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x-andre committed revision 189 to the XFLR5 SVN repository, changing 1 files.
2009-12-06 19:10:57 UTC by x-andre
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x-andre committed revision 188 to the XFLR5 SVN repository, changing 11 files.
2009-12-06 07:24:25 UTC by x-andre
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2009-12-06 08:11:20 CET
Yes, the performance changes for different CoG positions, mainly because the equilibrium aoa changes. The equilibrium aoa is the point for which Cm=0. Which means that changing the CoG position does not change the Cl(alpha) or Cd(alpha) curves, but it changes the point to consider on these curves. Further more in Tye 2 analysis, this will change the balance speed, and.
2009-12-06 07:12:10 UTC by x-andre
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The performance of a glider, namely gliding ratio and sink speed, in QFLR5 don't seem to change with different CoG positions. Is this correct? Isn't it that an aft CoG position (within limits) improves performance due to less tail load etc?
Also, why options for different number of elements in each wing panel in the x-direction? Shouldn't that be the same along the wingspan, just like in FEM...
2009-12-06 01:53:04 UTC by nobody
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x-andre committed revision 187 to the XFLR5 SVN repository, changing 1 files.
2009-12-04 13:01:12 UTC by x-andre
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1. if by "on-screen" is meant "on the 3D view", well, there are issues with opengl - see the messages aove in this thread. If it's something else, could you be a bit more specific ?
2. Symmetric and asymmetric only relate to the foil definition. The feature is provided to enable different flap settings on the left and right wing. The geometry (span, chords) itself remains symmetric...
2009-12-02 20:19:19 UTC by x-andre
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Running QFRL5, we discovered two bugs:
1) When running a 3D panel analysis, the number 6 is non-existent in the on-screen information. Instead just a black space appears.
2) It seems impossible to make an assymetric 3D wing. When defining a new wing, checking or unchecking the 'symetric'-box makes no difference.
2009-12-02 10:35:57 UTC by nobody
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thanks Andre, I was trying to "dial in" the NP that's why the CG was close to the NP.
2009-12-02 03:54:50 UTC by nobody
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In your file, the CG is positioned close to the neutral point. Therefore, the coefficient Cm is more or less independent of lift, and the Cm vs. alpha curve reflects the dependence on the induced and viscous drag, both of which are non-linear functions of the aoa.
Try position the CG forward, and the curve will become a line.
andre.
2009-12-01 19:43:38 UTC by x-andre
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Andre, my analysis doesn't include a body
http://www.optimumsolution.com/OS_FTP/outcoming/airplane.jpg.
2009-11-29 18:44:28 UTC by jhosee
