On Sunday, October 13, 2019 at 10:52:21 AM UTC-4, wrote:
It looks like a flow restrictor that was placed in the total energy line to slowdown a nervous needle on mechanical vario’s like the Schumann , back when we didn’t have good TE probes.
JJ

It does! When I was a kid, we made these flow restrictors ourselves by heating laboratory glass tubes and then drawing them apart while blowing air through it to keep it from closing off. Out of ten trials, we would get maybe one or two good ones, which we places into slightly larger tubes and siliconed them in to keep them from breaking. Eventually, we would get decent TE compensation for our club gliders.

Uli
'AS'