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  #1  
Old 02-15-2011, 01:22 PM
pierre smith's Avatar
pierre smith pierre smith is offline
 
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Default Say, Dynon...or anyone knowledgable..

I forgot to press "Full" (on my D-120) after filling up today and was climbing out when I remembered and THEN pushed the full button, after 5 minutes or so of flight. Obviously, I had less fuel than it indicated but I discovered after landing that I can add or subtract fuel with the menu use.

The question I have is not covered in the manual....The fuel transducer counts gallons flowing/fuel use, while the fuel gauges sense fuel levels and mine are spot on. If the fuel falls low enough for the floats to see the quantity (they only show 22 gallons per side because of dihedral), say 15 gallons per side, but the transducer has only counted 25 gallons used, instead of 30, (because of an erronious "add fuel" entry by me), will the fuel level senders trump the transducer's calculations and correct the indication of fuel remaining to correctly read 30, instead of 35? The -10's hold 30 per side.

Thanks,
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  #2  
Old 02-15-2011, 01:24 PM
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Radomir Radomir is offline
 
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Default

IIRC they're independent of each other.. so they won't be correcting each other.. (you don't want that, really). The way it works now is good for a cross-check as either of the two can start showing incorrect values.
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  #3  
Old 02-15-2011, 03:24 PM
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Default

What he said..totally independent systems.
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  #4  
Old 02-16-2011, 05:33 AM
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pierre smith pierre smith is offline
 
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Default Thanks guys, but.....

...I felt that in the interest of safety, if the transducer is lying and you think you have more fuel than the reality of the situation, that the tank gauges would be the ones to follow, or better yet, override the transducers values.

Best bet would be to land, fill up and push the "Full" button.

Thanks again,
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Pierre Smith
RV-10, 510 TT
RV6A (Sojourner) 180 HP, Catto 3 Bl (502Hrs), gone...and already missed
Air Tractor AT 502B PT 6-15 Sold
Air Tractor 402 PT-6-20 Sold
EAA Flight Advisor/CFI/Tech Counselor
Louisville, Ga

It's never skill or craftsmanship that completes airplanes, it's the will to do so,
Patrick Kenny, EAA 275132


Dues gladly paid!
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  #5  
Old 02-16-2011, 06:31 AM
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N941WR N941WR is offline
 
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Default

Pierre,

You can set the Dynon to reset the amount in the tanks when you add fuel. That way you don't have to hit the "full" button.
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  #6  
Old 02-16-2011, 07:55 AM
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pierre smith pierre smith is offline
 
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Default How is that possible?

....because the floats reach their upper limit of travel when there's 22 gallons per side. How does the Dynon know when you add 8 more gallons per side without pushing the "full" button, since the floats don't move any more than 22 gallons?

Thanks,
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RV-10, 510 TT
RV6A (Sojourner) 180 HP, Catto 3 Bl (502Hrs), gone...and already missed
Air Tractor AT 502B PT 6-15 Sold
Air Tractor 402 PT-6-20 Sold
EAA Flight Advisor/CFI/Tech Counselor
Louisville, Ga

It's never skill or craftsmanship that completes airplanes, it's the will to do so,
Patrick Kenny, EAA 275132


Dues gladly paid!
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  #7  
Old 02-16-2011, 08:29 AM
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Default

The Dynon fuel computer always shows gallons remaining. When you press FULL, it just goes to the value you have configured for full and starts deducting from that.

If you forget to press FULL after getting fuel, the computer will show you have less fuel than you really do. All you need to do is go into the fuel add menu and tell it how many gallons you added and presto, your computer is correct again.

This works even if you have flown some time after adding the fuel.

All of this is totally independant of the fuel level indicators...

I have the auto fuel added trigger set on mine but it works sometimes and other times it does not. I have the capacitive senders and they are slow to respond when you first power them up and I think that has something to do with this working or not.
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Check out my RV-10 builder's BLOG
RV-10, #41942, N?????, Project Sold
---------------------------------------------------------------------
RV-7/TU, #72823, N159SB
Lyc. O-360 carbed, HARTZELL BA CS Prop, Dual P-MAGs, Dual Garmin G3X Touch
Track N159SB (KK4LIF)
Like EAA Chapter 1494 on Facebook
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