Fuel Gauges Correct?

[Mooney13]

Second try at posting this I'll shorten it in case the original appears...

I have a flight coming up that will be close to gross weight.. So I want to be sure I am calculating weight corretly.

Has anyone created a fuel dipstick to fugure levels on an M20J (mine is '78, but maybe they are all the same)

Also, as soon as the outer portion of my tanks are empty, my gauge reads "1/2"...I thought this was an error, but looking in the filler hole towards the inner portion of the tanks, there is certainly a good amount of fuel in there. I am just not certain if it "half of the tank" or not ??........Does anyone know if this is correct?  (I guess that dipstick would not do me any good if this is the case once my tank was below 1/2 )

This would mean that right at the point the outer portion is empty, you have 1/2 a tank...and my gauge would be correct..

I just have a hard time trusting an airplane gauge from 1978

Thanks for any advice / help as always

[Cruiser]

If your gauge says ½ tank, can you put 16 gallons in it? I assume you have 32 gallon tanks. I use the JPI700 FF for my calculations but if you need to have a "rough" idea, just monitor the gauge and fill to full at different levels to compare. That is about as close as I would rely on the gauges anyway.

[FlyingAggie]

I was taught fuel gauges only have to be accurate at two positions: empty and full.  Using them for anything in between is pure conjecture.

Alan

[piperpainter]

I use a stick I got from the store. I had my tank empty after changing the fuel sump valve and I put in 5 gallons measured. Then every 2 gallons till I was to about 15 ( I have 26G tanks) Once I got to 15 I measured every gallon. Yes it took me a bit longer at the fuel pump but i know how much I have in my tanks now! The stick is really nice to. I even marked the lower part red to show its low for flight. Cost was about $.94!

[N207LS]

I created a similar stick with a home depot paint stick (free).  Took a dry tank (after the sealant repair a few years ago) and added 5 gal, and then 2 gal at a time after that until full.  Then went and got another 10-12 paint sticks and just marked them with the same lines.  I now have the EI Fuel Flow which is even more accurate (although it took resetting the K factor several flights to get within .2 gal of actual after a long flight), but I still check with the sticks each time (out of redundancy) before I fly.  I have new sending units (done at my strip and reseal) and actual gauges are still not much better than semi accurate.  I really use the EI and the sticks as my "primary gauge" for heavy loads and accurate planning.

Aaron

[Flybeech21]

Quote: FlyingAggie

I was taught fuel gauges only have to be accurate at two positions: empty and full.  Using them for anything in between is pure conjecture.

Alan

[Mooney13]

Thanks for all the advice / opinions. I am certainly going to work on my own fuel dipstick for the future. It's tough to start off because I see the fuel in the inner part of the tank, yet my dipstick would read "no gas" if I put it in the filler hole. I guess I will need to empty my tanks completely to have a base to start with...That way i will know how much is in the inner part of the tanks...Doing that in flight does not sound like a good time   

I hear of people running a tank dry, but have no experience doing it and would hope that  it would strt right up again..something  I would rather do alone in the plane....

Thanks again!

[Guest Anonymous]

Quote: Mooney13

...    It's tough to start off because I see the fuel in the inner part of the tank, yet my dipstick would read "no gas" if I put it in the filler hole. I guess I will need to empty my tanks completely to have a base to start with... ...

Thanks again!

[Mooney13]

Yes, with my tank directly below the filler cap empty, as I look inward there is at least 5 gallons,looks more like 10+. I was told there is approximetely 1/3 tank (12 gallons). However, I will still need to empty them and start from zero at the pumps to feel comfortable moving forward..

thanks

 

[piperpainter]

I've run a tank dry before on purpose. I was high above the airport waiting and even doing knowing a sputter was coming was freaky. I switched quickly to the other (almost full) but I still didn't like it. And I'm amazed the Mooney POH says to do that normally!

[j3gq]

Before you run your tanks dry again, check fuel pump make and model. Somewhere in the maintenance manual there is a note indicating that some pumps may not like it.

[j3gq]

Quote: Flybeech21