So i was out buzzing around the backyard and i could hear a distictive whistle that sure sound like one of the motors. Anybody else expirence this? any ideas?

Could you happen to provide a small video of the issue?

I found different sounds coming off the propellers depending on the humidity, and the largest and most alarming sound from a prop with a scraped tip.
Don't know how it got scraped, must have been a big bug.

Swapped out the prop and sounds much better.

Worth a try in your case, will rule out the props being the cause.

No video that would help. It Flies perfect. Just makes a loud whistler or ringing sound. I'll check the props, could be something about them. I have spares so I'll try it tomorrow. I'm really hoping its not a motor bearing. Thanks all.

There are other threads one with great audio of the sound.  I don't have time to research now plus can't post links from android tablet comments I recall were normal.

I have the same issue.  My Phantom 4 sounds a bit like a "jet engine" as the motor turns.

Same here, I think it is 'normal' although it does sound a bit unusual.