MK4S-style dual fan shroud for MK3S

I'm currently reviving a used MK3S and decided to upgrade cooling to print overhangs better. Unfortunately the 5015 fans you can buy in Prusa webshop are much weaker than the original fan of the MK3S, so I bought some FYSETC fans. I decided to use two of these and in the last couple of month I tried almost all dual fan shrouds I found for the MK3S, but almost all of them either provided uneven or insufficient cooling. My theory is that the airway is to complicated in most of the designs resulting in a significant pressure drop, but I'm not an expert. As I read quite good reviews about the MK4S cooling, I remixed the MK4S fan shroud. In this setup the fans blow almost directly to the molten plastic.

Some considerations:

• As with other dual fan setups, connect only the red and black (power) wires of one fan to the other fan's same wires, the yellow wire is for RPM feedback and you only need it from one of the fans
• As the fans are mounted in a lower angle, the horizontal dimensions of the printhead gets considerably bigger. This is important for sequential printing.
• I use Klipper, but this setup should work with the original firmware too.
• FYSETC fan specific: under Klipper I had to set 0.1s PWM cycle time, otherwise the fans didn't work under 30% fan speed.

Print instructions:

• Print shroud-body upright, it should print fine
• Print the fan arms on laid on their sides

Assembly:

• You can mount the fans two ways:
  • install heat set inserts to the holes in the fan arms and use some 2 M3x20-25 screws per fan to mount the fans
  • You can also two long (at least 45-50mm) screws to mount the fans
• Align the fan arms to each other and press them into the slot on the rear of the shroud body, use some superglue or epoxy to hold them in place

• Changed height to fit under the MK3S printhead
• Changed the mounting point to fit the MK3S printhead
• Added a fan inlet and fan holder arms to mount two 5015 fans