A High Quality (and Cheap) Airfoil Program!

[green66]

Hi All,

Normally I don't go around playing "salesman" touting a particular product. This will be an exception, as I'll give credit where it's due (I have no affiliation to the product / person).

Anyone designing model aircraft, or otherwise interested in airfoil selection and performance comparisons, should look at Profili 2.0 (and its price ==> $10 )

The author, Stefano Duranti, has released a new version (latest is 2.03d as of this writing) that will generate polars for any of the 2200+ airfoils in its database (which can all be modified, e.g. change camber, thickness, etc), or for any custom airfoil per user-entered coordinates.

Now, priced at $10, you're probably thinking "The analysis capability can't be very sophisticated," however consider that the analysis engine built into Profili is the well-known XFoil program by Dr. Mark Drela, professor of Aero / Fluids at MIT, whose research specialty is computational aerodynamics. Basically, Profili delivers the power of XFoil in a user-friendly format, coupled to an extensive airfoil database. In addition, XFoil's processing parameters can be modified via a Windows menu.

Just a few mouseclicks generates not only standard polars, but multi-airfoil comparison plots, or plots of various combinations of Cl, Cd, Cl/Cd, Cm, AOA, Re.

Given the complexity of CFD analyses, even if not highly accurate in terms of actual numbers, the results can be insightful for comparative purposes, or to see effects of modified airfoil geometries, different Re, etc.

No doubt Profili will continue to evolve, but this version 2 marks a huge refinement over the previous version dealing with airfoil geometry alone.

Get Profili here: http://www.profili2.com

Below are a couple Profili outputs (I pasted the legend; it actually appears above the charts). Here's a standard polar of 5 airfoils at Re = 70000, predicting low-Re breakdown of the E387 & Zagi 12.

[green66]

And here's airfoil L/D for the same five sections at Re = 120,000

[airboss]

thanks for posting about the airfoil program
had heard it referenced but did not realize it's power
am building a biplane with two delta wings
however one is turned so flat edge is leading
was having problem with airfoil and I think you have inspired the solution at a nominal sum of $10

owe you a beer
allen

[wayne]

Hi

I just bought the software and for making ribs its great. One question with all the charts and graphs what are we looking at for the best airfoil. I guess I don't know what Cl, Cd, Cl/Cd, Cm, AOA, Re really means. There is no help in software but is there any good web sites to explain this. For the price its a great deal a very large data base on airfoils.

Thks
Wayne

[bullseye000]

Hey Wayne

I was considering purchasing the package. I just can't force myself to pay for Compufoil for the little amount of work I would do with it.

Couple of questions...

How do the spar and sheeting functions work? Have you tried to export to cad yet?

I'm looking at the analysis functions less than I'm looking the tools to help in creating wing drawings. How do you think it fairs in this function?


Thanks

[Sparky Paul]

Profili exports .dxf which TurboCad reads.
For wing design it's a very useful tool, even without the aerodynamic functions.

[wayne]

Yes it does export .dxf files, and did test it did work with autocad okay. With the older version 2.0 you were limited to 4 spars on top and bottom. With the new version 2.03 you can have 20 more spars, which is more than you want. Still to early to test all the functions out, but so far looks great for the price. Try the demo and make sure you update the version to 2.03.

Wayne

[bullseye000]

Thanks

I'm going to go ahead and download the demo. At first it seemed like he crippled everything after the last version so I didn't want to download a bunch of stuff then try it and not have it work.

I'll download it and give it try then.

[green66]

One question with all the charts and graphs what are we looking at for the best airfoil. I guess I don't know what Cl, Cd, Cl/Cd, Cm, AOA, Re really means. There is no help in software but is there any good web sites to explain this

wayne - You mean one question involving six concepts, each of which could be the basis for a book!
Cl = lift coefficient
Cd = drag coefficient
Cl/Cd = ratio of above
Cm = moment coefficient
AOA = angle of attack
Re = Reynolds number

A couple educational aero sites:
http://www.grc.nasa.gov/WWW/K-12/airplane/short.html esp. the sections "Aircraft Forces," "Lift," and "Drag"
http://aerodyn.org/

Keep in mind that airfoil analysis considers only a 2D evaluation of an ideal profile, not the characteristics of a real wing having aspect ratio, induced drag, surface defects, building inaccuracies, interference drag, etc.

[green66]

FYI - A new version (2.10) of Profili / XFoil has just been released. One of the new features that caught my attention is the ability to analyze a turbulated airfoil! Haven't downloaded the upgrade yet; should be interesting.

Hope the analysis of flapped airfoils has been cleaned-up (crashed every time I tried it in ver 2.03).

[green66]

The analysis of flapped airfoils has been cleaned up nicely. Now if only English units could be entered for all of Profili's other features; will rec. it for next version.

Another nice feature has been added which enables direct comparison of up to 8 polars, where each airfoil can be at a different Re and have all sorts of mod's:

[orectolobus]

Another alternate to Profili that is very easy to use
and allows modifications to standards airfoil data files
is the Airfoil Design Workshop.

Airfoil shapes can be exported to DXF format or text
files for hand plotting. Tapered wings can be designed
with different root and tip airfoils and chord widths.

The software doesn't include analysis tools but is
quick and easy to use for a non-technical oriented person.




Airfoil data files are simple text files of ordinates.
Profili airfoils can be exported as text files and easily
adapted for display and modification in AFD

The software is only $9.95 for for a full version that runs
in all Windows operating systems or you can get a FREE demo.

For more info visit
The Airfoil Design Workshp Homepage

[coltranian]

Originally posted by green66

[...] Now, priced at $10, you're probably thinking "The analysis capability can't be very sophisticated," however consider that the analysis engine built into Profili is the well-known XFoil program by Dr. Mark Drela, professor of Aero / Fluids at MIT, whose research specialty is computational aerodynamics. Basically, Profili delivers the power of XFoil in a user-friendly format, coupled to an extensive airfoil database. In addition, XFoil's processing parameters can be modified via a Windows menu. [...]

Very interesting. I can't seem to get to the page with the URL given; I get an error page from Lycos in Italian and am then redirected to the Lycos main page.

Out of curiosity, does it use the xfoil engine as a LGPL library? Xfoil (http://raphael.mit.edu/xfoil/ ) is GPL'd free software, so linking proprietary code against it or selling it, without source code, for anything but the cost of distributing it would be a breach of the licensing agreement. Not to draw conclusions; I haven't quite had a chance to look at it yet.

Looking forward to checking this out if/when I can reach the site... Looks like it might be a fine tool! I'd love to check out that database of airfoils...

[green66]

Stefano Duranti (Profili's author) notified Profili owners that his main site had been removed by Lycos, for whatever reason, and that he's waiting to obtain a profili2.com url.

Msg edited: http://www.profili2.com is now active.

Out of curiosity, does it use the xfoil engine as a LGPL library? Xfoil (<http://raphael.mit.edu/xfoil/> ) is GPL'd free software, so linking proprietary code against it or selling it, without source code, for anything but the cost of distributing it would be a breach of the licensing agreement.

Since Mark Drela (XFoil's author) posted on the same topic at rc universe http://rcuniverse.com/showthread.php...684&forumid=19, he's aware of the Profili arrangement, so I'm sure that "all's well" w/respect to the licensing / distribution issues.