Why?

[TIMTS]

The picture is taken at TNCM and is a 737 BBJ. The question is: Why does the spinner have this white twisting line painted on it? Just for looks or does it have a purpose?

[simfly]

You'll find that most turbo fans have this, it helps show whether the fan is turning or not for a start...

[TIMTS]

ok..makes sense..thanks.

Is it just me or is this thing just a beautiful piece of engineering?



This one is not far behind!!

[SeldomFixit]

There was/is a theory that it helps deter birdstrikes by oscillating and giving the hapless avion something to see/avoid.
Definitely helps se/avoid for any hapless plod that thinks getting up close and personal at the wrong time might be fun

[Hay Ewe]

There is already at least one thread on pprune about this- I dont know how to post a link to a search. from memory, it is a visual thing for ground people, with all noise on the ramp / stand call it what ever it is a visual clue

Hay Ewe - take a look at this