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Old Nov 18, 2010, 09:24 PM
Thou who know not
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USA, MI, Mason
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Pitot tube vs. GPS speed differential in OSD

Pitot tube vs. GPS speed differential in OSD.

Has anyone brought this up or do any OSD manufacturers plan on implementing it?
I was looking at a newer OSD today that offered Mah consumed vs. speed to calculate efficiency and thought about my desire to read wind speed from the OSD.
I'm sure this is doable but who will incorporate it first?
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Old Nov 18, 2010, 09:33 PM
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Quote:
Originally Posted by Po73 View Post
Pilot tube vs. GPS speed differential in OSD.

Has anyone brought this up or do any OSD manufacturers plan on implementing it?
I was looking at a newer OSD today that offered Mah consumed vs. speed to calculate efficiency and thought about my desire to read wind speed from the OSD.
I'm sure this is doable but who will incorporate it first?
Do you mean Pitot Tube?
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Old Nov 18, 2010, 09:34 PM
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Old Nov 18, 2010, 09:37 PM
Thou who know not
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Originally Posted by Tarro View Post
Do you mean Pitot Tube?
Too many hours typing broken English will get the better of ya.
LOL yes to determine speed differential in the OSD showing +2mph traveling downwind and -2mph pushing against the wind.
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Old Nov 18, 2010, 09:40 PM
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Originally Posted by mark hitchman View Post
Dosd+
Daniel did do that? Cripes, now I have to read the manual all over again.
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Old Nov 18, 2010, 09:43 PM
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Originally Posted by Po73 View Post
Daniel did do that? Cripes, now I have to read the manual all over again.
whoops, nah he didn't, just reads air speed if you have one attached, just ask him, he loves adding stuff

Mark
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Old Nov 18, 2010, 09:50 PM
Thou who know not
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Originally Posted by mark hitchman View Post
whoops, nah he didn't, just reads air speed if you have one attached, just ask him, he loves adding stuff

Mark
I'd like to have Mah consumed vs. airspeed vs. ground speed.
I don't trust a GPS reading further than I can throw it but would love the option to fly against it's readings with a few other variables thrown in with it.
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Old Nov 18, 2010, 10:02 PM
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Po73,

I think for this to be meaningful, you probably want power/distance rather than power/speed. Speed is instantaneous and if that's what you want, the current drawn rather than mAh would be more useful. So, you either want:-

(instantaneous power)/(instantaneous air speed)

or

(cumulative power)/(distance travelled)

or the above over a limited time period. Using GPS speed or distance for this is quite useless so if you want to, you'd need to integrate air speed to get "air" distance. I'm not sure if this has been tested and/or how well it would work.

Daniel
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Old Nov 18, 2010, 10:13 PM
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Originally Posted by Daniel Wee View Post
Po73,

(cumulative power)/(distance travelled)

Daniel
It would be a formula to displayed for distance travel. I think the sporting thing would be:
Display one. Mah consumed vs speed in unit of measure(take you pick of speed sensor elasped over 30 seconds?)
Display two. Airspeed differential GPS vs pitot tube + or - unit of measure

It's not a perfect method from GPS standpoint and battery/ESC/motor efficiency, but it IS an interesting tool if you understand the variables.
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Old Nov 19, 2010, 11:54 AM
Thou who know not
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Originally Posted by Po73 View Post
:
Display one. Mah consumed vs speed in unit of measure(take you pick of speed sensor elasped over 30 seconds?)
On second hand 30 elapsed average is a bit excessive, maybe somewhere in the 3-5 second range would be more fitting?
This is merely a suggestion, I obviously haven't thought anything through, I'm happy that you are at least toying with the idea.
I just thought having airspeed versus ground speed calculated output on the screen would be an awesome feature as no matter how you measure wind speed and direction it's never the same at different altitudes or over different geological features. Having this would be innovative.
I remember you saying that you would rather not add power consumption versus speed/distance as it can be rather misleading if there were some fictitious theoretical "range left" that would be displayed. I say don't worry about trying to show any kind of range based on capacity and speed, just give us a couple tools that will give the user an idea of how things are going up there like headwind/tailwind in a +/-KPH\MPH format and 200Mah/KM.
If I were doing a long range flight I would really be watching the output on both of those displays.
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