;C7 :Powered by a 75hp
Michigan Rover four-cylinder inverted inline piston engine (13 built) ;C7A :Powered by a 95hp
Cirrus Hi-Drive four-cylinder inverted inline piston engine (58 built). ;C7B :Powered by a 125hp
Menasco C-4 Pirate four-cylinder inverted inline piston engine (eight built). ;C7D :Powered by a 90hp
Wright Gipsy four-cylinder upright inline piston engine (one C-7C and 22 C-7D built). ;C7E :Powered by a 125hp
Warner Scarab seven-cylinder radial piston engine (11 built). ;C7F :Powered by a 145hp
Warner Super Scarab seven-cylinder radial piston engine (nine built). ;C7G :Aerobatic version, powered by a 145hp
Warner Super Scarab seven-cylinder radial piston engine (six built). ;XR2K-1 :Military designation for one Scarab powered Model 22 impressed into service and used by
NACA. ;NX14768 :Experimentally designed wing added to the 1933 Fairchild 22 owned by
Charles Townsend Ludington under the Ludington-Griswold Incorporated company, Saybrook, CT. Test flown in 1944, the wing had a series of flaps and wing tip fins. The design proved disappointing and the airplane was later sold. , Texas ==NACA variants==