Original Posted By: Fisherman Caye
Pietenpol-List: fixed leading edge wing slats Pietenpol
RE: Pietenpol-List: fixed leading edge wing slats Pietenpol
Original Posted By: "Michael Brusilow"
Anybody tried building and installing a set of fixed leading edge wingslats on a Pietenpol? With the Clark Y airfoil, I do not know if it would be appropriate andwork? I haven't a clue on how those things are designed? Anybody have a source?RayRay, the Pietenpol did not use a Clark Y airfoil. According to BHPietenpol, the airfoil is pretty close to an Eiffel 36, with the ordinatesincreased by about 25%. My brother (also an engineer) did some research andthe closest airfoil he has found to the Pietenpol airfoil is a USA 27. Idon't know where he found it. I looked in my "Theory of Wing Sections"book, but it doesn't list the USA series of airfoils (curious, because theUSA 35B was the airfoil used in the Piper Cub, and every rag-wing Piper everbuilt, also in the Aztec twin engine).Anyway, designing a leading edge slot would not be a trivial task. Movableslats like DeHavilland provided on their Moth biplanes would be even morecomplicated. The benefits probably would not justify the extra weight andcomplexity. If you notice, most planes that have fixed slots in theirleading edge (e.g., Globe Swifts, some Stinsons) just have them on theoutboard portion of the wing, in line with the ailerons. These are not somuch to generate high lift as to keep the boundary layer attached to thatportion of the wing at high angles of attack to maintain aileron controlthroughout the stall. There is a drag penalty at cruise for such features.Generally, when you look at a wing that has slots in it, you know someengineer screwed up somewhere in the initial design and the slots wereprobably added during the initial flight testing of the aircraft to correctsome undesirable flight characteristics.The Pietenpol already has a pretty good high lift (and high drag) airfoil.It is simplicity itself. If you want it to perform better, build itlighter. In all these old planes (including my much more modern 1947 Cessna140) any additional weight makes a huge difference in the way it flies. Ican tell a great deal of difference in the Cessna's performance just goingfrom half full tanks to full tanks, and that is only a difference of 75 lbs.Jack________________________________________________________________________________
Anybody tried building and installing a set of fixed leading edge wingslats on a Pietenpol? With the Clark Y airfoil, I do not know if it would be appropriate andwork? I haven't a clue on how those things are designed? Anybody have a source?RayRay, the Pietenpol did not use a Clark Y airfoil. According to BHPietenpol, the airfoil is pretty close to an Eiffel 36, with the ordinatesincreased by about 25%. My brother (also an engineer) did some research andthe closest airfoil he has found to the Pietenpol airfoil is a USA 27. Idon't know where he found it. I looked in my "Theory of Wing Sections"book, but it doesn't list the USA series of airfoils (curious, because theUSA 35B was the airfoil used in the Piper Cub, and every rag-wing Piper everbuilt, also in the Aztec twin engine).Anyway, designing a leading edge slot would not be a trivial task. Movableslats like DeHavilland provided on their Moth biplanes would be even morecomplicated. The benefits probably would not justify the extra weight andcomplexity. If you notice, most planes that have fixed slots in theirleading edge (e.g., Globe Swifts, some Stinsons) just have them on theoutboard portion of the wing, in line with the ailerons. These are not somuch to generate high lift as to keep the boundary layer attached to thatportion of the wing at high angles of attack to maintain aileron controlthroughout the stall. There is a drag penalty at cruise for such features.Generally, when you look at a wing that has slots in it, you know someengineer screwed up somewhere in the initial design and the slots wereprobably added during the initial flight testing of the aircraft to correctsome undesirable flight characteristics.The Pietenpol already has a pretty good high lift (and high drag) airfoil.It is simplicity itself. If you want it to perform better, build itlighter. In all these old planes (including my much more modern 1947 Cessna140) any additional weight makes a huge difference in the way it flies. Ican tell a great deal of difference in the Cessna's performance just goingfrom half full tanks to full tanks, and that is only a difference of 75 lbs.Jack________________________________________________________________________________
Re: Pietenpol-List: permanent fixed leading edge slats on Pietenpol
Original Posted By: Fisherman Caye
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