Original Posted By: "Brian Kraut"
Guys I have another perplexing problem, at least for me, on the ailerons. WhenI laid out my aileron horns according to the '34 Hoopman drawn plans, they don'tseem to exactly match up to the side view of the horn and the aileron together,as shown on the lower left side of the plans. The issue is the side viewof the aileron and horn shows the upper and lower cable attach points being ina straight line through the hinge point. When I laid out the horn and aileronin autocad with the top cable hole of the horn on the hinge centerline, it appearsthat the bottom cable hole is 1/2 inches forward of the centerline. Alsothe two arms of the aileron horn are not equal in length, again measured fromthe hinge. The lower arm is 1-1/2" longer.My question.... is this right? Do the two cable attach points, on the aileron hornhave to be on the same center line as the hinge? Do the aileron arms needto be of equal length. I can certainly redraw the horn to make things line up,but is it necessary?I'm pretty sure my aileron horn layout is accurate, since when I print it to thesame scale as the drawing, the two match up pretty close.Rick Schreiberin frigid Valparaiso, Indiana________________________________________________________________________________
Pietenpol-List: aileron horn geometery
Re: Pietenpol-List: aileron horn geometery
Original Posted By: walt evans
Thanks for the reply Walt. I didn't even think about the different arm lengthsbeing intentional to control adverse yaw. I was looking at my Tri Pacer this morningand the upper and lower aileron horns are also of unequal length, now Iknow why. On the Piet I was concerned about uneven cable tension, but it appearsthat is normal. As an aside I did alter the geometry on my elevator horns/walking beam, to makeit more of a parallelogram rather than a trapezoid. This was probably similarto what Ken Perkins has done. It did take care of the problem of the cables goingslack, but I still have some uneven cable tension.Rick SchreiberValparaiso, In----- Original Message -----
Thanks for the reply Walt. I didn't even think about the different arm lengthsbeing intentional to control adverse yaw. I was looking at my Tri Pacer this morningand the upper and lower aileron horns are also of unequal length, now Iknow why. On the Piet I was concerned about uneven cable tension, but it appearsthat is normal. As an aside I did alter the geometry on my elevator horns/walking beam, to makeit more of a parallelogram rather than a trapezoid. This was probably similarto what Ken Perkins has done. It did take care of the problem of the cables goingslack, but I still have some uneven cable tension.Rick SchreiberValparaiso, In----- Original Message -----
Pietenpol-List: aileron horn geometery
Original Posted By:
Pietenpol-List: Re: aileron horn geometery
Original Posted By: "MikeD"
[quote="aa5flyer(at)gmail.com"]I'm currently building a Pietenpol. A friend hasa Continental A-75 for sale. He was told, when purchased several years ago,it was just overhauled with 2 to 3 hours test stand time on it. Four yearsago he mounted it and ran it for approx 20 minutes with no problems. It hassince sat in his hangar. It is complete with mags (Eisenman?), carburetor,oil tank, etc. He has not yet given me a price. What would be a reasonableprice range for this engine? Being new to homebuilding any other advice concerningthis engine is appreciated. Tim White > Do check around, but I just bought a clean, low time A-75 for $3000 and based onwhat I had seen in some casual research I consider that a pretty good deal.Mike D.--------Piet-builder-who-hopes-to-be-flying-next-summerRead this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: aileron horn geometery
[quote="aa5flyer(at)gmail.com"]I'm currently building a Pietenpol. A friend hasa Continental A-75 for sale. He was told, when purchased several years ago,it was just overhauled with 2 to 3 hours test stand time on it. Four yearsago he mounted it and ran it for approx 20 minutes with no problems. It hassince sat in his hangar. It is complete with mags (Eisenman?), carburetor,oil tank, etc. He has not yet given me a price. What would be a reasonableprice range for this engine? Being new to homebuilding any other advice concerningthis engine is appreciated. Tim White > Do check around, but I just bought a clean, low time A-75 for $3000 and based onwhat I had seen in some casual research I consider that a pretty good deal.Mike D.--------Piet-builder-who-hopes-to-be-flying-next-summerRead this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: aileron horn geometery
Original Posted By: "Dick Navratil"
waltdak(at)verizon.net wrote:> Rick,> Didn't go over the spacifics of the print that you refer to, but keep in mindthat the control system on the Piet work differentially> Which means that when one aileron goes down 5 deg's, the other goes up ,say 8 deg's. This is to try to eliminate adverse yaw. (or is it the opposite,can never remember). walt evans> NX140DL> You got it right. The down moving aileron increases camber, and thus lift, butthis is with the penalty of more induced drag. The up moving aileron decreasescamber, thus lift, reducing induced drag. The differential in drag causes adverseyaw.--------Piet-builder-who-hopes-to-be-flying-next-summerRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________
waltdak(at)verizon.net wrote:> Rick,> Didn't go over the spacifics of the print that you refer to, but keep in mindthat the control system on the Piet work differentially> Which means that when one aileron goes down 5 deg's, the other goes up ,say 8 deg's. This is to try to eliminate adverse yaw. (or is it the opposite,can never remember). walt evans> NX140DL> You got it right. The down moving aileron increases camber, and thus lift, butthis is with the penalty of more induced drag. The up moving aileron decreasescamber, thus lift, reducing induced drag. The differential in drag causes adverseyaw.--------Piet-builder-who-hopes-to-be-flying-next-summerRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________