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Author
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Topic: Airfoils? How?
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jedi
Pilot
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posted 03-31- 05:05 PM
   
OK, I've looked at the wing-extractor thing, and the .sm files for some of the "custom" airfoils guys have built. So what information do I need for that? Cl,Cd,etc at all the angles of attack? Assuming I can find those numbers, do I just plug them into the wing-extractor, or is there some manipulation to be done to the values?Anybody know of a good tutorial on how to do this? I gather that simply editing an existing airfoil and renaming it will not necessarily work either, unless it has the same number of letters in the name? Seems a little odd, if the whole premise of Open Plane is to permit the creation of entirely new aircraft... Also, I looked at some of the sites in the Bibliography section, but does anyone know of a good site with tabulated values for the various NACA airfoil sections? ------------------
--jedi-- IP: Logged |
charmstar
Pilot
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posted 03-31- 06:38 PM
SV helped me out some on this. You have to rename your airfoil to something that has the same number of letters. Open the airfoil in notepad, and change each of the instances of the name to your new name (I think there are four occurances, and all are at the beginning).The way I changed values was by this weird ratio thing. If I wanted to make the number bigger, I just changed the ratio to be about right, and tried it (in the alpha range I wanted to change). Then I would save it and reload it, and see what the new value was, and then I did fine adjustment by changing the ratio to be like 1.1:1 or .9:1. It is sort of a pain in the butt, but not too bad once you get the hang of it. Of course, I only was looking at 0-15 degrees alpha :-) charm IP: Logged |
Sv
Pilot
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posted 03-31- 10:06 PM
OpenPlane is an open format to let you create new planes, but it is just file formates/etc. - not a tool for humans. The inteded goal if for people to create apps (like wing extractor) that work on the file format.You can change the name and edit the airoil. Rename it in a binary editor and be sure the file name keeps the exact length. You can fool with the data a bit and save it. Also make sure the new airfoil is in the startup.ppf file on your Fighter Squadron folder. Data is more or less unavailable. The origianl data for SDOE was created by a NASA program running on a Cray supercomputer. The name is like CFLD, it is a standard app used by many people. I think it may run directly on a SGI box. The code is free if youare in the US. There may be other apps that do an OK job for starters too. Pang is working on some real WWI airfoils. For now poeple have been grabbing a foil from the plane that most closly matches. ------------------
-Sv =FC=
WWI in SDOE!
IP: Logged |
Falck
Pilot
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posted 03-31- 10:14 PM
If I ever find the time I want to write a airfoil generator based on a given NACA number. Going to be a lot of work and i prolly couldnt start until summer.IP: Logged |
Snickers
Pilot
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posted 04-04- 11:56 AM
Falk -
You mean like this: http://www.sm.go.dlr.de/~jens/NACA.html (Something I happened across while researching things for the PBY...)
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Snickers
=FC= [This message has been edited by Snickers (edited 04-04-2000).] IP: Logged |
Falck
Pilot
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posted 04-04- 01:06 PM
That would be part of it.
That program only generates the shape of the foil. I'd then have to go through and compute Coeff's of Lift Drag and Moment for that foil shape at angles -179 through 180 degreesIP: Logged |
juzz
Pilot
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posted 04-05- 06:37 AM
Erm, but how are you going to calculate the coefficients without any data other than a 2D aerofoil section? Isn't that why Parsoft got the data from NASA in the first place?IP: Logged |
Kraftwerk
Pilot
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posted 04-05- 07:41 AM
Hey, I've been making a matlab script for calculating CD CL and Drag polars for a given 3d foil. Right now it is coded for hydrofoils and has a set parasitic drag for a given foil.
(Anyways Cd parasitic is usually 0.016. )
BUT! I can't give it to you at all,since this is my senior project and I don't have copyright But I'll gladly ablige if ya got any questions!
btw, read Hoerner's book on Drag...it is GREAT. Even has a detailed breakdown of the drag of a Me 109 G6.[This message has been edited by Kraftwerk (edited 04-05-2000).] IP: Logged |
Falck
Pilot
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posted 04-05- 10:33 PM
Thanks for the tip Kraftwerk, Ill look for that book.IP: Logged |
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