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Author
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Topic: WANTED: Pang
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ArgonV
Pilot
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posted 11-26- 06:00 PM
   
Pang, what airfoil would I use if I wanted the most amount of lift and the least amount of drag at really low speeds? Right now Im using NACA0021. It was WAY better than NACA0012 which it was origonally.IP: Logged |
Snickers
Pilot
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posted 11-26- 07:28 PM
NACA0021 is a fat very eliptical wing (top and bottom are about the same shape). My $.02 worth.------------------
Snickers
=FC=
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ArgonV
Pilot
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posted 11-26- 07:56 PM
Thanks for that bit of info Snickers! That probably explains why it has a descent amount of lift at relativly low speeds. But I want more lift and no drag!  Oh Pang.......IP: Logged |
Sv
Pilot
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posted 11-26- 08:20 PM
Just create a new airfoil, it is very easy! You can even create one where there is a constant lift coef over all angles of attack! You can also do the same thing with the drag...Here are details on how to create a new airfoil:
http://www.schoolmusic.com/chickencoop/se5a/fm/3/index.htm
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-Sv =FC=
WWI in SDOE!
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ArgonV
Pilot
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posted 11-26- 08:31 PM
Hey Sv, Im going to have to check into this... IP: Logged |
ArgonV
Pilot
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posted 11-27- 12:14 AM
Hmmm... I got it but I still havent gotten the BIG picture of what Im doing.....  Sv, Pang, Zur, could you create me an airfoil with little to no drag and VERY high lift at all AOAs? Also, make sure the airfoil is unstallable, or make the stall speed like 1-10 mph. I would give you a medal if you did this for me!!!! PLEASE I BEG YOU!  IP: Logged |
Sv
Pilot
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posted 11-27- 09:19 AM
What problems are you having? Just start with any airfoil and then edit the lift so that it is high and constant, it will end up being a horizontal line across the top. Now edit the drag so that it is a horizontal line at 0, centered.Although this is technically "unstallable," the aircraft speed is still key, at a certain speed not enough lift will be created to hold the ship up, and at too high a speed the ship will rise. Creating a hidden helicopter-prop is the only way to get a floater - only trouble is that now you can not get the real zep engines to work too  IP: Logged |
Sv
Pilot
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posted 11-27- 12:00 PM
Ok, here is a start:This is a simple aifoil with only 6 sample points, a constant lift coef of two, a constant drag coef of .1, and a constant moment coef of 0.  Here is the airfoil file:
http://www.schoolmusic.com/chickencoop/zep.ppf Remember to add the zep.ppf to your startup.ppf file! Just add the zep foil to your wing instead of the one you are using now. IP: Logged |
ArgonV
Pilot
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posted 11-27- 12:49 PM
Thanks! Im not having any problems really, I justneed to figure out how all this affects the FM with the AI.A few questions... what is moment? What does it do? Also, does it matter how many points you have and why? IP: Logged |
Sv
Pilot
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posted 11-27- 02:03 PM
Moment is the tourque force applied to the wing that effects pitch. At different angle of attacks differnt amounts of tourque forces effect the wing, working to either increase or decrease the AOA.More sample points just allow for more detail in the airfoil. Since the one I just made is flat, you only really need 1 sample. maybe 2 depending on how SDOE interpolates the coefs. Interpolation means finind the correct value between two known samples. So if you just put 2 sample is, -45 AOA = coef of 1 and 45 degrees = 0, then SDOE will figure .5 for the coef at 0 AOA. Generally, for a real aifoil, you want more samples in critical areas such as the stall and around 0 AOA. The foilUp and foilDn airfoils represent the coef's for the wing when the control surface is deflected in the extreme up and down position. SDOE will then interpolate the value based on the three coefs depending on how much control surface deflection there is. IP: Logged |
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