Chief Oshkosh was Wittman's first homebuilt racer. The Chief was designed for closed course competition where it often held it's own against aircraft equiped with much larger engines. Construction started in April 1931 and was completed in time to race at the '31 National Air Races in Cleveland. At it's premier race 'Chief Oshkosh' developed aileron flutter at high sdpeeds and only finished two events after dropping out of several others. After some post Cleveland redesign, Wittman took 'Chief Oshkosh' to the New York Races where he won 5 firsts in the 350 cubic inch races and took second in the free for all where he was bested only by Frank Hawks in a 450 hp Travel Air 'Mystery Ship.'

In 1932 Wittman beat the Howard Pete in a race. In 1933 he won the 350 cubic inch class at the National Air Races. Wittman placed 'in the money' in many races while flying 'Chief Oshkosh'. In 1937 Wittman/Chief set a new 'in class' world record of 238.22 mph over a 100 km course. Due to constant improvement Chief had an enviable record until it was wrecked in 1938. The remains were shoved in the corner of a hanger until 1946 when the fuselage and a spare set of wings were used along with a C-65 engine to create 'Buster'. Buster can be seen at the National Air and Space Museum while a replica which was made from Chief's original wings and gear can be seen at the International Sport Aviating Museum in Lakeland, Florida.