I photographed these Waco ATO examples at the Waco Museum in Troy, Mich., and the WAAAM in Hood River, Ore.
Engine and landing gear are the only difference between this and WACO’s other Taperwing aircraft, the WACO CTO.
1929 Waco ATO #A-118
The signage at the WACO Museum in Ohio labels its plane as a Model CTO Mackey Taperwing… but the registration identifies it as an ATO.