The Decathlon traces its lineage back to the
Aeronca Champ, by way of the Citabria. Like the Citabria, the Decathlon features tandem seating and center-stick controls. The
fuselage and tail surfaces are constructed of welded metal tubing. The outer shape of the fuselage is created by a combination of wooden
formers and
longerons, covered with fabric. The cross-section of the metal fuselage truss is triangular, a design feature which can be traced back to the earliest
Aeronca C-2 design of the late 1920s. The strut-braced
wings of the Decathlon are, like the fuselage and tail surfaces, fabric covered, using
aluminum alloy ribs. The wings of Champion and Bellanca Decathlons were built with wooden
spars. American Champion has been using aluminum spars in the aircraft it has produced and has made the aluminum-spar wings available for retrofit installation on older aircraft. Compared to the Citabria's wingspan of , the Decathlon's wingspan is shorter, at . One of the major developments of the 8KCAB Decathlon over the 7KCAB Citabria is the Decathlon's wing, which employs a semi-symmetrical
NACA 1412
airfoil, as opposed to the Citabria's flat-bottomed airfoil. This change gives the Decathlon better inverted flight and negative-g maneuver capabilities. The landing gear of the Decathlon is in a conventional arrangement. The main gear legs of most Decathlons are made of
spring steel, though American Champion began to use aluminum gear legs in 2004. Like the 7KCAB, the engine of the 8KCAB has a
fuel injection system, as opposed to a
carburetor. To facilitate negative-g flight, the fuel system incorporates a 1.5 gallon header tank beneath the instrument panel, and the engine is fitted with a
Christen Industries inverted oil system. Champion and Bellanca built the Decathlon with several
Lycoming IO-320 engine variants, all of , and with the choice of a fixed-pitch or
constant speed propeller. The major improvement in Bellanca's introduction of the Super Decathlon was the change of engine to the
Lycoming AEIO-360-H1A or –H1B, both of , which was accompanied by a selection of constant speed propellers. The American Champion Super Decathlon uses the AEIO-360-H1B, along with a constant speed propeller. ==Operational history==