Electric Hydrofoil/E-Foil

Boats, Jet Skis, Kayaks etc., including hovercrafts
kiter_UK   10 mW

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Re: Electric Hydrofoil/E-Foil

Post by kiter_UK » Sep 05 2017 10:28am

@waterfox

Like your design. Was thinking of screwing down through aluminium tube too.

Looks like you have nice aluminium conical tail piece? Did you make or buy? (Or is this spray on 3d print?)

nanni   1 mW

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Re: Electric Hydrofoil/E-Foil

Post by nanni » Sep 05 2017 1:39pm

parabellum wrote:
nanni wrote: anodised aluminum tube made as close as possible to the outrunner rotor will eliminate the air for a quicker thermal exchange with the outside water;
You may want to choose non conductive material around a rotating magnetic field or have a gap, big enough to leaking magnetic field not reach conductive static cylinder, generating recirculating current. Think magnet through cooper pipe trick.
Matthias Spindler seems run with an outrunner in aluminium tube

https://www.youtube.com/watch?v=qYigcnRl0sk

photo and discussion here https://endless-sphere.com/forums/viewt ... &start=125

Hiorth   1 W

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Re: Electric Hydrofoil/E-Foil

Post by Hiorth » Sep 05 2017 2:13pm

kiter_UK wrote:Thanks all. Gutted I ordered a 10mm shaft.

More haste, less speed! (More cost!)
Pretty normal situation during building ;)

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parabellum   10 MW

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Re: Electric Hydrofoil/E-Foil

Post by parabellum » Sep 05 2017 2:29pm

nanni wrote: Matthias Spindler seems run with an outrunner in aluminium tube

https://www.youtube.com/watch?v=qYigcnRl0sk

photo and discussion here https://endless-sphere.com/forums/viewt ... &start=125
I am not saying it will not spin.
This is last post of Matthias on ES, do you see something strange in the numbers and his statement to?
The torqeedo prop is desingned to work at 1300rpm most efficient so i choose the gear reduction a little higher to get around 1500rpm. I'm not sure what the trust is but it feels like 30 kg. i dont know why i cant get more trust :( at full speed the multimeter shows me 4kw of power consumption.

nanni   1 mW

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Re: Electric Hydrofoil/E-Foil

Post by nanni » Sep 05 2017 4:02pm

parabellum wrote: I am not saying it will not spin.
This is last post of Matthias on ES, do you see something strange in the numbers and his statement to?
The torqeedo prop is desingned to work at 1300rpm most efficient so i choose the gear reduction a little higher to get around 1500rpm. I'm not sure what the trust is but it feels like 30 kg. i dont know why i cant get more trust :( at full speed the multimeter shows me 4kw of power consumption.
Ok, I understand thanks Parabellum, you are right.
Do you think an outrunner screwed on an aluminum flange in contact with water could be a better solution for cooling? Or would I have the same problems? The tube will be made either in fiberglass or pvc.

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parabellum   10 MW

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Re: Electric Hydrofoil/E-Foil

Post by parabellum » Sep 05 2017 5:12pm

nanni wrote: Ok, I understand thanks Parabellum, you are right.
Do you think an outrunner screwed on an aluminum flange in contact with water could be a better solution for cooling? Or would I have the same problems? The tube will be made either in fiberglass or pvc.
Unfortunately, I am wrong man to answer that question as I only managed to fail cooling out runners by static thermal conductance, even removing anodising layers an adding thermal pastes and big aluminium chunks with lot of convection area, I just went back to forced through winding cooling by EDF. The bottle neck is somewhere inside the motor, between copper>magnetic steel>ALU core, I did not manage to get heat quick enough to the sink, maybe, mentioned custom cooper core could do the trick.

waterfox   1 mW

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Re: Electric Hydrofoil/E-Foil

Post by waterfox » Sep 06 2017 10:51pm

Here is a video of me trying to ride my E-foil. Warning: it may be a little demoralizing. The prop I used was designed for 14 knots at max RPM.


Gege2000   10 mW

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Re: Electric Hydrofoil/E-Foil

Post by Gege2000 » Sep 07 2017 1:23am

waterfox wrote:Here is a video of me trying to ride my E-foil. Warning: it may be a little demoralizing. The prop I used was designed for 14 knots at max RPM.
Hi waterfox,
My vision of your problems, if it can give you some help. I think it's multi-causes
1 Size of the board : for me it's important to use a board where you can stand up, the slingshot wakefoil has a too low volume.
2 Position of your body : you must be able to maintain le board flat on the water when stand up on the board (see the vids of the Slingshot Academy) so you must be more close of the nose. For me you must move the staps forward (if possible, 2 points). You must be stable in speed before trying to fly with the back weight transfer during a short time.
3 length of the mast : the more the mast is long, the more it's difficult, and your mast is very long,
4 controler : it must be hard to vary the power with a stick controler
5 you could maybe add angle down to your motorisation (propeller higher than motor, 2-3°), to pull down the foil.

My 2 cent. :wink:

kiter_UK   10 mW

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Re: Electric Hydrofoil/E-Foil

Post by kiter_UK » Sep 07 2017 1:34am

I would give yourself a break! You did great.

If you've ever tried kite foiling (for which your board is designed), it takes several hours of falling in before it clicks.

I agree a bigger board is easier to start, but ultimately you are riding the foil not the board. And you were able to get to that stage.

Your movie gives me good hope, as I'm planning on a "water start" too on a small board.

Riding any foil isn't easy in my view. (But worth it!!)

kiter_UK   10 mW

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Re: Electric Hydrofoil/E-Foil

Post by kiter_UK » Sep 07 2017 1:39am

Ps. I'd take the straps off. If you didn't already. They're not position forward enough for powered board and will get in the way.

Advice when learning (kite foil) is generally to take back strap off to allow back foot forward to help keep weight forward over centre of lift.

Just2807   10 W

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Re: Electric Hydrofoil/E-Foil

Post by Just2807 » Sep 07 2017 9:23am

Try playing with foil angles. Hiorth said it helped him stabilize his flight a lot. Not sure did he inverted "backwing" (contra lift to oppose kite pull+getting more lift ; however i am not sure are kite and wake foil 2 different setups) or just changed total angle of the fuselage but he looks freaking stable pretty fast, and he was not the only1 trying to foil. I agree with bigger board. Yes, u eventually foil but u can be more precise and easier to start flying with a board u can freely stand on. Well at least till u get it 2nd nature. And yes, throttle looks very jerky like some1 said up, try to ease the power.
Happy flights and landings! thumbs up!

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fechter   100 GW

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Re: Electric Hydrofoil/E-Foil

Post by fechter » Sep 07 2017 9:28am

waterfox wrote:Here is a video of me trying to ride my E-foil. Warning: it may be a little demoralizing. The prop I used was designed for 14 knots at max RPM.
It looks like you're really close there. It seems like the motor had enough juice to get up on the foil.
"One test is worth a thousand opinions"

dirkdiggler   10 kW

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Re: Electric Hydrofoil/E-Foil

Post by dirkdiggler » Sep 07 2017 3:29pm

@waterfox
If that's your first time out you did awesome. Foiling isn't as easy at it looks. You are constantly having to weight your foil to keep it in the right spot. I've spent hours behind a boat with that Slingshot and I still find myself nose diving when I'm not paying attention. The hardest part is always getting up as the boat speed changes so does the reaction of the foil. Same with the power from your motor, its tough to judge how far back the pressure should be as your board is accelerating.
So, nothing broke while you were out there, and you seem to have had plenty of power? What voltage were you running again?

Just2807   10 W

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Re: Electric Hydrofoil/E-Foil

Post by Just2807 » Sep 07 2017 5:58pm

dirkdiggler wrote:@waterfox
What voltage were you running again?
12S 16Ah: 2X Tattu Plus 6S 16Ah.
I am interested in startup amps and "when up foiling" amps :)
I think his motor tops out on 120 volts/100 amps if i remember specs correctly.
Also, this wake foil seems a bit smallish, its designed with a lot of power in mind so i guess it isnt much stable at "lower speeds"? In comparison, i saw a lot beefier foils marketed "for beginners". Maybe that is giving him a hard time too.

waterfox   1 mW

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Re: Electric Hydrofoil/E-Foil

Post by waterfox » Sep 07 2017 8:21pm

Hey guys,
Thanks for the kudos and tips.

This is a slingshot NF2 kitefoil. I can ride it with my kite and behind a boat without any trouble (although you do indeed have to pay constant attention or surprise stall, and I can't jibe yet). I'm 165lbs and start to foil at slow speeds below 10 knots on my kite.

I think the difficulty in riding comes from a new force balance on the board with the thruster at the bottom of the long mast creating a large pitch-up moment. This has to be counterbalanced by moving much farther forward on the board.

When kiting or foiling, force normally comes through your harness / handle located above the board, creating a pitch down moment that the foil may be tuned for.

So you're now accounting for the loss of the normal pitch down moment, and increased pitch up moment from the thruster, all by moving your CG.

I'm hoping increasing the angle of my tail adds more pitch down moment and solves this.

I don't think the size of the board is going to change much as the thruster has no problem getting the small board on plane and eventually I'll be able to stand up on it, almost can already.

Straps off are a great idea!

Unfortunately I don't know the currents, I would really like to know them. My 12gauge wire doesn't seem to get hot.

I think the plan will be just to go to full speed (14knots ish) and stop playing with the throttle.
I also think I need to cool the ESC, so my next rev will have a static water intake, which at speed, will generate enough pressure to run water up a tube and through the ESC.

Gawd I wish I lived closer to water.

Just2807   10 W

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Re: Electric Hydrofoil/E-Foil

Post by Just2807 » Sep 07 2017 10:20pm

I hope u extend your quiver from lightwind to nowind ;) Thumbs up!

dirkdiggler   10 kW

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Re: Electric Hydrofoil/E-Foil

Post by dirkdiggler » Sep 07 2017 11:01pm

Waterfox-
Would you recommend using a shorter mast? I'm hoping tomorrow for my first attempt, just need to wire up some longer phase wires, strap the case to the board and I am good to go. Finally got some free time.

waterfox   1 mW

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Re: Electric Hydrofoil/E-Foil

Post by waterfox » Sep 08 2017 5:37pm

Good question! I'm not sure. Probably yes to start.
How did your test go?

Vincentbraillard   100 µW

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Re: Electric Hydrofoil/E-Foil

Post by Vincentbraillard » Sep 09 2017 4:40pm

Work in progress!!!
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dirkdiggler   10 kW

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Re: Electric Hydrofoil/E-Foil

Post by dirkdiggler » Sep 09 2017 5:06pm

Didn't go as well as I'd liked. The story of my life. My setup uses a c80-100 outrunner fully exposed to water. I was using a 110mm or so prop from Hiorth and the Slingshot wakefoil setup. The board is a 4'8" if I remember correctly. The board ran well without me on it. When I was laying on it, it would just plow water. Wish I had a bigger board to use while I get things working! Mistakenly I was trying to lean forward on the board to get it to plane. I should have done the opposite and leaned further back to get the foil up. Also had the foil on the most reward setting, which was bad for weighting and also because I have an exposed prop I was worried about. I ended up getting some water somehow in the waterproof container for the ESC, remote receiver and batteries. I was running on 12s with a Turnigy 80a Hv ESC and didn't want the water to burn it up. Decided to call it. I did have a amp meter hooked up and tried to check the numbers before I unplugged everything while out in the water. I pulled 110 amps at 50 volts, which is around 5500 watts. Should be enough to be riding?
So, a couple of things to look at. First, foil placement - maybe having it further forward as I'm laying prone before standing. Next should I try using an ebike controller at higher voltage? The problem with that will be having to use a tethered controller and having a larger sized ESC that will somehow need to be kept out of the water. Prop - should I try using a little bigger prop? That might get me a bit more speed, but draw even more amps. The wires going from the amp meter to battery were pretty toasty! I tried not to touch too much stuff as my hands were wet. I do weigh around 195 lbs. so weight is an issue. I'm positive anyone weighing less than 150 lbs. would have had been riding. Maybe slapping on a super tight speedo would decrease some drag?
Other option would be to quit on the c80100 and just buy the motor and ESC everyone else is using. I already have the neugart reducer. I'd still be under the $12,000 Lift wants for their efoil.

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parabellum   10 MW

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Re: Electric Hydrofoil/E-Foil

Post by parabellum » Sep 09 2017 9:27pm

Vincentbraillard wrote:Work in progress!!!
Nice machining.
Could you make and share no load current draw on max rpm with 1) bare motor and 2) with allu bell mounted?
What is the air gap between rotor and bell?

Gege2000   10 mW

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Re: Electric Hydrofoil/E-Foil

Post by Gege2000 » Sep 09 2017 10:21pm

dirkdiggler wrote:I pulled 110 amps at 50 volts, which is around 5500 watts. Should be enough to be riding?
Yes, according to my calculations, 5500W is enough (with a good propeller/rpm and board/foil).

Vincentbraillard   100 µW

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Re: Electric Hydrofoil/E-Foil

Post by Vincentbraillard » Sep 10 2017 3:16am

Of course 5500 watt is huge! A single men using his knee can fly over the water. A man can produce between 300 to 800 watt max!

https://youtu.be/QjUbbtSNR3Q
[youtube]https://youtu.be/QjUbbtSNR3Q[/youtube]

Álex.b.g   1 µW

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Re: Electric Hydrofoil/E-Foil

Post by Álex.b.g » Sep 11 2017 9:43am

Hi. we congratulate them all for their work. Excuse my English, what do you think of this engine and without reductora? which type of propeller or turbine would use to achieve maximum efficiency. without reduction gear. Thank you


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