Most are familiar with the fuel line with a clear section in the cockpits of drop tank equipped Bf109s.
Should it be clear, though ?
It occurs to me that if the drop tank has fuel in it the sight glass should be fuel coloured. 80 Octane: A3 - Light Blue colour, 87 Octane: B4 - Dark Blue colour , 100 Octane: C3 - Dark Green colour.
Thoughts?