Editor's Notes: This is the 12th and final installment of the current series of "Restoration Corner" articles. The intent of the series was to present information of a general rather than highly detailed nature: therefore, more could have been written on each subject. We encourage readers to share their restoration techniques with us for future "Restoration Corner" articles.-Gene. R. Chase While Gene and Norm wrote these words nearly 20 years ago, they still hold true today. We're only as good as the information and experiences our members share with us. Feel free to drop us an e-mail at vintageaircraft@ eaa.org, or drop us a note in the mail. The address is on the contents page.-H.G. Frautschy
Steve Wittman on taxi tests, first flight, and debugging BY NORM PETERSEN
It is one thing to spend years re storing an airplane with attendant sore hands, tired muscles, and a flat pocketbook-only to suddenly re alize that now you have to fly the critter! To enlighten us on the many details of flying a newly rebuilt air plane for the first time, we asked the old master, Sylvester "Steve" Witt man, to give us his thoughts on the proper procedure. The first item on the agenda, ac cording to Steve, is to properly rig the airplane during final assembly. This includes putting in the proper wing dihedral and wing incidence . And when establishing incidence, don't forget the all-important wash-out at the wingtips per the manufacturer's recommendations. "Wash-out" tips the trailing edge of the wingtip up ward, allowing the wing to stall first at the root of the wing, with the stall progressing to the wingtip in a very controllable fashion. "Wash-in" low ers the trailing edge of the wingtip, causing it to stall first. This is a bad situation for two reasons: The stall is violent and uncontrollable, and the wingtip can suffer structural failure from overloading. Don't be lulled into using the old "eyeball" method. Use proper means to establish the necessary measure ments, be it a plumb, inclinometer,
transit, or incidence board . A final measurement to determine that both wings (or four on a biplane) are square with each other and the fuselage is most important. And along this line, make sure the stabi lizer has the proper incidence (most often negative).
Don't be lulled
into using the old
"eyeball" method.
Use proper means
to establish
the necessary
measurements,
be it a plumb,
inclinometer,
transit, or
incidence board.
Steve says that years ago it was common to rig for "torque"-the large, imaginary hand that would twist the fuselage opposite to the crankshaft ro tation. "This was a bunch of gobbledy gook!" according to Steve. " I once flew Bonzo into Cleve REPRINTED FROM
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MAY 2007
Vintage Airplane JANUARY
1987
land for the National Air Races, only to read a story in the evening paper claiming that it couldn't fly! Suppos edly, there was insufficient aileron to offset the huge amount of torque! The newswriter estimated that 300 mph was necessary before Bonzo would fly straight and level! I am most happy to report that such was not the case!" Steve went on to explain that when you have a midwing aircraft using a thin wing section with a large chord, the propeller slipstream is "anti torque" as it goes by the wing, allow ing the aircraft to be nicely controlled by the ailerons about the roll axis. Once the rigging is determined to be okay, the taxi tests may begin. This is almost an art in itself and should only be attempted on a taildragger if you have tailwheel experience. Without experience along this line, the taxi tests can be dangerous en deavors! If you don't feel comfortable making the taxi tests yourself, by all means, swallow your pride and find a competent taildragger pilot whom you can trust. The taxi tests allow you to check many items, including wheel align ment, brakes, tailwheel control, rud der effectiveness at low speeds, and control pressures in general. This au thor well remembers a Minnesota pi lot who had finished a total rebuild of
