Airfoil ?
02-14-2008, 10:49 PM
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Airfoil ?
How do you draw a wing rib airfoil without a cad program. I have heard of Clark y andNACA airfoils but don't have any idea how to start drawing one. Can someone in layman terms tell me how it is done? I have scratch built several planes but used an airfoil from another set of plans. I am working on a set of plans for a b5n2 Kate. Thanks Rich
02-14-2008, 11:33 PM
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RE: Airfoil ?
Use a sheet of graph paper. The coordinates given are in percentages, ie, the length of the airfoil (the chord of the wing) ranges from 0 to 1.0. The vertical dimension of the airfoil is also in percentages above (+) and below (-) the chord line. You will have to multiply each of the coordinate values by a factor to scale the data up to where you can plot an airfoil of the size you need, then plot the points and connect them with a french curve. The section of the curve that you use should connect at least 3 points. For example, the first section of the curve would cover points 1, 2, and 3. The next portion would cover points 2, 3, and 4. And so on, until you have the complete curve.
An alternate way to do it would be to multiply each coordinate by 10 (move the decimal point one position to the right to do this) and plot the airfoil. Then use a copier to enlarge/reduce the airfoil you just plotted to the size you need.
It might be worthwhile to look for a free basic CAD program to do the drawing using a spline curve.
Good luck.
An alternate way to do it would be to multiply each coordinate by 10 (move the decimal point one position to the right to do this) and plot the airfoil. Then use a copier to enlarge/reduce the airfoil you just plotted to the size you need.
It might be worthwhile to look for a free basic CAD program to do the drawing using a spline curve.
Good luck.
02-14-2008, 11:55 PM
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02-15-2008, 02:53 AM
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RE: Airfoil ?
It's pretty easy actually. You go to www.profili2.com and download the program. In the freeware mode you can print out single airfoils. For a small charge it opens up a lot of extra features.
The other guys have indicated the old way and way back I did just that to get a brand name true shaped airfoil. But since you obviously have a computer if you're posting here then Profili 2 is by far an easier option.
The other guys have indicated the old way and way back I did just that to get a brand name true shaped airfoil. But since you obviously have a computer if you're posting here then Profili 2 is by far an easier option.
02-15-2008, 08:12 PM
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RE: Airfoil ?
Thanks Guys for the input. I am going to try it both ways just so I will know. I might have more questions later. Thanks Rich
