Robbe, Futaba, F1673, TEK compensation nozzle T
An uncompensated variometer simply displays the aircraft's vertical speed.
However, if a glider's forward speed changes, it also gains or loses height.
In actual flying this ensures that the pilot is kept informed of climb or sink rates excluding those caused by his stick movements (so-called "stick-generated thermals").
The glider pilot is only interested in the model's total energy (sum of kinetic and potential energy). He wishes to know whether he is flying in an area of lift or sink; changes in height due to changes in speed are to be filtered out by the variometer.
This is achieved by " compensation nozzles". These nozzles measure "nozzle pressure", which equates exactly to the difference between static pressure and dynamic pressure.
The TEK kit includes all the parts required for TEK compensation, including nozzle and hose.