E3D V6 50mm Fan Duct (high airflow version - see video below)

I searched for a 50mm fan duct and found the version from VeryEvilBetty ( https://www.thingiverse.com/thing:860872 ). But this and many other fan duct designs have a design flaw. The Airflow is... bullshit. So I decided to remix the design an make it much much better. The airflow is so strong, I can reduce the fan speed to a lower level. The result is much less noise and the temperature of the part from the hotend that has to be cooled is also lower.

I added on the fan only 1mm holes for the