The Hall Airspeed Indicator is a simple, reliable way to keep track of your airspeed while flying. An airspeed indicator will help you to fly at the appropriate speed for a given situation and when compared with variometer readings yields a wealth of information about the performance of your wing. Whether you’re applying speed-to-fly theory to your inter-thermal glides or trying to get the most out of the house thermal, the Hall Airspeed Indicator will help.

The design of the Hall type airspeed indicator involves using a ram air versus static pressure differential to raise a disc in a tapered tube against the force of the weight of the disc. Because of this the ASI has certain operating limitations:

  • It is only accurate in one G flight. If you are turning at a bank angle of more than 30 degrees, the ASI will read artificially low as a result of the G loading of the turn. Reliance on the ASI for limiting airspeeds in high banked sustained spiral maneuvers will likely cause you to exceed the placarded speed limitations of the glider and will compromise your safety.
  • It is only accurate when within 15-20 degrees of the vertical orientation.
There are four color coded bands on the ASI

White: This is the range from 18 m.p.h. to 28 m.p.h.. This is the normal thermalling speed range for light to moderate thermalling conditions. Try to keep your speed within this range when thermalling in light to moderate conditions. Very strong or turbulent conditions will warrant a faster flying speed.

Green: The top of the green region represents the placarded maximum rough air and maximum maneuvering speeds. This speed of 48 m.p.h. should not be exceeded except in smooth air, and no abrupt large control deflections should be used above this speed. In significant turbulence it is recommended that you keep the airspeed “in the green” for best control and stability and best structural margin at all times.

Yellow: This region represents the upper speed range between maximum rough air / maximum maneuvering speed and the speed never to exceed. You should fly in this range only in smooth air as described above.

Red Line: This is your never to exceed speed. At no time should you fly faster than this speed.


  • Easy-to-read display
  • Never needs batteries
  • Storage Pouch Included


Description Part # Retail
Downtube Bracket fits round and airfoil tubes 70K-3060 $8.00

Some options may be incompatible with others. See your Wills Wing dealer for details.


Specification Hall
Spd. Range (mph) 0…70
Spd. Res. (mph) 5
Units mph
Dim. (in) 1 x 4
Wt. (oz) 1.6
Sugg. Retail (US$) $28.50
Retail prices listed are Wills Wing's suggested retail prices not including packaging for shipment from the factory, freight costs to the destination, import and local taxes, and dealer preparation and delivery charges.