Fuel "dip stick"

[Pooldoc]

Hi,

I'm a new member and new owner of a 1975 M20F. I love the plane and am just getting use to it after my complex checkout.

Does anyone know of where I can get a "Dip stick" for directly measuring the amount of fuel in each tank of an M20F? If someone has one, maybe I could just get the measurements and make it with a thin piece of PVC or wood.

Thanks,

Larry

[carusoam]

Welcome aboard PD...

There are a few existing discussions regarding your request.

You may be able to access by going to the search box at the top and click the forums button...

You may find the phrase 'stick the tank’ helpful...

Fun stuff ahead,

-a-

[DaV8or]

You have to make your own. Nobody sells one. I have a free wooden yardstick that I put marks on when I had my tank empty once. I filled it one gallon at a time. I always intended to transfer my measurements and make a more official stick, but haven't got around to it yet.

 

I will say that when I do, it will be made of raw unfinished wood. The reason being, the fuel shows really well on that. It's super obvious. If it were metal, plastic, or a lacquered wood, it might be tough to tell where the gas level is. Maybe somebody else can chime in.

[chrisk]

I had a few large paint sticks from Lowes or Home Depot.  I then ran a tank dry, and filled it 5 gallons at a time, and drew lines.  I have 37 gallon tanks, so a gallon at a time would take forever.  I also have anti-siphon plates, and these need to be pushed out of the way to get a clean line on the dip stick.

[Hank]

This is mine, made from Sportys universal stick.

[TTaylor]

Welcome to the 75F club! I used 3/4" diameter gray PVC tubing. Notched it to make markings. I have a spreadsheet I can send when I get back to my computer. Tim

[Andy95W]

If you have 52 gal. tanks, the following works: (cut and pasted from a previous posting)

Fuel tank stick markings

My archive has a post I salted away from Rob Hoyle, who graciously provided the measurements and markings from the dipstick he (and the prior owner) calibrated for his 1964 C model, and which seems to be VERY well calibrated to my '66 E model. I stick the tanks before filling to see what I expect, and compare the result to my fuel totalizer and the numbers off the gas pump- the stick is usually right on the money.

Get a wooden paint stir stick from Home Depot or similar, then mark it with a finepoint sharpie. The fuel soaks into the wood just enough to make it easy to see the level when you pull it out, but is dry enough to be easy to measure the next tank by the time you've walked over and pulled the cap.

Inches - Gallons

9 - 26

8 1/2 - 25

8 - 24

7 5/8 - 23

7 1/4 - 22

6 7/8 - 21

6 1/2 - 20

6 1/16 - 19

5 3/4 - 18

5 7/16 - 17

5 1/16 - 16

4 13/16 - 15

4 1/2 - 14

4 1/8 - 13

3 7/8 - 12

3 1/2 - 11

3 1/16 - 10

2 11/16 - 9

2 3/8 - 8

2 1/8 - 7

1 3/4 - 6

[Lood]

I alos bought a Fuel Hawk universal dipstick from Spruce. Drain the tanks completely and then start adding fuel at 5 gal intervals. The dipstick comes with a chart on which you plot the different fuel levels. This way, you will have a dipstick that is specific to your airplane and trust me, these are extremely accurate!

[Pooldoc]

Thanks to everyone for your help. I would appreciate those measurements when you get back to your computer, Tim.

I already did a little tank experiment when the tank was last filled. I didn't run it dry, but the gauge said empty and looking in the tank , I could see the bottom from directly under the fill cap and the gauge float resting on the bottom. The odd thing was, when filling, it only took 25 gallons. I have 32 gallon tanks. I assume there is approximately 5-7 gallons held on the fuselage side of the fill cap (downhill, near the drain sump), when the bottom of the tank (directly under the fill cap, where the dip stick would measure) is dry. Therefore, when the dip stick reads empty, it can really have 5-7 gallons left. Is this assumption correct?

Another question is, when filling it, what is full? I stop about 1/2" below the fuel cap flange. Is this correct to get 32 gallons?

Thanks again,

Larry

[gsxrpilot]

I used to have a dip stick that had been carefully calibrated and marked by the previous owner.  Somewhere, somehow I've misplaced it. But let me ask a different but related question.

 

Assuming gross weight, density altitude, runway length, etc. are not issues, is it best practice to keep the tanks full?  I don't have bladders so thinking of the best way to keep the tank sealant wet and prolong my leak-free tanks.  My practice has become to always top off the tanks before putting the plane back in the hanger.  That way it always sits with full tanks.

 

And finally I'll echo Larry's question.  Does fuel need to be overflowing and running down the wing to get the full 26 useable in my C?  Or is 1/2 inch below the lip full?

 

Thanks,

[Hank]

I've always thought of Full as being up to the cap. That's what I do before flights and at fuel stops. When refueling after landing, I leave 1/2" for thermal expansion so it doesn't vent onto the ground.

[aaronk25]

When did mooney start putting wing tank gauges in the wings? My j has them and they are spot on accurate

[FloridaMan]

When did mooney start putting wing tank gauges in the wings? My j has them and they are spot on accurate

 

My 67F has them as well and they are also spot-on. I'm going to go out on a limb and guess that when the previous owner had the tanks resealed at "weep-no-more" that the gauges were recommended and installed then. 

[Bob - S50]

I bought a "fuelstik master" and calibrated it for our J one gallon at a time.

 

Here's a link:

 

http://www.mypilotstore.com/MyPilotStore/sep/8868 

 

Just barely wet under the cap is 7 gallons.  The stick does not measure anything below 11 gallons.  We calibrated it from 11 to 25 gallons.  Anything between 25 and 32 gallons I fill to the tabs then use the gas pump reading to add what I need to get to what I want.

 

Bob

[chrisk]

I bought a "fuelstik master" and calibrated it for our J one gallon at a time.

 

Here's a link:

 

http://www.mypilotstore.com/MyPilotStore/sep/8868

 

Just barely wet under the cap is 7 gallons.  The stick does not measure anything below 11 gallons.  We calibrated it from 11 to 25 gallons.  Anything between 25 and 32 gallons I fill to the tabs then use the gas pump reading to add what I need to get to what I want.

 

Bob

 

Thanks for the link.  I was thinking of getting one of these, but lost the link.  It sounds like it should work well. Is it easy to calibrate?

[Lood]

Pooldoc, on my '67 F, I can actually put in 34 gal per tank, when I fill them right up to the top. In fact I always do this when refuelling before any longish flight. However, I've found that if I fill the tanks right to the top and leave the airplane outside on a hot day, the fuel will expand when the wings heat up and it will simply vent out through the overflows.

When the fuel level is such that you can actually still see it, but the dipstick just can't measure it anymore, directly below the fill cap, you are spot on with your finding. There will still be around 7 gallons of fuel in the tank.

[Bob - S50]

Thanks for the link.  I was thinking of getting one of these, but lost the link.  It sounds like it should work well. Is it easy to calibrate?

Well... depends on your definition of easy.

 

Forgot to mention the reason I got one is because I was unhappy with a piece of wood.  When we made a stick out of wood, we found that fuel would wick its way up the stick and give a falsely high reading.

 

We drained one tank until empty then added the unusable fuel.  We then started up on the other tank and taxied over to the fuel pump.  We added one gallon at a time.  Like I said, we needed 11 gallons before the fuelstik would register a reading.

 

The stick comes with universal markings.  That is, evenly spaced marks.  To use the gauge, you put it in the tank and the center portion rises out of the middle.  For each gallon that we could get a reading we wrote down the number reading.  That is supposed to be the end of it.  You are supposed to keep the chart with your readings alongside the gauge.  You take a reading and refer to the chart to see how much fuel you have. Or, from their website:

 

"Mail or email the information to info@fuelstik.com and we will mail or email you a color coded "Aircraft Specific Scale" that you can slip into the float tube. Hint; Using your smart phone, take a picture of the completed work sheet. After previewing it to make sure it is clear, email it right from your device."

 

Those universal markings are removeable.  What I did was go home and use my word processor to make some markings that correspond to the actual number of gallons.  I would type a few underscore characters followed by the number of gallons and then start a new line.  I would use the ability of the word processor to micro-adjust the spacing between lines so that my markings aligned with the proper reading on the universal piece of paper.  I then printed, cut, and placed my calibration into the fuelstik.

 

Just in case, here is a link to the manufacturer's website:

 

http://fuelstik.com/

 

Bob

[Ned Gravel]

 

 

Just in case, here is a link to the manufacturer's website:

 

http://fuelstik.com/

 

Bob

  

Be careful here.  My anti-virus software picked up the following trojan from this website:  

 

The requested URL contains malicious code that can damage your computer.

 

Infection type: JS:HideLink-A [Trj]

[M20F-1968]

I bought some thick walled plastic pipe and plan on scribing a line using a metal lathe to correspond to every 5 gallons.  Then you can either engrave by hand

or use a machinist's lettering set (with some mild heating of the metal) to engrave the numbers.  Cheap and accurate.

 

John Breda

[DXB]

If you have 52 gal. tanks, the following works: (cut and pasted from a previous posting)

Fuel tank stick markings

My archive has a post I salted away from Rob Hoyle, who graciously provided the measurements and markings from the dipstick he (and the prior owner) calibrated for his 1964 C model, and which seems to be VERY well calibrated to my '66 E model. I stick the tanks before filling to see what I expect, and compare the result to my fuel totalizer and the numbers off the gas pump- the stick is usually right on the money.

Get a wooden paint stir stick from Home Depot or similar, then mark it with a finepoint sharpie. The fuel soaks into the wood just enough to make it easy to see the level when you pull it out, but is dry enough to be easy to measure the next tank by the time you've walked over and pulled the cap.

Inches - Gallons

9 - 26

8 1/2 - 25

8 - 24

7 5/8 - 23

7 1/4 - 22

6 7/8 - 21

6 1/2 - 20

6 1/16 - 19

5 3/4 - 18

5 7/16 - 17

5 1/16 - 16

4 13/16 - 15

4 1/2 - 14

4 1/8 - 13

3 7/8 - 12

3 1/2 - 11

3 1/16 - 10

2 11/16 - 9

2 3/8 - 8

2 1/8 - 7

1 3/4 - 6

This might be a dumb noob question, but I have a '68 C with 54 gallon bladders.  Since the wing is the same, I'm wondering if these measurements would work as rough values for my tanks, underestimating slightly as an extra safety buffer given the slightly larger capacity.   Or does the configuration of the bladders change the levels significantly?    I also haven't been able to figure out what the bladders do for usable fuel quantity yet- not that the original 1968 POH even bothers to address usable fuel.  

[Hank]

Bladders change everything.

My 1970 Owners Manual says (from memory) that each tank holds 26 gallons, and some number less than 1.0 is unusable fuel, maybe 0.6 gallons?

[cnoe]

In the interest of accuracy you can plan a leg where you fly straight and level on one tank until the engine starves for fuel then switch to the fuller tank. After landing, fill in increments of your choosing (2 gallons is good) and mark the stick of your choice. Soft-wood sticks will wick up the fuel a bit as previously mentioned but you can see the markings with a small light while sticking the tank (don't drop the light). As others also said the stick is useless for gauging tanks with relatively little fuel.

I advise against doing this with individuals fearful of a sputtering engine. And don't do it at 500' AGL.

Cnoe

[carusoam]

If unsure..l

Too full = W & B challenge...

Too empty = excess distance to the airport without excess fuel to get there...

The only way to KNOW what you have comes from the POH or STC.

Or do it yourself.

Or pay a mechanic.

The summation of all the errors can be quite large when you don't Know your tanks...

Best regards,

-a-

[bonal]

Because I have bladders and have not calibrated my universal stick I only use it as a check before fueling. When I'm going to fly I hit the pumps and put in required amounts plus 1 hour. Often this fills it to the neck. One thing about Bladders you have to let them sit for a few minutes to allow the fuel to pass into the lower chambers 5 to 10 minutes at least. If you top off and come back later you will see the level has dropped a couple of inches.

[Guitarmaster]

Hi,

I'm a new member and new owner of a 1975 M20F. I love the plane and am just getting use to it after my complex checkout.

Does anyone know of where I can get a "Dip stick" for directly measuring the amount of fuel in each tank of an M20F? If someone has one, maybe I could just get the measurements and make it with a thin piece of PVC or wood.

Thanks,

Larry

Congrats on the new (to you) Mooney! I also have a '75 F. Her name is Riley. Great plane!

Welcome to Mooneyspace!