Mini motor for SUP surfing

Well its time to build something new. I have been building my own electric surfboards for 10 + years and really enjoyed the process and the ease of surfing with some extra boost to get me out the back and on the waves.

So now I’m into foiling and im in love ! After learning to ride the foil behind my boat (11,000kg 40 foot power boat ) it gave me the opportunity to learn to ride and also SURF the waves. After achieving free surf NO rope properly for the first time on the weekend its made me re think by e foil approach and spawned this new design.

excuse the excited family member [https://www.youtube.com/watch?v=_a_EmHwBTEI]

So I will now be building 2 sperate E foils to do very different things.

1: will be conventional efoil, submerged prop for long range high power riding. Which I will use on of FR motor / mast on 12 S to get straight into this with less tinkering needed.

2: A surf dedicated setup for Sup paddle foiling with a boost! A small , light weigh wet and Dry motor setup ?

What I intend to do is mount a small 50mm 650 gram out runner with a and a 60 – 65 mm prop as close to the top of the bard as I can and run it on 700 – 900 watts MAX.
Why ??? well I want a board that I can foil in the surf without the drag and disturbed water flow that a lower wet motor system will always induce. The idea is when im paddling out the back to get to the no break zone I want help / boost to do that and reduce the time it takes to get in and out of the wave section. The motor will also help improve my surface speed to me get onto waves earlier as my paddling technique is far from perfect.

Once im up on the foil the motor will become airborne and trun off and most importantly no longer interfere with the water /wave giving me back the pure wave riding feeling I have felt behind my boat.

Further to this my current SUP has a hole in the board that is perfect for running some wires up into a battery / ESC box that can mount to the surface of the board without any permanent modifications to the board needed. So I can try lots of different combos and still remove the system completely at any time + the mast doesn’t need to be modified in any way either as the wires are external.

please excuse the very rough mock up as i came up with this idea 15 mins prior to leaving for the airport and had to do a quick mock-up

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Battery system will be bigger though.

I have just flown out for a 8 day work trip so progress wont start till then but im excited to give this a try as foiling on a wave without drag is something I want try.

what do you guys think ?

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NOTE : the green 3D printed mast bit in the photo is an off cut to hold the motor ONLY for the photo. Plant to make a smaller mast clamp version like the other out runner builds.

this is definitively the future! A little boost is all that is needed, have been thinking about this a lot, but never got the time to start build one. And not to many foilboard waves close to where I live.
looking forward seeing how it works !

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I’m also on the same page as you. I am gathering parts for my second build which will be my surf SUP.
I have decided to go for a jet unit built into the board that will give me 2000w.
Same goal different solutions.
I look forward to reading your build.

Similar idea here :slight_smile:

Sneaky…I missed that post somehow. Lift is definitely reading these forums.

Interesting that they put the pod at half mast distance…+ 1000USD folding prop that is definitely useful: 1- at the time you stop flying (brake effect) 2- at marginal speeds to avoid propeller touch downs during pumping (up and down movements of rider on the board to create lift and board speed) 3- less dangerous in case of fall, but still dangerous because no prop guard

Dear Mr Nick L,
A folding prop is surely a giant leap for the activity, … but
A prop with sexy lips would be a big step for its safety … then
Transport Canada would have nothing to say …:wink:

… just in case … :shushing_face:

A jet pump is an even cleaner solution not to mention extremely safe so good luck with that one.

yep that is 90% what i had envisaged except the motor and mast position IMO looks too low i would have thought that would catch in the water quite easily but it looks good. folding prop is beautiful

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Ok so sorry for the lack of reply but work got in the way. I recently after 12 years of using Auto CAD finally made the switch over to Solid works and am very new to it so excuse the rough model but this is what i have made so far. I sent the file home for printing while im away and should be able to get photos of them tomorrow and get the wife to test fit the part before my return.

i want a simply slide on and off system with NO external bolts facing forward but a simple grub screw or 2 to hold its height on the mast.


Down the back you can see there is a 3D printed motor PUCK that screws to the back of the motor. From there the Puck goes into the motor mast and then is secured into place with 4 screws on the outside.

This way i can release the entire motor quickly and clean it / oil it after each use without any stuffing around. I can even hit it with compressed air and then dunk it in corrosion X !

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Solidworks rocks for 3D modeling.
And for machine programing Mastercam is the best.The end! :slight_smile:

@rcjetman I have had a very similar thought process for a long time, with little time/ money to tinker and action the project.

The things that held me up mainly are sizing of the motor and battery components, I would like to think I probably only need a few mins run time per session (Although extra could be bonus for the first paddle out) and enough power to get planing on a fat wave.

My application would be for prone foiling, my spot has a huge number of days that the waves are almost pushy enough to nab them way off shore, and they reform all the way to the beach, fantastic for foiling, just that little bit more paddle power to get going down the face, then pop up and snap the board up and you’re laughing!

Cool to see you’re on Axis gear too, I have a 750 wing that I use most of the time here, and a 920 that i use wakesurfing and for pumping etc.

I have no RC background, but am electronics savvy, and I can draw and build boards. (I have a background in composites as well as Jet units for small jet boats.) I am very interested in this thread!

The boards I build have two 20mm high density stringers 70mm apart (for the foils 90mm track spacing). and on my longer boards (~5 foot) I have a bit of tail that a jet insert could drop into. Giving you the option of taking the pod off for the sake of a one board quiver.

I had thought an all in one self contained unit with a wired membrane switch (hack up a servo tester) just taped to the deck could be a good option, you put your hands there for taking off, and release it when you stand up, ensuring nothing runs dry.

Hoping it would be able to run relatively low cost components, as with our high lift surf foils we only need to get going something like 5 knots to produce useable lift.

If someone was to take a bit of time and suggest me a prototype setup, what would you suggest? I am hoping for a parts cost of under $200, but am open to anything that would be suitable. I was thinking of building 18650 packs, but LiPo packs are also an option.

The doodle was from a long time ago, and i would think i would use as bigger jet pump as possible so may have to adjust the layout a bit.

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This is an older board that I can donate to get chopped up in the name of research for a prototype version
image

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We i finally got home and was able to get this idea out of my mind / computer and onto the real board.

I quite seriously built this entire setup from scratch in 5hrs 15 mins before i had to go with the family for Easter holiday. It was super rushed but it did work !

So it only drew about 600 watts which is nothing compared to the bigger foil setups we all see on this forum BUT it did double the boards speed over the water compared to just paddling with a SUP paddle on its own.

If you have access to good waves it would definitely work well IMO to give you a boost or even help you get back out. Also it really light weight and this entire setup just slides ON and off and the box comes off too so its reversible.

However i did build a bigger motor combo as i wanted a lot more power to get me out the back faster and onto waves with a lot less effort and i will post this tomorrow.

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Ok so here is the turnigy 6364 245 KV motor version i made shortly after trying the 50mm motor that was under powered for what i wanted.

I tried a bunch of different props that i found on the forums and modded them in slightly different ways. some were standard , some i sanded of the sharp square edges to make them look more prop like and i also tried different scaled versions of the props.


I tested 3 different props all on 6S only i didn’t have a single prop that would run at 100% throttle without the motor squealing and stalling. i was surprised by this lack of torque the motor had ( or could it be a timing issue in the speedy making the motor do this ? )

either way the best prop was this one and i could get about 78% throttle before it squealed. thrust was decent and the power was about 1.3 KW but i could not get the board out of the water on motor power alone it just did not have quite enough forward momentum to get the foil to fly on flat water.
If the foil was flying and the motor down the bottom like a conventional one it would fly im sure but that high drag take off phase was too much.

super simple install again. just 2 x 6s 8000 packs gave me about 50 mins of staffing around in the surf / waiting for waves. i did add a water pump and a bigger box to make it easier to fit everything in… again fully removable.


As for increase of paddle speed this would be about 200% higher surface speed. Plenty of power to get you onto a wave and out the back so this would work well for sup surf foiling ONLY. I weigh 93 kg so i might give this to my dad who is 65 kg and get him to try it out.

im happy it works ! But i have more mods to come.

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you have the same AXIS foil as me !

As you say you want a super cheap setup… The post i just made could work for you ? if you just want to get boost onto the wave and out the back + you can do it all with cheap 6s hobby speed controllers and small lipo packs.

if your interested i can give you the stl files and parts list.

I think you should try the 149kv with 10-12s

You are correct a140 kv or even lower would be much better. I just happen to have 2 of these 235 in 6365 at home doing nothing s I gave it a try.