Support for Spin-a-Wind

First, as a disclaimer, realize that this is a simple app.  It has no official endorsements by any airplane manufacturer, or government aviation authority.  Please use at your own risk.

The app is set up with five tab buttons at the bottom of the screen, Wind, Temp, Altitude, Airspeed, and Info.  Touch any tab to select that page view in the app.

The Wind view is a simple device which separates out a wind into its components, headwind and crosswind.  There is a graphic showing the runway and the relative wind vector arrow.  Use the runway number closest to the actual runway heading.  After selecting the runway, wind direction and velocity, the wind will be broken down into headwind (tailwind) and crosswind.  The units are whole numbers, but are rounded in the direction which is most conservative.  For headwind, the number is rounded down to the next whole number.  For tailwind and crosswind, the number is rounded to the next higher number -- i.e. if it calculates a 9.74 kt tailwind, it will round it to 10.  If 10.1, it will round it to 11.

The Temp (temperature) view takes the wind velocity component from the Wind view and sets the picker to this value.  You then enter the local temperature and dewpoint temperature and the calculator computes the relative humidity percent, the Heat Stress Index, and, if valid, the wind chill temperature.  The windchill formula comes from the U.S. National Weather Service, and is also used in Canada.

The Altitude view computes the Metric Altitude, Pressure Altitude, Standard Temperature at the computed Pressure Altitude, a Density Altitude based on dry air, and a Density Altitude based on air with water vapor (water vapor is less dense than air).  The dewpoint temperature from the Temp page is used in the Wet Density Altitude calculation.

The Airspeed view page computes the Speed of Sound, a Mach Number, and True Airspeed based upon the selected Calibrated Airspeed, Pressure Altitude, and Static Air Temperature (not Ram Air Temperature nor Total Air Temperature) at that altitude.  When the altitude entry is changed, the temperature reel is reset to the standard temperature at that altitude.  The user can then change to the actual temperature.  The calculation takes into account compressibility of the air, and should be accurate through Mach 1.

The Settings view page allows changes in the threshold for the background colors of red and amber in the wind page, and to select speed units (kts, mph, kph) for the and temperature page, and Pressure Units (inHg, hPa, mb) for the altitude page.

If you have any problem with Spin-a-Wind, please contact us through the "Contact" link at the top of the page.  We would also be happy to hear about any suggestions that you may have on how to improve it.