Question Replacing USB fans in laptop cooler?

[ConfusedNoodle]

HeyHo, Wise ones of tech!
I have a CoolerMaster laptop cooler, USB connecting with a fan speed control dial. The moveable fans clip underneath the frame.
Have been happy with it, but the fans are failing now.
I like the frame, so thought to replace the fans and control dial with some nice quality components that will have better airflow and last longer.
I looked at 5v Noctua fans on Amazon that come with a USB connector. But there's the fan speed control, too. I want to be able to dial it down.
Is there a nice simple way of connecting the fans I choose to a speed controller, all powered through a single USB connection? Doesn't need to be fancy control, the up/down dial it used to have would be fine.
(There's a fault with the existing one, so I ruled out wiring new fans to the USB unit I have.)
Anything about choosing fans for a cooler that might not be obvious to a bear of very little brain? Like the range of airflow rating? How much space underneath the fan should there be, between the fan and desk?
Noodle

 

[Aeacus]

Is there a nice simple way of connecting the fans I choose to a speed controller, all powered through a single USB connection? Doesn't need to be fancy control, the up/down dial it used to have would be fine.

This thing?
Amazon: https://www.amazon.com/Controller-Adapter-Adjustable-Connector-Length/dp/B0BM4DHKRH

To get 3x fans to connect into single header, you need 3-way splitter as well. E.g this thing,
amazon: https://www.amazon.com/Cable-Matters-2-Pack-Way-Splitter/dp/B07PXLHNZ6

I looked at 5v Noctua fans on Amazon that come with a USB connector.

No need to go with USB connector fans. Regular 3-pin fans do, if you use the two i linked above.

Like the range of airflow rating? How much space underneath the fan should there be, between the fan and desk?

Airflow is usually measured in CFM. The higher CFM is, the more air the fan is able to push. There is no fixed CFM value, instead it all depends on the fan size (80mm, 92mm, 120mm, 140mm, 200mm) and blade design.

As of how far the fans should be, again, depends on a fan. If fan is airflow fan, with thin blades and big gaps between blades, it needs ample space behind it. But if space is restricted, then look towards a fan that has high static pressure (measured in mmH2O). Usually, high static pressure fans have thick/wide blades with small gap between the blades.

 

[ConfusedNoodle]

Thank you for your advice, that's brilliant! I'll get shopping, now that I know what to look for!