Dipsticks
My R44 came with a fuel dipstick.
It is inscribed 'Main tank/ U.S. Gallons' and is calibrated to 45 US max.
The main tank holds 30 US, the Aux 20 ( rounded values). The Aux feeds into the Main.
It therefore reads the contents of both tanks. Because the combined fuel capacity is 50 US, RHC presumably decided on a 5 US fudge factor, possibly to allow for uneven ground?
I can easily provide you with a drawing or photo with measurements if you wish.
Catcha
Jackboot