now i see what you mean - the auxilery compass.
this is NOT what i ment at all!
look at the normal "turning needle" compass. now instead of a turning needle, make the needle fixed at 12 oclock and let the N-E-S-W azimuth scale turn. this is the kind of compass every single plane or helicopter I ever flew, or flown in, had.
it is so much easier and intuitive to switch betwin absolut and relative directions. you want to know what is 2oc in azimuth, you just read the number at 2 oc on the scale. you want to know which way is WEST, look at the scale and it's the same "time" relative to the plane.
again, i dont know what was used in WWII.
I'll try to look for a pic.
Bozon