fan question?

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Gdub34

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I’ve seen many varying opinions on this but which way should the fan direct air for best cooling.. Away from the heat source (heatsink, motor, esc) or toward it? Might be a stupid question but I’m just leaning from you guys. one day I will be able to help others thanks to you guys sharing your knowledge. thanks
Toward the heat source makes the most sense to me. Your house ceiling fans don’t direct air upwards. Just want to get your opinions ok. thanks
 
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I have never thought of the fan pointing away, don't think it would make much sense. The fans come stock pushing air towards the heat source. Pointing away would only pull away the hot air around it but pointing towards is going to help cool down the object itself along with pushing the hot air away. If you were hot would you stand infront or behind a fan? Guess that's the best way to look at it.
 
You know a fan pushes air correct. So air pushes out the heat. Fans don't suck, a vacuum does.
 
I’ve seen many varying opinions on this but which way should the fan direct air for best cooling.. Away from the heat source (heatsink, motor, esc) or toward it? Might be a stupid question but I’m just leaning from you guys. one day I will be able to help others thanks to you guys sharing your knowledge. thanks
Toward the heat source makes the most sense to me. Your house ceiling fans don’t direct air upwards. Just want to get your opinions ok. thanks
FWIW house ceiling fans are all reversible, depending if you want cooling in summer or heating in the winter. Has to do with convection and the fact that hot air rises. Off topic. Sorry. :LOL:

EDIT:

Not to throw a wrench in the logic for puller vs pusher fans..... A scale car always uses Puller fans, located behind the radiator. The key is that pullers need very effective shrouding and the fans must have a high static pressure to effectively cool the radiator. In RC the HS would be the radiator. But with RC's the fans we use are just repurposed PC Computer fans. Pullers can work in RC. But impacts and shocks affect durability. Mounting an ESC fan for instance upside down, will usually break the fan's cage and crack apart. I experimented with this. For RC purposes pusher fans seem to work better. Using spacers can maintain the effective static pressure of a fan,, Sometimes slamming a fan against a motor HS works against you. Restricts airflow. Slows RPMs, the CFM's drop and over works the fan motor.
 
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You know a fan pushes air correct. So air pushes out the heat. Fans don't suck, a vacuum does.
Fans do a certain amount of sucking. I get grass sitting on top of my fans all the time because it's pulling in air. Air in one way and out the other. Also people use fans on larger scales to pull fumes and what not out of a room. So I get his thinking, just isn't completely correct.
 
You know a fan pushes air correct. So air pushes out the heat. Fans don't suck, a vacuum does.
Well technically that is all a vacuum is is a fan.
vacuum-cleaner-diagram.jpg
 
The general thinking with small-scale fans is that if a shroud is not used (which is 99% of the time in RC), air being pulled into the fan is coming from a large area, and the same area being pushed out the other side is directed into a more concentrated spot. That's why fans in RC should blow at the surface being cooled, because practically more airflow is being locally deposited.
 
That must be a fake diagram. Fans only push
No, fans can push or pull depending on how they are oriented like @Exc3l said.

Stick your hand in front of a fan that is blowing onto something, if the fan is strong enough you can feel it trying to pull your hand into it.
 
No, fans can push or pull depending on how they are oriented like @Exc3l said.

Stick your hand in front of a fan that is blowing onto something, if the fan is strong enough you can feel it trying to pull your hand into it.
No. As someone stated above. It depends on which way the blades are facing and in a scale car the Rad fan is sucking in air for the engine 🤷‍♂️ 🤷‍♂️
Unfortunately my sarcasm didn't go through there. I was mocking the dude above who said fans only push. I already addressed the fact that fans suck earlier in the thread 😁 my apologies on the lost sarcasm
 
Fans do a certain amount of sucking. I get grass sitting on top of my fans all the time because it's pulling in air. Air in one way and out the other. Also people use fans on larger scales to pull fumes and what not out of a room. So I get his thinking, just isn't completely correct.
Like I stated somewhere, puller fans, pull air. With a decent shroud, that becomes a Vacuum in reality.
 
Fan's work equally in both directions. Mounted them myself but there are unforeseen consequences.
Equal - the fan is rated at cfm and what comes in must go out i.e. air flow is equal on both sides. In push the outflow is more directed but that is not needed on a motor.

Push - on the exhaust side you must make sure that the outfloww is not obstructed, that includes mounting it too close to the cooling surface. Something known as static pressure works against the fan and makes it inefficient. You must use standoffs to allow the air to escape and not go back out where it came from i.e. block itself. This is typically audible as the fan spins up faster than normal.

Pull - you can use less distance as intake does not have as high a pressure, obviously you will need a gap but it's only a fraction of what is needed compared to the 'push configuration'. Roughly 1/3 based on my experience.

Fan mounting orientation and application makes a huge difference though. If you are jumping and landing, mounting the fan upside down will not work. There is no support holding the fanblades when mounted upside down. Destroyed 2 of them in a heartbeat, really makes no difference what size fan, they all break on hard impacts. The mechanical support is only on one side with our style fans.

Mounting fans at an angle: Same issue, the pull config will always be more susceptible to impacts. Obviously at 90 degree that issue is equal.

Speedruns or smooth surfaces, I'd always go with the pull config. You avoid high standoffs and looks cleaner. Cooling is identical.
 
Fan's work equally in both directions. Mounted them myself but there are unforeseen consequences.
Equal - the fan is rated at cfm and what comes in must go out i.e. air flow is equal on both sides. In push the outflow is more directed but that is not needed on a motor.

Push - on the exhaust side you must make sure that the outfloww is not obstructed, that includes mounting it too close to the cooling surface. Something known as static pressure works against the fan and makes it inefficient. You must use standoffs to allow the air to escape and not go back out where it came from i.e. block itself. This is typically audible as the fan spins up faster than normal.

Pull - you can use less distance as intake does not have as high a pressure, obviously you will need a gap but it's only a fraction of what is needed compared to the 'push configuration'. Roughly 1/3 based on my experience.

Fan mounting orientation and application makes a huge difference though. If you are jumping and landing, mounting the fan upside down will not work. There is no support holding the fanblades when mounted upside down. Destroyed 2 of them in a heartbeat, really makes no difference what size fan, they all break on hard impacts. The mechanical support is only on one side with our style fans.

Mounting fans at an angle: Same issue, the pull config will always be more susceptible to impacts. Obviously at 90 degree that issue is equal.

Speedruns or smooth surfaces, I'd always go with the pull config. You avoid high standoffs and looks cleaner. Cooling is identical.
Found the angle problem out real quick on my Vorza, it has 2 spots to mount fans on the motor mount, one on top and one on the side at a 60-70* angle. After the first bash the fan mounted at angle was just the case the blades where nowhere to be found.
 
Sorry for digging up an old thread but was researching various vehicles and which direction they recommend the air flow to go on fans. Oddly enough the Xmaxx wants the fans to pull the hot air away from the motor. From what I was told this is due to the orientation of the HS. Which leads me to this question.

Could it be safe to say that if the motor has a HS it would be best to pull air away from the motor since the HS is absorbing the heat from the motor? Or would it all be determined by the design of the HS?
 
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