I posted a video here awhile ago (can't find the thread now) and asked if the high pitched 'whistle' sound was 'normal' or not. I got one guy that said his does the same and others ignored it, meaning (I guess) that theirs doesn't make the same noise. Anyhoot, it turns out that I do have a bad motor (bearing). Just going to replace it as I couldn't ship it back for the $13 I paid for the motor. Not to mention DJI would likely charge me for the repair anyway.