The 'F' series was popular with private owner pilots for sporting and other uses and continued in production through the late 1930s.
The tandem cockpit UPF-7 was adopted by the Civilian Pilot Training Program and continued in production until 1942 by which time over 600 had been built.
[2] The 1934 model YMF was substantially redesigned with a longer and wider fuselage, larger rudder and other structural changes, and put into production in March 1986 by WACO Classic Aircraft of Lansing, Michigan as the YMF-5.
[3][failed verification] The WACO Aircraft Company of Ohio Inc had built three replicas by December 2011, which they designated MF.
Listed in approximate chronological order (per Simpson, 2001, p. 573) First letter of designation refers to engine installed.