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[email protected] June 21st 18 01:23 PM

Vario Comparison
 
Hi-

I've searched the archives of this oft-discussed topic, but am not finding specific answers I'm seeking. If you have good experience or knowledge about the specific issues below, I would much appreciate your insights.

1) Latency with accuracy. What is the quickest vario with accuracy? Are they all limited by a 1 sec. latency with updates, or do some update faster? While several now describe their inputs as including both pressure sensor and inertial inputs from gyros and accelerometers, I can't find clarity on the mixture of these in the protocol. Some seem to link inertial inputs more to wind/track sensing than vario responses.

2) TE Compensation. Most all offer pneumatic or electronic, and at least some a gain loop on a pneumatic source so that compensation can be adjusted. However, pneumatic comp alone will only be accurate for one condition (g loading, alpha delta, etc.) Whereas electronic gain loops have been around for decades, it seems rather archaic that modification of the input is limited to a single gain function. Does anyone provide modification to several points on a curve whether g loading, v, or another pertinent metric?

I am looking at designing a new set of sensors and instruments that would display fundamentally different parameters for a type of flight strategies/optimization which is inertially based in a rapidly changing frame of reference. However, in the mean time I fly very dynamically and would appreciate experienced and accurate input about current vario offerings. I would also appreciate specific comments from pilots who have experience with both AirGlide (Butterfly), LxNav S8 or 80, and/or ClearNav Varios. Pluses and minuses wrt the above two capabilities in particular and notable general issues would be greatly appreciated.

Thanks, and sorry for posting from my wife's account- I don't post often enough to remember my login commands and am away from home records. You can email me directly if you wish:

Gary Osoba

[email protected] June 21st 18 02:29 PM

Vario Comparison
 
Hi Gary,

I have flown with both, ClearNav (500h) and AirGlide varios (100h). I also used both in parallel last season. In terms of variometry, both varios have a comparable performance. In fact, the readings in climb mode were almost identical. But I preferred the AirGlide user interface, wind calculation and physical quality of the product, so I sold the CNv last year.

Regarding short latency with high accuracy: From my experience, the fastest latency with high accuracy rather depends on the quality of your TE probe than on the vario itself. There are significant differences in signal quality between different TE probes. Small latency is only needed while circling.. In cruise mode you may want to have a longer latency in order not to be distracted with every single turbulence.

Regarding TE compensation: Both varios offer TE probe and electronic compensation along with some kind of air-mass filter which reduces signals from horizontal gusts in cruise mode. With the AirGlide, this filter is based on inertial sensors - not sure about the ClearNav. TE probe compensation with both varios works well while electronic compensation of static pressure signal did not work at all with both varios in my setup (LS8 with fuselage side static sources). With TE probe compensation on an esa DN/ST probe, I used a slight electronic adjustment of 2-3%. This gave perfect results.

The AirGlide offers a wide range of configuration option for the air mass filters and I am still working on the perfect setup. Seems that a longer integration time works better.

My personal opinion on the topic on how to determine air mass information: It is not a matter of the sensors being used. Even older analog varios gave a signal quality comparable to AirGlide and CNv - specifically Zander 820D / 940 / ZS1 and Westerboer VW910 varios (I consider older LX types to be worse in that respect). It is rather about what conclusion the pilot draws out of the data being presented. A good user interface simplifies that.

Best
Christoph

Charlie Quebec June 21st 18 02:33 PM

Vario Comparison
 
Hi Gary,
Mike Borgelt is developing such a unit, see: http://www.borgeltinstruments.com/?p=126
Called dynamis.

[email protected] June 21st 18 02:44 PM

Vario Comparison
 
Hello Cristoph-

Thanks for your thoughts and insights. Much appreciated. Some comments interspersed below.

On Thursday, June 21, 2018 at 7:29:22 AM UTC-6, wrote:
Hi Gary,

I have flown with both, ClearNav (500h) and AirGlide varios (100h). I also used both in parallel last season. In terms of variometry, both varios have a comparable performance. In fact, the readings in climb mode were almost identical. But I preferred the AirGlide user interface, wind calculation and physical quality of the product, so I sold the CNv last year.

Regarding short latency with high accuracy: From my experience, the fastest latency with high accuracy rather depends on the quality of your TE probe than on the vario itself. There are significant differences in signal quality between different TE probes. Small latency is only needed while circling. In cruise mode you may want to have a longer latency in order not to be distracted with every single turbulence.


This is true when determining cruise speeds using S2F and related strategies, which I don't use. Since achieved XC velocities are relatively insensitive to precise cruise speed, a filtered average works well in S2F based methods. What I would like to find for what I am doing is something much faster during rapid transient events as a result of control inputs. Most of the modern varios claim "instantaneous" sensing but then something like "updated every second" which is very slow for my purposes.

Regarding TE compensation: Both varios offer TE probe and electronic compensation along with some kind of air-mass filter which reduces signals from horizontal gusts in cruise mode. With the AirGlide, this filter is based on inertial sensors - not sure about the ClearNav. TE probe compensation with both varios works well while electronic compensation of static pressure signal did not work at all with both varios in my setup (LS8 with fuselage side static sources). With TE probe compensation on an esa DN/ST probe, I used a slight electronic adjustment of 2-3%. This gave perfect results.


I have a good TE probe. The instrument is the weak link in my system. Are the inertial sensors only used to provide delta adjustments of the horizontal components, or do some of them use inertial input for vertical variation. If so, is this giving faster, reliable indications that aren't filtered through a 1 second gate?

The AirGlide offers a wide range of configuration option for the air mass filters and I am still working on the perfect setup. Seems that a longer integration time works better.

My personal opinion on the topic on how to determine air mass information: It is not a matter of the sensors being used. Even older analog varios gave a signal quality comparable to AirGlide and CNv - specifically Zander 820D / 940 / ZS1 and Westerboer VW910 varios (I consider older LX types to be worse in that respect). It is rather about what conclusion the pilot draws out of the data being presented. A good user interface simplifies that.

Best
Christoph


Thanks again for your inputs, Christoph.

Gary


[email protected] June 21st 18 02:59 PM

Vario Comparison
 
Hi Gary,

please find my comments below.


Am Donnerstag, 21. Juni 2018 15:44:19 UTC+2 schrieb :
Hello Cristoph-

Thanks for your thoughts and insights. Much appreciated. Some comments interspersed below.

On Thursday, June 21, 2018 at 7:29:22 AM UTC-6, wrote:
Hi Gary,

I have flown with both, ClearNav (500h) and AirGlide varios (100h). I also used both in parallel last season. In terms of variometry, both varios have a comparable performance. In fact, the readings in climb mode were almost identical. But I preferred the AirGlide user interface, wind calculation and physical quality of the product, so I sold the CNv last year.

Regarding short latency with high accuracy: From my experience, the fastest latency with high accuracy rather depends on the quality of your TE probe than on the vario itself. There are significant differences in signal quality between different TE probes. Small latency is only needed while circling. In cruise mode you may want to have a longer latency in order not to be distracted with every single turbulence.


This is true when determining cruise speeds using S2F and related strategies, which I don't use. Since achieved XC velocities are relatively insensitive to precise cruise speed, a filtered average works well in S2F based methods. What I would like to find for what I am doing is something much faster during rapid transient events as a result of control inputs. Most of the modern varios claim "instantaneous" sensing but then something like "updated every second" which is very slow for my purposes.


The varios are technically capable of very fast responses, but I don't consider this useful while cruising. I am rather trying to optimize my flight path such that I stay in lines of lift rather than sink. I don't stick to the proposed S2F but prefer the concept of block speeds. Adjustable audio deadbands help with that.


Regarding TE compensation: Both varios offer TE probe and electronic compensation along with some kind of air-mass filter which reduces signals from horizontal gusts in cruise mode. With the AirGlide, this filter is based on inertial sensors - not sure about the ClearNav. TE probe compensation with both varios works well while electronic compensation of static pressure signal did not work at all with both varios in my setup (LS8 with fuselage side static sources). With TE probe compensation on an esa DN/ST probe, I used a slight electronic adjustment of 2-3%. This gave perfect results.


I have a good TE probe. The instrument is the weak link in my system. Are the inertial sensors only used to provide delta adjustments of the horizontal components, or do some of them use inertial input for vertical variation. If so, is this giving faster, reliable indications that aren't filtered through a 1 second gate?


The AirGlide has this capability, as far as I know the CNv does not. It provides an air-mass indication (blue dot on the display) which can be configured independently from the vario reading. This air-mass info can be set up to be 100% inertially measured. You can also adjust it to very fast latency cycles, but so far I did not test this.


The AirGlide offers a wide range of configuration option for the air mass filters and I am still working on the perfect setup. Seems that a longer integration time works better.

My personal opinion on the topic on how to determine air mass information: It is not a matter of the sensors being used. Even older analog varios gave a signal quality comparable to AirGlide and CNv - specifically Zander 820D / 940 / ZS1 and Westerboer VW910 varios (I consider older LX types to be worse in that respect). It is rather about what conclusion the pilot draws out of the data being presented. A good user interface simplifies that.

Best
Christoph


Thanks again for your inputs, Christoph.

Gary



[email protected] June 21st 18 03:58 PM

Vario Comparison
 
On Thursday, June 21, 2018 at 1:23:46 PM UTC+1, wrote:
Hi-

I've searched the archives of this oft-discussed topic, but am not finding specific answers I'm seeking. If you have good experience or knowledge about the specific issues below, I would much appreciate your insights.

1) Latency with accuracy. What is the quickest vario with accuracy? Are they all limited by a 1 sec. latency with updates, or do some update faster? While several now describe their inputs as including both pressure sensor and inertial inputs from gyros and accelerometers, I can't find clarity on the mixture of these in the protocol. Some seem to link inertial inputs more to wind/track sensing than vario responses.

2) TE Compensation. Most all offer pneumatic or electronic, and at least some a gain loop on a pneumatic source so that compensation can be adjusted.. However, pneumatic comp alone will only be accurate for one condition (g loading, alpha delta, etc.) Whereas electronic gain loops have been around for decades, it seems rather archaic that modification of the input is limited to a single gain function. Does anyone provide modification to several points on a curve whether g loading, v, or another pertinent metric?

I am looking at designing a new set of sensors and instruments that would display fundamentally different parameters for a type of flight strategies/optimization which is inertially based in a rapidly changing frame of reference. However, in the mean time I fly very dynamically and would appreciate experienced and accurate input about current vario offerings. I would also appreciate specific comments from pilots who have experience with both AirGlide (Butterfly), LxNav S8 or 80, and/or ClearNav Varios. Pluses and minuses wrt the above two capabilities in particular and notable general issues would be greatly appreciated.

Thanks, and sorry for posting from my wife's account- I don't post often enough to remember my login commands and am away from home records. You can email me directly if you wish:

Gary Osoba



At the last BGA conference I asked a technical guy from LX Nav how the inertial platform was used in the variometry of LX 8/9000 family of instruments and he said it was only used in the wind calculations.


jfitch June 21st 18 04:28 PM

Vario Comparison
 
On Thursday, June 21, 2018 at 5:23:46 AM UTC-7, wrote:
Hi-

I've searched the archives of this oft-discussed topic, but am not finding specific answers I'm seeking. If you have good experience or knowledge about the specific issues below, I would much appreciate your insights.

1) Latency with accuracy. What is the quickest vario with accuracy? Are they all limited by a 1 sec. latency with updates, or do some update faster? While several now describe their inputs as including both pressure sensor and inertial inputs from gyros and accelerometers, I can't find clarity on the mixture of these in the protocol. Some seem to link inertial inputs more to wind/track sensing than vario responses.

2) TE Compensation. Most all offer pneumatic or electronic, and at least some a gain loop on a pneumatic source so that compensation can be adjusted.. However, pneumatic comp alone will only be accurate for one condition (g loading, alpha delta, etc.) Whereas electronic gain loops have been around for decades, it seems rather archaic that modification of the input is limited to a single gain function. Does anyone provide modification to several points on a curve whether g loading, v, or another pertinent metric?

I am looking at designing a new set of sensors and instruments that would display fundamentally different parameters for a type of flight strategies/optimization which is inertially based in a rapidly changing frame of reference. However, in the mean time I fly very dynamically and would appreciate experienced and accurate input about current vario offerings. I would also appreciate specific comments from pilots who have experience with both AirGlide (Butterfly), LxNav S8 or 80, and/or ClearNav Varios. Pluses and minuses wrt the above two capabilities in particular and notable general issues would be greatly appreciated.

Thanks, and sorry for posting from my wife's account- I don't post often enough to remember my login commands and am away from home records. You can email me directly if you wish:

Gary Osoba


As far as I can tell, the Air Vario is the only one using inertial sensors for variometry, represented in the Vertical Air Mass movement needle. This has a setting to be derived from any mix ratio of 100% barometric to 100% inertial. If set to 100% inertial I find it too twitchy, but set to 80% inertial it can be flown like a variometer, but leads it by a second or more. It is confused by other things, such as changing flap position. I can thermal with it even with the engine boom out, which totally hoses the tail pneumatics.

Every other vario since the 302 has had inertial sensors and some claimed to use them, but none seem to. Currently flying with both Air Vario and Clear Nav vario installed.

Steve Koerner June 21st 18 05:01 PM

Vario Comparison
 
This seems like maybe a fair place to interject a relevant advertisment... Just yesterday I posted an ad on wingsandwheels.com for an Air Vario, Display S (Butterfly vario) in perfect condition for $1950. It's in the "Misc" category there.

[email protected] June 21st 18 08:34 PM

Vario Comparison
 
Thank you. This is very helpful but it contradicts what an earlier poster stated. If it is adjustable as you have indicated, this is a very good feature.

Gary

As far as I can tell, the Air Vario is the only one using inertial sensors for variometry, represented in the Vertical Air Mass movement needle. This has a setting to be derived from any mix ratio of 100% barometric to 100% inertial. If set to 100% inertial I find it too twitchy, but set to 80% inertial it can be flown like a variometer, but leads it by a second or more. It is confused by other things, such as changing flap position. I can thermal with it even with the engine boom out, which totally hoses the tail pneumatics.

Every other vario since the 302 has had inertial sensors and some claimed to use them, but none seem to. Currently flying with both Air Vario and Clear Nav vario installed.



jfitch June 22nd 18 05:26 AM

Vario Comparison
 
On Thursday, June 21, 2018 at 12:34:06 PM UTC-7, wrote:
Thank you. This is very helpful but it contradicts what an earlier poster stated. If it is adjustable as you have indicated, this is a very good feature.

Gary

As far as I can tell, the Air Vario is the only one using inertial sensors for variometry, represented in the Vertical Air Mass movement needle. This has a setting to be derived from any mix ratio of 100% barometric to 100% inertial. If set to 100% inertial I find it too twitchy, but set to 80% inertial it can be flown like a variometer, but leads it by a second or more. It is confused by other things, such as changing flap position. I can thermal with it even with the engine boom out, which totally hoses the tail pneumatics.

Every other vario since the 302 has had inertial sensors and some claimed to use them, but none seem to. Currently flying with both Air Vario and Clear Nav vario installed.


I don't think is contradicts. The Air Vario draws several virtual needles on the screen, one is the variometer which is strictly barographic like others. The VAM needle (actually a blue ball) represents vertical air mass movement, and can be used like a variometer to a great extent. It is that reading that can be varied from barometric to inertial. You have both displayed at all times. The audio represents the barographic variometer needle (a triangular pointer). Both are useful - in theory the VAM does not react to horizontal gusts and leads the variometer. There are several adjustments to filtering on both to play with.


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