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?
On Friday, February 10, 2023 at 2:08:20 PM UTC-5, jp wrote: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
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
On Friday, February 10, 2023 at 2:00:18 PM UTC-8, Hank Nixon wrote: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.
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.
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 kineticBUT, 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
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.
On Friday, February 10, 2023 at 2:00:18 PM UTC-8, Hank Nixon wrote: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.
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.
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 kineticBUT, 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
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.
On Friday, February 10, 2023 at 5:18:32 PM UTC-5, jp wrote: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.
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.
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 kineticBUT, 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
tell you how fast you are going up or down without speed changes messing up the information.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
UHThank 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.
On Friday, February 10, 2023 at 2:00:18 PM UTC-8, Hank Nixon wrote: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.
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.
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 kineticBUT, 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
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.
A TE vario does tell you whether you're going up or down. As UH noted, it just removes the temporary swings caused by exchanging speed for altitude
or, said another way, exchanging kinetic energy for potential energy). The total energy of the glider is always declining as we glide down--until we find lift.
What you might be looking for is a netto vario, which tells you how fast
the air is rising or sinking, regardless of what the glider is doing (assuming everything works properly which, as has been said, requires tuning). I flew with a netto vario for many years before the advent of the newer computerized varios (Cambridge Mk II, for you old timers) and loved
it. More recently, another flavor usually called relative netto subtracts
out the glider's sinking speed in thermaling flight from the netto reading
to tell you how fast you would be going up or down if you stop to circle. I had that, too; I just put a mark on vario dial at about 1.5 kts. If the needle went above that, I could climb if I stopped to circle.
Others might have a more elegant explanation but that's how I think of it.
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.
Bob,
End of history lesson. :) If you made it this far, thanks for humoring me.I thank you *for* the stroll down memory lane! I infer you may've been in the set of humanity for whom "Better is the enemy of good enough," while I was definitely a "Good enough!" sort, in terms of cockpit displays.
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.To be completely accurate, the TE connected vario is telling you the *rate of change* of potential energy. Not potential energy. These are somewhat different things. The rate of change is the velocity up or down in the gravitational field, added to the
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?
Which means that the glider's total energy is increasing, at thisThank you all again. And I'm sorry R that I have not answered your question. I'm a low-time glider pilot and I do not own a glider. I am happy to rent gliders and sometimes, rarely but sometimes, I get a glider that has an audio vario but usually the
specific time it is increasing in kinetic energy only. When you take
off your potential energy starts increasing and will add to the reading
on the vario. Once off tow, the TE needle tells you the same thing
except that changes in air mass movement, drag, and airspeed are the
what cause changes in total energy.
Dan
5J
On 2/10/23 16:43, jp wrote:
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
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
On Saturday, February 11, 2023 at 10:16:05 AM UTC-8, Dan Marotta wrote:glider just has a mechanical vario - no audio.
Which means that the glider's total energy is increasing, at this
specific time it is increasing in kinetic energy only. When you take
off your potential energy starts increasing and will add to the reading
on the vario. Once off tow, the TE needle tells you the same thing
except that changes in air mass movement, drag, and airspeed are the
what cause changes in total energy.
DanThank you all again. And I'm sorry R that I have not answered your question. I'm a low-time glider pilot and I do not own a glider. I am happy to rent gliders and sometimes, rarely but sometimes, I get a glider that has an audio vario but usually the
5J
On 2/10/23 16:43, jp wrote:
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
There are several things about gliding and especially about soaring that can twist my head around. I have to try hard to remember that low altitude is higher pressure and high altitude is lower pressure, etc.. I try hard to remember than the altimeterjust indicates the distance ( at an assumed 1000'/inch HG ) between what is set in the Kollsman window and the ambient air pressure where the glider is - and how the altimeter indication can be effected by colder or warmer than standard air temp and how
I think I do a fair job of controlling the glider but the varying descriptions of many of these weather / altimeter / variometer things just ties my brain in a knot.seeking lift. I am not yet persuaded that an increase in Total Energy always means lift and what the TE variometer indicates in an airspeed-increasing DESCENT is a complete mystery to me. I do know that the goodness of the TE variometer is in reducing
I have read a lot about TE variometers and still get easily confused. Some sources say the TE variometer does not indicate lift and sink but rather change rate of total energy. I understand that but don't know how to make use of total energy changes in
Anyway, I can live just fine with all this confusion. I just fly the glider and enjoy the view.
Thank you again.
On Saturday, February 11, 2023 at 2:11:48 PM UTC-5, jp wrote:glider just has a mechanical vario - no audio.
On Saturday, February 11, 2023 at 10:16:05 AM UTC-8, Dan Marotta wrote:
Which means that the glider's total energy is increasing, at this specific time it is increasing in kinetic energy only. When you take
off your potential energy starts increasing and will add to the reading on the vario. Once off tow, the TE needle tells you the same thing except that changes in air mass movement, drag, and airspeed are the what cause changes in total energy.
DanThank you all again. And I'm sorry R that I have not answered your question. I'm a low-time glider pilot and I do not own a glider. I am happy to rent gliders and sometimes, rarely but sometimes, I get a glider that has an audio vario but usually the
5J
On 2/10/23 16:43, jp wrote:
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
altimeter just indicates the distance ( at an assumed 1000'/inch HG ) between what is set in the Kollsman window and the ambient air pressure where the glider is - and how the altimeter indication can be effected by colder or warmer than standard airThere are several things about gliding and especially about soaring that can twist my head around. I have to try hard to remember that low altitude is higher pressure and high altitude is lower pressure, etc.. I try hard to remember than the
in seeking lift. I am not yet persuaded that an increase in Total Energy always means lift and what the TE variometer indicates in an airspeed-increasing DESCENT is a complete mystery to me. I do know that the goodness of the TE variometer is in reducingI think I do a fair job of controlling the glider but the varying descriptions of many of these weather / altimeter / variometer things just ties my brain in a knot.
I have read a lot about TE variometers and still get easily confused. Some sources say the TE variometer does not indicate lift and sink but rather change rate of total energy. I understand that but don't know how to make use of total energy changes
Thank you Hank. I will do just that. I really like your reccomendation.Anyway, I can live just fine with all this confusion. I just fly the glider and enjoy the view.
Thank you again.When flying forget about total energy and just use the variometer to guide you about climbing or sinking. no other brain effort is required.
Assuming it is working right, up is up(good- happy) down is down(not so happy).
End
UH
Hank has it right (as usual). If you really want to wade deeper into this stuff, G Dale's book, The Soaring Engine, Volume 4Confusion over the TE compensated vario may be caused by a horizontal gust producing a transient lift reading; it does indicate the energy available from the extra airspeed, but this is hard to use .( except in the case of climbing into positive wind
explains most of what you would want to learn about variometry.
ROY
On Saturday, February 11, 2023 at 3:26:29 PM UTC-5, Roy B. wrote:Hi Roy,
Hank has it right (as usual). If you really want to wade deeper into this stuff, G Dale's book, The Soaring Engine, Volume 4Confusion over the TE compensated vario may be caused by a horizontal gust producing a transient lift reading; it does indicate the energy available from
explains most of what you would want to learn about variometry.
ROY
the extra airspeed, but this is hard to use .( except in the case of climbing into positive wind
shear just after take off).
I believe some of the latest varios will remove the gust transient from the vario reading.
In normal inter-thermal flight this is useful and I plane to modify my trusty Winter vario
to do this pneumatically.
John Firth
old , no longer bold , out of date pilot.
PS I used to make the gust filters for Cambridge; the plastic 1/2l bottle
was fine unless mounted somewhere a G transient could squash it.
John, I've seen your name numerous times on this forum. Given your comment about being old and no longer bold, I wonder if you were the pilot who electrified the crowd at the Elmira Nationals in 1968 by exploding out of the ground as you approachedfrom the SE. I was 17 and visiting with my family for a few days and was watching another glider on final glide when (if I am correct) your HP-11 came climbing steeply from below the Hill, then finished. Still one of the most dramatic arrivals I've seen.
Chip Bearden
ASW 24 "JB"
John Firth
old , no longer bold , out of date pilot.
PS I used to make the gust filters for Cambridge; the plastic 1/2l bottle was fine unless mounted somewhere a G transient could squash it.
On Friday, February 10, 2023 at 3:32:12 PM UTC-8, Hank Nixon wrote: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.
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.
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 kineticBUT, 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
tell you how fast you are going up or down without speed changes messing up the information.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
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.UHThank 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 -
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.
On Friday, February 10, 2023 at 4:43:40 PM UTC-7, jp wrote: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.
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.
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 theBUT, 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
to tell you how fast you are going up or down without speed changes messing up the information.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
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.UHThank 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 -
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.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 (
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