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Old 08-01-2010, 10:27 PM   #54 (permalink)
3-Wheeler
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Since the tail extension build is getting about two feet in length now, I decided it was time to ensure that the master template I made from AeroHeads Streamlining Airfoil was correct in shape.

To do this, I cropped his streamlining airfoil to a smaller size and placed it in a CAD program for analysis.

I drew several large diameter circles, as you can see in picture one.

For the first 60% or so, the circles seem to be a good match for the curvature of the streamlining airfoil. This is the portion of the curve that matters most to me since my tail extension will not be longer than this.



Here is a closeup of the two red circles as they fit above and below the streamlining airfoil.

It shows that my constant master template does indeed match this shape as I did my best to get this shape into a constant curvature.

This same master template is now ready to create the curvature of the remaining two feet or so of tail extension.



I think that there may be a rendering problem with the airfoil shape from 70% to 100% length. I made several larger circles (shown in forth picture with blue line) that hugged the airfoil from 70% t0 90%, then veered away from the airfoil from 90% to 100%.

The next picture shows how shallow the airfoil shape is in this region. If anyone has any ideas, please let me know.



This picture shows how the 90% to 100% line looks distorted in shape. Notice how far away the blue line is from the airfoil at 90%, but then suddenly gets much closer at 100%?

I tried extracting data from the airfoil and placing values in a spreadsheet, and that's when I noticed there was something fishy with the airfoil rendering. The angular numbers did not make sense from 60%, on.




Jim.
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Last edited by 3-Wheeler; 08-01-2010 at 10:50 PM..
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