Actual square inches of fan surface is fairly meaningless.
Consider ... the hub area is basically useless when it comes to moving air ... two fans have twice the hub area.
Blade tip speed is important ... single larger fan can have more blade square inches traveling at a higher average speed for the same rpm compared to two smaller fans.
Single larger fan often has more room for a larger blade and greater blade pitch ... which moves more air.
So ... while it's perfectly possible two fans move more air ... it's not as simple as square inches of fan coverage.
|