Fluttering noise…fan clutch????

I have been hearing this noise coming from the engine compartment that sounds like when we were kids many years ago and we put cards on our bicycles and the card flaps against the wheel spokes, except very loud… (best description I could come up with..)

It happens when I start up to take off and when the rpm’s get up around 2000. When I let off the gas the sound goes away. It usually only happens now and then, and there is no effect on engine power when the noise is heard.

I am wonder if it is the fan clutch?? Anyone had this before?? Thanks for any help!!...

does it sound like an airplane when you're driving? if so your clutch may be stuck