The Computer Fan that I installed in my LG Incubator blows downward....BUT, I also installed a "baffle" made from a Coffee Can lid....which re-directs the air-flow horizontally. I see no reason why blowing upward would'nt be just as good.....as long as there is some space left at the top for the air to go. (Offsetting the fan with spacers)
Here's a picture of how I did mine. (Sorry...not a very good picture - cheap camera. But should show well-enough to get the idea of the spacers and the baffle.)
-Junkmanme-
Here's a picture of how I did mine. (Sorry...not a very good picture - cheap camera. But should show well-enough to get the idea of the spacers and the baffle.)

-Junkmanme-
