electric fan cowling

i have a 16 inch pacet electric fan that fit directly onto the radiator. i have been thinking recently that it will only cool the part of the rad it touches, outside the fan area there will be no cooling! it does work well but i cant help thinking if i can mount it on a cowling that fits around the edge of the rad tapering out slightly leaving a hole 16 inch or so in diameter it will suck air through the whole rad.......
has anyone done this and if so where did cowling come from?

bump

I have done a similar thing to my SWB Frontera that I use for off roading, I have also been toying with the Idea of a cowling and I have even visited a scrap yard hoping to find something that would do but I have had no joy yet.
With a bit of modification would the existing cowling not do

its long gone! and it wasn't anywhere near the shape i need