The TEK nozzle is an expansion accessory that can be used with the GPS Logger 2/3 and the MicroVario telemetry modules. When used together it provides identical information as experienced by full-sized sailplane pilots such as accurate readings of climb, sink and airspeed. The TEK nozzle works according to the principle of the "Braunschweiger Nozzle" which is used almost exclusively in full scale airplanes. The TEK nozzle is made entirely of stainless steel and is hard soldered.
TEK in simplified terms means, the suppression of the "control stick thermals" by taking into accounts the movement of the model. This is achieved by connecting a TEK nozzle to the Vario sensor.
For slow models, that fly at constant speed, a Vario without TEK is often sufficient. Here the errors caused by controlled altitude changes are not so great and you can clearly sense thermals through the Vario (audio or visual) cues provided by a telemetry radio. The smoother you fly and the lower the speed changes, the better the Vario works without a TEK nozzle.
However, with dynamic models or even with a less than perfect flying style, there are always Vario outputs that do not show the true climb or descent of the model. They are often, unnoticeably caused, by the pilots own stick movements "control stick thermals" resulting in incorrect readings of climb or descent.
Practically, the only thing of interest when searching for a thermal is whether you are flying in ascending, descending or neutral air mass as independently as possible of how the aircraft is currently moving.
To be able to measure such trend you will need a TEK nozzle connected to the variometer. The nozzle generates a negative pressure dependent on the airspeed simulating a climb with increasing airspeed. The TEK nozzle compensates for this by displaying a climb for the increasing airspeed when pressure is applied. The conversion of altitude (potential energy) into speed (kinetic energy) is therefore no longer incorrectly interpreted as sinking or climbing with the TEK nozzle.
Ideally, with full compensation, the Vario will always show the current natural sink rate of the aircraft in completely still air. Of course, this is not a constant value, but depends on speed, lift and other factors.
The MicroVario has a TEK connector at the front. The hose of the TEK nozzle is simply attached to this. In principle, all types of TEK nozzles can be used here, including the well-known Nicks nozzle or the “Braunschweiger Nozzle”. The nozzles differ in their sensitivity to shift the angle of inflow and in compensation factor.
TEK Stainless Steel Nozzle