Wittman D-12 Bonzo

The Wittman D-12 "Bonzo" was an air racer designed by Steve Wittman for the Thompson Trophy races. The aircraft's top speed of 325 mph made it faster than any United States military aircraft of the era.

Development
Wittman purchased a Curtiss D-12 engine in 1934, and designed "Bonzo" around it. In 1935, it took part in the Thompson Trophy Race. In 1936, a spring steel landing gear was installed. In 1937 a ducted fan was added to the spinner inlet, flaps were added and wingspan was reduced to 17 ft. Ram air was added for the carburetors, and modified several times to get even fuel pressure.

Design
"Bonzo" featured a mid-winged taildragger design with a small squarish cross-section. The aircraft was finished in red and silver, like Wittman's smaller racer "Chief Oshkosh". The spinner featured a center cut-out to provide cooling air to a radiator. The wings were made of wood with aircraft fabric covering and closely spaced wing ribs.

Operational history
"Bonzo" was not ready for the 1934 National Air Races in time.
 * 1935 National Air Races:Bonzo places second behind "Mr.Mulligan" with a speed of 218.69 mph.
 * 1936 National Air Races:Bonzo catches fire en route at Cheyenne, Wyoming.
 * 1937 Thompson Trophy races:Engine trouble forces Wittman from lead to fifth at 250 mph.
 * 1938 National Air Races:Third place with a leaking radiator.
 * 1939 National Air Races:Fifth place.

The D-12 engine was sold to the Falin Propeller Co. for propeller testing throughout World War II.

Variants

 * Only one Wittman D-12 "Bonzo" was built, but Wittman used the name "Bonzo" again on his second midget racer patterned after the Wittman Buster.

Aircraft on display
The D-12 "Bonzo" was donated by Wittman to anchor the EAA Airventure Museum in Oshkosh, Wisconsin in December 1959, it was later restored for display in 1982.