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Author
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Topic: Airfoil Q
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Nat
Pilot
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posted 07-14- 12:16 PM
   
Guys, how do airfoils work.. what I would like to know specificaly is this.. is an airfoil made to produce more lift the faster it goes.. that being the case, is it possible to reverse this.. produce an aifoil that gives more lift the slower it goes? I have no idea about them at all, I just know that some of you guys know how to make them.. see, if it could be done, then flying boats are possible by adding a reverse airfoil, enebeling it to produce enough lift to keep the boat afloat on water.Just a freaky idea that could solve alot of problems for Snick and flying boats in general. ~Nat~ I'm hoping that an airfoil can be made to do this by manipulating the data in it, but then, I guess ppl that can make their own airfoils are the only ones that can answer this, or maybe even understand what I'm saying... lol IP: Logged |
Falck
Pilot
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posted 07-14- 12:24 PM
I dont think you can get around an airfoil's lift increasing with speed. Otherwise there would be lift when the airfoil wasnt moving, and that violates some laws  IP: Logged |
Maury Markowitz
Pilot
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posted 07-14- 12:41 PM
quote:
Originally posted by Nat:
Guys, how do airfoils work.. what I would like to know specificaly is this.. is an airfoil made to produce more lift the faster it goes.. that being the case, is it possible to reverse this.. produce an aifoil that gives more lift the slower it goes
Airfoils always produce more lift with more speed. They work by having less air on top than on the bottom, and the faster you go they more of that crosses the wing. It's the same reason it's easier to turn skis or cars at higher speeds for instance, more stuff to push against so you don't have to push as hard. In the game this is all handled for you, you input the lift/drag curves in relation to the angle of attack and that's that, the game figures out the lift by figuring in the speed. However this isn't really true, at higher speeds all sorts of weird things start to happen when shock waves start forming on the wings, and this is something the game doesn't have a model for. Maury IP: Logged |
Nat
Pilot
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posted 07-14- 04:17 PM
Maury, thats what I thought, you input the data to specify how the airfoil will function... ok, so could an airfoil be made that produces lots of lift at very low speeds just by inputing data that will make it so?IP: Logged |
Falck
Pilot
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posted 07-14- 05:05 PM
Data in the airfoil files is a function of Angle of Attack, not airspeedIP: Logged |
Nat
Pilot
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posted 07-14- 05:22 PM
thanks, it was just a thought.. that if it were purely data based, then we could make one that would give say the PBY an airfoil that would give it lift when it "lands" on water just to stop it sinking..Ahwell, worth the thought.. lol IP: Logged |
Snickers
Pilot
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posted 07-14- 05:23 PM
BTW NAT -
Pang was kind enough to make a NACA21 airfoil for us to use. He said its good to +/- 60 degrees..... The PBY would almost always stay in that range  ------------------
Snickers
=FC=
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Snickers
Pilot
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posted 07-14- 05:25 PM
Double post[This message has been edited by Snickers (edited 07-14-2000).] IP: Logged |
Sv
Pilot
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posted 07-14- 07:36 PM
The airfoil files only effect the lift drag and moment coefs that are used in the hard coded lift and drag equations. I'm not sure what OpenPlane uses, but the old lift equation I remember is something like:L = .5 p cl v^2 s Where:
L = lift force
p = air density
cl = lift coef for the given angle of attack
v = airspeed
s = wing surface area I'm not sure I'm remembering it correctly though, but there will always be more lift when you have more airspeed... or less left if you have a neg cl The real way to get boats and water planes in SDOE would be to have the OpenPlane engine enhanced to support it - I don't think it is a huge deal, but it is something. I hope OpenPlane grows to support this kind of stuff
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-Sv =FC=
WWI in SDOE!
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