Comment by ForOldHack
6 hours ago
From what I remember from my NASA friend, a few companies, hired a few fluid flow engineers, during the defense bust, and designed fan blades that remarkably increased air flow. ( think profiles like air plane wing ). Something happened and in a few years, there were good fans, and there were great fans.
I happen to own a pair of Noctura fans, and wow! They are great, so I would assume that some heavy lifting was done in fluid flow.
It better have been, considering what they charge and how long they take to come out with new ones.