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 . . . .

[highflyer77]

Hi folks, getting this up again: I bought my M20E, a nice '64 #341 last autumn. In general, I am quite happy at all (otherwise I would have bought a other plane ;-) ), but my useful load is somewhat limited. Before the aircraft was sold to me, a new w&b was done in France: 803kgs./1.770 lbs. empty weight, empty c.g. 48,03 in. I was quite sure that they did a mistake when doing this w&b, so I did a new one here in Austria a few days ago with an Austrian A&P. Outcome was 801,6 kgs./1.767 lbs., but empty c.g. shifted foreward to 46,77 in.  Still I am wondering about the empty weight - we drained all tanks and thoroughly emptied the plane :-) ! My M20E has literally all speed mod´s available, GTN650, KX155, ASPEN 1000, Century IIB autopilot, Monroy L/R tanks. On the other side wheelen led landing light, lightweight starter, concorde battery. I am still missing about 100 lbs. of useful load ;-) !     

[ArtVandelay]

Hi folks, getting this up again: I bought my M20E, a nice '64 #341 last autumn. In general, I am quite happy at all (otherwise I would have bought a other plane ;-) ), but my useful load is somewhat limited. Before the aircraft was sold to me, a new w&b was done in France: 803kgs./1.770 lbs. empty weight, empty c.g. 48,03 in. I was quite sure that they did a mistake when doing this w&b, so I did a new one here in Austria a few days ago with an Austrian A&P. Outcome was 801,6 kgs./1.767 lbs., but empty c.g. shifted foreward to 46,77 in.  Still I am wondering about the empty weight - we drained all tanks and thoroughly emptied the plane :-) ! My M20E has literally all speed mod´s available, GTN650, KX155, ASPEN 1000, Century IIB autopilot, Monroy L/R tanks. On the other side wheelen led landing light, lightweight starter, concorde battery. I am still missing about 100 lbs. of useful load ;-) !     

Did they follow the procedure (level the plane, put seats in proper positions, etc)?

Those speed mods will add weight, so will a paint job if they don’t strip the old paint.

[highflyer77]

Everything was done properly (I was with the A&P all the time - fuel was drained completely, aircraft was levelled as ordered by the weighing instructions etc.) - therefore the CG moved foreward by more than an inch... I am just wondering what could be the "fat" on my M20E ... does anybody know the weight gain (either part for part or accumulated) for the speed mod´s ? I cannot imagine that from a roughly 1.000 lbs. payload only 800 will be left ;-) !