|Sep 04, 2013, 06:26 PM|
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.
|Sep 05, 2013, 05:17 AM|
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,
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.
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 !
|Sep 05, 2013, 10:33 AM|
"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."
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)
|Sep 05, 2013, 02:51 PM|
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.
|Sep 05, 2013, 03:50 PM|
|Sep 06, 2013, 04:27 AM|
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:
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.
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