WhizWheel is a simple iPhone application for pilots that provides a faster alternative to the primary navigation calculations generally performed with a circular slide rule (such as the CRP-1). Namely the calculation of track, ground speed and flight time for a given air speed and heading, given the current wind speed and direction.
As well as calculating the wind effect for a single point, the application can help with ad-hoc navigation (such as diversions) by generating a textual "wind rose" that shows the effect of wind in all directions; at either 30 or 45 degree intervals.
The source code for WhizWheel is available under the GNU General Public License (version 2) and can be downloaded from the project website.