XFLR5 Activity
XFLR5 is an analysis tool for airfoils, wings and planes
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Activity for XFLR5
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André posted a comment on discussion Developers
Hello, I'm a bit surprised because so far xflr5 had compiled and run on all OS with Qt6 without a hitch. What was the error and how did you fix it? André
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Karoliina Salminen posted a comment on discussion Developers
Hi, Since could not push to xflr5 repository, I created a new repository which has the fixes. https://github.com/savannahcatlady/xflr5-qt6-fixes Best Regards, Karoliina On Fri, Apr 24, 2026 at 1:40 PM karoliina.t.salminen@gmail.com karoliina.t.salminen@gmail.com wrote: Hi, There is a problem in the xflr5 (as published) that it does not run on modern Macs. I downloaded official release half a year ago or so and didn't work, and tried today again, still didn't work, only a blank window. Well then I...
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Hi, There is a problem in the xflr5 (as published) that it does not run on modern Macs. I downloaded official release half a year ago or so and didn't work, and tried today again, still didn't work, only a blank window. Well then I tried to compile from source and it is using Qt5 and didn't quite build with Qt6. What's up with the xflr5? What's up with the xflr5? Does someone want a patch (Qt6 + blank window fix)? Andre's email was not valid anymore. Best Regards, Karoliina
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The interpolation of the viscous drag using the local apparent angle is less reliable than the interpolation based on the lift coefficient. The latter method is marked "recommended" and should be preferred. Also please keep in mind that there is no such thing as "ground truth" in xflr5 and flow5 given all the approximations made in the potential flow model and in the evaluation of the viscous drag using 2d data. In the future, please post all flow5 related questions on the flow5 project page. An...
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Ahmed Reda Elshazly modified a comment on discussion Open Discussion
Hello, I am working on the aerodynamic design of a 10kg UAV and have encountered a major discrepancy between the "from CL" method and the "from α (Viscous Loop)" method in Flow5 v7.55. The Issue: When running a Type 2 (Fixed Lift) analysis, the induced drag (CD,i) values for both methods coincide perfectly, but the total drag and viscous drag (CD,v) are drastically different. Specifically: The Viscous Loop method converges across the AoA range but shows significantly higher total drag. The CL...
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Hello, I am working on the aerodynamic design of a 10kg UAV and have encountered a major discrepancy between the "from CL" method and the "from α (Viscous Loop)" method in Flow5 v7.55. The Issue: When running a Type 2 (Fixed Lift) analysis, the induced drag (CD,i) values for both methods coincide perfectly, but the total drag and viscous drag (CD,v) are drastically different. Specifically: The Viscous Loop method converges across the AoA range but shows significantly higher total drag. The CL...
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Hello, I am working on the aerodynamic design of a 10kg UAV and have encountered a major discrepancy between the "from CL" method and the "from α (Viscous Loop)" method in Flow5 v7.55. The Issue: When running a Type 2 (Fixed Lift) analysis, the induced drag (CD,i) values for both methods coincide perfectly, but the total drag and viscous drag (CD,v) are drastically different. Specifically: The Viscous Loop method converges across the AoA range but shows significantly higher total drag. The CL...
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Hello, I am working on the aerodynamic design of a 10kg UAV and have encountered a major discrepancy between the "from CL" method and the "from α (Viscous Loop)" method in Flow5 v7.55. The Issue: When running a Type 2 (Fixed Lift) analysis, the induced drag (CD,i) values for both methods coincide perfectly, but the total drag and viscous drag (CD,v) are drastically different. Specifically: The Viscous Loop method converges across the AoA range but shows significantly higher total drag. The CL...
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upgraded XFoil-lib to v1.1 for compatibility with flow5
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Stefan posted a comment on discussion Open Discussion
Yes, it is. Stefan
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Dusan Vuletic posted a comment on discussion Open Discussion
Hello everyone, Is it possible in XFLR5 (or Flow5) to compute rolling moments (about the longitudinal x-axis) by assigning asymmetric flap deflections — e.g., upward deflection on one wing and downward on the other — to simulate aileron effects? Thank you!
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There won't be any new development for xflr5. In fact v6.62 is intended to be the last version before the project closes formally at the end of the year. Please consider upgrading to flow5 which can handle asymmetric configurations.
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Kostia RONCIN posted a comment on discussion Open Discussion
I am working on kite wings whose control relies on the asymmetric deformation of their shape. XFLR could handle this if the ‘asymmetric’ option were ‘enabled’. I am sure that XFLR is used by many kite designers and that they would very much like to be able to take advantage of such an improvement.
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Andrew Klos posted a comment on discussion Open Discussion
Thanks, I will start using Flow 5.
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Hi everyone, v6.62 is intended to be the last version of xflr5, barring any new major bug which would need fixing. The plan is to close the project at the end of 2026. Please consider upgrading to flow5. All xflr5 features except for inverse foil design have been ported to the new application. André
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Mixed inverse design - aoa or Cl selection
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closed in version 6.62
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Sideslip simulation problem on version v6.61
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Fixed in version 6.62
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tagging version 6.62
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releasing v6.62
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XFLR5 released /6.62/xflr5_v6.62.dmg
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OK, the operating points take graded colours when the style of the parent plane or polar is changed. There is no option exposed in xflr5 to change this behaviour. I recommend that you upgrade to flow5 where the option is disabled by default and can be set in the preferences.
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Didn't make much difference, the "rainbow" is different but the gradient is still there. Can't get all the points to be unform colour. it is difficult to see the bottom colours on the graph this way. Some graphs are uniform others graded. it was never like that before and never been in this menu before...
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Preferences/Display Options/Flow down changes....
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Preferences/Display Options/Flow down cganges....
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Hi, I'm getting these graded graph colours. Can't seem to make them one solid colour. Don't remember seeing it before, this is version 6.61 What is wrong? Cheers Andrew
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Hi, I'm getting these graded graph colours. Don't remember seeing it before, this version 6.61 What is wrong? Cheers Andrew
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Hi, Yes, the origin of the components is at their leading at the root. You can also double check this using the Z view in the plane editor, offsetting the tail a small amount in Z and then setting the x offset of the tail to 0. You will see that the origins (root leading edges) align. Cheers, Stefan
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Caio Alves Assumpção posted a comment on discussion Open Discussion
Hello, I am trying to confirm how XFLR5 interprets the longitudinal position of aircraft surfaces in the Plane Editor. When I assign an x-position to the main wing and to the horizontal tail (elevator), is this x-distance measured from the leading edge of the root section of each surface? In other words, if the main wing is at x = 1.900 m and the horizontal tail is at x = 5.140 m, should I interpret the 3.240 m difference as the distance between the root leading edges of the wing and tail? I am asking...
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Guillermo posted a comment on discussion Open Discussion
Hi, I'm finding trouble when trying to add flaps to my wing. I have defined a foil with flap in the foil design section, I noticed that there isn't the red hinge that's supposed to appear when defining the flap (according to what I found on the internet). I've tried open and closed foils (I'm using NACA 1312) but nothing seems to change. I need the flaps to appear in the control section for the full wing analysis. Could someone help me please? (I'm on macbook btw)
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Dis this literally more than 20 years ago, so I don't really remember the reasoning. Also I used XFoil as a black box, so I may not have made the best choices. André
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Andreas Sittig posted a comment on discussion Developers
Hi André, Many thanks for your work and for making flow5 open source. Your generous decision motivated me to have another go at XFoil.dll. I am currently updating the flow5 XFoil.dll c++ code with changes from XFoil 6.999 Fortran sources that Harold Youngren gave me a few days ago. I have a question about specal() and speccl(). In XFoil.dll c++ code, both functions return false if the convergence loop fails. The callers then stop the analysis. In the Fortran code, this is different. I checked XFoil...
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Dmitry posted a comment on discussion Open Discussion
Hi! Why do I have two curves at Hmom vs Theta graph? First I thought this is due to L.E. flap, but it is not added in my project.
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Shouq Almazrouei posted a comment on discussion Open Discussion
Dear Radchenko, Could you please provide me with your model? Thank you.
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mkravos posted a comment on discussion Open Discussion
Hi everyone, For my Bachelor's thesis I am currently working on a blended winglet design for a fixed-wing UAV (root chord = 280, halfspan = 750mm, AR = 6.15), but I'm facing some issues with numerical instabilities at the wing-winglet junction and meshing problems with VLM. To aid with inputting the geometry into XFLR5, I developed a custom Python script (image: Python_code) to generate the coordinates for the blending radius and the straight section of the winglet, to ensure a smooth transition...
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Yogesh Khadka posted a comment on discussion Open Discussion
Hello everyone, I cannot download the xflr5,i dont know why .Could you guys help me?
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Ignacio Sandoval posted a comment on discussion Open Discussion
André. Thank you for all your work. Xlfr5 is great and flow5 is the best. My best regards and a very good 2026 year for you. ignacio
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Anuj kumar modified a comment on discussion Open Discussion
Thankyou for developing and providing flow5 software,
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Thankyou for developing and providing flow5 software, I cannot find the download link anywhere, can you please direct me where i can download flow5.
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As of January 1st 2026, flow5 is public and open-source.
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Rebecca posted a comment on discussion Open Discussion
Thank you so much, Stefan! it works out
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Hi, Everyone! I am currently need to design ruddervator of an X- tail. I have two questions regarding of that: 1. This is my current rudder and elevator (look at picture that i gave). I added the rudder and elevator half of the semispan. Is it right to add them half of the semispan or should it be starting from the root? because I see drawing in the internet mostly starting from the root but at the same time i heard that it is not allowed to start from root for non-conventional tail. 2. Because my...
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In the upper left corner of the wing editor is a checkbox that allows you toggle the symmetry of the wing. I also recommend watching Andrés set of tutorials, which cover most of the basic functionality: https://youtube.com/playlist?list=PLtl5ylS6jdP6uOxzSJKPnUsvMbkmalfKg&si=Cw3tu2TIu1abKNVw Cheers, Stefan
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Hi everyone! I want experiment the rolling moment by making the right wing up and left wing going down at 5 degree angle. I already make the flap, but when I try to use the flap. It simultaneously for both side of the wing. Do you know how make them working indepedently? thank you
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As long as the leading edge sweep of your wing is 0 deg the offset is 0 for all sections and this is fine. If it isn't it will change the distribution of the area and therefore impact the pitching moment and some other parameters. It depends on what you want to analyse.
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Oh sorry, I forgot to mention the wing is slightly tapered. I already recalculate and the wing are not changing anymore. But I only do calculation for the chord and keep the offset as zero. Is it still okay if I dont input the offset as well?
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Hi Rebecca, when changing the span of an aileron, you only need to change the position of the inner section, as long as the wing is not tapered. If it is tapered, you need to recalculate the chord length of the section and its offset. The wing area should not change then. Cheers, Stefan
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Hi everyone! I have a question regarding aileron design. So, I want to make iteration of aileron span, where there are short aileron and longer aileron. But when I changed the aileron span the wing area also changing. I need to maintain the same wing area with different aileron span. Please, let me know if you ever encounter this problem, thank you
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The coordinate system should be aligned with the foil and independent of angle of attack, so there should be no projection necessary. Cheers, Stefan
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Thomas Dalmas posted a comment on discussion Open Discussion
Thank you for your reply. I am referring to the foil analysis module.
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I suspect the shift is due to viscous and numerical effects, but I would need to look into in detail to say for sure. Are you referring to the plane analysis module or foil analysis module in your second question? Cheers, Stefan
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You can export an operating points data by right clicking on it. The export gives you the pressure coefficient for every panel, which you can use to calculate the forces. Cheers, Stefan
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Owen Maclennan posted a comment on discussion Open Discussion
Hello, I am looking to do FEA on a wing, and therefore need a way to know the force acting upon the wing. Is there a way to export the F/s data from the 3D plane view? Ideally I end up with some data that shows the force across span, chord, and on the top vs bottom surface. Thanks
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If I am not mistaken, on xflr5, Cm is defined relative to the point Xref = 0.25 (that cannot be changed). The approach of determining XCp by XCp = 0.25 - Cm/Cl can give results that are quite different from the XCp given directly by XFLR5. I imagine it is therefore better to use the XCp directly. What I don't necessarily understand is why, in the case of a symmetrical section, when AoA tends towards 0 (and therefore Cm and Cl tend towards 0), I get an XCp that tends towards 0.26 and not 0.25. (Except...
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If I am not mistaken, on xflr5, Cm is defined relative to the point Xref = 0.25 (that cannot be changed). The approach of determining XCp by XCp = 0.25 - Cm/Cl can give results that are quite different from the XCp given directly by XFLR5. I imagine it is therefore better to use the XCp directly. What I don't necessarily understand is why, in the case of a symmetrical section, when AoA tends towards 0 (and therefore Cm and Cl tend towards 0), I get an XCp that tends towards 0.26 and not 0.25. (Except...
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A blank screen is usually the sign that something is wrong with the OpenGl settings. Try to launch from the command line with xflr5 -o 21 for a 2.1 context xflr5 -o 31 for a 3.1 context and finally xflr5 -o 41 for a 4.1 context which is the highest that macOS supports.
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A blank screen is usually the sign that somthing is wrong with the OpenGl settings. Try to launch from the command line with xflr5 -o 21 for a 2.1 context xflr5 -o 31 for a 3.1 context and finally xflr5 -o 41 for a 4.1 context which is the highest that macOS supports.
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connor bune posted a comment on discussion Open Discussion
i have the newest Macbook air M4, running sequioa 15.5 (24f74)
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Hi Connor, what macOS version are you running? And do you have an intel mac or one of the newer apple silicon ones? Cheers, Stefan
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Hi, i am trying to install this on my macbook, i have heard of other people being able to, all i am getting is a white screen when i open, can someone help me try to fix this please? thanks
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Hi Safa, Sorry, I did not read your initial post carefully the first time. The difference in pitching moment coefficient slope you are seeing is likely coming from the shift in reference point through the tilt angle and some additional numerical effects. The tilt is applied around the wings leading edge and therefore would shift the reference point. Since the mass point you defined, which is used as the reference point in the calculations, is in the aircrafts system and therefore does not tilt with...
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Safa Aslan posted a comment on discussion Open Discussion
Hi Stefan, Thank you very much for your detailed response and for taking the time to clarify this. I understand that the VLM method is an idealized representation, and the differences can indeed fall within its numerical tolerance. However, in my case, what I’m changing is the tilt angle of the wing — which is essentially equivalent to changing the angle of attack. Since I’m only analyzing the wing (without tail or fuselage effects), I would expect that the lift coefficient (Cl) of the aircraft with...
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Hi Safa, I think the variations you are seeing are within the errors of the method itself, since the shift is not that large. Keep in mind that the VLM is a very much idealised representation, so the results for trim etc. will be different. The real wing will most likely not behave in the linear way you are expecting as well. Cheers, Stefan
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Dear XFLR5 Team, I hope this message finds you well. I would like to ask for your technical clarification regarding a situation I encountered while performing VLM analyses in XFLR5. Before starting the analyses, I defined different tilt angles on the same wing geometry and carried out three separate analyses. All other parameters — such as airfoil, mesh configuration, and analysis settings — were kept completely identical across all cases. Based on the difference between the applied tilt angles,...
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Dear XFLR5 Team, I hope this message finds you well. I would like to ask for your technical clarification regarding a situation I encountered while performing VLM analyses in XFLR5. Before starting the analyses, I defined different tilt angles on the same wing geometry and carried out three separate analyses. All other parameters — such as airfoil, mesh configuration, and analysis settings — were kept completely identical across all cases. Based on the difference between the applied tilt angles,...
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It worked i.e. I deleted XFLR5 folder & XFLR5.ini file, then reinstalled XFLR5. Thank you Stefan.
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I found this file and I will play with the re-installation over the weekend. Thank you Stefan :).
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Start by using XFLR5s option to reset to default settings in the options menu. To delete the config file: I rarely ever use windows, so I am not 100% sure, but there should be a XFLR5.ini file in your users AppData/Roaming/ folder. For the older version file: I was referring to the airfoils and its polars. So I would try to delete the airfoils, import them again & regenerate the polar mesh in airfoil analysis module. Then select the airfoil for each section in the plane design modules wing editor...
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Start by using XFLR5s option to reset to default settings in the options menu. To delete the config file: I rarely ever use windows, so I am not 100% sure, but there should be a XFLR5.ini file in your users AppData/Roaming/ folder. For the older version file: I was referring to the airfoils and its polars. So I would try to delete the airfoils, import them again & regenerate the polar mesh. Then select the airfoil for each section in the plane designs wing editor and try to run the analysis again....
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How do I delete config files? I noticed when re-installing, the XFLR5 still new about all my previous files (in the Files Open). I'm referring to plane polars.
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Your second file works fine for me. If that is giving you the same error: Try not only re-installing XFLR5, but also resetting to default setting, or better yet, deleting config files that might be stored elsewhere. I might be able to try it on the windows version tonight, but no guarantees. This is exactly what I was doing; I deleted one polar, tried to re-create it and would give these errors. Are you referring to plane or airfoil polars here? From your first message I got the impression you tried...
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It is deactivated on mine.
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In the Analysis/advanced settings, there is an option to store or not unconverged points "Store points outside the polar mesh". The option used to be activated by default, however I was unconfortable with the storage of potentially erroneous points, so the option is now deactivated by default. I recommend to keep it deactivated since the potential method reaches or even oversteps its limits near stall angles.
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"Try deleting your polars and regenerate the polar mesh." This is exactly what I was doing; I deleted one polar, tried to re-create it and would give these errors.
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And some results.
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Here is the file created in 6.61
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Thank for that. The airfoils were there of course. But I noticed the same problem in a model created in 6.61. I will attach a file created entirely in a 6.61.
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When I try to open your file I get a reading error and only the valid parts are opened. These do not include any airfoils. If the file was created in a much older version there might be a compatibility issue. Try deleting your polars and regenerate the polar mesh. Re-importing the airfoils before doing that would most likely also be a good idea. Even if the names of the foils do not change you should reselect the foils for the sections in the wing editor again. Stefan
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When I try to open your file I get a reading error and only the valid parts are opened. These do not include any airfoils. If the file was created in a much older version there might be a compatibility error. Try deleting your polars and regenerate the polar mesh. Re-importing the airfoils before doing that would most likely also be a good idea. Even if the names of the foils do not change you should reselect the foils for the sections in the wing editor again. Stefan
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When I try to open I get a reading error and only the valid parts are opened. These do not include any airfoils. If the file was created in a much older version there might be a compatibility error. Try deleting your polars and regenerate the polar mesh. Re-importing the airfoils before doing that would most likely also be a good idea. Even if the names of the foils do not change you should reselect the foils for the sections in the wing editor again. Stefan
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Here it is, an old project. I just deleted one of the existing runs and wouldn't recreate it
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Not as far as I know.
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Yes. Is there a size limit?
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Can you post your project file so I can have a look?
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No, this is not a reason. I have been using XFLR5 for many, many years. Suddenly, the program won't even reproduce the results which were already in the file i.e. as a test, i deleted a run and tried to run it again. I have reinstalled the program, still the same
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Hi Emanuel, it is generally not recommended to include the fuselage (or in this case the rocket body) in the analysis. The question is what you mean when saying more accurate results. What are you trying to analyse? The "could not interpolate" error means your polar mesh does not extend to the required Reynolds number / lift coefficient / angle of attack. Check Andrés tutorial series to get a better understanding of the software. Tutorial 11 deals with your error. https://youtu.be/_8thw2CQCaI?si=wwsiS68ChQSF-6Vl...
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Your polar mesh does not extend to the required Reynolds numbers and lift coefficients. Check tutorial 11 in Andrés tutorial series: https://youtu.be/_8thw2CQCaI?si=wwsiS68ChQSF-6Vl Cheers, Stefan
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Your polar mesh does not extend to the required Reynolds numbers and lift coefficients. Cheers, Stefan
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Hi, The XFLR5 suddenly stopped working in the middle of a performance analysis and gives this error, as shown. I tried different projects, it won't even reproduce the old results! Depending on a file, the analysis is sometimes even shorter. Please help, I need my XFLR5! :)
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Emanuel Conceição Grativol posted a comment on discussion Open Discussion
I've been trying to develop a small set (about 160mm semi-span) of canards for an amateur rocket, what is the best setup in order to obtain more accurate results? i say what calculating methods, using inertia or not, introducing the rockets body or not, what range oa aoa, number of panels, this sort of things, I've been having a reocurring "could not interpolate" error in my last runs.
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Yes, that is correct.
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Julien Macaux posted a comment on discussion Open Discussion
Thank you for your answers and time. About the trimming, do we agree that it will allow to increase or decrease the speed at wich I can fly at a stable height, but at the cost of adding drag, and consequently increasing fuel consumption ? I will do some RC version before putting my life at risk.
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