Instruments
The instruments tell the pilot what is happening.
Air Speed Indicator records the speed of the glider through the air. This may be quite differentfrom the speed over the ground, depending on the wind speed and direction.
Variometers tell the pilot whether the glider is flying through rising or sinking air. Why three? Well glider pilots really need this information, and they are all a bit different! One of them gives an audible indication so that the pilot gets the information without having to look at the instrument.
The Altimeter tells the pilot how high the glider is above the airfield, or sea level depending on how it is set.
Generally the instruments are used only for quick reference, to confirm what the pilot sees by looking out.
