Fuel Tabs

[StinkBug]

I did all my PPL training in an Archer that had tabs in the fuel fillers which made it really easy to do a partial fill up for short trips, or if you needed the weight. My C of course does not have these and I'm curious if anyone has come up with something similar. At my home field I get fueled by the truck, often before I even arrive, so being able to say "fill it to the tabs" is quite convenient. Right now my only options are "fill it" or "Put X gallons in _____ tank" which would require me to know how much is already in it to end up at the total amount I want. Easy enough for me to measure when I'm there, but a little more difficult when I'm making the fuel order from home before heading to the airport.

[Hank]

There's nothing that I know of, Stinky. I rarely do less than a fill up; when necessary, though, I dip the tank and fill to my desired level. Had to do that once with a fuel truck, and I monitored his fill and did a dip to confirm before he changed tanks or left. It's a much easier process with self-serve fuel, though.

[gsxrpilot]

The Mooney problem of leaky tanks and the fact that I own the airplane and am the only one ever flying it means I keep the tanks topped off.  I've never been in a situation where I needed to leave fuel behind. I'm sure there will be such a situation at some point, but would expect it to be rare. So keeping the tanks full keeps the sealant from drying out/cracking and ensures I'm always ready to go fly :-)

[omega708]

+1 on dipping the tank and then noting how many gallons should be added to each side.  I've only had to do it a handful of times when I was operating near gross weight in a high density altitude conditions.

[mooniac15u]

I did all my PPL training in an Archer that had tabs in the fuel fillers which made it really easy to do a partial fill up for short trips, or if you needed the weight. My C of course does not have these and I'm curious if anyone has come up with something similar. At my home field I get fueled by the truck, often before I even arrive, so being able to say "fill it to the tabs" is quite convenient. Right now my only options are "fill it" or "Put X gallons in _____ tank" which would require me to know how much is already in it to end up at the total amount I want. Easy enough for me to measure when I'm there, but a little more difficult when I'm making the fuel order from home before heading to the airport.

 

You could dip your tanks after each flight and write down how much is remaining in each tank.  Then when you call in your fuel order you know how much to request in each tank.

[ArtVandelay]

My J has tabs from the factory, maybe you could retrofit them?

[StinkBug]

You could dip your tanks after each flight and write down how much is remaining in each tank.  Then when you call in your fuel order you know how much to request in each tank.

 

So far this seems to be the only solution, but probably not one that I'll actually adhere to. I generally dip the tanks after any longer flights just to keep an eye on fuel burn, but don't write it down. I also rarely do it after a shorter training flight or burger run. My C has enough useful load that I doubt this will be a real issue very often, but I'm sure it will come up at some point. 

 

I am thinking about making a couple little aluminum pieces that hang in the filler neck with tabs on them, just so I can tell the fuel guy to fill to the tabs and not have to measure before, during and after. I'll still need to be there to pull the caps and drop the tabs into place though.

[flyboy0681]

I was under the impression that all M20's have the triangular tab which is the 25 gallon fill line.

[StinkBug]

If mine had that tab it would be a little useless since they are 26 gallon tanks

[Browncbr1]

I read somewhere that mooney put out a retrofit kit or SB on the tank tabs. Problem is that they don't seem very intuitive. Somewhere on the forum I saw someone noted that on 32gal tanks, the bottom of the hole in the tab is 25gal usable... I think he said the tip of the tab is 5 or 7 gal less?? I can't remember. Just fill them up!!

[Flymac]

As I continue to try and learn every detail and history of my new 78J I'm a but perplexed on the fuel tab/labels/bladders we have in the plane.  Traced back in 1996 the logbook entry for O&N bladders install, notes Config 2, 60 Gal usable...our fuel selector has a sticker on it that states 30 Gal by the left and right tank selection, those match.  Theres sticker on each cap which state 32 usable Gal, which does not match.

What is confusing me most is we still have the metal fuel tabs in the tanks and they are not the factory 25 Gal, but stamped as 20 Gal, which doesnt make any sense to me?  If I fill exactly to the tab, then see how many gallons it is to fill to the top, its ~8 gallons, exactly what the stock 25 Gal would be, ie 25+8=33 Gal that should be in each tank roughly, 

If it were truly 20 Gal now that someone replaced the tabs, 20+20 = 40, then fill from tabs to top 8+8 = 16 thats 56 gallons total, not 60.

maybe I'm missing something?

[dlthig]

IMO, for the near term, I'd figure out exactly what the tabs represented. You could drain the tanks and then fill them with known quantities and write down what you've got at the tabs and full. After you've satisfied the safety/planning aspect you could move on to ensuring that you are in compliance with the STC. I'm not familiar with the STC and don't know what placards are required, but I'd assume that some congruency is required inside and out. Theoretically, your IA should be able to take care of this during the annual.

[Yetti]

A self calibrated fuel stick is the best.  I keep making mine.  sharpie and a paint stirrer.  my 75 F has tabs  You have to use a flashlight but there is a line and an arrow that shows the 25 gallon mark.   Doubt a ramper would see that and just fill to the bottom of the tabs which would not be 25 gallons.

 

[Marauder]

I think the previous owner found out that he can't get the full 64 gallons useable that O&N claimed. I found the same on the 54 system. I would take the suggestion above and drain the tanks and measure it for yourself.

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[Robert C.]

Can a fuel totalizer be retrofitted? 

When I shut the aircraft down the last thing I do is record the TIS and Fuel before turning off the Master. Makes it easy to call in the fuel order before leaving home for the next flight.

[carusoam]

1) The POH has an amazing amount of detail regarding fuel level, placards and how to get accurate fuel information.

2) Since there is a retrofit by adding the bladders, you get a new document to add to the POH.  That is the STC.

3) Since somebody other than the factory installed the new hardware, you might get a variation based on the quality of the worker... There are things that go under the bladders like pieces of foam(?).

4) No matter who did the install, it is proper to verify the volume of the tanks early on in your ownership.  Might as well calibrate a stick while you are doing it, or consider the other mechanical fuel level gauges if possible...

5) Adding a FF gauge with an FT is really good too...

Best regards,

-a-

[Flymac]

Carusoam- fully agree, which is why im chasing this, im early to mooney ownership, i saw something is amiss to factory/poh, and conflicting labels and want to know my plane. And this install was done at o/n in factoryville.

No better way then to drain a tank to know for sure, which comically leads into several other threads on arguing safety of doing in flight, into containers, etc, ha...not interested in that discussion here.

On a very interesting note, i called griggs, and spoke with a Kenny? Who apparantly helped design these back in the day 20+ years ago, and maybe even did mine in 1996...when i told him about the 60 gal usable vs 54.8 or 64 and how that was never an option yet my logbook entry, the 20 gal tabs vs 25 etc, and noting i had an extra inspection cover...he almost instantly recalled waaaay back when they were trying to figure out the 64 gallon system, there was literally 3-4 mooneys out there that they played with a 60 gal setup and the extra panel before they got the 64 setup right....apparantly im one of those 3-4, perhaps mystery solved!

see the pics, can someone with 64 gal confirm they only have 4 covers correct, i believe 2 larger ones were factory.

 

[cnoe]

On 2/25/2015 at 8:01 PM, Browncbr1 said:

I read somewhere that mooney put out a retrofit kit or SB on the tank tabs. Problem is that they don't seem very intuitive. Somewhere on the forum I saw someone noted that on 32gal tanks, the bottom of the hole in the tab is 25gal usable... I think he said the tip of the tab is 5 or 7 gal less?? I can't remember. Just fill them up!!

I'm fairly certain that on my J the "tip" of the tab is the 25 gallon level. Filling to the hole gives you some quantity (?) more than 25. In fact if you take a flashlight and look closely at the tab you'll see a "down arrow" stamped on the tab itself which points to the tip and not the hole.

I've run my tanks dry in flight (on purpose) and refilled 2 gallons at a time making a custom (and quite accurate) fuel-level stick which also shows 25 gallons at the tip of the tabs.

Sometimes "just filling them up" isn't such a great idea, like when I departed Durango last Monday morning at 10 am. Density altitude was already 9,500' and with "variable winds" I needed quite a bit of runway to get off the ground and on my way. Just sayin'...

[Bryan1016]

Does anyone know how many gallons the K takes to level with flapper thing in filler neck? I rarely need 76 gallons.

That said, my factory fuel gauges are dead nuts. Never seen it before, but they prove out on fill up. Crazy, I know. Where's the guy who sells senders?

[FlySafe]

Happy New Year Mooneyspace Members.  Anyone happen to have an image of the mysterious 25 gal fuel tabs from a C model they could post?  I see them referenced in forums and my owner manual but elusive as a  Yeti in my experience.  On my 74 C, I usually just tell the line folks to fill to their 2nd index finger joint and round down to 25 gals as verified with my calibrated stick and jpi830  

Also sharing happy owner image of panel work in progress replacing the #2 kx155 with the gnc335 and the gtx335 with a 345; think I'm done for awhile.

I look forward to seeing someone's fuel tab picture. Take care.

k

[Fly Boomer]

On 2/25/2015 at 3:23 AM, StinkBug said:

Easy enough for me to measure when I'm there, but a little more difficult when I'm making the fuel order from home before heading to the airport.

I didn't read all the other suggestions, but I would stick the tanks after I put it back in the barn, and jot down the numbers each time.

[T. Peterson]

On 8/3/2016 at 8:51 PM, Bryan1016 said:

 

Does anyone know how many gallons the K takes to level with flapper thing in filler neck? I rarely need 76 gallons.

That said, my factory fuel gauges are dead nuts. Never seen it before, but they prove out on fill up. Crazy, I know. Where's the guy who sells senders?

I realize this is a 6plus year old post and it’s probably a moot point, but 36 gallons is the answer.