Airflow through AC51, which way ??

Hi

can anyone tell me for sure which way the cooing air flows through an AC51

Im about to design the front mount and I want to include a duct for fan forced clean air

(motor is going in a 4x4 ) It will make things so much easier for me if the built in cooling blades (if it has any) move the air from front to rear .

I spun my motor up to 3000rpm on the bench and could detect no air movement , so I guess it would not be hard to overcome with ducted fan forced air either way !!