Original Posted By: "Douwe Blumberg"
Ken, where are you located. I have kids in Colorado Springs and glen wood springs and I get out there often. My Piet has the cut out. And the WWII corvair. Gardiner Mason (Airlion)Sent from my iPadOn Apr 17, 2013, at 8:54 PM, Ken Bickers wrote:> Avill, > > I've given this question a lot of thought over the past several years. I, too, operate out of a fairly high airport, KLMO, which has a field elevation of just over 5k, but with density altitudes that are typically between 7k and 9k during the summer. > > On my Pietenpol project, which is not yet flying, I've done at least three things to compensate for altitude. One, I lengthened the wings by 9 inches on each side. I know that isn't much, but the spar blanks I bought from Aircraft Spruce were 14' long. I decided not to cut off the 9 inches, and instead to take advantage of the extra length. That works out to a 5% longer wingspan. The attach points for the diagonal spars moved out approximately 6 inches from what is called out in the plans. I did lots of calculations using the formulas on the WestCoastPiet.com website before deciding whether (and where) to shift the strut attach points, as the section of the wing outside the struts is where the greatest lift stresses are located.> > Two, I decided not to do a cutout over the rear cockpit. Everything I read suggests this reduces lift by a significant amount. Were I nearer to sea level, I wouldn't hesitate for a moment to build with the cutout. I love the look. But I want to retain every last measure of lift. Instead, I built a flop section. That gives me ease of access to the rear pit and preserves lift. > > Three, I decided to use a Corvair engine. I'm going fairly stock, ala William Wynne's conversion manual, with a set up to produce approximately 100 hp at sea level, or about 70-75 hp on a typical summer day here in Colorado. > > Not specific to altitude but just in general, I've tried to be judicious about things that add weight. I have made a couple of concessions. I've used the Jenny-style landing gear. It is a bit heavier than the J3-style gear. I just like the way it looks. Also, I've installed a second fuel tank. Again, I wouldn't have done that if I still lived in the midwest where there is an airport every few miles. Where I fly, airports can get awfully far apart. When they do, I'd swear the winds are directly off the nose. > > Tell us all where you are. If you are in the Colorado area, feel free to drop me a PM. There are a few other Pietenpols in the area -- a couple that are finished and a couple, including mine, that are advancing toward completion.> > My best, Ken> > > On Wed, Apr 17, 2013 at 5:16 PM, Avill wrote:>> >> I have been wondering this exact same thing. Thanks for bring it up Bill. My reasons are different though. I would be operating a Piet off of airports at altitudes of 5-6,000 ft before factoring in DA. Hence why I would be interested in any experiences operating at these altitudes, or folks that have extended their wing, and how they did it.>> >> >> >> >> Read this topic online here:>> >>
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MmmmmmmmClifThe only thing that interferes with my learningis my education. A. Einstein> >> You used paper bags -- I used large plastic drinking cups. C>________________________________________________________________________________Subject: Pietenpol-List: Re: Newbie needed help and info.