Experimenter

March 2013

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/113663

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When Is a Cozy III Not a Cozy III? Te highly refective fnish of Dennis' Cozy IIIP resulted from two coats of clear top-coat, with half of the fnal coat sanded away with 1500, then 2000 grit wet sandpaper.  Tis was followed by bufng with two successively fner grades of bufng compound. Obviously drawn to space flight, he found the perfect slot in Houston working on the Space Shuttle; when that program ended, he found an even better gig. He explained, "I'm now working on the Dream Chaser space plane. It's closer to being an airplane than a rocket and can land on any large commercial airport. It's a fun project!" While most pilots can trace their interest in flying to a specific event, Dennis can't. "It's just one of those things that has always been there," he said. "I learned to fly in the usual Cessna stuff and discovered Sport Aviation in the early 1980s." One fact that certainly separates him from the rest of the sport aviation herd is that he didn't attend EAA Oshkosh until he'd already started building his Cozy. (We don't know what else to call it.) He said, "My dad was a carpenter, so I grew up knowing that building something is really just a matter of knowing what needs to be done and learning the applicable skills. I looked around and saw that a lot of people build airplanes, and it appeared to be something where you read books and watch videos and then go do it." He makes it sound easy, but if you think about it, he's right: Figure out what needs to be done and learn how to do it. 14 Vol.2 No.3 / March 201 3 "While I was working on the Space Shuttle, a friend there mentioned [Burt] Rutan and, as he phrased it, his strange airplanes," Dennis said. "I was initially attracted to the Long-EZ, but at the time it wasn't readily available. However, Nat Puffer was doing the Cozy, and he was well along with producing plans. Unfortunately, it was just too small, and Nat swore up and down that he wasn't going to do a four-place. But I wanted at least a three-place and more room. So I figured I'd start where Nat left off and redesign the Cozy to be what I wanted it to be. Of course, Nat eventually came out with the four-place Mk. IV, but by that time I was so far into my project, I wasn't going to change direction." Although Dennis was highly educated and could talk about astrophysics and space flight with ease, that wasn't going to help him much in redesigning the composite structure of the Cozy. Significant changes were needed to handle more people and the structural requirements the 10-percent larger size was going to demand. So, what did he do? He read some books and sought advice from friends, just like any other successful homebuilder. "Mostly, I used the Modern Aircraft Design text by Martin Hollmann," he said. "I first validated his algorithms by applying them to the Cozy III and verifying that the spar sizing and other critical structural elements matched the Cozy III plans. That gave me confidence to use Hollmann's

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