Help with XFLR5

[Mike Switzer]

Anyone here using XFLR5 to analyze airfoils?

I am trying to figure out how to use it, wanting to analyze Eppler 1230 & Glasgow GU25-5(11)8 (for starters).

I am following the (limited) instructions I found online & no matter what I do I get an error along the lines of "failed to converge after 100 iterations"

There is probably something simple that I am missing but I sure can't find it.

Any ideas?

[Mike Switzer]

OK, now I'm really confused. This software has a built in profile generator for NACA airfoils, and it is running a NACA 4414 just fine. It wont run anything I get from the U of I database, yet that is where the instructions I have found tell you to download the profiles from.

[Mike Switzer]

OK, I think I figured it out. The coordinate system used in the UIUC database is not compatible. It appears you need to start with the trailing edge (usually 1,0 or 1, something close to zero) then list the coordinates in order coming back across the top of the airfoil, around the nose, and back along the bottom to the trailing edge again. I opened it up in excel & sorted the data to get it in the correct format. There are also a couple extra numbers in there that need deleted, not sure what they are for but they sure aren't airfoil coordinates.

[Mike Switzer]

A couple notes for anyone who uses this software:

1) I couldn't get it to run on Win 2000, it seems to like XP
2) It runs really really slow if your machine does not have a math coprocessor. I was running it on my newer netbook with an Intel Atom processor, & it kept locking things up. I Upgraded my good (8 or 10 year old) engineering workstation from Win 2000 to XP Pro & it runs about 10 times faster doing the calculations, but it still has to think for a while displaying polars with a lot of data - I wouldn't recommend having curves for any more than 40 different Reynolds numbers in a file unless you have something with a lot of video memory.