Industrial machined brass propeller / fan blade or ??????????

[Gspragge]

I have this heavy brass propeller like object, though I doubt it propells anything ?
But I have no idea of it's use or identity etc. It is unmarked. All machined brass
of good quality. it's 27 inches across and constructed so that the blades can be rotated on the horizontal
axis - If any one has a clue as to what it's for and from I'b be delighted to know.
It's almost an industrial art thing in itself.

 

[sksvlad]

I can't ID this item, it looks archaic and maybe some old cooling fan for some heat generating piece. What I do know is that if you place it into "Identification" tab above, you'll get more guesses or maybe outright answers.