Flex fan

[pedalpowerceo]

Previous owner installed one which I just replaced with a normal fan and clutch. Wow, I can hear the engine. And the exhaust. And the radio.

Sorry, I just had to tell someone.

 

[RonnyB]

Sometimes I feel the need to demonstrate my ignorance.

What's the deal with these flex fans? I've heard about them for years, but don't know much about them.
Are the blades made out of some kind of plastic?
I've just assumed they're light weight, and that's the benefit.

If you had one with a fan clutch, would it be as noisy as a regular fan?