Usable Fuel

[Matthew P]

Searched but didn't find that this was posted previously....1966 M20E, what is the un-usable fuel, can't find it anywhere in the manual and haven't flown an aircraft yet that had 100% usable?

 

TIA,

 

Matt

[McMooney]

my 1974 manual states 52 gallons "useable"

[outermarker]

look here for useable fuel for your model

Microsoft Word - 2A3.doc (accelerationtech

 

[OR75]

34 minutes ago, Matthew P said:

Searched but didn't find that this was posted previously....1966 M20E, what is the un-usable fuel, can't find it anywhere in the manual and haven't flown an aircraft yet that had 100% usable?

 

TIA,

 

Matt

should be in the manual 

one of the reasons (probably others), it is not 100% usable is because the fuel pick up is not the lowest point to avoid feeding the engine contaminants. the fuel drain is the lowest point.  

[Matthew P]

59 minutes ago, outermarker said:

look here for useable fuel for your model

Microsoft Word - 2A3.doc (accelerationtech

 

Thanks, so if I understand NOTE 1, in regards to fuel capacity, it is already accounted for so there is 26 gallons of usable fuel in each tank

[Utah20Gflyer]

I have a usable fuel capacity of 52 gallons.  If remember correctly there is 1.25 gallons unusable per side.  So total capacity would be 54.5 gallons with 52 usable.  I don’t know why some manufacturers use total instead of usable to describe fuel capacity, just seems like a bad idea.  

[Matthew P]

4 hours ago, Utah20Gflyer said:

I have a usable fuel capacity of 52 gallons.  If remember correctly there is 1.25 gallons unusable per side.  So total capacity would be 54.5 gallons with 52 usable.  I don’t know why some manufacturers use total instead of usable to describe fuel capacity, just seems like a bad 

That's what I'm gathering, coming over from a Piper...which states total capacity then usable quantity...

[Hank]

7 hours ago, Matthew P said:

Thanks, so if I understand NOTE 1, in regards to fuel capacity, it is already accounted for so there is 26 gallons of usable fuel in each tank

My C also has 52 gallon capacity. Looking at the TCDS, which I can't find right now, has the unusable amount. When myntanks were revealed, they were filled to the caps and the receipt showed 52.2 gallons. So almost al of our fuel is usable. 

Thenp biggest difference between my C and your E is the engine--yours comes with fuel injection and adjustable cowl flaps, and associated changes. Cowl flaps on the C were riveted in place beginning in 1969.

Enjoy flying your "new" Mooney!

[Matthew P]

1 hour ago, Hank said:

My C also has 52 gallon capacity. Looking at the TCDS, which I can't find right now, has the unusable amount. When myntanks were revealed, they were filled to the caps and the receipt showed 52.2 gallons. So almost al of our fuel is usable. 

Thenp biggest difference between my C and your E is the engine--yours comes with fuel injection and adjustable cowl flaps, and associated changes. Cowl flaps on the C were riveted in place beginning in 1969.

Enjoy flying your "new" Mooney!

Thanks Hank

[Shadrach]

It seems you are looking for useable and unusable. The TCDS gives useable fuel in volume and unusable in mass...  It may seem odd but it's practical as useable fuel is measured in gallons at the pump, but unusable fuel is used for W&B data, so giving it in weight is more practical. 

The answer to your question(s) by volume and using round numbers is 26gals useable and .28 gals unusable per side.

[Hank]

1 hour ago, Shadrach said:

It seems you are looking for useable and unusable. The TCDS gives useable fuel in volume and unusable in mass...  It may seem odd but it's practical as useable fuel is measured in gallons at the pump, but unusable fuel is used for W&B data, so giving it in weight is more practical. 

The answer to your question(s) by volume and using round numbers is 26gals useable and 1.25gals unusable per side.

Per the TCDS, both my own C and OP's E have 3.4 lb unusable fuel. It's in Note 1 at the end of the file below.

Mooney TCDS 2A3 Rev 52 dtd 9DEC10.pdf

[Shadrach]

20 minutes ago, Hank said:

Per the TCDS, both my own C and OP's E have 3.4 lb unusable fuel. It's in Note 1 at the end of the file below.

Mooney TCDS 2A3 Rev 52 dtd 9DEC10.pdf 214.61 kB · 0 downloads

Yup! I edited it to reflect what it says rather than what I read.  At quick glance I misread the 15lbs for the mid bodies as being for the short bodies.

[AndreiC]

Anyone knows how this changes with addition of bladders? My fuel tanks are placarded “27.2 gallons” but is this the useable amount?

[Shadrach]

55 minutes ago, AndreiC said:

Anyone knows how this changes with addition of bladders? My fuel tanks are placarded “27.2 gallons” but is this the useable amount?

Does your Owners Manual have an AFM supplement?  I would think it would be covered there. 

[jamesm]

so am I reading /understanding Note 1  correctly for the Short Body C Models. 15 lbs/6lbs/gal = 2.5 Gal total ?  or 1.25 Gal per side?

If I recall correctly ... there was Mooney an earlier model C landed in at my home airport RNT (Renton, WA) after having icing  or a shitty PNW weather encounter. I believe he declared an emergency  the engine had died on him on short final as he lowered the engine engine came back to life giving him enough to make it to the runway. As I recall he had landed with 2.5 gallons a board or may have been dry either way I would not  want to find myself in this situation.

I have been way too chicken to try it lowest I ever gotten it ~ 6 gal on one side  and I was near airport with open area.

Thanks

James '67C

[Shadrach]

10 minutes ago, jamesm said:

so am I reading /understanding Note 1  correctly for the Short Body C Models. 15 lbs/6lbs/gal = 2.5 Gal total ?  or 1.25 Gal per side?

If I recall correctly ... there was Mooney an earlier model C landed in at my home airport RNT (Renton, WA) after having icing  or a shitty PNW weather encounter. I believe he declared an emergency  the engine had died on him on short final as he lowered the engine engine came back to life giving him enough to make it to the runway. As I recall he had landed with 2.5 gallons a board or may have been dry either way I would not  want to find myself in this situation.

I have been way too chicken to try it lowest I ever gotten it ~ 6 gal on one side  and I was near airport with open area.

Thanks

James '67C

You’re reading it wrong. It 3.4lbs for the C model and 15lbs for F’s and Js.

[M20F]

I heard of an F that once took 65.5 gallons after a flight.  

[RoundTwo]

45 minutes ago, M20F said:

I heard of an F that once took 65.5 gallons after a flight.  

Sounds like the pump meter might have been off a bit. 

[ArtVandelay]

Sounds like the pump meter might have been off a bit. 

The tanks actually hold a little more than spec, mine measured 65.5 when doing my JPI calibration.

[Hank]

19 minutes ago, ArtVandelay said:

The tanks actually hold a little more than spec, mine measured 65.5 when doing my JPI calibration.

When I had my tanks resealed, they held 52.2 gallons, and fuel ran down with wings when I opened the caps during preflight. 

But if you haven't checked yours, you don't really know.

[RoundTwo]

5 hours ago, ArtVandelay said:

The tanks actually hold a little more than spec, mine measured 65.5 when doing my JPI calibration.

That’s reasonable, but putting in 65.5 AFTER a flight?

[ArtVandelay]

That’s reasonable, but putting in 65.5 AFTER a flight?

Good point, maybe he had the long range tanks?

[skydvrboy]

I have ran both sides of my F dry in flight (different flights of course.  One side took 33.0 gallons and the other took 33.2, so it is possible though obviously not advisable!

[M20F]

1 hour ago, ArtVandelay said:

Good point, maybe he had the long range tanks?

Could be her or she was an idiot, just a story I “heard”. 

[bcg]

I have ran both sides of my F dry in flight (different flights of course.  One side took 33.0 gallons and the other took 33.2, so it is possible though obviously not advisable!

I've done the same with my 63 C which is supposed to have a total of 24.4 with 24 usable per side. I put 24.4 in one side and 24.5 in the other.

Sent from my Pixel 6a using Tapatalk