Best way to cool this motor. With fan only or heatsink & fan?

[parcou]

Fam

Not a new question for me. Asked before and it was for a motor with aluminum ribs around it. I took the heat sink off and added a PowerHobby motor fan mount and placed a 40mm motor on the mount to cool the motor directly. Worked a lot better compared to having an Arrma heat sink on it that covered the ribs.

I have a spare PowerHobby motor mount and 40mm fan. This motor DOES NOT have the aluminum rib bands on the motor.

For the Firma 2050kv motor

• Do I keep the heatsink and swap to the better 40mm fan?
• Do I remove the heatsink and use the PH mount and run the fan directly to the motor?

Which way would cool better in this case of a smooth can motor?

 

[dure16]

Heat dissipates faster with more surface area, which is why many motors have built in fins. Heatsinks basically do the same thing.

On a smooth motor like that, I’d recommend a heatsink and a fan.

 

[fish]

I agree a fan is essential!

But which way to blow the air???

Ive called a few Pro-Hobby shops and got a 50:50 split for Suck:Blow

Im using a low profile YR Heatsink on a 6S Typhon.

So what direction??

 

[parcou]

I agree a fan is essential!

But which way to blow the air???

Ive called a few Pro-Hobby shops and got a 50:50 split for Suck:Blow

Im using a low profile YR Heatsink on a 6S Typhon.

So what direction??

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View attachment 227336

The fan is a must.

Not sure if I need to use a heat sink on a smooth motor or use a PowerHobby motor fan mount so the fan only blows onto the motor directly, no heat sink.

Thx

 

[fish]

Im my opinion, which is mostly based on computer Hot-Rodding. You first need the heatsink, then a fan to improve efficiency.
Blowing a fan across smooth IC's does nothing much, And an Intel i7 CPU can get as hot as the electric motor, just in a smaller area.

I bought a 40mm Fan and mount. Unfortunatly its coming from China and wont be here till sometime in August. NO More EBAY for me.
But after reading allot seems it doesn't do much compared to a HS/Fan properly setup on these motors.

I use to cool my PC's with Fluid. Ran all sorts of radiators. Cooled the CPU, N/S-Bridges and GPU. Then I got this GIANT Heatsink n Fans and its on Par just much larger. Its also very quite.
Id love to water cool a RC Car motor and ESC. Problem is the weight :-/

So Which way?
With a computer or processing board you would blow down onto the Heatsink, but the heatsink would be better, bigger. thermally bonded. Not Thermal Tape, that stuff sucks. Yet low profile HS/F on IC's do suck the heat away. The space between the HS and fan matters. Sucking up and away may be the better choice for most of these RC heatsinks. With stand-offs Blowing down is the only choice. And the voltage in these ESC don't go all that hight. adding a dedicated battery ads weight.
A DELL style cooling duct with HS/Fan would be ideal for these cars!. I need a damn 3D printer now.

 

[Hector_Fisher]

Depends on how much power your pumping through the motor, but you can still get decent cooling just by blowing lots of air across the motor with a fan. The difference between the motor and cpu is that there really isn't anywhere for the air to "pass by". If you blow directly on to the cpu, you may not get good enough mass flow to soak up and remove heat.

For a heatsink to be effective and not hinder performance you'd need to get good contact. Unlike a CPU heatsink, it's not typically to use thermal paste. I have used 0.5mm or 1mm silicone thermal pads on a yeah racing (power hobby) fan on a smooth can with good results. The pad gives better contact and allows better heat transfer to the actual heatsink.

My two cents: fan blowing directly on the motor is decent cooling. Using a heatsink can be better SOMETIMES, but there are more variables involved there that can make it tricky to be effective.

 

[parcou]

Depends on how much power your pumping through the motor, but you can still get decent cooling just by blowing lots of air across the motor with a fan. The difference between the motor and cpu is that there really isn't anywhere for the air to "pass by". If you blow directly on to the cpu, you may not get good enough mass flow to soak up and remove heat.

For a heatsink to be effective and not hinder performance you'd need to get good contact. Unlike a CPU heatsink, it's not typically to use thermal paste. I have used 0.5mm or 1mm silicone thermal pads on a yeah racing (power hobby) fan on a smooth can with good results. The pad gives better contact and allows better heat transfer to the actual heatsink.

My two cents: fan blowing directly on the motor is decent cooling. Using a heatsink can be better SOMETIMES, but there are more variables involved there that can make it tricky to be effective.

Thx...what do these pads look like?

 

[dure16]

I agree a fan is essential!

But which way to blow the air???

On a hot day, do you prefer a fan pointed toward you or away from you?

Blow the air toward the motor.

 

[fish]

On a hot day, do you prefer a fan pointed toward you or away from you?

Blow the air toward the motor.

I was surprised to find so many people doing the opposite. Trying to make sense if it and why they do. 2 were RC Track racers. Is it that they don't heat up the motors nearly as much?

 

[Hector_Fisher]

Thx...what do these pads look like?

https://a.co/d/jahPL2P
Does your firma motor have the stock heatsink? The one in the picture you showed above? If so, I would try running that first and see how it does.

 

[rotauq]

I agree a fan is essential!

But which way to blow the air???

Ive called a few Pro-Hobby shops and got a 50:50 split for Suck:Blow

Im using a low profile YR Heatsink on a 6S Typhon.

So what direction??

View attachment 227334


View attachment 227336

A heatsink gives more heat containing capacity. It helps a little with evening out the heat from the motor. It's large surface and fins specifally make heattransfer to a different medium (air) with plenty capacity and a lower saturation easy.
Thermal pads are good for flat contact with pressure, where all the micro gaps are filled. It doesn't work well when you have a tight fit camping 50-60% round the motor. Some cpu thermal paste does help a little.

As for airflow. You want continues contact with new air. Two fan's in the same direction next to each other. It can create a hot pocket in between. Air is easily compressed, but big inlets and hardly any outlet is not gonna be efficient. So the air is pushed on a surface with no place to go, it might be better to force the air to go from the one to the other. Preventing the inlet from drawing air from the outlet might inprove it even further. A little piece of cardboard in between for example.

 

[fish]

Two fan's in the same direction next to each other. It can create a hot pocket in between. Air is easily compressed, but big inlets and hardly any outlet is not gonna be efficient. So the air is pushed on a surface with no place to go, it might be better to force the air to go from the one to the other. Preventing the inlet from drawing air from the outlet might inprove it even further. A little piece of cardboard in between for example.

I think you are right.
I had it that way at first, photo above. Was thinking that may rip air across the fins quickly but in a localized area. I may try to fit (2) 40mm on it for some overhang. Also i have some short stand-offs.

Yeah Racing Aluminum Heat Sink for 1:8 Motors

I'll let you know. Im trying them all sorts of ways. I soldered the fans in with heat-wrap. Easy enough to swap but I hope these fans last for a while.

BTW, I put a strip(s) of thick double-sided tape at the bottom of the HS which let the top (where the fins are) wrap tightly up-against the can. I may try some very thick thermal compound between but it may make a mess and not enough gain in performance.

Arrma needs to come up with a cooling solution for their RC's. What the do is insufficient.

 

[rotauq]

Arrma needs to come up with a cooling solution for their RC's. What the do is insufficient.

You can always drop a tooth on the pinion or drive a little less agressieve. A motorcan very good at cooling iteself, if it's overheating it's because of the load patern. Extra cooling can only do so much.
Arrma marketing will want to see the highest possible mph on the box, which might not always be the best gearing for your usages...

 

[parcou]

You can always drop a tooth on the pinion or drive a little less agressieve. A motorcan very good at cooling iteself, if it's overheating it's because of the load patern. Extra cooling can only do so much.
Arrma marketing will want to see the highest possible mph on the box, which might not always be the best gearing for your usages...

Very true... Thx

Most all my rigs have higher/hot running motors/ESC removed to lower KV motors and pinion accordingly to balance the stock power but run lower temp. Fans for me help greatly more in my region living in the hot delta south of the Mississippi River region that feels like an open oven. Humidity that's a killer, not just the heat alone.

Even at 8:30 pm it's still 92F in the dark....so with cooler electronics need a little more help here!

 

[Warby]

I agree a fan is essential!

But which way to blow the air???

Ive called a few Pro-Hobby shops and got a 50:50 split for Suck:Blow

Im using a low profile YR Heatsink on a 6S Typhon.

So what direction??

View attachment 227334


View attachment 227336

The way I see it, if you have the fan "sucking" air from the heatsink, it's drawing the hot air through the fan, which heats the fan and reduce the servicelife of the fan. If its pulling cold air it's self cooling. Not scientifically proven. Just my thinking.

 

[Hector_Fisher]

Sucking air is less "direct" than blowing it. It's a bit hard to explain, but essentially: you can "channel" air by blowing it (for example using a fan), but you cannot "channel" air that is being sucked outside of the body of the fan (it draws in air from every direction). So your effective volume of cooling would be significantly smaller by using a sucking air method than blowing air method. Blowing air is turbulent air, which mixes better and increases heat transfer. Sucking air has its uses, but generally not in active heat convection

Just my 2 cents.

 

[jkflow]

This sucks, no it blows!

If you are 'blowing' onto a motor can, always do the 'blow' as the directed airflow actually gets around the can.

If you are using anything that is actually channeling the airflow, example is the Firma heatsink you can do either one to pretty much get the same or slightly better cooling performance. That heat sink is deep enough to not create back pressure and 2 fans blowing could possibly be impacting each other and be less effective. With these little plastic fans I doubt it will make a difference.

Using higher performance fans, it would matter.
90% of the fans posted here on the forum are incorrectly mounted and pretty much waste a lot of their capability. They are too close to a surface and the back pressure will decrease the fan's effectiveness. Most people won't notice, as these fan setups are overkill, and they don't notice that 50% is wasted.
Simply inserting a 1/4" spacer would make them more effective, the typical incorrect setup is a fan on the ESC where the fins are rather shallow.

The best motor setup is blowing on the can with a high power fan(s), 'sucking' won't work here as the air intake will have little impact on air flowing around the can.

Whatever you do, make sure you know the fan spec and the static pressure, that will give you an idea on what the mounting distance has to be from a reflecting surface. Else, you will just have a noisy fan that is doing 10% of what you think it is doing. If you are just using the 30 mm alu type rocket fans, you don't have to worry much, but the principle remains the same.

 

[fish]

I used a Punk to confirm the air flow on a Stock Typhon 3S.

Both ways. Longer Fin Heatsinks blow down into. Shorter low profile heatsinks channel suck the heat away. Much like on computer electronics and boards.

You cant effectively blow down onto a low profile heatsink. And whats important is that many of these cars Only have the room for low profile HS/Fans. My Typhon's for sure.
But this design below Will channel the air from the sides and effectively cool.

These with stand-offs are blowing down and around the fins and can.

The way I see it, if you have the fan "sucking" air from the heatsink, it's drawing the hot air through the fan, which heats the fan and reduce the servicelife of the fan. If its pulling cold air it's self cooling. Not scientifically proven. Just my thinking.

Either way that Fan is getting HOT! Doesn't matter.

 

[fish]

Ran the Typhon 6S-Animal all day today on grass. Ripping and running cones over the chewing them up mostly!
New HS/fans are keeping temps 25+ degrees lower. Blowing the Air down down towards the HS.
Now in tolerable range with a 18t pinion. Was fine with a 20t too.
Ripped though a 100C 8000mAh with no overheating at all.

 

[fish]

Now That’s a Heatsink n Fan(s)!!

In my MacHack stuffed in an Original Lian-Li PC60 from the 90s. I was one of the first kids oh the block with one - that much a geek back then
My work horse - I have 2 of them always running.

That’ll keep a 12S Kraton cool, on a hot day in Ecuador!