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Old 09-12-2011, 08:11 PM   #1
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Default Whats your favorite heat sink??

I was just wondering about this because im planning to get a new heatsink soon.

P.S my old heatsink doesnt work correctly either.
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Old 09-12-2011, 09:50 PM   #2
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Originally Posted by Little John View Post
I was just wondering about this because im planning to get a new heatsink soon.

P.S my old heatsink doesnt work correctly either.
I use two fans mounted on the car not on the motor, if you are asking heatsink for the motor, don't... it holds the heat in the motor.... I use the Muchmore (http://www.amainhobbies.com/product_...PM-Cooling-Fan) fans.... Glued together... Then servo taped to the car. or you could shoegoo them to the car... You want to make sure you the fan on the endbell, I have seen a 20 degree difference between the can (with a fan on it) and the endbell with out the reaching it.

Hope this helps....
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Old 09-12-2011, 10:13 PM   #3
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if you are asking heatsink for the motor, don't... it holds the heat in the motor...
Assuming good contact between motor and heat sink to allow for the movement of heat via conduction, and that the thermal conductivity of the heat sink is equal to or greater than the motor can, then it is impossible for the heat sink to act as an insulator. Unless there is some other NEW type of Physics that I did not learn at Uni that causes heat not to move from an area of High temperature to an area of Low temperature.

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I was just wondering about this because im planning to get a new heatsink soon.
I do not use one, there is no need. My motors run ice cold as it is. Use correct gearing, don't over rev the motor or load it up, and all will be fine.
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Old 09-13-2011, 03:06 AM   #4
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My single fan for high turn and cool weather is this one: http://www.yeahracing.com/catalog/ya...pe-p-2736.html

About my twin for low turn and hot weather is this one: http://www.yeahracing.com/catalog/ya...rs-p-2903.html
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Old 09-13-2011, 06:36 AM   #5
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Default Thanks!!!!!

Thanks for the recommendations keep em comin!!!!
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Old 09-13-2011, 06:54 AM   #6
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Are you racing or just bashing and want to keep things cool? ROAR rules, and most local rules, allow for ONE fan only for the motor, and one on the ESC. Choose wisely. If you're just bashing, you can load up as many fans as you can physically fit!

When I came back to RC a little over a year ago, I started down the road of heatsinks and fans based on my experience with brushed motors. I didn't listen to the guys who had been running brushless for the last few years and already had cooling figured out. I now have a box full of upwards of 30 broken fans and nearly two dozen different heat sinks of all nature and design. At one point on one certain day I tried over 20 different fan/heatsink combinations on controlled 4 minute runs, always starting at the same motor temp with a freshly peaked battery running the same number of laps. Kept a very nice chart, too.

I'm sure that some will disagree with the wall of text below, but I have yet to burn out a motor due to heat, and my cars are as fast as the fast guys on my track (it's my driving, not the car!)

Yes, some heatsinks actually did little or nothing to help cool the motor. None of the heatsinks actually made the motor hotter, as there aren't any cooling vents on the cans of the motors (like old brushed motors) to block the flow of air! The motor itself is generating the heat. Unless the heatsink itself is actually generating more heat than the motor, it can't make it hotter!

Most fans are pure, highly distilled, certified crap. When used on brushless motors, most heatsinks are in that category, too.

NOTHING, and I do mean NOTHING worked better in my testing than a simple Boss/Geisha/Fantom fan wired directly to ESC +/- and shoe goo'd to the chassis behind the motor, blowing air onto the motor. This particular set up keeps the motors cool even slightly overgeared on large outdoor tracks with ambient temps over 100*F.

This is what I learned:
  1. Not all heat sinks are created equal or fit well enough to actually work. Without a perfect fit, they don't actually conduct much heat. Many brushless motors have corregated stator cans to increase surface area to assist in radiating heat
  2. Using thermal paste between the heatsink and motor can is messy, and allows the heatsink to move around more when in a crash, but it does help the heatsink move heat away from the motor, as long as your fan is actually moving enough air and the design of the heatsink does not impeade that flow of air.
  3. Most heat sinks move around in a crash, and since most of them have sharp fins, can cut through motor wire insulation and short things out (ask me how I know)
  4. Not all fans on heat sinks are created equal. Some will work on direct ESC+/-, some only on BEC voltage
  5. Most fans aren't up to the task because they don't move enough air or the design of the heatsink impeads the flow of air. Some are also fragile enough that in a crash they'll actually flex blades enough to break them off or shed the entire rotor completely
  6. The Boss/Fantom/Geisha fans are by FAR the best. Check out Sidepiece racing, should have more available soon
  7. A good close second to the above fans is the Yeah Racing Tornado fan (30mm). One half step down from that is the Muchmore super fan
  8. Good fans can be had for under $15, but supply is spotty, at best
  9. Most of the fans available on ebay are crap
  10. A good 30mm fan, wired to ESC +/-, shoe goo'd to the chassis blowing on the motor, is lighter and cools the motor better than any of the dozens of heat sink/fan combos that I tried

All of the fast guys in blinky gear for the track, then gear up as fast as temps will allow them to go without going into thermal shut down on the ESC or damaging the motor. Having a fan on your motor is essential to being able to get enough speed to compete in any blinky class. If you can get a 10-12*F (or more) advantage to be able to swing more teeth on your pinion, you'll be physically able to go faster. From there you'll want to adjust motor physical timing to get back some torque.

Most brushless motors, by dialing back the timing from max, will deliver more torque to spin a bigger pinion than they will deliver RPMs to spin a slightly smaller pinion at higher RPMs. Advantage: lower physical timing+huge pinion+fan=faster car.

Summary: a cooler motor allows for more pinion teeth=more speed. Less physical timing in the motor=less heat. Low physical timing(more torque, lower total RPM) + large pinion often is faster than high physical timing(less torque, higher total RPM) + smaller pinion for a given motor temperature.

But I could be wrong. It's happened before.
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Old 09-13-2011, 09:00 AM   #7
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Quote:
Originally Posted by Buckaroo View Post
I'm sure that some will disagree with the wall of text below, but I have yet to burn out a motor due to heat, and my cars are as fast as the fast guys on my track (it's my driving, not the car!)

Most fans are pure, highly distilled, certified crap. When used on brushless motors, most heatsinks are in that category, too.
bravo!

(the entire post that the above excerpts were taken from is fantastic, and should be bookmarked and/or pasted into some kind of brushless motor 'black book').

for some reason, everyone loves to believe the hocus pocus crap about horsepower. it's very simple, and not even that critical in many of the cases. ..

in fact, i think most of us choose to believe in the 'magic' so that we don't have to face the 'music'.
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Old 09-13-2011, 04:21 PM   #8
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Quote:
Originally Posted by Buckaroo View Post
Are you racing or just bashing and want to keep things cool? ROAR rules, and most local rules, allow for ONE fan only for the motor, and one on the ESC. Choose wisely. If you're just bashing, you can load up as many fans as you can physically fit!

When I came back to RC a little over a year ago, I started down the road of heatsinks and fans based on my experience with brushed motors. I didn't listen to the guys who had been running brushless for the last few years and already had cooling figured out. I now have a box full of upwards of 30 broken fans and nearly two dozen different heat sinks of all nature and design. At one point on one certain day I tried over 20 different fan/heatsink combinations on controlled 4 minute runs, always starting at the same motor temp with a freshly peaked battery running the same number of laps. Kept a very nice chart, too.

I'm sure that some will disagree with the wall of text below, but I have yet to burn out a motor due to heat, and my cars are as fast as the fast guys on my track (it's my driving, not the car!)

Yes, some heatsinks actually did little or nothing to help cool the motor. None of the heatsinks actually made the motor hotter, as there aren't any cooling vents on the cans of the motors (like old brushed motors) to block the flow of air! The motor itself is generating the heat. Unless the heatsink itself is actually generating more heat than the motor, it can't make it hotter!

Most fans are pure, highly distilled, certified crap. When used on brushless motors, most heatsinks are in that category, too.

NOTHING, and I do mean NOTHING worked better in my testing than a simple Boss/Geisha/Fantom fan wired directly to ESC +/- and shoe goo'd to the chassis behind the motor, blowing air onto the motor. This particular set up keeps the motors cool even slightly overgeared on large outdoor tracks with ambient temps over 100*F.

This is what I learned:
  1. Not all heat sinks are created equal or fit well enough to actually work. Without a perfect fit, they don't actually conduct much heat. Many brushless motors have corregated stator cans to increase surface area to assist in radiating heat
  2. Using thermal paste between the heatsink and motor can is messy, and allows the heatsink to move around more when in a crash, but it does help the heatsink move heat away from the motor, as long as your fan is actually moving enough air and the design of the heatsink does not impeade that flow of air.
  3. Most heat sinks move around in a crash, and since most of them have sharp fins, can cut through motor wire insulation and short things out (ask me how I know)
  4. Not all fans on heat sinks are created equal. Some will work on direct ESC+/-, some only on BEC voltage
  5. Most fans aren't up to the task because they don't move enough air or the design of the heatsink impeads the flow of air. Some are also fragile enough that in a crash they'll actually flex blades enough to break them off or shed the entire rotor completely
  6. The Boss/Fantom/Geisha fans are by FAR the best. Check out Sidepiece racing, should have more available soon
  7. A good close second to the above fans is the Yeah Racing Tornado fan (30mm). One half step down from that is the Muchmore super fan
  8. Good fans can be had for under $15, but supply is spotty, at best
  9. Most of the fans available on ebay are crap
  10. A good 30mm fan, wired to ESC +/-, shoe goo'd to the chassis blowing on the motor, is lighter and cools the motor better than any of the dozens of heat sink/fan combos that I tried

All of the fast guys in blinky gear for the track, then gear up as fast as temps will allow them to go without going into thermal shut down on the ESC or damaging the motor. Having a fan on your motor is essential to being able to get enough speed to compete in any blinky class. If you can get a 10-12*F (or more) advantage to be able to swing more teeth on your pinion, you'll be physically able to go faster. From there you'll want to adjust motor physical timing to get back some torque.

Most brushless motors, by dialing back the timing from max, will deliver more torque to spin a bigger pinion than they will deliver RPMs to spin a slightly smaller pinion at higher RPMs. Advantage: lower physical timing+huge pinion+fan=faster car.

Summary: a cooler motor allows for more pinion teeth=more speed. Less physical timing in the motor=less heat. Low physical timing(more torque, lower total RPM) + large pinion often is faster than high physical timing(less torque, higher total RPM) + smaller pinion for a given motor temperature.

But I could be wrong. It's happened before.
+1 Good post.
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Old 09-13-2011, 07:52 PM   #9
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WOW!!! thats very good to know i guess ill worry more about the fan then!!!
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Old 09-13-2011, 09:27 PM   #10
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Ok, anyone willing to share some pictures of both the fan mounted on the ESC (I have a tekin RS) and to the motor...

Just to get some ideas....

I thought the reason for the tall posts on the Tekin was the heat sync... Thus do you face the fan at the posts?

From the motor I want to see if you put the fan out on the end bell, center or more to the inside.

I was not aware that ROAR only allows one fan, many thanks and good to know....
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Old 09-13-2011, 09:28 PM   #11
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If you're using Novak motors I find their Motor Sleeve Heat Sink works well. It replaces the colored sleeve on Novak's Ballistic, Velociti and SS-Series motors and wraps directly around the stator. Used with thermal paste it works quite well...



...here it is installed.

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Old 09-13-2011, 09:39 PM   #12
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Great reading so far. I have been worried about fan/heat sink combo since coming back and having to learn brushless motors.

Just 1 thing did you test having a heat sink on the motor and the fan on the chassis at all?
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Old 09-13-2011, 09:42 PM   #13
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Originally Posted by @Art_Mighty View Post
If you're using Novak motors I find their Motor Sleeve Heat Sink works well. It replaces the colored sleeve on Novak's Ballistic, Velociti and SS-Series motors and wraps directly around the stator. Used with thermal paste it works quite well...
Have you tried this with a fan mounted on top of the sink? What is the difference in temp with just the sink?
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Old 09-13-2011, 09:56 PM   #14
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Great reading so far. I have been worried about fan/heat sink combo since coming back and having to learn brushless motors.

Just 1 thing did you test having a heat sink on the motor and the fan on the chassis at all?
Theoretically you would want to position the fan to be moving air over the greatest surface area, so ontop of or on the side of the heatsink would be best.

A few posts up someone said they point at fan at the endbell of the motor and have good results with that, what they have done is inadvertently moved air over a greater surface area, and thus have better cooling results. Endbell + the entire can and motor mount if its alloy is better than just 1 side of the can alone.
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Old 09-13-2011, 10:11 PM   #15
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Default Heatsinks

For stock racing with our old weight limit of 1425..I used the LRP Heatsink combo http://www.lrp.cc/en/products/new-pr...efter/details/.. it provides a little improvment over the Yeahracing Tornado Fans.. 5 or so Degrees approx.. hard to tell.. for our old weight limited I needed the extra weight on the motor side so thought it would be better being a heatsink then lead..

Now that the weight has dropped down for us to 1380 I have changed to just a fantom fan and its running cooler.. when the car was over 1425 could not get away with this..
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