Brodhead Pietenpol Association

Original Posted By: clif
Subject: Pietenpol-List: Incidence for stabilizerI'm getting ready to mount my stabilizer, and figure I may have to change the angle of incidence after I test fly it. Can anyone offer suggestions on max-min incidence? I'm figuring to attach the stabilizer with the trailing edge shimmed to a maximum negative incidence, with the stabilizer spar having no shims under it, and then shimming under the spar to take out negative incidence as warranted. The bottom of the vertical fin will get shims to keep the rudder hinges aligned and as shims go under the stabilizer spar, they'll come out from under the fin leading edge. Am I on the right track here?Matt Paxton________________________________________________________________________________Date: Sat, 20 Apr 2002 23:25:33 -0700

Original Posted By: "Richard Navratril"
Subject: Re: Pietenpol-List: Incidence for stabilizerIn a message dated 4/20/02 8:43:57 PM Pacific Daylight Time, Woodflier(at)aol.com writes:> I'm getting ready to mount my stabilizer, and figure I may have to change > the > angle of incidence after I test fly it. Can anyone offer suggestions on > max-min incidence? I'm figuring to attach the stabilizer with the trailing > edge shimmed to a maximum negative incidence, with the stabilizer spar > having > no shims under it, and then shimming under the spar to take out negative > incidence as warranted. The bottom of the vertical fin will get shims to > keep > the rudder hinges aligned and as shims go under the stabilizer spar, > they'll > come out from under the fin leading edge. Am I on the right track here?> > Matt Paxton> > > Matt,I use the following method and it works well for my planes. Mount the horizontal stab onto the longerons per the drawing and rig neutral. Then, after the first flight, if required, very slightly adjust only the (4) forward turnbuckles to wash in or wash out the outer forward sections of the horizontal stab. The amount on my two Piets is about 1/4 to 1/2 turn. Don' t move the rear ones, so the rear spar of the stab remains straight. This may sound strange, but it's the simplest way I could think of and I can see the same result on the Piets in the museum at Oshkosh. I make this slight adjustment until the plane flies hands off in pitch at my average weight. It is just a tweak; hardly noticable, but effective. Doug Bryant________________________________________________________________________________