Chris Reed wrote:
Without TE, you pull back on the stick and the vario cries "lift". Push,
and you hear "sink". Even local soaring, this will have you confused
enough to be back on the ground faster than you intend.

Having once flown a club glider with defective TE, so that in practice
it was completely uncompensated, the only way I could soar it was to
turn off the audio and fly by the seat of my pants, looking at the
needle only when established in a circle at a steady airspeed.

Just to offer a different perspective on this, I've been doing a lot of
flying this year in a friend's borrowed 1-26 with no audio vario at all.
This so disturbed me that I bought one of Mallettec's Mini Varios, the
kind that's about the size of a box of matches and just clips on to
something. (For me, the hat, because I can't hear it if it's any farther
away in a noisy cockpit.)

This vario is obviously uncompensated. Worse, I'm pretty sure it's
actually negatively compensated. The vent effectively provides pitot-like
pressure to the cockpit and, I believe, will cause it to indicate *more*
than the true rate of climb in a stick thermal. With a constant airspeed
it is surprisingly good; I had thought that cockpit leakage would cause a
lot of inconsistency, but unless I do something like open the spoilers it
does great.

To get to the point of all this, I've done pretty well with this vario.
I'm sure I'd do better with a compensated one and it certainly took some
getting used to at first. When I first hit a thermal I hold speed to see
how big it is, and when I turn in I ignore the beeping until I slow to
thermalling speed. Once I've established speed, I can start listening to
the beeps again to figure out the structure of the thermal. I really just
have to remember that the frantic beeping it gives me when I pull up is
not because I'm in a boomer, but just because the vario is
temporarily delusional.

I'd certainly recommend a compensated vario given the choice, and it may
matter a great deal more in higher performance gliders, but at least for
me it hasn't been the end of the world.

--
Michael Ash
Rogue Amoeba Software