WINTER 3 VARIOMETER 8064 EBV 1000 FT MIN LOG

Vane type variometers measure the change in air pressure inherent to changes in altitude. The instrument consists of a cylindrical chamber with a precision-fit baffle plate (vane) rotating on shock proof jewel bearings and centered by a coil spring. The vane divides the chamber in two: one section is open to static pressure, while the other is connected to an expansion tank, in which a volume of air is insulated against the thermal effects. Differences in pressure are compensated by the narrow gap between vane and chamber wall. There is a change in static pressure when an aircraft climbs or descends, and a differential pressure is established between the two sections of the chamber. The resultant deflection of the vane provides a measure of the vertical speed and this deflection is transferred to the pointer of the instrument. The response rate of a variometer is important. In high-performance gliding, up currents can be identified all the quicker and used all the more efficiently if the variometer respond