Plug&Play motor fan shroud for Kraton 6s

[Dan_OZ]

Hello!
I thought I share what I've been working on the last few days

As an alternative for a heatsink + fan.

3D printed, angled motor shroud to suit a 40mm fan. I got the fan off eBay for $7.
It's only a prototype so far as it's still due to proper testing which I can't because of crappy weather atm...

Specs:
- fits perfectly on stock Kraton 6s motor without modifications
- wraps the motor about 220 degrees without the need of cable ties or other fasteners. Simply snaps and stays on.
- suits a 40x40x10mm fan which sits on a 20 degree angle to the motor axis for streamlined airflow
- has integrated air channels to dissipate heat quickly
- very little contact surface to minimize heat getting trapped
- quickly removable for cleaning

Things which will probably get optimized soon:
- fan cover mesh
- designing an external air intake (basically cut out a hole on the body so it sucks in cold air)

What do you guys think?

Cheers
Dan

 

[SrC]

Excellent work. a 40mm fan with high CFM volume is a great idea. Watch for static pressure loss by keeping fan's distance accordingly to keep CFM at its max. Trial and error.

 

[Dan_OZ]

Thanks!
I didn't do any math equations for this one as it would be nearly impossible to calculate any air flow parametric with all these radii and angles haha
Though I can give you the specs for the fan and the STL of the shroud so you can have a crack at it if you want

Otherwise trial and error testing. Might be even today as it's sunny here atm

 

[Dan_OZ]

Went out for a first proper test. Was working well until I did some jumps at the skate park. It broke 5 out of 9 fan blades at the end, now I need a new fan first.
Guess the fan mount got a bit loose and kept smashing on the motor at every jump, shattering the fan blades.
Trying now to fix it properly to the motor, as it looks like just snapping the mount on it is not enough.

I'll keep you posted

Dan

 

[Droste78]

For the fan mount side, try some reinforcement for the fan supports. If it is a plastic fan, the blade breakages may be due to the fan supports flexing.

 

[Dan_OZ]

Thanks for the advise!
Do you mean these fan supports?

 

[Droste78]

Thanks for the advise!
Do you mean these fan supports?

View attachment 89195

Those are the ones

 

[GRC]

My plastic Arrma 4s motor fan got trashed after 2 runs, the fan cover didn't last 1 run. I got an aluminum motor fan recommended by another on this forum. It's held up to all the abuse I've put my RC through. I have a feeling other aluminum fans will perform just as well, but I'm very happy with my Yeah Racing Tornado motor fan. For a fan cover, this is dirt cheap and has also stood up to all abuse. (This is the 30mm version)
https://www.amazon.com/gp/product/B07DGWCZG8/ref=ppx_yo_dt_b_asin_title_o05_s01?ie=UTF8&psc=1

 

[SrC]

Remember that these RC fan are in fact just repurposed PC fans found in computers that are stationary devices that were NEVER designed to see the impacts and shocks these fans undergo in hard RC bashing rigs. Aluminum framed fans are much better to prevent frame flexing and blades cracking. It can still happen however from my exp.

My plastic Arrma 4s motor fan got trashed after 2 runs, the fan cover didn't last 1 run. I got an aluminum motor fan recommended by another on this forum. It's held up to all the abuse I've put my RC through. I have a feeling other aluminum fans will perform just as well, but I'm very happy with my Yeah Racing Tornado motor fan. For a fan cover, this is dirt cheap and has also stood up to all abuse. (This is the 30mm version)
https://www.amazon.com/gp/product/B07DGWCZG8/ref=ppx_yo_dt_b_asin_title_o05_s01?ie=UTF8&psc=1

That open grille fan cover will really do nothing except keep fingers away. And when I bash hard, my fingers are not near my fans. That would be a neat trick. A finger inadvertently hitting a spinning fan can crack blades. Been there. But thats User Error. It wont stop debris from entering for the most part, like twigs and pebbles that can also crack blades. This fan grille cant do that effectively. I have these grilles also. For my on road stuff. For dirt and big air they aren't effective from my experience. I use a tighter/closed mesh screen in that scenario. Good luck.

 

[Dan_OZ]

Those are the ones

Ok cool, I will revise my design to support these structures. New 40mm fan should arrive in the next 3 days

Remember that these RC fan are in fact just repurposed PC fans found in computers that are stationary devices that were NEVER designed to see the impacts and shocks these fans undergo in hard RC bashing rigs. Aluminum framed fans are much better to prevent frame flexing and blades cracking. It can still happen however from my exp.

True that! But it's already hard to get decent 5V 40mm fans here in OZ let alone ones with a frame made out of aluminium. I will try different support structures first with maybe some rubber dampers to reduce impact forces.

 

[SrC]

Cushioning if applied correctly without affecting CFM'S helps alot for sure. Get creative.

Ok cool, I will revise my design to support these structures. New 40mm fan should arrive in the next 3 days





True that! But it's already hard to get decent 5V 40mm fans here in OZ let alone ones with a frame made out of aluminium. I will try different support structures first with maybe some rubber dampers to reduce impact forces.

I have experimented with PC fans from PC vendors with decent results. Much better selection. The RC fans we use are just PC spec'd using the standard PC fan sizing.

 

[SrC]

"Floating" the fan using rubber isolators should help. Supporting the center of the fan also.. Many do this. Chassis slap while bashing creates a lot of shock to the fan's casing.

 

[Dan_OZ]

"Floating" the fan using rubber isolators should help. Supporting the center of the fan also.. Many do this. Chassis slap while bashing creates a lot of shock to the fan's casing.

Yep, I redesigned the fan mount and added a support for the middle of the fan as well as for the 3 "arms" which are holding the magnet.
Haven't printed it yet, will do tomorrow.
I also increased the angle which is wrapping the motor from 220 degrees to 230 degrees and decreased the inside diameter to 39.5mm.
It will hopefully snap on tighter

Rubber isolators/dampers will be my last resort...

 

[Mongoose]

Ooooh me likey!!! Care to share the model? Good job!

 

[SrC]

@Dan_OZ nice work.

 

[Droste78]

Looks fantastic!

 

[Dan_OZ]

Thanks for the feedback guys! Very appreciated!
I finished the print today and it fits on the motor very tight which is good.
New fan is installed and works fine so far, haven't been out for a bash yet.

Only air restricting part is the new fan cover I made which unfortunately has too small holes.
You can literally hear the fan slowing down trying to get more air when it's installed.
Need to redesign this one a bit.

I'll keep you posted!

Ooooh me likey!!! Care to share the model? Good job!

Maybe I'll share when it's all properly tested and I'm happy with it

 

[Dan_OZ]

Ok boys!
I thought the mount sat really tight on the motor and wouldn't move but I was wrong...
Have been shooting some birds with the Kraton at the skate park around the corner and still managed to lose some fan blades

So I took the mount and the fan off and saw that the whole thing cracked and became loose, smashing on the motor after every jump...

Looks like I have to change my initial aim of an easy installation to something different. So I added some slots for zip ties.

Now it sits solid on the motor. I also turned the motor 90 degrees which gives me more space to install the mount and also blocks less air at the outlets. Printed a little clip to hold the motor wires in place and increased the fan cover honeycomb size a bit for more airflow.
It's white now for some contrast haha

More testing to be done!

 

[Droste78]

Looking fan-tastic! Sorry for the stupid pun, couldn't help myself.....
Looking like I need a 3d printer. Some of these side projects are beautiful!

 

[Dan_OZ]

Thanks bud!
There are sure some useful and one of a kind creations out there made on a 3D printer.
Pretty amazing and well priced devices especially for hobbyists like us