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Old Sep 04, 2013, 06:26 PM
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Quote:
Originally Posted by Joe W View Post
His choice (assuming you meant the word akin to selection) is that he wants to actually use the data being generated in a timely fashion. I'd politely suggest that reviewing the data via data logging may be slightly less useful than the proverbial 3 second lag in terms of using the sensor for its desired purpose.


(RCG needs an ignore function)

Of Robbe Modis also a wireless system was available of course.
Robbe Modis was the first wireless datatransfer system, also speed and vario but maybe it'snever introduced in the USA!
A picture of my own system, not wireless, only data logging for research.

Cees
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Old Sep 05, 2013, 05:17 AM
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Subject accuracy.

Polar? Speed to fly? "SpeedPilot"?

While we are waiting for the results of investigation of marnochs we walk around in some subjects. Let's take "accuracy", related to doubtful data that's offered.

A document in the thread "SpeedPilot " post 25,

http://www.rcgroups.com/forums/showp...1&postcount=25

uav_avionics_airspeed.pdf / Title: Airspeed Sensors & Pitot Tube Mathematics

Even it looks like a professional document I can qualify the content in a few seconds.

The note:
So, to measure airspeed up to 111 mph, we need a pressure transducer that can read at least .22 psi. I have three Motorola MPX2010G
pressure transducers that are rated at 1.4 psi. They should work up to 318 m/s or 705 mph (in an incompressible flow, which at 705 mph
is not true, but anyway...) No problem

.....contents a huge principial fault showing the person is not experienced at all.
Better forget this document but also the other of this post because it will be too complicated the determine the value !
Cees
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Old Sep 05, 2013, 07:45 AM
launch low, fly high
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Use ^2 rather than ^1...

Not too complicated after all!
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Old Sep 05, 2013, 10:33 AM
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http://www.rcgroups.com/forums/showp...&postcount=118

"My fullsize Citabria has the static port open in the cockpit so I thought "what the heck" lets try it out.....seemed to work OK"

Interesting airplane that must be with that static port open in the cockpit, I am not impressed!
(I was engineer on the Northrop NF5 so I know a little bit about airplanes, still remember hearing the details about a Thunderstreak accident at Air Base Eindhoven related to this subject)


I also still remember this statement of marnochs:"The RC Electonics system is a Netto Vario since you can adjust the vario tone “window” for glider rate of sink."
http://www.rcgroups.com/forums/showp...9&postcount=21
OK

Calibrate is more important than Citabria in this situation so I show what is needed to calibrate our glider instruments, first, barometric pressure and for sensitive variometers we have to know if that barometric pressure is falling or rising on moment of zeroing. I visualise the barometric pressure and differentiator on a Siemens Halske double indicator.
To calibate the lowest range of an airspeed transmitter we need an instrument to indicate the dynamic pressure we connect with the p dyn. port. A Thommen indicator, range 10 mmwk. (+/-12 m/s-1, +/-24 knots)



Cees
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Old Sep 05, 2013, 02:51 PM
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I see I received the first star for the thread, thanks. I saw who was logged in at that moment!.

A video recording I made a few days ago.

The barometric pressure and a rainstorm passes by. (2 min 54 sec)
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Old Sep 05, 2013, 03:26 PM
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subscribed. very informetive
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Old Sep 05, 2013, 03:44 PM
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Off topic but important;
marnochs, I did a little check for your airbike, maybe it's a good case to visit the bike shop because I am afraid you lost some plumbing!!

Cees
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Old Sep 05, 2013, 03:50 PM
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Quote:
Originally Posted by tip stall tomba View Post
subscribed. very informetive
You'r welcome tip.
Just a question, off topic.
Do you know of a team of engineers that work for a while in Deventer, the Netherlands. 2006, Kazakh Oil Company. Engineering a waste water treatment plant.

Cees
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Old Sep 06, 2013, 04:27 AM
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What is the most first wanted add we want to see at the basic variometer?
'Speed to fly!'
When that isn't told by the vario, we have to use "best guess" based on some observations on the ground, windspeed, wind direction, combined with modern input GPS. Next step is trust the trim of the glider and go with the Banana.
Not a bad choice to be on the safe side.

I was interested in what was used for XC flying, expecting something more sophisticated. but now I am dissapointed, have to argue about basic principles of airspeed measurements and for me there is nothing to learn.
But, we have to finish the thread some day so I made three pictures.
One with still air. one "down" air and the third with wind!

These are made with the diagram I found in an performance test of the SBXC glider, see this link:
http://soaring.goosetechnologies.com/



I only used the data of Dan Edwards because he did use an airspeed measurement system.

Result, the grey surfaces.
When I observe these graphs, it makes no sense to write about any kind of "speed to fly", manual or some kind of automatic.

Not knowing the quality of data results in a lot of armchair modeling without any tangible results. I'lI wait for a while to see with what kind of solution Anker or other people is coming and look around what's used elswhere.

Cees
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Old Mar 03, 2014, 11:39 AM
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Hi Taurus Flyer,
I am trying to read all threads about the vario's, TE vario's, airspeed meters, ... Lots of information to consume.
Do you know any commercial device that fits in our RC gliders that can provide information like speed to fly or netto vario? And are you planning to make your designs commercially available?
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Old Mar 03, 2014, 02:23 PM
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Hello Glider Fan,

No I am not planning to make my instruments commercial available and I also don't know if there are instruments with these capabilities in this period.

I started this thread a few years ago to have information about more advanced variometers and I discovered there weren't there, also not used for XC flying

Some time ago people shown in this thread there is more interest voor airspeed indicators and because contributers keep on writing about aispeed indicators I changed the title, see for example post 95.
It was never my goal to contribute in a debate what would be better, that the pilots have to discover themselves.

When writing about the feasibility of more complete variometer systems (but also airspeed measurement) the accuracy and so costprice will be the problem.
To make instruments real usable the accuracy has to be much better than what is shown commercial these days. For example when observing the graphs of post 129 (above this post) the spread (grey surfaces) of the measured date is much too diverse and so and disadvantageous to use for 'speed to fly'.

The future will show if the modern telemetry systems will show up with more advanced variometers if these aren't there already.

For who is interested, some time ago I showed a video of one of the latest variometer developements.
Model airplane variometer response at low vertical speed. (1 min 30 sec)

show the video again, to show what kind of response sensitivity is needed to have a signal available that can be used for calculations, netto variometer or speed to fly.
Also an airspeed measurement system has to be as accurate as the variometer so it isn't the weakest link in the calculations.

Cees
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Last edited by Taurus Flyer; Mar 03, 2014 at 02:29 PM.
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Old Mar 05, 2014, 06:02 AM
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Thanks for the information!

If I understand well, there are no devices available (yet???) that can be compared with the functionality of the counterparts from the full size glider world. That confirms my findings after weeks of Googling.

As a newcomer in the world of RC gliding with some full size soaring experience, I am disappointed to see that the instrument support is limited to the simple height vario's with maybe TE compensation probes. It's a pity that you are not offering your solution as a product.

RC community seems to be able to scale build every part of an airplane in incredible detail except the necessary flight instruments... Why is that?
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Old Mar 05, 2014, 06:13 AM
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Thus, the missing instruments that would improve the (cross country) soaring experience would be:
  1. A reliable calibrated airspeed sensor
  2. A netto variometer with option to switch to the TE or to the Relative Netto Modus.
  3. Speed to fly advice depending on the current flight phase
  4. ...???

In order to do this, we should be able to measure the polar of the aircraft in a given configuration. (There was a French or Belgian group who are performing this kind of measurements. I have to find their URL again.)
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Old Mar 05, 2014, 06:27 AM
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Quote:
Originally Posted by GliderFan View Post
(There was a French or Belgian group who are performing this kind of measurements. I have to find their URL again.)
Hi GliderFan,

I think that you are looking for this site:
http://www.xerivision.com/index.html

Check also this interesting document:
Which CL are you really flying?

And the missing instruments are coming soon. I will start a new thread about what I am building.

Best regards,
Sinan
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Old Mar 05, 2014, 06:59 AM
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@Papa Hotel,

Yes, that's where I was looking for. I have done so much browsing about this subject the last weeks that i have lost the track a little bit. Thanks!

Do i understand well that you know other suppliers of relevant instruments? Why don't you let us know about it?
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