 In 1937, piloting his second homebuilt, "Chief Oshkosh", Wittman placed second in the Greve Trophy Race.Wittman flew "Bonzo" in the Thompson Trophy race, and he led for the first 18 laps of the 20 lap race, at an average speed of over 275 mph (442.57 km/h).Suddenly his engine began to run rough, and Wittman was forced to throttle back to remain in the race, finishing in 5th place.