Activity for Juan
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Juan posted a comment on discussion Open Discussion
I found my mistake, and it was a silly one... I did not realize the X axis points backwards not forwards relative to the airfoil, so I was setting the CoG forward of the airfoil leading edge, rather than at 25% chord, causing much higher Cm..... When I entered the CG as 0.05 rather than -0.05, the CM trend and magnitude becomes similar to that of the airfoil. Sorry for the silly question, and thanks a lot for your help.
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I made a simple high aspect-ratio wing with NACA0008, 5m span, 0.2m chord (1.0 m2 Area), and anlyzed it using LLT, with the CG at 25% chord at 200K Re. I'm confused about the CM results i'm getting. The NACA0008 CM at 200K starts at 0 at 0 alpha, then goes down to a minimum of about -0.009 at 2 degrees alpha, then increases from there on. However, the CM of the wing monotonically decreases, and at 2 degrees angle of attack is already at -0.12 which seems to big. If we scale this CM by the reference...
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Here is the file
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Thank you Andre. For the wing analysis I set the CoG at 25% of the chord, so this shouldn't be the issue. The LLT method should be using airfoil data direclty to calculate wing data, so I dont see why the cms can be so different.
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Thank you Andre. For the wing analysis I set the CoG at 25% of the chord, so this shouldn't be the issue. The LLT method should be using airfoil data direclty to calculate wing data, so I dont see why the cms can be so different.
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I made a simple high aspect-ratio wing with NACA0008, 5m span, 0.2m chord (1.0 m2 Area), and anlyzed it using LLT, with the CG at 25% chord at 200K Re. I'm confused about the CM results i'm getting. The NACA0008 CM at 200K starts at 0 at 0 alpha, then goes down to a minimum of about -0.009 at 2 degrees alpha, then increases from there on. However, the CM of the wing monotonically decreases, and at 2 degrees angle of attack is already at -0.12 which seems to big. If we scale this CM by the reference...
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