ESC and motor fan direction: Blow in or out?

[cmu3rd]

What direction should my ESC and motor cooling fans blow? In or out? My fans are blowing in which sucks unwanted material like grass and sand into the heatsink and clogs the fan. It seems logical to me they would blow out to remove the heat and keep debri out.

 

[Lukedavis]

They should suck in because that will push cold air onto the heat sinks

 

[tntpoof]

in

 

[ahr43]

Agree. In.

Some manus offer optional screens for their fans. Screens, though, reduce air flow. Cure one problem and deal with another. Have to choose which is the lesser. Good luck. Cheers. 'AC'

 

[Greywolf74]

You can really run them either way. They are a bit more efficient when pushing air on to the heatsinks but they will work when pulling air across the heatsinks too.

 

[WickedFog]

I doubt you would even notice a difference either way. Pulling air through the heatsink through the side and out the top or pushing from the top and out the sides - both are going to work. But heat does rise, and my thinking tells me a puller would do best to keep the heat going up, rather than trying to push it down. The reason I say this is I tested both directions on my enclosed amp rack (exposed hear sink) in my old Mustang. Fan outside on the heatsink. It made no difference which way the air blew. Same temps.

 

[tntpoof]

he is also thinking it will repel rocks and debris.

 

[ahr43]

he is also thinking it will repel rocks and debris.

Yeah. My experience running a fan on my backyard grasstrack oval, pine needles would jam the fan blades until I fit a screen. My events were of short duration so extended ESC fan cooling was less a consideration.

Vibration and mild noise of fan did serve to remind me I had not forgot to switch on the power before staging for an event. Were it not for that, would probably have taken the fan off altogether.

Those little motors move air well but lack the torque to power through or discharge debris. 'AC'

 

[bill_delong]

Always in, and it's a really good idea to replace the stock fan with an aluminum enclosed fan mount which won't break after a hard landing or nasty tumble. The stock plastic fans are junk, I typically toss them in the trash before I solder anything.