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Questions about ESC cooling

Vimana89

Well-known member
#1
So, I see this topic around randomly and most seem to agree that some sort of air flow to cool the ESC is necessary. My upcoming Dash 8 build will have this naturally due to intakes on the nacelles, but my V-Sliver and RETjet do not have any openings for air flow into the fuselage(by design, though they are a bit wonky after crash and repair) and they operate fine. The battery is warm but not hot and the ESC is cool by the time it's landed and I pop the hood. The V-Sliver will be rebuilt here soon, and I am wondering if I should add a small hood scoop to the design? It will definitely look cool, but will it improve performance or be necessary?
 

Chuppster

Well-known member
#2
So, I see this topic around randomly and most seem to agree that some sort of air flow to cool the ESC is necessary. My upcoming Dash 8 build will have this naturally due to intakes on the nacelles, but my V-Sliver and RETjet do not have any openings for air flow into the fuselage(by design, though they are a bit wonky after crash and repair) and they operate fine. The battery is warm but not hot and the ESC is cool by the time it's landed and I pop the hood. The V-Sliver will be rebuilt here soon, and I am wondering if I should add a small hood scoop to the design? It will definitely look cool, but will it improve performance or be necessary?
If I am concerned about ESC cooling in the cockpit, I typically cut a NACA duct in the nose somewhere. It'll help pull air in without creating as much drag. Don't forget you need an exit hole!

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Merv

Well-known member
#3
The battery is warm but not hot and the ESC is cool by the time it's landed and I pop the hood.
That sounds like you are not over heating things. Additional air flow is not going to hurt anything, but in you case, may not necessary. The outside air temperature makes a huge difference, I would continue to check your equipment as your summer progresses. What works in 80 degree weather will may not work at 100 degrees.

With the motor ESC & battery, warm is OK, but if so hot you don't want to hold it for 30 seconds or so, that too hot.
 

sprzout

Knower of useless information
Mentor
#4
Air across the ESC is important. It's not the end all be all situation, but it IS recommended. Some of the things I've done have been to reroute the ESC by putting some small holes in the bottom of the power pod on my MiG-3. This way, the ESC was below the power pod, which allowed for the battery to sit more forward in the power pod, which was better for the CG, and it allowed some air from the prop to blow across the ESC. I also notched the faux air scoop so that it was functional, and actually acted like a real scoop, pulling air into the fuselage and creating a venturi effect behind the ESC. Was it necessary? Probably not, but it made it look cleaner inside. :)
 

Vimana89

Well-known member
#5
Thanks for all the responses! I will be adding a small scoop on my next rebuild, to be on the safe side. Won't take much work, and will actually add some aesthetic detail and character(in other words, it will look friggin' cool.) Good call @Merv on watching the weather. It's going from 70-80 to like 90-100 degree heat here, and the plane I'm flying most often is primarily black, and will probably remain so on the rebuild.
 

Hondo76251

Well-known member
#6
I myself have often wondered how much of a difference it really makes, but just to be safe ive always tried to keep at least some airflow on anything that generates heat...

Has anyone seen a heat sink installed on brushless esc? I've got a few brushed ones with them but I have yet to see one on a brushless... Kind of seems like if your esc makes that much heat your motor might be too much for it...
 

sprzout

Knower of useless information
Mentor
#7
I myself have often wondered how much of a difference it really makes, but just to be safe ive always tried to keep at least some airflow on anything that generates heat...

Has anyone seen a heat sink installed on brushless esc? I've got a few brushed ones with them but I have yet to see one on a brushless... Kind of seems like if your esc makes that much heat your motor might be too much for it...
Actually, yes, I've seen a couple. :) Castle has several ESCs that have a heat sink on the ESC; I THINK the Thunderbird 36A ESC that I have uses one, but I honestly don't remember. I don't care much for it because it has this tendency to beep at random, and I don't know why. I figure it's some sort of setting with it, but I haven't been able to figure it out.
 

skymaster

Active member
#8
Quick question so if an esc has to stay cool why is it wrapped in shrink wrap. i know its to protect the electronics but wouldn't it make it more cool without the shrink wrap
 

Merv

Well-known member
#9
Quick question so if an esc has to stay cool why is it wrapped in shrink wrap. i know its to protect the electronics but wouldn't it make it more cool without the shrink wrap
It would be slightly cooler without the shrink wrap, but then you have a huge risk of shorting something out. The better solution is to go with a slightly larger ESC that can handle the load without getting so hot.

Remember warm is OK, but if you can not hold it for 30 seconds, that's too hot.