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Mysteries of the (actual) F-22 wing

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Mysteries of the (actual) F-22 wing

Old 07-27-2008, 12:06 AM
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Mike James
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Default Mysteries of the (actual) F-22 wing

I'm building a (non-RC) 3D/CAD model of the F-22. ( http://www.mikejamesmedia.com/f_22_01_intro.html ) and am interested to see if any of you might be able to help me solve a puzzle.

Usually, I can figure these things out in a few minutes, with some drawings and a little CAD work. In this case, I haven't solved the issue yet, which is...

Looking at the Lockheed-Martin front view of the F-22, there appears to be some odd combination of anhedral, twist (washout) and curvature. Having tried many combinations, none of which produced an image like the drawing, I'm wondering if some of you (perhaps a Lockheed-Martin employee) might know why this is. (And, assuming that it's not proprietary, I hope you'll clue me in!)

Thanks in advance for any who know the answer. The images and explanation are at http://www.mikejamesmedia.com/f_22_edits_04.html
Old 07-28-2008, 03:59 AM
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Mike James
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Default RE: Mysteries of the (actual) F-22 wing

I've just solved the problem, using a very simple tool. A few years ago, I did an article on slicing up a plastic display model, for the purpose of obtaining cross sections for plans. At the time, I had no intention of building an F-22, but used it as the example. ( http://www.nextcraft.com/plastic_to_rc01.html ) I kept some (low-res) copies of the scans I produced from that model, and have used them several times in my F-22 project. They obviously used Lockheed-Martin drawings, as well as photos, etc., and it's remarkable how well those scans fit.

Anyway, in 3D, I created some "spars" from those scans, and also created a test wing. (My test wing had 1 degree positive AOA at the root, twisting to -4 degrees at the tip. (for a net total of 3 degrees twist) and 3 degrees of anhedral. It wasn't quite right. But, when I did a boolean operation, where those spars and my test wing were combined, the differences stick right out. (images attached) I can definitely make an accurate wing out of that result.
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