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Post by n3480h on Jan 25, 2012 20:27:33 GMT -5
Wow, I'm learning a lot here. ;D
Scott, I've seen your 3 point stall landings, and they are well done. Pretty sure I've seen others 3 point stall a plans built Sonerai, also very nice.
If I were a noob here, I might think I could hang an IO540, a 96" CS prop, and a Storch gear on my Sonerai . . . and fly away. Guys, there's nothing wrong with a plans built Sonerai: It does what it was designed to do and it does it better than almost any other comparable aircraft, usually for lower cost. Not dissing the serious experimental efforts at all, but if you are contemplating substantial modification of any proven aircraft design, you might want to first consider an Aeronautical Engineering degree - and substantial PIC flight time in a variety of aircraft.
Tom
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Post by dayflyer47 on Jan 25, 2012 21:50:12 GMT -5
maybe they just have 1 foot longer wings on each side thus allowing them to stall slower and get better lift on take of even with greater weight. Just a thought
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Post by splischke on Jan 25, 2012 22:12:42 GMT -5
Well said Tom but you do realize that you just earned the moniker “purist”? Scott
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Post by n3480h on Jan 25, 2012 22:59:09 GMT -5
That's ok Scott, as soon as I get the turbine mounted the moniker will come off. ;D ;D
Tom
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4trade
Junior Member
Posts: 51
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Post by 4trade on Jan 26, 2012 5:35:14 GMT -5
Sonerai have low landing gear anyway. You cant do three point stall landing, or you drag tail in a ground. Are you making this statement with respect to a Sonerai that is built to plans? I have almost 1000 landings in my IIL and have no trouble making 3 point stall landings. -Scott It is based three thing...what i read at previous forum....Great planes site (they give all models 10 mph bigger landing speed than stall speed) and mostly at Sonerai flying manual. Manual ask drop speed close to stall, then "hook" tail in ground and after that, hold back pressure until main is down. You can not do this if all three wheel is design to touch at same time. 64A212 airfoil stall at 15 degrees. If wing is at zero incidence for upper fuse tubing, plane (and wing) should sitting at 15 degrees angle in a ground to stall at three point. At photos, Sonerai look like closer ten degrees than fifteen.
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4trade
Junior Member
Posts: 51
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Post by 4trade on Jan 26, 2012 8:53:01 GMT -5
If Sonerai landing gear is build by plans, and it can make perfect three point stall landing, airfoil don´t achieve 15 degree AoA.
NACA 64A212 airfoil have very small radius at LE. If that radius is even slightly smaller than it should, it will stall smaller AoA...10-13 degree. Smaller AoA mean smaller coefficient of lift too...higher stall speed....
Some plane types, that have twist build in wing, stall of course lower AoA than plain airfoil should be.
New builders should be careful when skinning wing. Little more radius at LE don´t really mean nothing, but when radius get smaller, it will affect very much for stall and angle of attack.
12% thick Sonerai airfoil LE radius is 0.994 % of chord and AoA 15 degree/ stall.....when same airfoil family NACA 64A210 (10% thick) LE radius is 0.687 % chord and AoA 12 degree/ stall....
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Post by splischke on Jan 26, 2012 10:18:47 GMT -5
4trade,
What is the purpose of this discussion?
Reality and theory sometimes are not a perfect match. You are taking wing section theory and using it as though you are modeling the entire aircraft and its flight environment. Have you considered such things as ground effect? Why don't you put the calculator away and go have some fun and fly a light, nimble, plans-built Sonerai.
-Scott
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4trade
Junior Member
Posts: 51
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Post by 4trade on Jan 26, 2012 10:36:26 GMT -5
Sometimes builder and plans are not perfect match, rather than theory.....
I was thinking that i can give something here, at this discussion....i was obviously wrong.....
--Vesa--
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Post by schrome on Jan 26, 2012 12:31:18 GMT -5
I'm coming late to this discussion but Vesa's observation about the tailwheel hooking first in a full stall landing holds true for my airplane, which is bone stock. Could be though that the slightly shallower deck angle (if that's the right term) of the stretch explains the difference between mine and Scott's.
Ed 2LS
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Post by Schmleff on Jan 26, 2012 15:15:57 GMT -5
Sometimes builder and plans are not perfect match, rather than theory..... I was thinking that i can give something here, at this discussion....i was obviously wrong..... --Vesa-- Don't sweat it (American for don't worry about it). I don't think Scott is mad or trying to belittle you. Typed text often comes across wrong. Do you have an info on how an airfoil reacts in ground effect? I would also think that the wing tip plays a big part in what happens when slow and close to the ground.
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4trade
Junior Member
Posts: 51
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Post by 4trade on Jan 26, 2012 16:41:17 GMT -5
Ground effect add lift, but most unwanted effect is big raise of airfoil moment. Compressing air tend to add "nose down" moment very much, when air is compressing under a wing that is at high angle. That "nose down" effect need much bigger elevator, to stall airplane than normal flight. Whole wing start to work like your Hoerner wing tip in ground effect. Here is something in WIG page: www.se-technology.com/wig/html/main.php?open=aero&code=0
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Post by bobthebuilder on Jan 26, 2012 18:48:03 GMT -5
.... So from what I understand from your link 4 trade, a tapered wing should generate smaller vortices, and thus less induced drag. Right? Apart from a greater cruise speed, a tapered wing would provide less drag in ground effect too.
Not that this would be applicable to a Sonerai with its cosnstant chord wing.
As a complete newbie, I feel more comfortable building a stock aircraft, with a stock vw based engine. Is there any point in trying to improve an already tried and tested design?
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Post by oahupilot on Jan 26, 2012 21:47:24 GMT -5
If Sonerai landing gear is build by plans, and it can make perfect three point stall landing, airfoil don´t achieve 15 degree AoA. NACA 64A212 airfoil have very small radius at LE. If that radius is even slightly smaller than it should, it will stall smaller AoA...10-13 degree. Smaller AoA mean smaller coefficient of lift too...higher stall speed.... Some plane types, that have twist build in wing, stall of course lower AoA than plain airfoil should be. New builders should be careful when skinning wing. Little more radius at LE don´t really mean nothing, but when radius get smaller, it will affect very much for stall and angle of attack. 12% thick Sonerai airfoil LE radius is 0.994 % of chord and AoA 15 degree/ stall.....when same airfoil family NACA 64A210 (10% thick) LE radius is 0.687 % chord and AoA 12 degree/ stall.... You are miss using the term AOA, which stand for angle of attack, which is the relation ship between the wing and the relative motion of the air. Wing section can go to any AOA its just an anlge, how they perform at that AOA is another story.
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Post by oahupilot on Jan 26, 2012 21:53:21 GMT -5
.... As a complete newbie, I feel more comfortable building a stock aircraft, with a stock vw based engine. Is there any point in trying to improve an already tried and tested design? Build what ever makes you happy, I personally enjoy the challenge of improving and doing new things. I like building and working on stuff, that is just me. As to the point of improving a tried and tested design I think the point is to improve it. ;D
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4trade
Junior Member
Posts: 51
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Post by 4trade on Jan 27, 2012 4:10:14 GMT -5
If Sonerai landing gear is build by plans, and it can make perfect three point stall landing, airfoil don´t achieve 15 degree AoA. NACA 64A212 airfoil have very small radius at LE. If that radius is even slightly smaller than it should, it will stall smaller AoA...10-13 degree. Smaller AoA mean smaller coefficient of lift too...higher stall speed.... Some plane types, that have twist build in wing, stall of course lower AoA than plain airfoil should be. New builders should be careful when skinning wing. Little more radius at LE don´t really mean nothing, but when radius get smaller, it will affect very much for stall and angle of attack. 12% thick Sonerai airfoil LE radius is 0.994 % of chord and AoA 15 degree/ stall.....when same airfoil family NACA 64A210 (10% thick) LE radius is 0.687 % chord and AoA 12 degree/ stall.... You are miss using the term AOA, which stand for angle of attack, which is the relation ship between the wing and the relative motion of the air. Wing section can go to any AOA its just an anlge, how they perform at that AOA is another story. Oahupilot, you are absolutely right! I understand AoA in therm. I use it here just to example that in this particular AoA angle airfoil stall. It is different real angle if compare horizon line, when aircraft is glide mode, or stall with power. In landing configuration, compressing air and floating in that air keep that wing angle quite same than airfoil AoA stall. This is why i use it at here. Sonerai is great plane without any modifications....build it like you want and enjoy that journey!
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