Average useful load of a Mooney

[amillet]

@kortopates posted this in 2020:

AVGAS <> 100LL,  Avgas weighed ~6 lbs/Gal, but Avgas is no longer and 100LL weighs less and why modern Mooney POH's now say to use 5.82lbs/gal for 100LL

But be careful, Mooney still uses or assumes the AVGAS weight in their documentation including the TCDS and POH when specifying unusable fuel weight. They only clarify with a note that says use 5.83 Lb/Gal with 100LL but otherwise pretty much uses or assumes 6lb/gal when they give weight numbers for fuel in both POH & TCDS.

Of course such details are only of importance to owners/pilots wanting to get as much legal useful load as possible out of their airframes. 

 

 

[Igor_U]

1967 M20F with some J mods (windshield, gaps, windows  etc…):

2740 MTOW, just short of 1690 empty weight and 1050+ useful load.  Payload is 666lb with 64 gal fuel. 

[larrynimmo]

My 1981 M20J with updated electronics (but old heavy Century 41 AP) have 917.6# useful load.

it is my expectation, if I were to weigh the plane I would get up to about 930# of useful load, as lots of the upgrades never got calculated.

[ArtVandelay]

26 minutes ago, JohnZ said:

The scales don’t lie though. 

They do if the AP didn’t weigh it correctly. And most don’t.

currently 999lbs, will gain about 15+lbs with next avionics upgrade.

[Ragsf15e]

11 hours ago, amillet said:

@kortopates posted this in 2020:

AVGAS <> 100LL,  Avgas weighed ~6 lbs/Gal, but Avgas is no longer and 100LL weighs less and why modern Mooney POH's now say to use 5.82lbs/gal for 100LL

But be careful, Mooney still uses or assumes the AVGAS weight in their documentation including the TCDS and POH when specifying unusable fuel weight. They only clarify with a note that says use 5.83 Lb/Gal with 100LL but otherwise pretty much uses or assumes 6lb/gal when they give weight numbers for fuel in both POH & TCDS.

Of course such details are only of importance to owners/pilots wanting to get as much legal useful load as possible out of their airframes. 

 

 

Took me a while to find a good resource documenting only 100ll, not “avgas”, but I finally found an AOPA page showing that it weighs 5.56lbs/gallon at 40c (104f) to 6.3lbs/gal at -40c (-40f).  Ill stick with 6lbs/gal for my math, but it appears 5.8 might be ok too.

[Hank]

26 minutes ago, Ragsf15e said:

Took me a while to find a good resource documenting only 100ll, not “avgas”, but I finally found an AOPA page showing that it weighs 5.56lbs/gallon at 40c (104f) to 6.3lbs/gal at -40c (-40f).  Ill stick with 6lbs/gal for my math, but it appears 5.8 might be ok too.

I operate in the upper half of that temperature range, so definitely less than 6 lb/gal. But it's easier to do in my head . . .

[MikeOH]

Let’s see, 0.2 lb times 64 gal equals 12.8 lbs.

How accurate is your useful load number??

This is in the measure with a micrometer cut with an axe category, IMHO.

[carusoam]

M20R POH uses 5.82LBs/g for 100LL…

-a-

[Hank]

1 hour ago, MikeOH said:

Let’s see, 0.2 lb times 64 gal equals 12.8 lbs.

How accurate is your useful load number??

This is in the measure with a micrometer cut with an axe category, IMHO.

You left out "mark with chalk"! But the sentiment is accurate.

For me, 52 gal x 0.2 lb/gal "savings" = 10.4 lb, or the hatrack contents.

For those with 130 gal tanks, it's 26 lb, or enough to notice. That's almost 30 minutes fuel for me.

But some people enjoy splitting hairs . . . .