Forgotten racers: Mr. Wittman's Bonzo

Air Classics, Aug 2003 by O'Leary, Michael

STEVE WITTMAN CREATED THE SMALLEST AIRFRAME THAT HE COULD WRAP AROUND A MASSIVE CURTISS D-12 POWERPLANT

Born on 5 April 1904, Steve Wittman was a life-long resident of Wisconsin. Fascinated with, aviation, Steve learned to fly at the Fond du Lac airport in 1924 and began earning his keep as a barnstormer. Later, he would also handle testing duties for Dayton Aircraft Company and Pheasant Aircraft Company. In 1931, he started managing the Winnebago County Airport in Oshkosh, Wisconsin, while also operating a flying school and flight service (today, of course, this is Wittman Field-home of the EAA).

As well as being a talented pilot, Steve Wittman was also a self-taught aeronautical engineer and aircraft builder. Always operating on the principle of minimalism, Wittman began partcipating in racing events during 1926 and he entered the 1931 Cleveland Air Races with his first race craft-Chief Oshkosh. For much of his life, Steve was interested in creating small airframes with small engines that would rely on aeronautical efficiency for exceptional performance-with one great exception!

During 1934, Steve got an excellent bargain on a military surplus Curtiss D-12 powerplant that was utilized to power numerous military designs. Soon to be antiquated, the Curtiss engine did give the buyer a whopping (by 1934 standards) 435-hp at a give-away price. Wittman rapidly set about designing an aircraft that would wrap around the liquid-cooled engine-creating a machine that would be called an "Unlimited" in today's Reno parlance.

Sketching out his design, Steve once again decided to make the aircraft completely "minimal." The airframe would be as small as possible, the landing gear fixed, and the whole plane built in an extremely rugged manner. There was nothing fancy about the construction-the fuselage was of steel tube, while the wings were all wood with two spars-inserted into the aircraft's center section-and heavily braced with two flying wires. What rolled out of Steve's Oshkosh hangar was not exactly elegant-in fact, it was extremely crude!

True to his concepts of aeronautical minimalism, the new plane-named Bonzo - was small, tough, and compact. A crude sheet metal cowling wrapped around the D-12 which, in itself, was not the most reliable of powerplants. The landing gear was a unique tripod set-up to offer resistance to the unimproved nature of most landing strips. Initial flight testing showed Steve that he had a tiger by the tail and any thought of getting the plane to the 1934 Cleveland event was scrapped.

With numerous modifications, Steve and Bonzo were ready for the Thompson Trophy event at the 1935 edition of the Cleveland air races. Seven planes were entered for the 2 September event - the one the record crowd had come to see. This year, it was to be a 150-mile all-out race and race favorite Roscoe Turner quickly took the lead with his Wedell-Williams racer but with just 20 miles to go, Roscoe had to pull up and out as the engine poured a thick trail of smoke. The flamboyant pilot pulled off a skilled emergency landing.

The lead was taken by Harold Neumann who won the race flying Benny Howard's Mr. Mulligan at a slow 220.2-mph. Wittman, who had flown a polished race, came in a very close second at 218.7-mph but his Curtiss engine was running red-hot! Even though Wittman had converted the engine from water to Prestone cooling, engine temperature was still off the gauge - a problem that would plague the craft through its racing life.

For various reasons, the 1936 race was transferred to Los Angeles - held at Mines Field, site of today's LAX. Bonzo was out of the running because of an engine backfire that had set the plane afire but he entered his little Chief Oshkosh and narrowly avoided death following a forced-landing crash into an Air Corps A-17.

For 1937, Bonzo was back and ready to race. Numerous improvements included a modified cowling and an open spinner which allowed cooling air to enter a fan which crammed the air directly into the Prestone-cooled radiator. However, the engine still ran hot. On 6 September, nine racers took off for the big event. During the race-horse start, Wittman somehow got airborne first and was going around the first lap before some the others had gotten airborne. On the 18th lap, Bonzo suddenly pulled up. Steve had hit a bird, bending a prop blade and the vibration loosened an oil line which covered his windshield with blinding fluid.

Slowly entering back into the race, Steve fought to regain his lead but it was not to be. Although he had qualified first at 276.25-mph, Steve finished fifth at 250.1-mph - a sure disappointment for the homebuilt racer which probably would have finished first except for the bird strike (collecting $1900 in prize money).

For 1938, Steve and Bonzo were back against a sophisticated field of racing machines. The 1938 Thompson would cover 300 miles and there were eight racers. Roscoe Turner in the LTR-14 was able to win with an average speed of 283.4-mph after several other racers dropped out but Wittman held in to take third at 259.2-mph even though the Prestone radiator was spraying fluid over his windscreen.