Gearbox DIY (4,5:1)

This is awesome Andreas !

Fantastic work and thanks for sharing! Indeed will be interesting to hear about the durability over time.

can you explain to me what is the purpose of this piece and can also give the dimension of the spacers, thank you

still a small thing the reference 22444500 Madler is an internal gear with 45 teeth is an outer diameter of 70 mm, is this the right reference, because we need 56 mm outside, thank you

The part on the picture is to fix the motor in the tube, it is screwed with the tube, and the ground plate of the gearbox is the opposite part.
The diameter of the gear has to be adapted, the step file shows the diameter and the position of the M 2.5 holes for fixation.

The spacers depend on the position of the motor pinion, so that all gears are on the same level.
I do the fine adaptation with 0.2mm spacers.

How is the gearbox holding up? :slight_smile:

Very nice project. Why did you increase the pod size ? What do you think of your Slingshot Fwind 1 windfoil ?

It is easy to mount / unmount, and I can change the angle of attack by cutting the mast little bit less or more than 90 degrees. (Change the angle of the tube to the mast and / or the angle of the fuselage to the mast.)

The Foil is very stable but very heavy and for windsurf foiling, there is needed some concentration to control it. For e-foiling, it is easy to control and works good.
Next season, I will test the infinity 76 front wing instead of it.

The gearbox was used meanwhile about 10 times without problems.
At the moment, it is too cold, and I use the time to build a board.

Yeah, warm days coming soon, fun days are coming!. Do u use graphite grease or some kind of a lubricant or u drive it dry? Get any vibrations between gear and propeller?

I use grease that is usually used in bearings.
The gearbox has a running noise, caused by the big teeths of modul 1 producing more bearing shake than smaller moduls but this makes it stable, and it’s no problem so far.
There are no vibrations to feel, it runs very true.

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In the winter month I found the time to build a board, the gearbox was not changed any more an works well so far. :grinning:

Electric Hydrofoil Board


Hello Andreas,

Thank you very much for sharing all this information.

May I ask you how did you get these pieces made ?

Do you think it would work if these pieces were in plastic ?

Hi Nicolas,

the pieces are made from round alu material in diameter 16 and 8mm and flat material 8mm thick.

To cut the round material I used the chopsaw, the rest of work was done on my small DIY CNC milling machine.

The load on the gearbox is really high, round about 100 kg over all have to be put above the water, and it gets hot in the tube what is really terrible for the durability of almost all plastics. So I think that these parts too only work in alu or steel.

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Thank you for your answer Andreas. I hope I’ll find a way to make these pieces in metal.

I have one last question :
Where are these 3 and 6 ball bearings going ?

Hi Nicolas,
they have to be turned or milled (press fit) in the gears lying flush with the face. There are two ones on top for better durability (5x11x4) and one on the bottom (5x9x3).