January 2014

Experimenter is a magazine created by EAA for people who build airplanes. We will report on amateur-built aircraft as well as ultralights and other light aircraft.

Issue link: http://experimenter.epubxp.com/i/247918

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Page 16 of 38

then provide performance gains second." The flaps go all the way down to 70 degrees (!) and the ailerons droop at the same time. At maximum deflection, the ailerons are down 22 degrees. All of Frank's weight-saving eforts have resulted in a sophisticated airplane that weighs 685 pounds with the fat tires and 85-hp-plus engine, as compared to the factory weight of a 65-hp J-3 Cub of around 765 pounds. The airplane's gross weight is 1,300 pounds, so the useful load nearly matches the empty weight. That's an efcient airplane! Of course, it is optimized for short-field performance, so it pays a penalty, as in a 62-mph cruise, "…70 mph, if going downhill a little," Frank added. I'm betting a diferent prop that isn't so short-field oriented would up the cruise considerably. But then it might take him as much as 100 feet to take of and land. Gee! Speed isn't what it's all about. Frank said, "The most fun is flying the rivers with a 10- to 15-mph breeze. I'm just sightseeing, going nowhere while riding the next puf of air to a near stop all afternoon long. At the same time, should I want to visit a sandbar or small valley, I know it will more or less hover to a landing." Frank has two basic methods for making his spectacularly short landings: 1. a low-and-slow approach using up all possible inertia; once crossing the line, pull back and mush to a one-bounce landing, converting some of the remaining inertia into the ground. Immediately remove any flap/droop and use brakes to help stop. 2. a higher stabilized approach slowing to behind the power curve and controlling the touchdown point with pitch and throttle. Once on the ground, immediately remove any flap/droop and use brakes to help stop. This provides the shortest landing; however, it's more difcult to pinpoint the spot. Frank even drilled lightening holes into his control stick to reduce weight. Don't try this at home, children. Frank and his ilk are professionals and do the impossible on a daily basis. Still, when you see the hardware he has developed for the task, doesn't it make you want to start modifying a Cub and go visit places where airplanes aren't supposed to go? Budd Davisson is an aeronautical engineer, has flown more than 300 different aircraft types, and published four books and more than 4,000 articles. He is editor-in-chief of Flight Journal magazine and a flight instructor primarily in Pitts/tailwheel aircraft. Visit him at www.Airbum.com. EAA Experimenter 17

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