fuel quantity

[Wayne Pearce]

I have 337G, it has 123 gal total fuel with 118 gal useable (446.6 litres) The aircraft also has 3 tanks in each wing I know 'cause one of them cracked and had to be welded, this is what was known as long range fuel before the 4 tank system, I wonder what extra load this puts on the outboard area of the wings when aircraft is at rest ?

Regards ..... Wayne