VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #1  
Old 07-03-2017, 03:15 PM
DonFromTX's Avatar
DonFromTX DonFromTX is offline
 
Join Date: Oct 2010
Location: La Feria Texas
Posts: 3,518
Default Moeller Float Gage Accuracy

My newly purchased 12 has the fuselage fuel tank with the Moeller gage. As delivered, it shows about 3/4 full, but it is actually near 1/2 full. I hear that they are so far off as to be useless, but I want to re-label it or something to be more accurate. Has anyone else had this trouble and made a solution?
__________________
AF1 (was RV12) EAB Air Force One, SN 461, N461DG VIKING/HONDA ENGINE POWERED! AND N756TS ROTAX POWERED
A&P, PP-SEL, Pathological Flier, EAA Technical Counselor
EAA Chapter 595 President,http://www.595.eaachapter.org/index.htm
Retired US Army Officer
http://www.mykitlog.com/users/index....X&project=1903
Reply With Quote
  #2  
Old 07-03-2017, 03:29 PM
tomkk's Avatar
tomkk tomkk is offline
 
Join Date: Apr 2014
Location: Port Orange, Fl
Posts: 626
Default

I, frankly, pretty much ignore it. Although it goes against every "Thou shalt never rely on your gas gauge" instruction I've ever had, My Skyview (measured) fuel quantity is VERY accurate and I've come to believe. No so with the Moeller.
__________________
Tom
Port Orange, Fl
RV-12 N121TK ELSA #120845
First flight 06/10/2015
Reply With Quote
  #3  
Old 07-03-2017, 03:32 PM
Top Cat Top Cat is offline
 
Join Date: May 2014
Location: Fort Mill SC
Posts: 291
Default

Don
When I first got my SLSA the Moeller gauge was pretty accurate as compared to expected fuel burn and fuel loaded. After three years I've gotten my k-factor down so as the fuel burn I've experienced is reflected on the SkyView EMS and backed up by the Moeller gauge.

That said over this past year my Moeller gauge began to stick or not move. Possibly due to my mechanic removing the tank a couple of times for annual and installing mods.
Lately the Moeller will stick after adding fuel until I repeatedly tap the gauge to make it move to where it should be. In flight the gauge won't move until a full tank has burned down to about 15 gallons then it will move down accurately reflecting tank level.

The RV-12 fuel system has been frustrating in my experience. I'd much prefer to have fixed wings and a fuel tank in each say 12 to 15 gallons with no cabin tank.
Ive managed the fuel with a combination of eyeball, fuel loaded v fuel used , tapping the Moeller, and now fine tuning the k-factor.

Last edited by Top Cat : 07-03-2017 at 04:29 PM.
Reply With Quote
  #4  
Old 07-03-2017, 03:49 PM
DaleB's Avatar
DaleB DaleB is offline
 
Join Date: Sep 2012
Location: Omaha, NE (KMLE)
Posts: 1,607
Default

I have three fuel gauges...
  1. The float gauge. Displays on the D-180. Very accurate, but only when the fuel level drops down to 14 gallons or less, otherwise it's pegged at full. I use it as my primary indication when I'm flying, after the first hour or two.
  2. The D180 fuel totalizer. Fairly accurate, but the more fuel you burn the further off you geet. Fortunately its little white lies tell me I have a little less fuel than I really do. It's close enough that really, if I have to worry about HOW accurate it is I know I'm way too close to empty. And, I don't think it's just the K factor. Sometimes the cruise fuel burn shows what I expect, sometimes it's one or more GPH higher than I know I'm probably burning. I don't know what's up with that.
  3. The Moeller gauge. I think it's about right at the bottom end, but all I really use it for is a rough idea of how far I have to go when dumping gas into the tank. It's a nice little double check during pre-flight, but I don't really count on it for any sort of accuracy.

Point is, all three tell me the same thing under all but completely full tank conditions. If I see one out of whack, I know it's time to investigate.

Mine originally had a sight glass too. It's gone. It leaked like a sieve, and was opaque enough to be useless anyway.
__________________
Dale
Omaha, NE
RV-12 # 222 N980KM "Screamin' Canary" (bought flying)
Fisher Celebrity (under construction)
Previous RV-7 project (sold)
-=VAF=- 2017 dues paid
Reply With Quote
  #5  
Old 07-03-2017, 03:56 PM
tomkk's Avatar
tomkk tomkk is offline
 
Join Date: Apr 2014
Location: Port Orange, Fl
Posts: 626
Default

Quote:
Originally Posted by Top Cat View Post
Don
The RV-12 fuel system has been frustrating in my experience. I'd much prefer to have fixed wings and a fuel tank in each say 12 to 15 gallons with no cabin tank.
I've not had any frustrations with the fuel system - it's worked as advertised without any problems. Having said that, like you, I'd prefer to have the fuel in the wings rather than behind my passenger ...
__________________
Tom
Port Orange, Fl
RV-12 N121TK ELSA #120845
First flight 06/10/2015
Reply With Quote
  #6  
Old 07-03-2017, 04:16 PM
Piper J3's Avatar
Piper J3 Piper J3 is offline
 
Join Date: Nov 2014
Location: Hinckley, Ohio
Posts: 621
Default

I have four ways to determine fuel quantity before flight: Moeller, sight-gage on side of tank, Dynon D-180, and dip stick.

The only one I completely trust is the dip stick – very accurate / never lies…
__________________
-
Jim Stricker
Hinckley, Ohio
PPL - 1970
80 hrs Flying Aeronca Chief 11AC
1130 hrs Flying 46 Piper J-3 Cub
RV-12 E-LSA #120058 AWC 7/12 Bought Flying 10/2015 with 48TT - Hobbs now 261
Reply With Quote
  #7  
Old 07-03-2017, 06:17 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 6,588
Default

Quote:
Originally Posted by Top Cat View Post
In flight the gauge won't move until a full tank has burned down to about 15 gallons then it will move down accurately reflecting tank level.
Quote:
Originally Posted by DaleB View Post

Point is, all three tell me the same thing under all but completely full tank conditions.
Since the RV-12 fuel tank by design slopes upward as it moves aft, neither the float sensor for the EFIS fuel gauge or the float on the Moeller gauge are at the highest fuel level point when the tank is totally full (the fuel filling the aft portion of the tank is above the highest float levels), so neither will show any change until you have burned off 3-4 gallons of fuel (The Moeller is further aft so it will begin to show a change a little sooner than the EFIS gauge).
__________________
Any opinions expressed in this message are my own and not necessarily those of my employer.

Scott McDaniels
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
Reply With Quote
  #8  
Old 07-03-2017, 07:00 PM
DonFromTX's Avatar
DonFromTX DonFromTX is offline
 
Join Date: Oct 2010
Location: La Feria Texas
Posts: 3,518
Default

Thanks a lot guys, that is very helpful. I have wing tanks in my main RV12 largely for those reasons. The ferry pilot told me the K factor for the red cube is way off, needs a much larger number put in.
__________________
AF1 (was RV12) EAB Air Force One, SN 461, N461DG VIKING/HONDA ENGINE POWERED! AND N756TS ROTAX POWERED
A&P, PP-SEL, Pathological Flier, EAA Technical Counselor
EAA Chapter 595 President,http://www.595.eaachapter.org/index.htm
Retired US Army Officer
http://www.mykitlog.com/users/index....X&project=1903
Reply With Quote
  #9  
Old 07-03-2017, 08:01 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 6,588
Default

Quote:
Originally Posted by DonFromTX View Post
Thanks a lot guys, that is very helpful. I have wing tanks in my main RV12 largely for those reasons.
This is not a problem with the RV-12 (and not exclusive to the RV-12 either... all of the other RV models have gauges that can't read the upper 4 gallons or so because of wing dihedral). When is it that important to have a absolute gauge indication of the first 3 or 4 gallons that get used. The important thing is for accuracy at that last 3 or 4 gallons. The RV-12 tank does well with this.

A long / full span skinny tank in the wing with the dihedral tilt will be effected even worse than any of the other RV's are.
__________________
Any opinions expressed in this message are my own and not necessarily those of my employer.

Scott McDaniels
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
Reply With Quote
  #10  
Old 07-04-2017, 05:47 AM
Pat Stewart Pat Stewart is offline
 
Join Date: Jan 2005
Location: Granbury Texas
Posts: 1,068
Default

Just like the wing tanks in most RVs the first 5 gallons or so must be burned before any gauge will be effective. I found the Moeller to be pretty accurate from about ten gallons down. Once you start experimenting with K Factor the fuel burned indication will start to become more accurate but the gauge itself is no different from the Moeller. I always kept track of climb time and cruise time and never took off in the 12 with less than 10 gallons. My 7A with duel Skyviews will only show 15 gallons when full and will not move until it is down to that level but the fuel flow is pretty accurate.
__________________
Built, RV 8, RV8A, RV 10, RV12, Purchased RV7A
Restored J3Cub and PA28R180
Pecan Plantation
Eagles Nest Mentor

Last edited by Pat Stewart : 07-04-2017 at 06:32 AM.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 08:41 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.