40cfm, 44dba, 17" x 2.5" x 2.5"
those are very uncompetitive figures
2.5" is basically 60mm, you could fit 7x 60mm fans in this area.
Papst make a 14.7cfm 60mm fan, it makes 19dba. 7 x 14.7cfm is 103cfm, for much much less than 44dba.
Please explan why the cross flow fan is so good, I'm missing it. Papst's catalogue says they are good for high flow, low back pressure, which probably isn't the thing we want in a fan.
Papst also make a 172mm fan that goes from 53cfm at 18db to 353cfm at 65dba, the rate is controllable through a small potentiometer, or through a thermistor. Wouldn't this be the perfect radiator fan?