Hello, when trying to replicate the results in the sample project provided in sourceforge, I am encountering some strange errors, when alpha=3, the result is as shown in the attached image, the pressure coefficient on the wing is clearly wrong and is "stripey". It also appears something strange is happening at the wingtips; the centre of pressure is far forward of the wing. When a higher a.o.a is input, eg. alpha=5, the result is not converged due to, for example: "Cl = 1.40 could not be interpolated". At lower a.o.a, eg. alpha=1, the angle is skipped due to negative lift. None of the settings were changed from a fresh reinstall and none of the project was changed other than my computer doing the calculation. I have tried the glider in the sample project and my own models but I encounter the same problems.
Hello Julian,
as far as I could check in short time, the project file looks ok.
- the stripes in the pressure distribution are due to a change in the visualization: Every panel has a single colour (equals to the result of the calculation) - and no more artifical color gradient
- you could extend the airfoil polar calculation to higher alpha. This would lead to higher alpha of the plane ("Cl = 1.40 could not be interpolated")
- for T2-polars no negative lift is allowed
But - there are grafical artefacts in the plane view when panels are displayed...
@techwinder - André could you have a look at it? (see attachment - it happens when clicking between "plane" and an "analysis" in the obkect explorer)
My issue is that I'm unable to recreate results seen in the sample project provided in the files section of xflr5 sourceforge. What I have described in my original post is symptoms of what happens when I try to recreate those results. I will attach an example. The first image is the oppoint for alpha=3 when you first open the sampleproject. The second image is the exact same oppoint, just that my computer did the calculation. They look very different.
For the glider in the project (not the flying wing), the unedited files show T2 oppoints from 0 to 7 but I am still getting the negative lift error up to alpha=5 when I try to calculate them. For alpha>5, I get the Cl could not be interpolated. So it seems it can be interpolated but for some reason when I run the program it requests too high a CL.
These problems seem to be caused by incorrect settings. To restore the default configuration, delete the .ini files
Windows: "C:\Users\your_user\AppData\Roaming\XFLR5.ini"
Mac: "/Users/your_user/.config/XFLR5.ini"
Linux: "/home/your_user/.config/sourceforge.net/XFLR5.ini"
The menu option "restore default settings" will not be enough; the .ini needs to be deleted.
Not sure why this occurs all of a sudden but it will be fixed in the next version.
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Hello, when trying to replicate the results in the sample project provided in sourceforge, I am encountering some strange errors, when alpha=3, the result is as shown in the attached image, the pressure coefficient on the wing is clearly wrong and is "stripey". It also appears something strange is happening at the wingtips; the centre of pressure is far forward of the wing. When a higher a.o.a is input, eg. alpha=5, the result is not converged due to, for example: "Cl = 1.40 could not be interpolated". At lower a.o.a, eg. alpha=1, the angle is skipped due to negative lift. None of the settings were changed from a fresh reinstall and none of the project was changed other than my computer doing the calculation. I have tried the glider in the sample project and my own models but I encounter the same problems.
Any help would be greatly appreciated, thank you.
Hi Julian,
could you provide your project file?
regards
Jochen
Hello, please see attached.
Thanks
Hello Julian,
as far as I could check in short time, the project file looks ok.
- the stripes in the pressure distribution are due to a change in the visualization: Every panel has a single colour (equals to the result of the calculation) - and no more artifical color gradient
- you could extend the airfoil polar calculation to higher alpha. This would lead to higher alpha of the plane ("Cl = 1.40 could not be interpolated")
- for T2-polars no negative lift is allowed
But - there are grafical artefacts in the plane view when panels are displayed...
@techwinder - André could you have a look at it? (see attachment - it happens when clicking between "plane" and an "analysis" in the obkect explorer)
Hi Jochen, thanks for your help.
My issue is that I'm unable to recreate results seen in the sample project provided in the files section of xflr5 sourceforge. What I have described in my original post is symptoms of what happens when I try to recreate those results. I will attach an example. The first image is the oppoint for alpha=3 when you first open the sampleproject. The second image is the exact same oppoint, just that my computer did the calculation. They look very different.
For the glider in the project (not the flying wing), the unedited files show T2 oppoints from 0 to 7 but I am still getting the negative lift error up to alpha=5 when I try to calculate them. For alpha>5, I get the Cl could not be interpolated. So it seems it can be interpolated but for some reason when I run the program it requests too high a CL.
Again thanks for helping.
These problems seem to be caused by incorrect settings. To restore the default configuration, delete the .ini files
Windows: "C:\Users\your_user\AppData\Roaming\XFLR5.ini"
Mac: "/Users/your_user/.config/XFLR5.ini"
Linux: "/home/your_user/.config/sourceforge.net/XFLR5.ini"
The menu option "restore default settings" will not be enough; the .ini needs to be deleted.
Not sure why this occurs all of a sudden but it will be fixed in the next version.
André, thank you, this has fixed the problem.