In a simple variometer, tubing runs from a reference chamber to an outside static source. The static air pressure decreases in a climb and the air inside the chamber expands; the variometer measures the rate of airflow coming out of the chamber, either mechanically or using a heat-sensitive electrical resistor.

How do glider planes work?

The powered aircraft has an engine that generates thrust, while the glider has no thrust. In order for a glider to fly, it must generate lift to oppose its weight. To generate lift, a glider must move through the air. The motion of a glider through the air also generates drag.

How do gliders find thermals?

Glider pilots can find blue thermals, without Cu markers, by gliding along until stumbling upon a thermal. With any luck, other blue thermal indicators exist, making the search less random. One indicator of a thermal is another circling glider.