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[Bruno_Marc]

Guys, I don’t know how relevant this is. But I noted the fact that the PTBs of American aircraft do not correspond to the volume declared in them. As an example, tanks of 75 US gallons. There, in fact, if you take two of 75 gal, then you get the weight along with the tanks 312 kg. Which corresponds to 126 liters (60 kg weight of two tanks). At the same time, there should be ~ 284 liters of fuel in one tank. In total, the weight of the fuel tanks should be ~ 600 kg to the mass of the aircraft. But as indicated above, this is not the case.
The loss of range is a total of 850 kilometers !!!
And the fuel in the tanks is enough for 533 km instead of 1700 km

[Vampire_pilot]

1 gallon of fuel weighs about 6 lbs or 2.7 kg.  (depending on the exact stuff, there are decimal discrepancies. For example diesel weighs in at about 7 lbs/gal, water at 8.4lbs/gal)

The 75gal tank I looked up real quick is coded to contain 205 kg, which is the weight of fuel you get when you take 75*2.7.  This weight value is inside the FuelTank class of the respective tanks.

I then extracted and looked at the stock game 75gal tank class and indeed, that one weighs in at only 156 kg. That is too low by a large margin me thinks.

It may be so that certain tanks suffer from faulty calculation though, it can happen. Don't convert to liters, go directly to weight, as the game deals in kg mass.
The weight value in the class is net fuel. There is no distinction for weight of the dry tank. It's a simplification of the game, for all I know.

I looked at a another 44gal tank class which weighs in at 158kg, which obviously adds a dry weight since the number is too high (120kg fuel mass would be it) . But in game, all of this mass will be treated like fuel.

Then I looked at a 100gal tank, which only comes at 195kg in the class, where it should be 272kg!
The 108gal tanks on the other hand were spot on at 294kg.....

maybe I'll make this a little project to look over for the next BAT update.

[Bruno_Marc]

1 gallon of fuel weighs about 6 lbs or 2.7 kg.  (depending on the exact stuff, there are decimal discrepancies. For example diesel weighs in at about 7 lbs/gal, water at 8.4lbs/gal)

The 75gal tank I looked up real quick is coded to contain 205 kg, which is the weight of fuel you get when you take 75*2.7.  This weight value is inside the FuelTank class of the respective tanks.

I then extracted and looked at the stock game 75gal tank class and indeed, that one weighs in at only 156 kg. That is too low by a large margin me thinks.

It may be so that certain tanks suffer from faulty calculation though, it can happen. Don't convert to liters, go directly to weight, as the game deals in kg mass.
The weight value in the class is net fuel. There is no distinction for weight of the dry tank. It's a simplification of the game, for all I know.

I looked at a another 44gal tank class which weighs in at 158kg, which obviously adds a dry weight since the number is too high (120kg fuel mass would be it) . But in game, all of this mass will be treated like fuel.

Then I looked at a 100gal tank, which only comes at 195kg in the class, where it should be 272kg!
The 108gal tanks on the other hand were spot on at 294kg.....

maybe I'll make this a little project to look over for the next BAT update.

Thanks for looking. The problem is spreading to all planes with these tanks. I saw a Tempest mod and there are more plausible tanks.
The Mustang is a fighter that is still in flight condition in many countries. There are a huge number of manuals and instructions for it in the public domain. Where it is described how much and what unit weighed. Based on this data, you can make the fuel realistic.

[Dreamk]

The data for fuel tanks in core IL2 and its successive versions are not to be trusted, still less the dimensions of the models of these fuel tanks (the F4U are the worst of all)

A few data on the empty weight of the 75 Gal tank (and other tanks used on the P-51):
There are 3 main problems:
a) A number of 75 gal existed and in practice it seems that all were used on the P51D, even when originally not intended too, as field modifications.

b) Surviving samples of the 75 gal tank show differences in overall dimensions:
3 variations: Length 7', Length 7' 4", length 9'(!)

c) There are a number of local production 75gal intended for P51 for which the exact dimensions and weight are not known, but teh photographic evidence shows different construction of the tank - example the "Hindustani" 75 Gal tank

The official data gives 60lbs as empty weight of the "regular" 75gal tank

The surviving plaque on one of the 75Gal tanks indicate: "75 Gal 62.3 Imp gal" though one would expect 62.45 imp gal, therefore "75 Gal" is a "class capacity" and not an exact capacity

1) The following is from Mustang: The Story of the P-51 Fighter by Robert W. Gruenhagen.
Empty weight Fuel Drop Tanks:
75 gal. combat tank = 60 lbs
150 gal. ferry tank = 120 lbs
165 gal. ferry tank (P-51H) = 135 lbs
110 gal. combat tank = 75 lbs

2) Drop tank empty weights as determined from the weight loadout tables published in America's Hundred Thousand by Francis H. Dean.
75 gallons (A-36A-1, P-51A, P-51D) = 60 lbs
75 gallons (P-39Q-1) = 45 lbs
75 gallons (P-47D) = 50 lbs

110 gallons (P-51D) = 90 lbs

150 gallons (A-36A-1, P-51A) = 105 lbs
150 gallons (P-63A-10) = 120 lbs

165 gallons (P-51D) = 115 lbs
165 gallons (P-47D, P-38J) = 87.5 lbs