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 19 of 38

THE SPORT PANTHER FOLLOWING A PROJECT TO completion takes dedication, brains, and a bit of luck. The more brains and dedication, the less luck is needed. Such is the case with the Sport Performance Panther, shown in complete and flying form at EAA AirVenture Oshkosh 2013. "I've been involved in aviation my whole life," said Dan Weseman, co-founder with wife Rachel of Sport Performance Aviation LLC, as we sat under his awning at Oshkosh. Twenty feet away, covered by showgoers, was their baby—a single-place, Corvair-powered, low-wing monoplane that features monocoque and steel tube construction, with aluminum skin and a fiberglass cowl that sits behind a Sensenich composite prop and spinner. It's called the Panther, and its engineering is stealthy; it looks simple and is simple to build, but it wasn't simple to design. Dan and Rachel Weseman have spent several years on this plane, which they first showed to the public at the 2012 Sun 'n Fun International Fly-In & Expo. It is the result of a lot of thinking and firsthand experience. In Dan's aviation life, he's been a draftsman (both pencil and CAD); he has run and programmed CNC machinery; and he's a self-educated engineer who tempers his own experience and ideas with those of an aerospace engineer friend. Dan said, "I taught myself CAD some five years ago; and I've read and reread Chris Heintz's book [Flying on your Own Wings], John Roncz, and others." In addition to having built a Corvair-powered Sonex (irreverently called a "Cleanex"), he has also built an RV-4 and parts for a Harmon Rocket; he currently owns a Glasair. It's called the Panther, and its engineering is stealthy; it looks simple and is simple to build, but it wasn't simple to design. The Panther in flight. It can be built as either a tail dragger or tri-gear. Dan is perhaps best known as a supplier to top-line Corvair engine builders, with his bolt-on "fifth bearing" setup, billet crankshafts, and alternator options now powering hundreds of homebuilts. Dan won the Cherry Grove trophy in 2009, which is given annually to the pilot who makes the greatest contribution to the Corvair movement. As pointed out in EAA Sport Aviation (January 2011), "A solid, safe, well-built Corvair can fit your firewall for well under $5,000. So can a crummy one, so it's important to learn a few things first." Dan is one of the people who makes the parts and has the know-how to help build the good ones. And so his Panther was designed to use the smooth six-cylinder Corvair as its primary engine. Still, Dan wanted to build, using an engineer's explanation: "my own set of compromises. I wanted to do my own." The single-place Panther has a sturdy roll-over structure. Looking at his dream not only as a fulfillment of his own ideas but also as a commercial kit from the start, he notes similarities between his Panther and other well-known kits. "We [designers] all started at about the same place," he said. "You might think of this as a cleaned-up and rounded Sonex, using only about 60 percent of the parts count of an RV-4." Continuing the comparisons, Dan said, "You could also think of it as an inexpensive, uncomplicated RV-3." "Uncomplication" takes a lot of thought. The folding wings emulate those of many sailplanes, with overlapping spars at the center section; four pins (two forward, two aft) are safetied. Folding or unfolding the wings is a 5-minute, one-person job. The dry-break fittings between the wings keep assembly and disassembly dry. And the tanks incorporate "flop tubes" in case the builder wants to do some aerobatics and has the powerplant to do it. FROM CONCEPT TO COMPLETION 20 Vol.3 No.1 / January 2014 Photography courtesy of Sport Performance Aircraft

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