On Friday, February 10, 2023 at 4:43:40 PM UTC-7, jp wrote:
> On Friday, February 10, 2023 at 3:32:12 PM UTC-8, Hank Nixon wrote:
> > On Friday, February 10, 2023 at 5:18:32 PM UTC-5, jp wrote:
> > > On Friday, February 10, 2023 at 2:00:18 PM UTC-8, Hank Nixon wrote:
> > > > On Friday, February 10, 2023 at 2:08:20 PM UTC-5, jp wrote:
> > > > > We know that a variometer with a TE probe fitted indicates total energy of the glider and not necessarily whether the glider is ascending or descending.
> > > > >
> > > > > Good enough, although I still find myself treating the vario as if it is telling me about lift and sink.
> > > > >
> > > > > BUT, if we are clear of mind to see the TE variometer as indicating total energy what then do the numbers on the vario face indicate?
> > > > We don't know what you stated. It does tell you lift and sink. TE is intended to take out the change in displayed lift or sink caused by a change in speed.
> > > > Maybe easier to think of it as a speed compensated vario.
> > > > UH
> > > Thank you Hank. As far as I understand the TE stuff (which is clearly not very far) the TE connected vario would only be indicating potential energy (i.e. up or down I guess) if the airspeed ( kinetic energy ) is held constant. If both the kinetic energy and potential energy are varying, which I confess if often what is happening when I am flying, the TE connected vario will indicate the algebraic sum of the kinetic and the potential energy..
> > >
> > > I was just curious. Most of the time I pretend the TE connected vario is just indicating the up or down of the glider regardless of the airspeed or altitude changes.
> > What you are "pretending" is just what the TE compensated variometer is supposed to do. If you want to get into fancy descriptions it is showing the rate of change of potential energy. That said there is no reason to out think it. It's purpose is to tell you how fast you are going up or down without speed changes messing up the information.
> > UH
> Thank you all for helping me understand this stuff. By the way, it would be nice if I had an audio vario but I don't.
>
> I will stop over-thinking this stuff. It confused me that the TE-connected vario ( by which I mean a vario connected to a TE probe rather than just to the "ordinary" static ports ) shows what looks like ascent when I am being pulled along the runway - clearly not ascending. From that experience I concluded that the vario was not indicating, at least not directly indicating, the glider is rising. I'm not at all sure that I can do anything with that knowledge anyway.
>
> I think it would be best for me to just forget about all the TE-vario I read about and just fly the silly glider.
>
> But thank you all for your helpful responses.

The TE-connected vario is supposed to indicate lift while you are accelerating down the runway even though you are still on the ground--BECAUSE due to your acceleration, you are gaining energy--kinetic energy, even though you are not climbing (potential energy. Your TOTAL energy (KE + PE) is increasing because while the PE (altitude) remains the same, the KE (speed) is increasing. Thus the vario indicates "lift". This is how it's supposed to work.

On Sunday, February 12, 2023 at 8:49:12 PM UTC-8, John Foster wrote:
> On Friday, February 10, 2023 at 4:43:40 PM UTC-7, jp wrote:
> > On Friday, February 10, 2023 at 3:32:12 PM UTC-8, Hank Nixon wrote:
> > > On Friday, February 10, 2023 at 5:18:32 PM UTC-5, jp wrote:
> > > > On Friday, February 10, 2023 at 2:00:18 PM UTC-8, Hank Nixon wrote:
> > > > > On Friday, February 10, 2023 at 2:08:20 PM UTC-5, jp wrote:
> > > > > > We know that a variometer with a TE probe fitted indicates total energy of the glider and not necessarily whether the glider is ascending or descending.
> > > > > >
> > > > > > Good enough, although I still find myself treating the vario as if it is telling me about lift and sink.
> > > > > >
> > > > > > BUT, if we are clear of mind to see the TE variometer as indicating total energy what then do the numbers on the vario face indicate?
> > > > > We don't know what you stated. It does tell you lift and sink. TE is intended to take out the change in displayed lift or sink caused by a change in speed.
> > > > > Maybe easier to think of it as a speed compensated vario.
> > > > > UH
> > > > Thank you Hank. As far as I understand the TE stuff (which is clearly not very far) the TE connected vario would only be indicating potential energy (i.e. up or down I guess) if the airspeed ( kinetic energy ) is held constant. If both the kinetic energy and potential energy are varying, which I confess if often what is happening when I am flying, the TE connected vario will indicate the algebraic sum of the kinetic and the potential energy.
> > > >
> > > > I was just curious. Most of the time I pretend the TE connected vario is just indicating the up or down of the glider regardless of the airspeed or altitude changes.
> > > What you are "pretending" is just what the TE compensated variometer is supposed to do. If you want to get into fancy descriptions it is showing the rate of change of potential energy. That said there is no reason to out think it. It's purpose is to tell you how fast you are going up or down without speed changes messing up the information.
> > > UH
> > Thank you all for helping me understand this stuff. By the way, it would be nice if I had an audio vario but I don't.
> >
> > I will stop over-thinking this stuff. It confused me that the TE-connected vario ( by which I mean a vario connected to a TE probe rather than just to the "ordinary" static ports ) shows what looks like ascent when I am being pulled along the runway - clearly not ascending. From that experience I concluded that the vario was not indicating, at least not directly indicating, the glider is rising. I'm not at all sure that I can do anything with that knowledge anyway.
> >
> > I think it would be best for me to just forget about all the TE-vario I read about and just fly the silly glider.
> >
> > But thank you all for your helpful responses.
> The TE-connected vario is supposed to indicate lift while you are accelerating down the runway even though you are still on the ground--BECAUSE due to your acceleration, you are gaining energy--kinetic energy, even though you are not climbing (potential energy. Your TOTAL energy (KE + PE) is increasing because while the PE (altitude) remains the same, the KE (speed) is increasing. Thus the vario indicates "lift". This is how it's supposed to work.
Hi John,

Thank you for your comment.

Yes, I do understand why it is the vario is indicating "up" as the glider gathers speed along the runway. It is a good example of how a TE vario presents rate of change of energy. What left me uncertain is just how I might make use of rate-of-change of energy when I am looking for lift. I understand now from all the helpful comments I've received here that, at least some of the time, I can just see the up-needle on the TE vario as an indication of lift. I can live with that.