corporation of the United States. Based on the design of the 1934 WACO (Weaver Aircraft Company) "YMF" model, the YMF 5 was introduced in 1986. Each is hand built, and while its design hails from the early days of aviation, the YMF 5 is hewn of modern materials and proven, state of the art systems, including modern alloys and glass touchscreen