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Dec 05, 2021, 05:45 AM
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Salto WIK (M 1-6 e393)


A digital copy of the original from WIK with the e393 airfoil "Strak" as discussed here.

To convert the .dat files to accurate .dxf I can recommend the open source Profil Converter.
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Dec 05, 2021, 07:32 AM
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Regarding airfoils I would suggest you to consider also "Profili 1.2" which is freeware, has a huge library of airfoils, a NACA generator, a good editor and can be downloaded here :

http://www.hoppenbrouwer-home.nl/ika...re/profi12.htm

it is also available "Profili 2.xx" with a lot af additional functions, but it is not freeware.
Dec 05, 2021, 08:35 AM
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Quote:
Originally Posted by eagle60
Regarding airfoils I would suggest you to consider also "Profili 1.2" which is freeware, has a huge library of airfoils, a NACA generator, a good editor and can be downloaded here :

http://www.hoppenbrouwer-home.nl/ika...re/profi12.htm

it is also available "Profili 2.xx" with a lot af additional functions, but it is not freeware.
Thank you for the comment, I know of Profili, also a great program. What I noticed on the 1.2 version is that it only has 4 decimal points ?.

What I am aiming for is a smoothing of the airfoil with B_Splines for better results when simulating in xfoil and easier manufacturing with .dxf. Also for optimising the airfoil a smooth starting airfoil is required. Have a look at "Improving the airfoil surface quality: Smoothing" here.
Dec 05, 2021, 11:12 AM
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I agree it could not be perfect specially on airfoil nose, but you can print (save) airfoils directly in dxf format that you can smooth afterward.
I could eventually suggest to get "Profili V2" (it should not be expensive, as far as I know) which has a lot of airfoil processing, included "smoothing" on 4 levels.
Last edited by eagle60; Dec 06, 2021 at 01:35 AM.
Dec 11, 2021, 10:35 AM
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Hi eagle60
I should test Profili again, do you know what smoothing he uses "4 levels".
The Chaikin's corner cutting algorithm as linked above and here is the only one I have found that does not destroy the curvature of the airfoil. Javafoils negative smoothing also does a good job once the points have been increased.
SMOOTH Y
This command uses the smoothing factor specified in the text field to the right of the button. Currently it supports two smoothing variants:
If the smoothing factor is positive, the coordinates are approximated by a smoothing spline curve. A reasonable smoothing factor is 0.1.
If the smoothing factor is negative, a filter is applied to the y-coordinates to reduce waviness. This filter applies a weighted average to each point and its two neighbor points. If for example the smoothing factor is -0.1, the y coordinate of the smoothed point is 90% of its initial value and 10% of the linear interpolation between the two neighboring points according to: (formulas)

dxf format smoothing do you mean something like this A Better Way to Draw Airfoils in NURBS Modeling Packages ?


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