I've done lots of testing on nozzle fan ducts and I have found a recipe that works for me. However, I've never tried CPAP or berd air (pump), so I will speak here for blowers as a source of airflow.

Image credit: Nozzle fan duct of BearExtruder V1 generated by Keith Bennett https://x.com/thisiskeithb

A small thread ⤵️

#3dprinting #cooling #shroud #duct

Keith Bennett (@thisiskeithb) on X

@MarlinFirmware team | 3D printing | serial modder | beta tester

X (formerly Twitter)
KFDR exhibiting textbook duct breakdown this morning. You can see the beams intercepting ground clutter at longer and longer ranges as the sun rises, the #duct begins to break down, and the #radar beams begin to bend back upward.