Electric Hydrofoil/E-Foil

parabellum · Aug 6, 2017

waterfox said:
based on the BPhobbies Cheetah A5330-9 on 6S but I didn't have enough power or enough cooling.

How much W in did you got? Any thrust measurements? What was the cooling path, considering its out-runner? It is so exiting to see real world chocking with reality!

P.S. You are the man, so ahead of my self, keep up the good work!

LogicalDIYBuilder · Aug 6, 2017

Hey guys, just started reading through this thread and what great info available!
I'm building my own diy electric hydrofoil with videos, posts, and photos as well http://www.diy-electric-hydrofoil.com/diy-electric-hydrofoil-video-series/. I have been following closely to pacificmeisters design as a few others I see 8) , but with a few of my own modifications.

Here are my main 3D printed parts for my first print run/test fit, along with custom ducted nozzle propeller.
I have a couple different prop size assemblies and will be testing 5:1, 3:1, and direct drive with various power settings.

Im just waiting on my hydrofoil board to arrive Wednesday and a couple more parts and it will be building and testing time!

Jezza · Aug 6, 2017

waterfox said:
Hey, does anyone have a CAD model or the measurements of the SSS 56104 motor. Specifically the bolt pattern diameter. Mine is on order but I would like to get to work designing before it arrives.
Foil: Slingshot Hoverglide NF2. I would like to switch to a Liquid Force hollow mast with an adapter plate once I prove this out.

Its much easier just to pull out the plastic inserts in the slingshot mast! I took a small drill bit and made a pilot hole. Then put a screw in and pull out with pliers. Each hole fits 2 wires.

LogicalDIYBuilder · Aug 7, 2017

I just wrote a short post called: Ducted Propellers Should Be Used with efoils.

It may shed some light for those with questions on what prop assembly should be used in my opinion at least.
http://www.diy-electric-hydrofoil.com/ducted-propellers-used-diy-electric-hydrofoil/

Clarin · Aug 7, 2017

Hi Waterfox,

How many Kv is your SSS56104? I have ordered the same gearbox has you, but was wondering if I should order the 500Kv or 700Kv?

Thanks to all of you for sharing your amazing build

LogicalDIYBuilder · Aug 7, 2017

Clarin said:
Hi Waterfox,

How many Kv is your SSS56104? I have ordered the same gearbox has you, but was wondering if I should order the 500Kv or 700Kv?

Thanks to all of you for sharing your amazing build

I got the SSS 56104 500kv and have 5:1 reduction, also 3:1 to test along with another prop as well.

Clarin · Aug 7, 2017

I was thinking to order the 500kv with 8:1 gearbox, hope it's not going to be to slow!

LogicalDIYBuilder · Aug 7, 2017

It depends on your prop diameter. With 8:1 with 500kv, you are likely going to need a 150mm diameter prop. I'm going smaller prop size for a couple reasons. They are much more affordable for a custom aluminum assembly, lighter, and smaller making it tougher to get a foot/toe into prop ducted area.

Hiorth · Aug 7, 2017

WE have also done some progress

Only waiting for the aluminium tube, and will assemble. Probably first test in the weekend!

More pictures and videos(will come):
https://www.facebook.com/nikolai.hiorth/media_set?set=a.10159438659855144&type=3

waterfox · Aug 7, 2017

parabellum said:
waterfox said:

based on the BPhobbies Cheetah A5330-9 on 6S but I didn't have enough power or enough cooling.

Click to expand...

How much W in did you got? Any thrust measurements? What was the cooling path, considering its out-runner? It is so exiting to see real world chocking with reality!
P.S. You are the man, so ahead of my self, keep up the good work!

I don't have much data. Just that a motor would blow up after ~5 minutes with a 3 blade 160mm prop and ~15 minutes with a 3 blade 130mm prop. The motor was sitting in a sealed can with air inside, so cooling was out the metal mount and through the air to the aluminum enclosure. After you took it out of the water the can would get really hot. It must have been a thousand degrees in there. One motor had copper splattered on the inside of the casing. I had a Mamba Monster 2 ESC which is good for ~100A at 6S that barely got warm. My 12 gauge wires were getting a little warm in the air.

kiter_UK · Aug 7, 2017

Bigger prop means easier start but lower top speed I'm guessing. (More drag for same motor power)?

waterfox · Aug 7, 2017

Clarin said:
Hi Waterfox,

How many Kv is your SSS56104? I have ordered the same gearbox has you, but was wondering if I should order the 500Kv or 700Kv?

Thanks to all of you for sharing your amazing build

Clarin, I bought the 500kV SSS56104. Given that pacific meister succeeded with a 500kV SSS, 7:1 gearbox and 10S battery. I wish we had more data than someone's youtube video..
3.7V/S * 10S * 500RPM/V * 1/7 = 2643RPM

Using 12S with a 8:1 gear ratio should be safe at 2775RPM.

My previous attempt used 6S with 260kV = 5772RPM. Had a pretty low pitch prop.
I was looking at marine outboard motors: Mercury Optimax 150hp: motor spins at ~5500RPM with a 2:1 gear reduction: 2750RPM prop

Some interesting considerations are the max input RPM of these Neugart gearboxes are 18000RPM and the recommended input is 5000RPM, so I would be exceeding that at 22000RPM (12S * 3.7* 500kV). I'm planning to heat sink the gearbox.
Also, the 8:1 gearbox has a much lower torque rating than the 5:1. 6Nm vs 14Nm nominal output Torque.

I bought the 8:1 because it was available.I might have selected a 5:1 if I could have due to the max torque and the ability to spin a smaller prop faster. That would be less efficient, but maybe a little safer.

I am hoping to end up using the 126mm ducted prop here.
https://www.aliexpress.com/item/Dia-126mm-3-Blades-Kort-Nozzle-Ducted-Propeller-Assembly-for-Electric-Motor-Underwater-Thruster-Robot-ROV/32823114033.html

Logical, it looks like that is approximately the size you are using. Has that been working out for you?

parabellum · Aug 7, 2017

waterfox said:
through the air to the aluminum enclosure

You mean, there was static aluminium shell around rotating out runner rotor?
You know, if the leaked magnetic field of the rotor reaches the shell, then you engineered a nice magnetic brake, resulting in drag on the motor and recirculating currents in the shell, adding even more heat to the equation.
How big was the gap?

P.S. To all those out runner inclined guys: The shell around an out runner motor should not be made of any conductive material, and you should be sure that the air gap is big enough for magnetic field of the rotor not reach any static conductive components

Clarin · Aug 7, 2017

Thanks Waterfox, very helpful answer. I have just printed the nose cone, so still pretty far from riding!
I printed the cone on a FFF in Nylon and it seems ok.

waterfox · Aug 7, 2017

Hey Hiorth:

Beautiful design! so close to foiling.

Any chance you could give me the bolt hole pattern diameter for the SSS56104 please?

Hiorth · Aug 7, 2017

waterfox said:
Hey Hiorth:

Beautiful design! so close to foiling.

Any chance you could give me the bolt hole pattern diameter for the SSS56104 please?

Thanks

bolt hole pattern diameter on the sss56104 is 6xm4 ø30mm

LogicalDIYBuilder · Aug 7, 2017

waterfox said:
Clarin said:

Hi Waterfox,

Logical, it looks like that is approximately the size you are using. Has that been working out for you?

Click to expand...

I'm testing a few different setups with props 80mm, 110mm, and a couple different reduction gear drives. I ditched my Minn-Kota trolling motor and commercial suction cup system two years ago, just didn't like that setup on old windsurfing board... LOL funny but true...

Dhouser8 · Aug 7, 2017

Anyone have stl files they're willing to share? I'm a willing and able test pilot with a printer and a lake

I'd pay for a decent preliminary design too, just not great with CAD and wanna be a part of this badassery!!!

Jezza · Aug 8, 2017

I want to urge all of those building to maybe do a waterproof test with the motor unit. I found that mine was not sealing properly and as a result it has potentially saved me a considerable amount of money! If water gets in and even if the motor doesn't go, your bearings will definitely corrode in both the motor and gearbox. Other than that, it's great to see everyone's progress!

Hiorth · Aug 8, 2017

Jezza said:
I want to urge all of those building to maybe do a waterproof test with the motor unit. I found that mine was not sealing properly and as a result it has potentially saved me a considerable amount of money! If water gets in and even if the motor doesn't go, your bearings will definitely corrode in both the motor and gearbox. Other than that, it's great to see everyone's progress!

Did it work with O-rings and screws? I will make this on my next version, but I belive the O-ring grooves should be machined in aluminium (not 3d printed) to ensure a good seal. The O-ring should be compressed about 30% to obtain a good seal, see drawing below of tube edge and o-ring groove. Have discussed this matter with a couple of very clever oil engineers, that works with this type of seals daily. If you need to be extra sure you can add in two rings, and bigger is better! In our case 2-3mm O-rings is ideal.

Cheers

Hiorth · Aug 8, 2017

Dhouser8 said:
Anyone have stl files they're willing to share? I'm a willing and able test pilot with a printer and a lake

I'd pay for a decent preliminary design too, just not great with CAD and wanna be a part of this badassery!!!

Will make my Onshape document (contains all 3d files etc) Public so that anyone can copy download and edit parts. Will also upload to grabcad, but will wait until I know it works (hopefully this weekend).

Cheers.

Jezza · Aug 8, 2017

Hiorth said:
Did it work with O-rings and screws? I will make this on my next version, but I belive the O-ring grooves should be machined in aluminium (not 3d printed) to ensure a good seal. The O-ring should be compressed about 30% to obtain a good seal, see drawing below of tube edge and o-ring groove. Have discussed this matter with a couple of very clever oil engineers, that works with this type of seals daily. If you need to be extra sure you can add in two rings, and bigger is better! In our case 2-3mm O-rings is ideal.
Cheers

I printed some test parts (without screws) and lowered the unit 1.5m under water. Then left it for 1hr 30mins and pulled it out. Didn't take a huge amount of water, but enough to cause trouble. But I agree with the not using seals on 3D printed parts. I will hopefully be cutting the new parts on the lathe this evening and will then test the seals again.

lwienhues · Aug 8, 2017

Hiorth said:
Will make my Onshape document (contains all 3d files etc) Public so that anyone can copy download and edit parts. Will also upload to grabcad, but will wait until I know it works (hopefully this weekend).

This would be awesome, thanks in advance!
I am especially interested in the prop and duct if that turns out to work well. Why did you print the duct a second time?

Oh and hi everybody! We're a group from southern Germany going down the Pacificmeister route with the difference of a Neugart PLE40 1:5 and a Sroka foil. Printing in PETG. I'll let you know how things work out.
We've been reading along for quite some time now...

Cheers,
Lukas

Hiorth · Aug 8, 2017

lwienhues said:
Hiorth said:

Will make my Onshape document (contains all 3d files etc) Public so that anyone can copy download and edit parts. Will also upload to grabcad, but will wait until I know it works (hopefully this weekend).

Click to expand...

This would be awesome, thanks in advance!
I am especially interested in the prop and duct if that turns out to work well. Why did you print the duct a second time?

Oh and hi everybody! We're a group from southern Germany going down the Pacificmeister route with the difference of a Neugart PLE40 1:5 and a Sroka foil. Printing in PETG. I'll let you know how things work out.
We've been reading along for quite some time now...

Cheers,
Lukas

Had to print the duct again as the countersunk holes for the screws was too small, also changed the Stators slightly (made them with a less steep angle and a bit thicker (optimized for 3d printing), I also shelled non structural parts of the duct to make it lighter.

Tip; If you are going to make water tight seals with glue; PETG is very difficult to adhere! Make sure to test the glue joints prior to assembly. I would suggest SLS nylon for important parts, super tough and possible to glue with epoxy. Got the parts wee needed for around 100 pounds. from an UK based company ( https://www.3dprint-uk.co.uk/ )

Cheers

lwienhues · Aug 8, 2017

Yeah, I thought about the glue problem, too.
I will probably end up not using glue at all and try sealing towards the aluminum tube with ORings as well. But thanks for the heads up!

Since for me the 3D printing part is almost the most fun part, I am not going to give that away!

Eventually we will probably have all the round parts made in aluminium by a friend.

So by using SLS, you did not have to use any support material for the prop and duct? I am curious to see how this will turn out with my filament based printer. Pacificmeister seems to have successfully FDM-printed his prop. We'll see.

Electric Hydrofoil/E-Foil

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