What is it?

[Ron]

This is easy enough to model, but what is it?



Looks like a pitot tube.
It's in the leading edge of the fin, but why is it pointing down, roughly at the angle of the fin?

[cvanscho]

I think that's the sensor for the vario (the thing wot pings at different rates/frequencies to tell the pilot if the glider is ascending or descending).

[Ron]

Oh that's interesting.
I always thought those things worked on atmospheric pressure changes.
You could be right though.
It's the pointing down bit that is the puzzle, otherwise it would just be airspeed.

[Alan_Perse]

Chris is right. It is for the Vario. I think its called the Total Energy Probe. It compensates for the false readings the vario gives when the glider turns into wind. When a glider turns into wind the airflow over the wings increases and thus the wing creats more lift and the glider climbs. You don't want your vario giving you a false reading at this point because you are not actualy in lift, it just the effect of flying into wind.

[Ron]

Ah yes, I see.
So you measure the actual air flowing upwards due to your wings, whereas in lift you are going up as well as the air.
Rather like being in a tidal flow where you are moving over the ground but not through the water, so if you want to measure the tide you would have to compensate for your movement through the water.

Interesting.