Modified Hiorth-build from Sweden

Hey everyone,

Thanks for setting up this site and sharing info. I’m building a slightly modified version of the Hiorth borthers efoil.
I started back in the days when gearboxes were being blown in Norway :slight_smile: Becuase of this I decided to do a threaded fuselage to be able to service the motor/gearbox in a simpler manner. During the build we have gotten bettter knowledge of how to save our gearbox so in retrospect I wouldn’t really recommend my version over the glued version. Threads comes with a price in complexity during manufacturing of part and assembly. Anyways, its been a fun build and soon, as soon as the ice is gone, there will be time for a test ride.

3D parts are maked in SLS nylon and PETG.

The foil is a Nobile foil.

The board used in a carbon gong sup that been modified to carry the foil and a pelican case for the electronics.

Pictures of the build can be found here:


That looks fantastic Riwi!
I did the clear parts with my first build, looks cool.

You could suck water in from inside the mast, and have water shoot out the side of waterbox, this way you can see the stream and know its running while riding to keep things cool. Maybe a filter/mesh over inlet or extra larger water inlet hole in the mast to pre-screen out debris.

Have you been up riding yet and ESC stood the test of time?

Keep up the great work and thanks for sharing!

Thanks VeFoil,

I installed a water pickup in the foil fuselage, the one holding the wings. A silicon tube leads the water trough the mast and board to the pelican case.

Still waiting for my new pump. The geard pump I first ordered sounds like an airplane so I won’t be using that :slight_smile:
I ordered a diaphragm pump that’s less noisy. My experience with water cooling is not to pump the water to fast through the system. The water needs to be able to pick up the heat from the esc and this is done more efficient when the water flow is low, the question is how slow.



I bought a diaphragm pump but it’s sitting there as I never used it, instead used the pressure of duct to power the line to reduce costs, build time, breakdowns, and cost.

I’m not sure your statement is correct about slower water cooling better. I’m pretty sure a steady stream of cold water works better than a slow stream getting warm as it passes through the ESC :slight_smile:

Ok, do you have a esc with heatsink? I don’t dare run tiny esc without water in it since there is no heat sink.

I had a friend who was in boat racing that worked with water cooling and according to his practical tests that water needs to move “slow” in order to maximize the heat absorption, he was not cooling a esc but my guess is that the theory still holds. Time will tell!

Interesting although it does not make sense to me, but I have been proven wrong many times before. Anyone wanna chime in confirm which is correct as I will alter my water flow if I needed.

One thing to keep in mind, if it doesnt burn it works :slight_smile:

I have access to a FLIR heat camera, I will use that to see how heat build up in the pelican case after a run.

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The only thing to be careful with the YEP120A esc, is that that the middle heatsink is not attached to the cooling pipes. It might be worth your while to put in a new piece of aluminium with cooling pipes attached and then all the fets will be properly cooled.

Good luck, let us know as we are all here to learn!

Awesome Work, your board looks much better than ours :stuck_out_tongue: ! hope everything works out!

Looks really nice Riwi!

I’m also based in Sweden and am currently in the early stages of exploring options for my build. Care to share your experiences in a seperate thread/PM?


What build are you following? I did Hiotrs with a modification. I dont have my own 3D printer but I have a supplier in Sthlm that makes perfect parts.

Working with the board was messy, the rest of the stuff can be made in the living room.

All info regarding my build is here and on if you are following hiorth.

Good luck



Va roligt! Vilket bygge skall du följa? Jag körde på hiorts med en mod. Jag har ingen egen 3D skrivare men har en jättebra kontakt här i Sthlm.

Brädan var bökigast. Mycket slip, damm, kladd. Resten kan man bygga hemma i vardagsrummet typ.

All info finns här, på Facebook och på om du skall bygga efter hiorts.

Hör av dug om du har frågor.



Tjenare Rikard!

Har inte valt modell ännu, än så länge måste jag säga att Hiortharnas ser bäst dokuenterad ut.
Vet du om pacificmeister har någon liknande logg?

Jag har (som tur är) access till ok 3d-skrivare som fixar de flesta material.
Får kika på Hiortharnas igen och se var man kan tänkas sourca grejor ifrån. Det är oklart för mig vilken ESC man måste välja eftersom jag inte har koll på mängden ström maskinen kommer dra. Har tidigare erfarenhet av VESC6 och har trivts bra med den, men misstänker att vi kommer överskrida dess maxgränser för ström.


If you are going for the hiorth build it will take approx 70A to get you up and about 40-50 when foiling. that if you use the same components.

Kör du på hiorts sånär det typ 70A innan du foilar och 40-50 när du är på vingen. Givet att du väljer samma komponenter.

Hmm, det är fan ruskigt nära gränsen på en VESC 6.4.
Cont. 80A, burst 120A

Hur långt har du kommit i ditt bygge?

@AgileCow og @Riwi, Pasificmeister har uttalt at han ønsker at engelsk skal være språket som brukes på forumet.

Vennlig hilsen @Flex fra Norge :slightly_smiling_face:

Crap, so sorry guys. Thought this was a seperate thread.

Anyhow, if you have any doubts about my statements try google translate or poke me and I’ll translate for you.

Again, sorry! @Flex thanks for pointing it out

I heard good things about VESC. Does it have a shunt to measure, and limit, the APM going through the esc?

the board and foil are done, that dosent meen that they work :slight_smile: Still have some small thing is the electtronics to settle before maiden flight.

I am a bit unsure of how the hardware for it works, however in the configuration tool there are parameters that allow you to control max draw and set the limits.

It also allows you to use different types of remotes, set throttle curves etc. But yeah, what worries me would be the draw on these systems.

@Hiorth, @pacificmeister, @VeFoil and anyone else that has the propulsion system up and running. Would it be possible for you guys to share data from your draws (preferrably before the foiling starts so we can see the worst cases)?

The VESC has 2-3 shunts (depending on version) and measures the battery amps and motor amps separately.