airfoils - how to compute?

try this program, you just select the airfoil. Enter beginning and ending dimensions...voila!

extremely highly recommended. The best program around for us mere mortals.

Well, looks cool enough, except I don't use Windows and it doesn't seem to exist for Mac or Unix. So my question remains. Thanks anyway.

-Lasse

David any chance your from up state New York . Don't find to many folks with the last name Poles

Martin Poles

I've used Compufoil

for a few years and love it. It is worth every penny.

Nah, the BEST program is Compufoil Pro.

Well, THERE's your problem! ;^)

If you have Linux, Go to

a trial copy of vmware - its good for 30 days.

You can then run any windows program from within Linux You'll be able to print out any airfoil from the previously mentioned airfoil programs.

Ed

PS: Wmware is THAT good.

let me know what you are trying to draw and I will try to output it to a format you are using.

XFOIL will do what you want. It was originally written for UNIX and has been adapted for Mac and Windows.

The NACA generator will generate 140 point coordinates of the airfoils you specified. Use the INTE command on the main menu to interpolate between the two airfoils, HARD to save.

To download XFOIL, go to

and you can also join the support/discussion group at Its free, and will teach you more about airfoils than you may want to know.

-Fritz

I checked out their DEMO. For plotting, and total lay-out control, compufoil definitely is the better program and a must have if you design kits. However, Profili offers integrated foil airflow , lift and drag simulation, together with ribs interpolation albeit with somewhat limited spar layout. For my allround airfoil needs, Profili still is the only program I will use, and it satisfies my plotting needs. (profili >>DXF>>CAD>>add-stuff>>plot)

The main advantage to Compufoil is (Compufoil>>plot)

I have found that for 99% of the models made, there is no need for airflow, lift or drag computations. The planes are grossly overpowered and will easily overcome any airfoil inefficiencies.

Take, for example, warbird racing. The common wisdom is that thinner airfoils are faster. If this is the case, why does the Great Planes P-51 go just as fast as purpose-built, thin racing section P-51s? I have no idea except that it appears that airfoils are far less important at very low Mach numbers we operate at. This was also reiterated to me by a full scale Mustang pilot. I asked about using the scale airfoil on a 1/6th scale I was building. He asked me if it would go over 350mph. I said no and he said any sport airfoil would do.

No problem actually, I'll just use xfoil on Unix. Thanks to all who answered!

-Lasse

I will not be lured into an endless airfoil discussion., as each participant in this group seems to have their own pet theory about this. Mainly you are richt, as long as the foil has no sudden stall at increased AoA. (for sports that is). The speed depends on the total induced drag, which is frontal area times drag coefficient. Nearly all sport foils score about the same in the drag department. Making the foil thinner reduces frontal area and thus increase speed. Here is where special foils enter the picture, because one must be able to round the pylons without entering a high speed stall and loose the edge again. Lap times will however depend mostly on the pilot's skill to get the most out of his plane. Each modelling niche has it's own set of requirements, as can be seen by the foils used. Some fashion also enters the picture due to the follow the leader syndrom. For the same reason, most flyers tend to buy or copy a plane they have seen perform well, so they do not need the airflow performance simulation and foil comparison. Yet, Profili is nice because it has that huge foil database and DXF-out capability, and version one still is free to download.

Actually, it is low Reynolds numbers which are the most important factor.