Kraton Castle 1717 1650kv Cooling Option (Kraton EXB)

[ChemEng]

I started modifying an 8s heatsink to fit the Castle 1717, but as i was sliding it on/off I noticed that it was wearing the paint on the heatsink in just a few small places, which indicated to me that it wasn't getting good contact for heat transfer. Since the 1717 can has built-in fins, I decided to use the direct cooling method with a few 40mm fans, but i wanted to get turbulent flow around more of the motor's surface area, so I designed and 3d printed a "shroud" to fit over the motor with a small annular space that would direct the flow of air from the fans around the can. Anyway, it seems like a lot of people struggle with cooling this motor, so I thought I would share this as another option. It does provide decent air flow, but i don't know if it provides enough cooling yet... I am still waiting on a longer sensor cable so I can take this thing out for its first run.

I am not a great modeler, so the design is a bit rough (I started with the 40mm fan adapter for the 8s heatsink, so there are some extra holes), but I would be happy to upload the files to thingiverse if anyone wants to try it out.

 

[zerocool135]

Could you upload those files I would like to try it out, Thanks.

 

[ChemEng]

Could you upload those files I would like to try it out, Thanks.

https://www.thingiverse.com/thing:4736620

Uploaded to thingiverse. Let me know how it works for you.

Note: I added ribs to keep the walls from collapsing on the motor, especially where the motor wires put some pressure on it. one side of the ribs are chamfered, make sure you put that side down when you print, it reduces the amount of supports needed.

Note #2: I had to rotate the little pin thing on the roll cage to get it out of the way, i drilled another hole for it.

 

[steveoooo]

I’m gonna grab this file .... what material are you printing in?

 

[ChemEng]

It needs to be TPU to get it to stretch over the motor wires. But don't use something super soft like ninjaflex as I don't think it would be rigid enough.

 

[steveoooo]

Awesome file , would it be easy to edit to a single fan design?

 

[Luv2GoFast]

Alza racing makes a 40mm fan mount that will fit that motor. I added it to my HW 1650.

 

[Dak08]

Very nice! Keep us updated once you take it out. I need a 3d printer now! Lol

 

[ChemEng]

Alza racing makes a 40mm fan mount that will fit that motor. I added it to my HW 1650.

View attachment 122295

That is interesting. I was looking for something that would direct the air all the way around the back of the motor without having the airflow interrupted by the wiring to take advantage of all the ribbing on the can. It would be very interesting to do a side-by-side test with the same fans with and without the 3d printed shroud.

My hypothesis is that the shroud would work quite a bit better (hence the reason i spent all weekend on it) HOWEVER if the fans fail, the shroud is essentially an insulator...

Awesome file , would it be easy to edit to a single fan design?

it would be easy for someone with more skills than me. It took me all weekend to bumble through this in tinkercad. I will take a stab at it for you sometime this week after work.

 

[SentFlying]

Hey if the cfm through your build correct for the proper heat transfer this will beat any other fan cooling setup.

In all seriousness I have been pondering this exact setup and was mocking it up. There is money to be made with this. Truely a game changer. Cheers.

 

[ChemEng]

Hey if the cfm through your build correct for the proper heat transfer this will beat any other fan cooling setup.

In all seriousness I have been pondering this exact setup and was mocking it up. There is money to be made with this. Truely a game changer. Cheers.

I used 40x20mm fans instead of 40x10 to try to get a little more static pressure, although they are 12V fans and my BEC is only 8 V so they are only running at 66% speed. The airflow feels pretty good coming out of the bottom of the shroud, but if it isn't good enough, i'll install a separate 12V BEC to try to get a little more out of it.

honestly as long as you have turbulent flow, there is diminishing returns on increased airflow in this setup. You are limited by the conductive heat transfer through the can and the surface area of the ribs. The real test will be when its 100 F outside in the summer and you only have ~50 deg temperature delta as the heat transfer driving force.

 

[SentFlying]

I used 40x20mm fans instead of 40x10 to try to get a little more static pressure, although they are 12V fans and my BEC is only 8 V so they are only running at 66% speed. The airflow feels pretty good coming out of the bottom of the shroud, but if it isn't good enough, i'll install a separate 12V BEC to try to get a little more out of it.

honestly as long as you have turbulent flow, there is diminishing returns on increased airflow in this setup. You are limited by the conductive heat transfer through the can and the surface area of the ribs. The real test will be when its 100 F outside in the summer and you only have ~50 deg temperature delta as the heat transfer driving force.

We are on the same page. I am an HVACR tech. I deal with heat transfer all day everyday, sometimes in my sleep
That said the turbulence in this setup isn't much of a problem as the motor fins are vertical and flow is not impeded bad were as the fins were horizontal. The air flow still makes great contact over the motor surface. Where as a motor with horizontal cooling fins would have a dead/ stagnant layer of air flow due to said fins. Hope I'm making sense.

 

[ChemEng]

Then you would appreciate this for some light reading, it is a rather well written (if not a bit dated) paper on flow through the annular space between two pipes... not exactly this use case as the flow around the motor is perpendicular not parallel to the cylinder, but a lot of the math could be easily adapted.

 

[SentFlying]

At work give me a few to read. I'll get back with you. Thanks.

 

[ChemEng]

This is the reason i am just going to run it to see if it works instead of doing the math:

 

[IrieWheeler]

I used 40x20mm fans instead of 40x10 to try to get a little more static pressure...

May I ask which fan specifically please? I'm on the verge of starting a "Best 40mm Fan?" thread. Cheers and great to have engineering-oriented people on the forum!

By the way, you could make some extra scratch printing those for Hobbywing 4985s, among others. I'd buy a couple for whatever you might ask. Just food for thought but perhaps too much trouble.

 

[ChemEng]

May I ask which fan specifically please? I'm on the verge of starting a "Best 40mm Fan?" thread. Cheers and great to have engineering-oriented people on the forum!

By the way, you could make some extra scratch printing those for Hobbywing 4985s, among others. I'd buy a couple for whatever you might ask. Just food for thought but perhaps too much trouble.

I just used some fans I had laying around (replacements for a network switch)

Wathai 40mm x 20mm 12V Dual Ball Bearing DC Brushless Cooling Fan https://www.amazon.com/dp/B07PYWVPMY/ref=cm_sw_r_sm_apa_fabc_mc2dGb9M8AM36?_encoding=UTF8&psc=1

They certainly don't belong on any best list....

I am not interested in selling prints, I have enough money but not enough time... I will share the design files with anyone who wants them for free though!

 

[SentFlying]

This is the reason i am just going to run it to see if it works instead of doing the math:
View attachment 122419
View attachment 122411

Yeah that's a bit. Too much math for a simple rc project.
In my line of work we shoot for a 20°F Delta. I'd start there and if you felt like shoot for more.
Very cool project. When I get a 3d printer I'll make one.

 

[jondilly1974]

This is the reason i am just going to run it to see if it works instead of doing the math:
View attachment 122419
View attachment 122411

The answer is 2

 

[Snackers]

as long as the shroud is working as a heatsink it should help a lot but if the shroud itself isn’t absorbing and releasing heat it would be better with fans alone. Make the shroud aluminum, thick, with as much area touching the can as possible to suck the heat away.