Original Posted By: Mike Hardaway
Pietenpol-List: permanent fixed leading edge slats on
Re: Pietenpol-List: permanent fixed leading edge slats on Pietenpol
Original Posted By: Dean Pacetti
> Fisherman Caye wrote:>> > http://www.zenithair.com/stolch701/7-design-wing.html> > Here is the theory on leading edge wing slats> > You design engineers, want to comment on whether the leading edge slatpermanently fixed on the Piet wing would work and increase lift? There isincreased drag apparently, but how bad that might be I could not guess?> >> > I'd be interested in some construction and design ideas if youconsider it practical?> >> > Ray>> Ray,> Keep in mind when you read this that my aeronautical engineering isyears behind me and clouded by distance.> The Pietenpols airfoil is a relatively thin section, is highlycambered, and has a slight trailing edge reflex.> A leading edge slat is intended to allow an airfoil to reach a higherangle of attack before stall than it is ordinarily capable of , which gets ahigher coefficient of lift. The slat ONLY gets you more lift by letting> you get to a higher angle of attack.> The camber of the Piet airfoil already achieves a fairly high angle ofattack. Even if you successfully built a slat, you probably wouldnt want totry to land with it because your tail wheel would contact the ground,> dropping the nose, while your mains were still way too high. You mighthave to build stronger main gear, adding yet more weight and cost.> A trailing edge flap, on the other hand, gets a higher liftcoefficient at any given angle of attack. This means you can land slower inthe same attitude as with an un-flapped wing.> Since the existing Piet airfoil section is slightly reflexed, atrailing edge flap makes a little bit more sense. On the Piet, a trailingedge flap could be built the same way the ailerons are and actuated by asimple> manual device of some kind.> The Piets been flying for a lot of years and lots of other people havefaced the same problems in the past. When I did a quick search in thearchive, I didnt find anything on flaps. This tells me that either there> hasnt been any real effort to develop any or my search skills need work.> All this aside, with 145 square feet, the Piet already has plenty ofwing and plenty of lift and, properly flown, can just about land inside itsown shadow. All it really fails on is power. Either leading edge slats> or trailing edge flaps will take more time and money and add more weightand complexity. And, even if you built the absolutely perfect wing, withslats, flaps, drooping ailerons and active boundary layer control, you would> still only get a few mph off your already slow landing speed.> Build the little bird light, go on a reasonable diet (have thecrawfish and gator steak but go easy on the butter), get the most horsepoweryou can afford and you wont have to pay the locals to hack down too manytrees> on that Maya Mountains ridge.>> MikeRay -I can only second what Mike ahs written. If you have to have more lift withthe Piet's wing, convert the section from the cabane strut to the aileroninto flaps. This will require some rethinking on wing spars, especially therear one. It will add weight and complexity.The Piet flies extremely well for what it is - it simply needs more power -to a point. When you start going over about 90 HP, you are adding fuelconsumption/weight without appreciable gain (too much drag!). Stick a Cont.85 on it, and have at it. It will climb, with the right prop, like ahomesick angel, get on and off the ground in just a little space, and belight and economical.Now I realize that you, like most of us, are on a tight budget, and that aC-85 will set you back $2.5 - 3.5 K. BUT! That is a one time expense,you'll get many hundreds, if not thousands, or hours of use from it, it willbe light and dependable, and easy on the fuel. That's the way the Piet isdesigned.. Keep it light, keep it simple. The old rule of airplanebuilding: Simplicate and add lightness!If you really want a STOL plane, you're going to have to part with many moredollars than you already have... My Duce gets on and off in about 300', butit is a lot bigger, more complex, and costs a whole lot more than that Pietwould!Off-list, send me your address so I can come visit!Craig________________________________________________________________________________Date: Fri, 22 Feb 2002 14:25:42 -0800 (PST)
> Fisherman Caye wrote:>> > http://www.zenithair.com/stolch701/7-design-wing.html> > Here is the theory on leading edge wing slats> > You design engineers, want to comment on whether the leading edge slatpermanently fixed on the Piet wing would work and increase lift? There isincreased drag apparently, but how bad that might be I could not guess?> >> > I'd be interested in some construction and design ideas if youconsider it practical?> >> > Ray>> Ray,> Keep in mind when you read this that my aeronautical engineering isyears behind me and clouded by distance.> The Pietenpols airfoil is a relatively thin section, is highlycambered, and has a slight trailing edge reflex.> A leading edge slat is intended to allow an airfoil to reach a higherangle of attack before stall than it is ordinarily capable of , which gets ahigher coefficient of lift. The slat ONLY gets you more lift by letting> you get to a higher angle of attack.> The camber of the Piet airfoil already achieves a fairly high angle ofattack. Even if you successfully built a slat, you probably wouldnt want totry to land with it because your tail wheel would contact the ground,> dropping the nose, while your mains were still way too high. You mighthave to build stronger main gear, adding yet more weight and cost.> A trailing edge flap, on the other hand, gets a higher liftcoefficient at any given angle of attack. This means you can land slower inthe same attitude as with an un-flapped wing.> Since the existing Piet airfoil section is slightly reflexed, atrailing edge flap makes a little bit more sense. On the Piet, a trailingedge flap could be built the same way the ailerons are and actuated by asimple> manual device of some kind.> The Piets been flying for a lot of years and lots of other people havefaced the same problems in the past. When I did a quick search in thearchive, I didnt find anything on flaps. This tells me that either there> hasnt been any real effort to develop any or my search skills need work.> All this aside, with 145 square feet, the Piet already has plenty ofwing and plenty of lift and, properly flown, can just about land inside itsown shadow. All it really fails on is power. Either leading edge slats> or trailing edge flaps will take more time and money and add more weightand complexity. And, even if you built the absolutely perfect wing, withslats, flaps, drooping ailerons and active boundary layer control, you would> still only get a few mph off your already slow landing speed.> Build the little bird light, go on a reasonable diet (have thecrawfish and gator steak but go easy on the butter), get the most horsepoweryou can afford and you wont have to pay the locals to hack down too manytrees> on that Maya Mountains ridge.>> MikeRay -I can only second what Mike ahs written. If you have to have more lift withthe Piet's wing, convert the section from the cabane strut to the aileroninto flaps. This will require some rethinking on wing spars, especially therear one. It will add weight and complexity.The Piet flies extremely well for what it is - it simply needs more power -to a point. When you start going over about 90 HP, you are adding fuelconsumption/weight without appreciable gain (too much drag!). Stick a Cont.85 on it, and have at it. It will climb, with the right prop, like ahomesick angel, get on and off the ground in just a little space, and belight and economical.Now I realize that you, like most of us, are on a tight budget, and that aC-85 will set you back $2.5 - 3.5 K. BUT! That is a one time expense,you'll get many hundreds, if not thousands, or hours of use from it, it willbe light and dependable, and easy on the fuel. That's the way the Piet isdesigned.. Keep it light, keep it simple. The old rule of airplanebuilding: Simplicate and add lightness!If you really want a STOL plane, you're going to have to part with many moredollars than you already have... My Duce gets on and off in about 300', butit is a lot bigger, more complex, and costs a whole lot more than that Pietwould!Off-list, send me your address so I can come visit!Craig________________________________________________________________________________Date: Fri, 22 Feb 2002 14:25:42 -0800 (PST)
Re: Pietenpol-List: project status
Original Posted By: "D.Dale Johnson"
Subject: Re: Pietenpol-List: project status
Subject: Re: Pietenpol-List: project status