Question for the history buffs

[Soviet Ace]

It's a simple answer really: Physiological Affect.

[haitch40]

i thought it was to make enemy pilots eyes go weird or even hypnotise them (2nd 1 is a joke)

[Robotic Pope]

Originally Posted by Soviet Ace

It's a simple answer really: Physiological Affect.

So what physiological affect does this have on ground staff in modern airports? lol

It is there so you can see it is spinning. It was often painted big and bright on german WWII planes because it looked good, like nose art. I don't think the germans ever used the usual coloured propeller tip method.