Speed of a vario

[[email protected]]

Which vario has lowest latency? (Least delay to indicate thermal we pass)

Anyone has done side by side tests?

S

[[email protected]]

Schuemann CV “taught band instrument, if you are talking about mechanical units. Too fast to use, without a restrictor installed.

Most modern electronic vario’s can be set too fast to use as well.

[Stephen Szikora]

I’ve never understood how a vario can be “too fast to use.� I would rather know I just flew into the lift/sink 1 second ago than 3 seconds ago. At the extreme, I want to know the moment I hit lift/sink. How I react to that information is another thing but I see nothing wrong with precise information.

[Tango Whisky]

Thermals are turbulent, and a 1 sec time constant means that the vario would be all over the place and completely useless. Use your butt instead.

[Martin Gregorie[_6_]]

On Sat, 08 Aug 2020 23:58:05 -0700, Tango Whisky wrote:

> Thermals are turbulent, and a 1 sec time constant means that the vario
> would be all over the place and completely useless. Use your butt
> instead.

Best fast electronic I've used is the (now quite ancient) Borgelt B.40.
Somehow it manages to be both fast and adequately damped: the needle
never jitters about, but I agree with Tango Whisky - never ignore what
your butt is telling you.


--
Martin | martin at
Gregorie | gregorie dot org

[jfitch]

On Saturday, August 8, 2020 at 7:49:02 PM UTC-7, wrote:
> Which vario has lowest latency? (Least delay to indicate thermal we pass)
>
> Anyone has done side by side tests?
>
> S
The Air Avionics (Butterfly) vario has inertially derived vertical air mass movement. This is nearly instant, the indicator moves perhaps 1/10 of a second after your butt. It leads the barometric needle (both it's own, and the two other variometers in my panel) by over a second, and I have them set to the lowest time constant.

[Dan Marotta]

To (mis)quote Obi-wan Kenobi - "Use the butt, Luke".

You'll feel it before the vario says anything.

On 8/8/2020 9:39 PM, Stephen Szikora wrote:
> I’ve never understood how a vario can be “too fast to use.� I would rather know I just flew into the lift/sink 1 second ago than 3 seconds ago. At the extreme, I want to know the moment I hit lift/sink. How I react to that information is another thing but I see nothing wrong with precise information.

--
Dan, 5J

[Corstian Boerman]

I like to open the window in order to hear what the air mass around the glider is doing. Works great when flying tight and weak thermals.

[BG[_4_]]

On Saturday, August 8, 2020 at 7:49:02 PM UTC-7, wrote:
> Which vario has lowest latency? (Least delay to indicate thermal we pass)
>
> Anyone has done side by side tests?
>
> S

Sage Vario's are the fastest mechanical I know, however the seat of your pants is be far the most accurate if you fly well. Our typical TE systems have flaw that would prevent even the fast electrical or mechanical from giving good information. Have you ever glanced at your TE on take roll? Any horizontal wind gust shows as lift and sink, a typical take off roll shows 4-5 FPM lift!!. Using the seat of pants combined with a averager works for most of us.

BG

[Scott Williams[_2_]]

On Saturday, August 8, 2020 at 9:49:02 PM UTC-5, wrote:
> Which vario has lowest latency? (Least delay to indicate thermal we pass)
>
> Anyone has done side by side tests?
>
> S

This interesting summary of the physiological delay of the visual system could be considered another reason a hypothetical 'instant' vario would be less than useful. If you like technicalities, that is.

Scientists have revealed the human brain has a 15-second lag that helps stabilize incoming visual information, which we don’t notice bombarding us in the course of our everyday lives.
Eyes tend to receive an enormous information load from dusk till dawn, and as one opens his or her eyes in the morning, the brain starts its intensive work, processing incoming pictures from the surroundings, including imagery from TV screens and computer monitors.

A team of vision scientists at the University of California, Berkeley and Massachusetts Institute of Technology (MIT) revealed this secret of the human brain: To save us from insanity induced by a constantly changing torrent of pictures, shapes and colors – both virtual and real world – the brain filters out information, failing in most cases to notice small changes in a 15-second period of time.

It actually means that what we do see is, in fact, a mixture of past and present. According to the research, published in the journal Nature Neuroscience, stability is attained at the expense of accuracy.

"What you are seeing at the present moment is not a fresh snapshot of the world but rather an average of what you've seen in the past 10 to 15 seconds," said study author Jason Fischer, Ph.D., a neuroscientist at MIT.

[Dan Marotta]

During takeoff you're adding kinetic energy to the total energy of the
glider.Â* I would expect the TE vario to show the increase. Remember, it
shows total energy; the up and down movements of the needle are telling
you how the total energy of the system is acting.

On 8/9/2020 2:00 PM, BG wrote:
> On Saturday, August 8, 2020 at 7:49:02 PM UTC-7, wrote:
>> Which vario has lowest latency? (Least delay to indicate thermal we pass)
>>
>> Anyone has done side by side tests?
>>
>> S
> Sage Vario's are the fastest mechanical I know, however the seat of your pants is be far the most accurate if you fly well. Our typical TE systems have flaw that would prevent even the fast electrical or mechanical from giving good information. Have you ever glanced at your TE on take roll? Any horizontal wind gust shows as lift and sink, a typical take off roll shows 4-5 FPM lift!!. Using the seat of pants combined with a averager works for most of us.
>
> BG
>

--
Dan, 5J

[Dan Marotta]

Well that all sounds scientific, but why then are sounds synchronized
with vision?Â* According to the below explanation it would seem that I
should see your lips moving 10-15 seconds after I heard what you said.

On 8/9/2020 2:46 PM, Scott Williams wrote:
> On Saturday, August 8, 2020 at 9:49:02 PM UTC-5, wrote:
>> Which vario has lowest latency? (Least delay to indicate thermal we pass)
>>
>> Anyone has done side by side tests?
>>
>> S
> This interesting summary of the physiological delay of the visual system could be considered another reason a hypothetical 'instant' vario would be less than useful. If you like technicalities, that is.
>
> Scientists have revealed the human brain has a 15-second lag that helps stabilize incoming visual information, which we don’t notice bombarding us in the course of our everyday lives.
> Eyes tend to receive an enormous information load from dusk till dawn, and as one opens his or her eyes in the morning, the brain starts its intensive work, processing incoming pictures from the surroundings, including imagery from TV screens and computer monitors.
>
> A team of vision scientists at the University of California, Berkeley and Massachusetts Institute of Technology (MIT) revealed this secret of the human brain: To save us from insanity induced by a constantly changing torrent of pictures, shapes and colors – both virtual and real world – the brain filters out information, failing in most cases to notice small changes in a 15-second period of time.
>
> It actually means that what we do see is, in fact, a mixture of past and present. According to the research, published in the journal Nature Neuroscience, stability is attained at the expense of accuracy.
>
> "What you are seeing at the present moment is not a fresh snapshot of the world but rather an average of what you've seen in the past 10 to 15 seconds," said study author Jason Fischer, Ph.D., a neuroscientist at MIT.

--
Dan, 5J

[Chris Wedgwood[_2_]]

On Sunday, August 9, 2020 at 10:46:25 PM UTC+2, Scott Williams wrote:
> On Saturday, August 8, 2020 at 9:49:02 PM UTC-5, wrote:
> > Which vario has lowest latency? (Least delay to indicate thermal we pass)
> >
> > Anyone has done side by side tests?
> >
> > S
>
> This interesting summary of the physiological delay of the visual system could be considered another reason a hypothetical 'instant' vario would be less than useful. If you like technicalities, that is.
>
> Scientists have revealed the human brain has a 15-second lag that helps stabilize incoming visual information, which we don’t notice bombarding us in the course of our everyday lives.
> Eyes tend to receive an enormous information load from dusk till dawn, and as one opens his or her eyes in the morning, the brain starts its intensive work, processing incoming pictures from the surroundings, including imagery from TV screens and computer monitors.
>
> A team of vision scientists at the University of California, Berkeley and Massachusetts Institute of Technology (MIT) revealed this secret of the human brain: To save us from insanity induced by a constantly changing torrent of pictures, shapes and colors – both virtual and real world – the brain filters out information, failing in most cases to notice small changes in a 15-second period of time.
>
> It actually means that what we do see is, in fact, a mixture of past and present. According to the research, published in the journal Nature Neuroscience, stability is attained at the expense of accuracy.
>
> "What you are seeing at the present moment is not a fresh snapshot of the world but rather an average of what you've seen in the past 10 to 15 seconds," said study author Jason Fischer, Ph.D., a neuroscientist at MIT.

We're gonna need to see that paper. Got a link?

[[email protected]]

Here's the link to the article (hit "download'). Though I commend Scott for slugging through the article and citing it (a welcome behavior for RAS), the authors do not conclude that the brain has a "15 second lag" to process the current visual field of an observer and has no connection with vario lag. It might have some loose relevance to a pilot's ability to pick out a moving, converging object from background when doing his/her scans. A 15 second lag would have meant more cavemen being eaten by dinosaurs.

https://www.researchgate.net/publication/261256203_Serial_dependence_in_visual_perception



> > Scientists have revealed the human brain has a 15-second lag that helps stabilize incoming visual information, which we don’t notice bombarding us in the course of our everyday lives.

> > It actually means that what we do see is, in fact, a mixture of past and present. According to the research, published in the journal Nature Neuroscience, stability is attained at the expense of accuracy.

>
> We're gonna need to see that paper. Got a link?

[[email protected]]

On Monday, August 10, 2020 at 10:45:16 AM UTC-4, wrote:
> Here's the link to the article (hit "download'). Though I commend Scott for slugging through the article and citing it (a welcome behavior for RAS), the authors do not conclude that the brain has a "15 second lag" to process the current visual field of an observer and has no connection with vario lag. It might have some loose relevance to a pilot's ability to pick out a moving, converging object from background when doing his/her scans. A 15 second lag would have meant more cavemen being eaten by dinosaurs.
>
> https://www.researchgate.net/publication/261256203_Serial_dependence_in_visual_perception
>
>
>
> > > Scientists have revealed the human brain has a 15-second lag that helps stabilize incoming visual information, which we don’t notice bombarding us in the course of our everyday lives.
>
> > > It actually means that what we do see is, in fact, a mixture of past and present. According to the research, published in the journal Nature Neuroscience, stability is attained at the expense of accuracy.
>
> >
> > We're gonna need to see that paper. Got a link?

If we had a 15-second lag in responding to visual stimulii, none of us could survive more than a few landings. Or the drive to the airport, for that matter.

[Scott Williams[_2_]]

On Saturday, August 8, 2020 at 9:49:02 PM UTC-5, wrote:
> Which vario has lowest latency? (Least delay to indicate thermal we pass)
>
> Anyone has done side by side tests?
>
> S

I agree that a 15 second delay in perception is demonstrably false, but the delay effect does exist, only the degree is questionable.
try this reaction time test.

https://humanbenchmark.com/tests/reactiontime

Scott

[Martin Gregorie[_6_]]

On Mon, 10 Aug 2020 14:17:56 -0700, Scott Williams wrote:

> On Saturday, August 8, 2020 at 9:49:02 PM UTC-5,
> wrote:
>> Which vario has lowest latency? (Least delay to indicate thermal we
>> pass)
>>
>> Anyone has done side by side tests?
>>
>> S
>
> I agree that a 15 second delay in perception is demonstrably false, but
> the delay effect does exist, only the degree is questionable.
> try this reaction time test.
>
> https://humanbenchmark.com/tests/reactiontime
>
Seems to me that, while simple reaction time is a fair measure for, e.g.
responding to a FLARM alert, its a bit more complex when responding to a
vario's audio and optical output.

For starters, you should be looking out the window, and only look at the
vario when its tones change - if then: I tend to use its sound and butt
feel for centering a thermal rather than looking at the waggling needle
until I'm reasonably centered. IOW, response to a vario is a complex
reaction to the feel of the air and the vario tone rather than a simple
response to an optical signal.


--
Martin | martin at
Gregorie | gregorie dot org

[Dan Marotta]

That was fun!

370 ms
301 ms
294 ms
290 ms
308 ms

That puts me in the 16.8 percentile.Â* What's that mean, anyway?

On 8/10/2020 3:17 PM, Scott Williams wrote:
> On Saturday, August 8, 2020 at 9:49:02 PM UTC-5, wrote:
>> Which vario has lowest latency? (Least delay to indicate thermal we pass)
>>
>> Anyone has done side by side tests?
>>
>> S
> I agree that a 15 second delay in perception is demonstrably false, but the delay effect does exist, only the degree is questionable.
> try this reaction time test.
>
> https://humanbenchmark.com/tests/reactiontime
>
> Scott
>

--
Dan, 5J

[SoaringXCellence]

Dan,

It means you're very slow, only faster than 16% of the test subjects. I got an average of 210, that's the 76 percentile.

MB

[Papa3[_2_]]

On Sunday, August 9, 2020 at 7:07:42 AM UTC-4, Martin Gregorie wrote:
> On Sat, 08 Aug 2020 23:58:05 -0700, Tango Whisky wrote:
>
> > Thermals are turbulent, and a 1 sec time constant means that the vario
> > would be all over the place and completely useless. Use your butt
> > instead.
> Best fast electronic I've used is the (now quite ancient) Borgelt B.40.
> Somehow it manages to be both fast and adequately damped: the needle
> never jitters about, but I agree with Tango Whisky - never ignore what
> your butt is telling you.
>
>
> --
> Martin | martin at
> Gregorie | gregorie dot org

I agree. There's something about the damping that seems to just work across multiple gliders, some with questionable pneumatic systems. If someone said I could have one and only one vario, it would be the B40 with the 9 volt battery strapped to the back.

I always found it funny that my sage was almost "too good". The reality, at least for those of us who fly in turbulent environments like mountains and ridges is that you need to do a lot of "soft averaging" to achieve decent climbs, and I have found with multiple varios from different manufacturers (Cambridge, Clearnav, Butterfly, LX) that I always end up configuring them for something like a 2 second or slightly more response time. Anything else makes it hard for me to integrate the information to form a picture. In other words, seat of the pants says we just flew into lift; old-fashioned pneumatic Winter Vario and the latest electronic gadget start to confirm a second or two later; trend seems to be continuing; now did one side feel better than the other; start the turn and keep the bank moderate at long as the trend is getting better...

With faster response, I usually found myself making a "panic bank" too early and having to take more turns to get centered.

But that's just how my brain is wired.

P3

[krasw]

There seems to be a misconception about time constant of variometer. Many (all?) think that 2 sec time constant means that it takes 2 seconds after hitting thermal for variometer to show any lift. This is not true. Time constant means that within that time variometer needle reaches 100% of the pressure change signal. That does not mean that variometer needle does not start to show at least something (needle starts to rise) before that 2 secs.

[[email protected]]

On Tuesday, August 11, 2020 at 12:01:37 AM UTC-4, krasw wrote:
> There seems to be a misconception about time constant of variometer. Many (all?) think that 2 sec time constant means that it takes 2 seconds after hitting thermal for variometer to show any lift. This is not true. Time constant means that within that time variometer needle reaches 100% of the pressure change signal. That does not mean that variometer needle does not start to show at least something (needle starts to rise) before that 2 secs.

What is the advantage of that 2 sec time constant, i.e. taking 2 seconds to reach 100% of the pressure change? Is the advantage that setting the time constant to a lower value (say, 1 sec or a half sec) means that the vario NEVER reaches 100% of the pressure change? i.e. you never get to know how good the thermal really is?

Ben Ethridge

[Dan Marotta]

Well, I'm 72 so I guess that's to be expected...

On 8/10/2020 7:57 PM, SoaringXCellence wrote:
> Dan,
>
> It means you're very slow, only faster than 16% of the test subjects. I got an average of 210, that's the 76 percentile.
>
> MB

--
Dan, 5J

[s6]

Le mardi 11 août 2020 Ã* 06 h 47 min 51 s UTC-4, Dan Marotta a écritÂ*:
> Well, I'm 72 so I guess that's to be expected...
> On 8/10/2020 7:57 PM, SoaringXCellence wrote:
> > Dan,
> >
> > It means you're very slow, only faster than 16% of the test subjects. I got an average of 210, that's the 76 percentile.
> >
> > MB
> --
> Dan, 5J

If I remember ok it is the time it takes to reach 80% of the thermal strenght.
S6

[James Metcalfe]

At 11:23 11 August 2020, s6 wrote:
>If I remember ok it is the time it takes to reach 80% of the
>thermal strength.

Actually (1− 1/e) (approximately 63 percent)
J.

[jfitch]

On Tuesday, August 11, 2020 at 6:45:05 AM UTC-7, wrote:
> At 11:23 11 August 2020, s6 wrote:
> >If I remember ok it is the time it takes to reach 80% of the
> >thermal strength.
>
> Actually (1− 1/e) (approximately 63 percent)
> J.
Also, the time constant of the electronics is after mechanical lags, so the delay may be somewhat longer.

[krasw]

On Tuesday, 11 August 2020 at 13:43:12 UTC+3, wrote:
> On Tuesday, August 11, 2020 at 12:01:37 AM UTC-4, krasw wrote:
> > There seems to be a misconception about time constant of variometer. Many (all?) think that 2 sec time constant means that it takes 2 seconds after hitting thermal for variometer to show any lift. This is not true. Time constant means that within that time variometer needle reaches 100% of the pressure change signal. That does not mean that variometer needle does not start to show at least something (needle starts to rise) before that 2 secs.
> What is the advantage of that 2 sec time constant, i.e. taking 2 seconds to reach 100% of the pressure change? Is the advantage that setting the time constant to a lower value (say, 1 sec or a half sec) means that the vario NEVER reaches 100% of the pressure change? i.e. you never get to know how good the thermal really is?
>
> Ben Ethridge

If lower time constant would be better, then everyone would set electrical vario time constant to zero.

Adjusting time constant is just a tool to filter out gusts from TE signal. Amount of disturbances would depend on your glider pitot static system, TE-probe, plumbing, variometers connected and most importantly, your personal preference.

There is no right or wrong here. I have my inertial variometer tc is set to 1 sec, electrical to 5 sec, and mechanical somewhere between. They have all different settings, because way of measuring signal is profoundly different between instruments.

[[email protected]]

On Tuesday, August 11, 2020 at 11:45:19 AM UTC-4, krasw wrote:
> There is no right or wrong here. I have my inertial variometer tc is set to 1 sec, electrical to 5 sec, and mechanical somewhere between. They have all different settings, because way of measuring signal is profoundly different between instruments.

Interesting. There may be no right or wrong, but what's the best way to use the instruments when you set the three of them differently this way, in your opinion? i.e. how do you get good useful info out of them, so that they don't just add instrument confusion?

[Eric Greenwell[_4_]]

jfitch wrote on 8/11/2020 8:22 AM:
> On Tuesday, August 11, 2020 at 6:45:05 AM UTC-7, wrote:
>> At 11:23 11 August 2020, s6 wrote:
>>> If I remember ok it is the time it takes to reach 80% of the
>>> thermal strength.
>>
>> Actually (1− 1/e) (approximately 63 percent)
>> J.
> Also, the time constant of the electronics is after mechanical lags, so the delay may be somewhat longer.
>
And then there is the time constant of the glider, which does not reach a steady
upward speed immediately; ie, the glider is a mechanical filter for lift with, I'm
guessing, a time constant between 1 second (low wing loading with stiff wings) and
3 seconds (high wing loading with bendy wings). Jon may have included the glider
lag in his "mechanical lags".
.
--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[krasw]

On Wednesday, 12 August 2020 at 01:53:16 UTC+3, wrote:
> On Tuesday, August 11, 2020 at 11:45:19 AM UTC-4, krasw wrote:
> > There is no right or wrong here. I have my inertial variometer tc is set to 1 sec, electrical to 5 sec, and mechanical somewhere between. They have all different settings, because way of measuring signal is profoundly different between instruments.
> Interesting. There may be no right or wrong, but what's the best way to use the instruments when you set the three of them differently this way, in your opinion? i.e. how do you get good useful info out of them, so that they don't just add instrument confusion?

TC between instruments is set according to their capability to measure reliable variometer data. Inertial variometer does not see the pitot-static errors, thus very fast tc. A good mechanical variometer is almost always best traditional way of showing TE signal, but is affected by gusts, thus couple of sec tc. Electrical variometer can be at best as good as (good) mechanical, but usually not. Mine is set up to show kind of "fast average" of thermal, thus 5 sec tc. I wan't to setup the instruments to complement their strength and hide the weaknesses. No reason to tune them to show identical signal (which is impossible with three different ways of doing things).

[Tango Eight]

Fast vario example: https://youtu.be/XAjwVPRTxQE?t=120

CNv set to "0.5s" for both pointer and audio. Panel is badly underexposed, but you can see the orange needle of the old CNv display on left side. I have the vario set to suppress sink tones (I don't need to be scolded when I'm not climbing).

What the TC refers to in this case is the low pass filter on the back end of the data stream. 0.5s effectively turns the low pass "off". There is plenty of digital filtering in front of this, and imo, it works quite well. I think it is about as fast as is useful for sailplanes. There's a reliable, repeatable sequence of boot in the bum followed a couple tenths of a second later by the audio for real thermals. If the boot is missing, that's a gust. It's very easy to train yourself to detect this difference (a good vario helps).

Not yet released CNv color display at upper right (it's quite visible in real life), should be out soon.

OT: At 2:25 you get a nice look at the Appalachian Trail as it ascends Old Speck Mountain just before plunging into Grafton Notch. We fly this route fairly often... but normally a bit higher :-).

T8

[jfitch]

On Tuesday, August 11, 2020 at 8:54:37 PM UTC-7, Eric Greenwell wrote:
> jfitch wrote on 8/11/2020 8:22 AM:
> > On Tuesday, August 11, 2020 at 6:45:05 AM UTC-7, wrote:
> >> At 11:23 11 August 2020, s6 wrote:
> >>> If I remember ok it is the time it takes to reach 80% of the
> >>> thermal strength.
> >>
> >> Actually (1− 1/e) (approximately 63 percent)
> >> J.
> > Also, the time constant of the electronics is after mechanical lags, so the delay may be somewhat longer.
> >
> And then there is the time constant of the glider, which does not reach a steady
> upward speed immediately; ie, the glider is a mechanical filter for lift with, I'm
> guessing, a time constant between 1 second (low wing loading with stiff wings) and
> 3 seconds (high wing loading with bendy wings). Jon may have included the glider
> lag in his "mechanical lags".
> .
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1
Yes, the glider is part of the mechanical lags. First a new angle of attack and/or airspeed has to establish over the wing. This itself has a time constant, as velocity gradients are always gradual. Then the wings bend. Then the fuselage begins to move - at that moment an inertial sensor can see it. After some movement the air in the tube from the triple probe begins to move. After some more time the hysteresis in the pressure sensor is overcome and it sends a signal to the electronics. From there the lags are electrical or software.

I'm not convinced that your butt can tell the difference between a horizontal and vertical gust. Take as an example a gust from ahead. This will increase both lift and drag. A sharp edged 10 knot gust will give you approximately 1.36G kick. That is about the same as a 4 knot vertical gust. You may sort out which was which by differentiating airspeed, and I think that is what the Butterfly attempts to do in its inertial system. Your butt has no airspeed sensor.

[Tango Eight]

On Wednesday, August 12, 2020 at 12:35:39 PM UTC-4, jfitch wrote:

> I'm not convinced that your butt can tell the difference between a horizontal and vertical gust. Take as an example a gust from ahead. This will increase both lift and drag. A sharp edged 10 knot gust will give you approximately 1.36G kick. That is about the same as a 4 knot vertical gust. You may sort out which was which by differentiating airspeed, and I think that is what the Butterfly attempts to do in its inertial system. Your butt has no airspeed sensor.

Gusts, like the wind in general, are 3D. The "useless gusts" we've all encountered might well be horizontal plus vertical downwards.

T8

[2G]

On Monday, August 10, 2020 at 9:01:37 PM UTC-7, krasw wrote:
> There seems to be a misconception about time constant of variometer. Many (all?) think that 2 sec time constant means that it takes 2 seconds after hitting thermal for variometer to show any lift. This is not true. Time constant means that within that time variometer needle reaches 100% of the pressure change signal. That does not mean that variometer needle does not start to show at least something (needle starts to rise) before that 2 secs.

The traditional meaning of "time constant" is exponentially based: after one time constant you reach 63% of its final value, after two time constants this is up to 86%, after three it is 95%. You never reach the final value of 100%.