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Vario Comparison



 
 
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  #11  
Old June 22nd 18, 08:15 AM posted to rec.aviation.soaring
krasw
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Default Vario Comparison

On Thursday, 21 June 2018 22:34:06 UTC+3, 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.


Why not just read Air Glide S user manual, available online, to get all answers to your questions?
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  #12  
Old June 22nd 18, 01:42 PM posted to rec.aviation.soaring
Waveguru
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Read the manual? What kind of a man are you?

Boggs
  #13  
Old June 23rd 18, 06:57 PM posted to rec.aviation.soaring
[email protected]
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Thanks jfitch- your comments are very helpful. I'm sorry if I gave the wrong impression- I thought someone had stated that none of the current offerings are using inertial inputs in the z dimension. Possibly someone wrote this to me privately. Your comments show that your vario has this capability as well as the ability to mix the inputs at different ratios. Clearly your experience with this is most helpful.

Gary
  #14  
Old June 23rd 18, 07:00 PM posted to rec.aviation.soaring
[email protected]
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Default Vario Comparison

Thank for this good suggestion. Of course seeking advice from people with much good experience is golden, as manufacturer's manuals are not always accurate with instructions or claims. Empirical results from reliable sources can lead to better decision.

Thanks again,

Gary
  #15  
Old July 15th 18, 03:56 AM posted to rec.aviation.soaring
Eric Greenwell[_4_]
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krasw wrote on 6/22/2018 12:15 AM:
On Thursday, 21 June 2018 22:34:06 UTC+3, 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.


Why not just read Air Glide S user manual, available online, to get all answers to your questions?


Perhaps too late to be useful, but I've read the manual, and it just covers the
basics. Not much in there that Gary is seeking, or even a less advanced pilot.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf
  #16  
Old August 28th 18, 09:23 AM posted to rec.aviation.soaring
[email protected]
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On Thursday, 21 June 2018 22:23:46 UTC+10, 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


test
  #17  
Old August 28th 18, 10:27 AM posted to rec.aviation.soaring
Mike Borgelt[_2_]
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On Thursday, 21 June 2018 22:23:46 UTC+10, 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.

------------
Charlie Quebec mentioned that I was developing such a unit called Dynamis.
It is actually done and entering production.
Immune to horizontal gusts, both long and short period. Also provides very accurate vector wind display updated once a second (averaged over much more frequent calculations. Currently flying in a Quintus here in Queensland. Will be re-installed in an ASH25 (the test vehicle) and LS8 and Nimbus 3DM within the next few weeks.

All pressure based instruments will suffer from much the same problems. It does not matter whether the TE compensation is by TE probe or derived from the pitot - static. TE probes are easier as pitot - static compensation introduces potential mismatches between the time the pressure signals arrive at the sensors and as you are subtracting two large signals to look at a small one it is easy to get large transient indications.There are also noticeable second order effects from changing G loads and angle of attack.
We did a nice little experiment by placing a blown up balloon over the end of a TE probe and recording the time constant of the pressure signal. Flasks or other capacities are bad news.

Eliminating horizontal gust effects is NOT a filtering problem as both real vertical motion of the air and horizontal gusts cause effects on the variometer of comparable time scales and magnitude. Because of these gusts, existing variometers cannot be made all that fast in response. A time constant of 2 to 3 seconds is what you end up with. Faster than this you will be averaging the pointer bouncing around by eye and this results in slower perception of changes and is work load intensive.

By eliminating sensitivity to horizontal gusts the variometer can respond more quickly to real vertical component changes in the air. During testing we were seeing more structure in the thermals because of this and lower workload by being able to rely on the indication instead of constantly trying to decide whether the change is due to a gust or real lift.
Dynamis works on principles not used before in variometers and is the end result of over 40 years of thinking, testing and experimentation.

No I'm not going to tell you how it is done. I've even managed to write the manual without revealing that. Sufficient that it works and works well.

Please do not reply to this gmail address. It NEVER gets checked. See our website for the correct one.

Mike Borgelt




  #18  
Old August 28th 18, 02:13 PM posted to rec.aviation.soaring
[email protected]
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Posts: 60
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Mike,

Congrats on the new gadget. It sounds great. Since you are here and talking about TE compensation, there is a dumb question that I've often wondered about.

In theory TE = MGH + 1/2MV**2

but ideally, should V be the plane speed vector with respect to the air or ground?

-Stu
  #19  
Old August 29th 18, 03:06 AM posted to rec.aviation.soaring
Mike Borgelt[_2_]
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Posts: 21
Default Vario Comparison

On Tuesday, 28 August 2018 23:13:24 UTC+10, wrote:
Mike,

Congrats on the new gadget. It sounds great. Since you are here and talking about TE compensation, there is a dumb question that I've often wondered about.

In theory TE = MGH + 1/2MV**2

but ideally, should V be the plane speed vector with respect to the air or ground?

-Stu


The air. But that isn't as simple as you might think.

More on Dynamis on our website. See the article "Horizontal Gusts" and under products - Dynamis Variometer System.

I'll put up some more articles and maybe comment under "blog" on the website over the next few days. Also pricing.

I'd like to get the next few local systems installed and test flown before release to the wider world.

Mike



  #20  
Old August 31st 18, 06:58 PM posted to rec.aviation.soaring
[email protected]
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Posts: 254
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On Wednesday, August 29, 2018 at 3:06:24 AM UTC+1, Mike Borgelt wrote:
On Tuesday, 28 August 2018 23:13:24 UTC+10, wrote:
Mike,

Congrats on the new gadget. It sounds great. Since you are here and talking about TE compensation, there is a dumb question that I've often wondered about.

In theory TE = MGH + 1/2MV**2

but ideally, should V be the plane speed vector with respect to the air or ground?

-Stu


The air. But that isn't as simple as you might think.

More on Dynamis on our website. See the article "Horizontal Gusts" and under products - Dynamis Variometer System.

I'll put up some more articles and maybe comment under "blog" on the website over the next few days. Also pricing.

I'd like to get the next few local systems installed and test flown before release to the wider world.

Mike


Hi Mike, would you consider putting the Dynamis user manual (or draft) on your website for practical information about fitment requirements etc?
 




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