I'm building a chloroplast plane. Well, the vert. and horizontal stabs are chloroplast. Some guys at the field have a cool sounding low pitched flutter in the tail. This is the stupidest question ever. How can I induce flutter?

Short answer: increase the mass, lower the stiffness.

> I'm building a chloroplast plane. <

I doubt that. You are actually buidling a coroplast plane. (G)

Duplicate the tail that flutters. Make sure to duplicate their hinging too. If it doesn't flutter for you, then loosen up the connections from your servo to the horns.

Have you ever seen a servo with the gears stripped from flutter? Kinda makes me wonder why anyone would want their airplane to be uncontrollable because it sounds "cool". Maybe you want to re-think this idea. Oh well, each to his own.

How about just putting in a plastic card piece edge on, affixed to the fuse, so it can create that "fluttering" noise in the wind for you?

That way you will not have to do anything as silly as TRYING to introduce flutter.

As long as one edge is held firmly and the other edge can flap around, you'll get that buzzing noise.
Much like, playing cards in a bicycle wheel....

use loosley supported nyrod, that will cause flutter.