Okay, engineers. Here's a great question. Can you answer it? We desperately need an axial fan that: Puts out as much cfm as an off-the-shelf 16" stand fan or box fan Does it at only 400 to 600 rpm! (ordinary fans from China run at 1,000 rpm or a little more.) I mean, why not? I don't see why it could not be done using a slighter larger diameter blade than normal, together with a lot more fan blade surface than regular, and maybe a heavy tilt to the blade...possibly it would have to be boxed in with a tube around it, I don't know... We need the smallest diameter blade possible, just for esthetic reasons. Anyway...I'm not an aeronautical engineer, just a product designer in a little over his head. Can anyone apply standard fan engineering and give me rough specs for such a thing? Thank you ever so!