Sk3 motor waterproofing?

That’s so cool. LMK when the files are done :smiley:

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if you ever get around to modeling the fluid dynamics of the air and find how many blades and what shape is optimal at what speeds I’d love to know.

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turn down your volume please! its so misleading because foc on the road is so quiet.

looks very similar.

testing with just my infrared thermometer didn’t show much if any improvement. made a bunch of designs that never really got a full test. was disappointed in results generally. but never added scoops. just going bigger motors seems a better solution.

but your motor spins like 3x faster so could do more.

with the large amount of space inside the rotor of most outrunners it would be nice to design an air sucker of some sort that connected on the inside of the motor and got .1mm off from the windings. a turbine on the inside with many blades blowing out the holes. with a printer. temp wouldn’t be a problem. a clip on. I don’t have that motor and wont be making it but would if I was better at fusion. would take me too long. gotta watch more lars on youtube.

@Hummie thanks for sharing the videos… I do wonder if the extra rpm on belt drives would provide more airflow. I’m not sure what blade designs would be best… but looking at gives me some ideas. I’m going to look into some programs for fluid dynamics testing.

I think it’d be easier to make some different designs and test them than to learn some program and for sure accurate. If you can install a more accurate mounted temp sensor instead of the infrared because it’s so wild than it’s just riding around a route.
I think the ego motor has a fan on its outside.

But I like inside the motor and a snap on 3d print, maybe it’s more efficient being on the inside than the out with the air it’s contacting being only what its trying to move. there’s not much room inside but if it were to juuust fit that would be slick. that’s what I’d like to see.

or maybe if the printer were good enough could make a mesh of blades with .5mm holes to screen out rocks.

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Heres a new version of the fan cover. I made it so it has 30 backward curved blades as well as a second design with 52 blades. This is a rendering of how one looks. They just requires 4 3mm screws. Go ahead a download it and print it! It’ll be a work in progress, so if you have any ideas you would like me to implement just ask! @Caleb1 @fraannk


That’s cool, John! I’ll have to print one out

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I recommend the 52 tooth fan. It seemed to have more air flow. If you wait a few more days ill have a new version of it with larger fan blades as well as more optimizations.


What program is that?

This is a great mod! Perfect for my 4 motors on my mtb. Thanks !


@wmj259 it’s Rhino 3D for Mac. Its a really easy cad program to learn and work with.

EDIT @barajabali @Caleb1 @fraannk
Just finalized the design. V2.2 is the one I would recommend for an Emtb or backwards mounted motors. It has the best airflow of any I have made, but it isn’t as strong as the others. (2mm wider fan blades in same form factor, as well as larger openings for the motor holes) Print em out and let me know how they work for you :grinning:

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Gonna print it out now. I see left and right but from what point of view ?

right of this pic bring the front


What if you continued the fan portion to cover the whole motor all the way up the can.

@barajabali if you are standing behind the board when its resting on the wheels. When you print it you can verify in your cam software by seeing if the blades are angled backwards from the direction the motor will spin. @wmj259 im not sure what you mean, like have it so the air will blow up the can of the motor?

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In your description for 2.2 on thingverse, what do you mean by “bottom mounted” motors?

My new motor won’t be here for a few weeks and my current one is already trashed. So I’ll wait until you have the designed finalized. Any more plans for revisions? Thanks!

Im talking about the motors that are mounted under the board, so they encounter a lot more road debris (curbs, rocks, sticks); I would feel safer personally with a stronger fan cover. However if your motors are mounted backwards and angled up like on @barajabali 's mountainboard, then they will only encounter small debris so they don’t need as strong of a fan. As of right now im satisfied with the current design for my use. If someone raises a good design idea though i’ll change it.

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Gotcha. Looks good. My only request would be a combination of 2.1 and 2.2. So the blade height of 2.2 combined with the “plate” thickness of 2.1 for added strength. I use a single-drive, so length is not really a concern for me. But the motor is mounted underneath in front of the rear truck and is subjected to more impacts (see image posted above where I broke a motor winding from an impact)

No worries if you don’t have time. Look forward to printing this guy out!

@jmasta ill see what I can do :grin: ill make one that extends out to the end of the axle to give it bigger fans for people that aren’t worried about the motor length sometime this week.


Ok I will have to try them

Will it fit a 63 mm sk3