Determining Fuel Quantity

[Jim Peace]

45 minutes ago, MikeOH said:

Bottom line, if I'm down to NEEDING to know "to the gallon" then I've screwed up, BIG time!

Oh okay....................

[Shiny moose]

The cheaper way, Make an acccurate stick for your plane, you will be missing the first 6-8 gallons on your stick, buy an FS450 or other FF totalizer, spend time making sure the K factor is accurate. Stick on the ground,  totalizer enroute

[Steveolyo]

15 hours ago, carusoam said:

Ceis is nice...

But, if you don’t have an accurate FF gauge...

It is really hard to tell you have leaned the engine properly...

Goofing up the leaning procedure can easily add a gallon or two to the burn rate...

Or... if something isn’t working properly... the FF can really be wrong...

Some old schoolers like that lean til rough, then add some mixture knob twist back in....
 

One semi blocked FI... lean til rough may be burning 14gph... enriching from there will be 14+... while expecting it to be near 10gph...

With precision instruments we get choices...

Without precision instruments...we get different choices... that aren’t as good...

Going Ceis is an optimum thing to do... it requires having a Decent engine monitor to support it properly...
 

So... by the time you have an engine monitor That supports primary engine information... Have the FF instrument connected to it... backed up with the Ceis fuel level instruments... and connect it to the WAAS gps...

There is one good thing.... downloading and sending data to savvy is still free... 

Don’t run out of fuel....  Whatever works is good. If it doesn’t work, that’s bad...

Best regards,

-a-

I've never run a tank dry. I'm frankly too worried that the engine won't come back on to try it. The valve switch being where it is I have to contort to get to it, so it takes me a few seconds of contortions to get to it. 

[Steveolyo]

Does CEIS work on a bladder tank? I don't see how it can account for the last 6 gallons.

 

[DXB]

On 10/27/2020 at 1:14 PM, TTaylor said:

Sent P-message with my data for a 54 gallon bladder stick.

Yup those are the numbers that I use for the 54.8 gallon bladders in my '68 C. Probably got them from you originally and they work quite well. I did  regression based on that data to come up with some additional marks on the stick for my C

[carusoam]

4 hours ago, Steveolyo said:

I've never run a tank dry. I'm frankly too worried that the engine won't come back on to try it. The valve switch being where it is I have to contort to get to it, so it takes me a few seconds of contortions to get to it. 

Education builds confidence...

rent a Mooney CFI, get over the irrational fears....

or do this while you are on the ground... it isn’t magic... 

 

There is a tool for that... too...

When you think you have a goofy question...

Use the search function...

not only has somebody had that fear already... somebody else solved the challenge... and shared their details...

Somebody actually sells a pvc pipe t-handle to help with the sector valve challenge...

-a-

[Steveolyo]

I finally drained the right wing tank and filled it up a gallon at a time. 

I took the data and printed this stick. 

[Steveolyo]

5 hours ago, carusoam said:

Education builds confidence...

rent a Mooney CFI, get over the irrational fears....

or do this while you are on the ground... it isn’t magic... 

 

There is a tool for that... too...

When you think you have a goofy question...

Use the search function...

not only has somebody had that fear already... somebody else solved the challenge... and shared their details...

Somebody actually sells a pvc pipe t-handle to help with the sector valve challenge...

-a-

I made a pvc pipe handle, but I usually just contort. I've only flown with a mooney CFI once. I was in Florida on vacation. I live in Utah, so that's how far I had to go to find one

 

[carusoam]

There is a list of Mooney CFIIs stored on the Mooney Flyer website...

nearly every other state has at least one....   https://themooneyflyer.com/cfi.html

Florida has some good ones... that are worth seeking out...

 

Choosing the right material for the fuel stick...

Rumor has it... some woods don’t absorb enough.... and won’t let you know what the reading is after you pull it out of the tank....

 

If you can reach the fuel selector unaided....  you are probably not carrying a spare tire around your midriff...  

Great pic of the fuel stick!

Thanks for sharing the details...

Best regards,

-a-

[PhateX1337]

9 hours ago, Steveolyo said:

I finally drained the right wing tank and filled it up a gallon at a time. 

I took the data and printed this stick. 

How does it compare to TTaylor's and DXB's #s above? Also - can you share the print file for that stick? Love the idea!

[gsxrpilot]

14 hours ago, Steveolyo said:

I finally drained the right wing tank and filled it up a gallon at a time. 

Just so you remember that an empty tank on the ground if different then an empty tank in the air. If you're not going to verify by running a tank dry in cruise, then use your stick as an estimate, not as an exact reading.  

23 hours ago, Steveolyo said:

I'm frankly too worried that the engine won't come back on to try it. The valve switch being where it is I have to contort to get to it, so it takes me a few seconds of contortions to get to it. 

Get an experienced Mooney CFI to go up with you and do this. You'll feel much more confident and be a more confident pilot after you do.

[Steveolyo]

7 hours ago, PhateX1337 said:

How does it compare to TTaylor's and DXB's #s above? Also - can you share the print file for that stick? Love the idea!

The measurements I made track fairly well. There is a bit of variation, expecially from the DXB numbers which are sparse since it is only given in 2 inch increments: 2,4,6; 4 data points compared to TTaylors 12 data points and my 19 data points.

At 2 inches TTaylor and I match at 13 gallons, but then at 4 inches we differ by more than a gallon. That trend of differing a gallon or more continues until 24 gallons at 6 inches, where all three sources converge again. 

I will probably do the experiment again. It's tough to drain those tanks. I removed the drain plug to drain the tank and I probably should have had my buddy with me to help because that gas comes out very fast and fills 5 gallon cans really quick. After I filled the 5 gallon tanks, I used a 1 gallon can to measure each gallon and fill the tank. I waited about 2 - 5 minutes in between to give the tank time to settle before measuring.

I started with the gas barely covering the bottom of the visible rubber bladder tank. Assuming that is 6 gallons could be off by a bit, so I'd really like to start with 0. Then you need to consider how much of that gas is unusable.

I looked through the engine log, the airframe log and the weight and balance sheets but I can't find a mention of unusable fuel with the install in 2002 of the ON bladder tanks. I have heard on this site of a mention of 2.X gallons of unusable fuel in the bladder. 

 

 

[Steveolyo]

On 10/27/2020 at 9:42 PM, carusoam said:

That would be a cool WnB automation step! 

There are a few things you can do... when you own the hangar...

Some people store their planes jacked off the ground for long periods.... good for donut health, and tire cords...
 

Cutting holes in the concrete to allow the installation of scales would be interesting... getting data wifi’d  Out of the scales would be a nice touch...   

The heights would need to match pretty closely to allow the plane to roll on/off the scales....

Some people have Heated their hangar floors... yours could automatically do the WnB!  

 

Nothing more important than good WnB data... especially when the plane is new to you... or when it is at MGTW... or a hot day... or a high altitude departure...

Nothing like good fuel info... we/MS has lost a few planes over the years due to empty tanks...

PP thoughts only, not a CFI...

Best regards,

-a-

 

 

Heated floors would be nice. In Utah it would help 6 months out of the year. I've got more pressing things though. This time of year (October) we have spider invasions in the hangar.

 

[Steveolyo]

On 10/29/2020 at 1:13 PM, DXB said:

Yup those are the numbers that I use for the 54.8 gallon bladders in my '68 C. Probably got them from you originally and they work quite well. I did  regression based on that data to come up with some additional marks on the stick for my C

I wanted to double check the numbers I got so this time I completely emptied the bladder tank by removing the sampling valve. I then filled the bladder tank but it would only take 25.5 gallons. even that was too much because the level is right up to the rim, leaving no room to put on the gas cap.

I don't have any documentation to confirm that the capacity can or can't drain out of that wing drain.

Based on the above post, maybe @DXB would know.

Is there another 1.5 to 2 gallons still usable at a lower level in the bladder? 

 

 

[carusoam]

Expect that the top of the fuel screen is where the start of the unusable fuel begins...

Air gets drawn into the pick-up there...

The fuel drain is lower than the fuel pick-up...

And there is a tiny volume below the drain that doesn’t move...

The bladders use a different sump drain...  so verify the rest of the details... the laws of physics demand that they work in a similar fashion...

PP thoughts only, not a mechanic...

Best regards,

-a-