About

This web site was put together as an experiment in airfoil selection for model R/C aircraft. As we're building our aircraft invariably the question of which airfoil to use comes up. We all have our favorites, but what others are available? What other ones are similar? We hope that this site helps address some of these questions.

Airfoils

Virtually all the airfoil data in the database was extracted from the University of Illinois at Urbana-Champaign Airfoil Coordinates Database. The data was extracted, processed (see below), and injected into this database and a web interface was put together to allow for easy browsing/searching.

The database was last updated on June 01, 2016 00:41. There currently are 1524 airfoils in the database.

Polars

The data for the various polar plots is generated automatically via an off-line script. The script extracts the airfoil data then uses Martin Hepperle's awesome Javafoil package. A fixed angle-of-attack range is used for all polar generation so any plots can be easily compared. The specifics of the modeling:

Stall model: Eppler
Transition model: Eppler, standard
Ground effects: No ground effect simulation
Aspect ratio: 0
Javafoil model parameters

The polar data is stored for plotting when a specific airfoil is selected. In addition to the polar data a few "characteristics" are also computed including the trailing edge angle, leading edge radius, top and bottom surface curvature and "similarities" to other airfoils. This additional information is stored in the database for searching.

Plotting

Polars

The polar data for a given airfoil is plotted using the Chart Director package (I know, it's the demo version for now). The data generated by Javafoil is read and plotted on demand.

Airfoils

The various airfoil contours (thumbnails and plots) are generated by custom software. The curves are generated in SVG which is then converted to PNG for display in the browser.

The airfoil plot can include grid lines (yes, they can get "confused" during conversion to PNG - we're working on it), leading edge radius giude, and trailing edge protractor. The radius guide is intended to give an indication of the fitted radius (wide blue circle) as well as several reference circles (1%, 2% and 3% as thin black lines). The trailing edge protractor shows angle gradations of 1o (shortest lines), 5o (medium length lines), 10o (longest length lines).

Layout

To ease the layout - and make the site pretty - Olav Bjorkoy's Blueprint CSS framework is used. Check it out, it's really quite nice.