Small Homemade Hydrofoil Boat

First trials of a small homemade hydrofoil boat.
The engine could not be run at more than 2/3 power because it was mounted too high. One can clearly see propeller spray, indicating the propeller runs too high in the water.
Therefore the top speed could not yet be determined, but at around 2/3 power, it reached 21 km/h. More testing to be done after modification of transom.

[@user-rm5cc1nh2w]

Well done Sir !!!

[@tgwhelan]

Very cool! That looks like the Pacific Northwest. Impressive speed for a 3.5 hp!

[@Vintabilly]

Lovely front strut setup. The leading skimmer works well. I'm very impressed with your pushrod controls slotted through the anti-ventilation fences. Well done.

[@Bazakilouis]

Wow very impressive. A flipsky motor and a flying rodeo prop with a VESC would make a very nice combination to make it electric

[@nosac1230]

Love it. Hope you can share more.

[@mhkatab]

congratulations..... simple and it works

[@DirectEnergySmirk]

Nicely done

[@michaelstanfield7530]

Is there a damping/preload mechanism or some kind on the ailerons? What kind of waves can it take before a feedback loop persists? Super neat I applaude your wonderful efforts 👍

[@stan-fo2po]

That is awesome!

[@jbreefer148]

Ingenious ❤ it.

[@allanpreston75]

Very cool! I am working on a similar project at University this year and would love to gain some insight from you if possible!

[@tsviper]

Nydelig båt! Første du har laga? Løysingane såg utrulig gjenom tenkte ut.

[@SciFiFactory]

Super cool! How does it behave when going through small waves?

[@bjofuruh]

I will comment on that when I have gone through some waves.

[@DGroenenberg]

@@bjofuruh have you gone through some waves?

[@Skidderoperator]

Big fuel savings & way faster.

[@JACK4904]

Have you compared the efficiency or speed differences between using the same engine in a conventional boat versus a hydrofoil?

[@Me30404938398]

10kmh normal vs. 23kmh hydrofoil

[@MrBrumla]

Good day. This is the best DIY hydrofoil boat I've come across on the internet so far. I have had the idea of building such a boat myself for a long time. Could I ask you some details about your boat? For example, what airfoil did you use for the hydrofoils, what angle of the hydrofoils to the fuselage do you have, etc. Thank you for your reply and your time. Sorry for my english but I use google translate.

[@bjofuruh]

I use the good old versatile Clark Y airfoil for the hydrofoils. It works great at these low Reynolds number. Angle of attack is between zero and one degree positive measured along the underside of the hydrofoil. They must be adjustable so you can find the exact angle for your speed and weight.

[@MrBrumla]

And can I ask for at least the approximate width and length of the wings? Thank you@@bjofuruh

[@bjofuruh]

@@MrBrumla The area of the rear foils are: 0.090 m², The front foil is 0.035 m². That gives a total hydrofoil area of: 0.215 m² Rear foils: 0.90 x 0.10 m Front foil: 0.50 x 0.07 m The all up gross weight is: 136 kg.

[@MrBrumla]

@@bjofuruh If I calculate my weight, the weight of the engine and the fuel, then in these items alone I will reach about 120 kg. My engine is a 6hp Yamaha 6DM 2 stroke, 2 cylinder. If I am very handy, I will manage to make the boat up to approx. 80 kg in weight. So the total weight will be approx. 200-220 kg. I am wondering if the dimensions of the underwater wings as you wrote to me will be enough, or if it would be better to increase the dimensions in percentage terms.

[@bjofuruh]

@@MrBrumla I previously had a heavier boat with a 5 HP engine and the same hydrofoils. It had an all-up weight of 167 kg. The top speed was 32 km/h. I think you can size up the hydrofoils to get the same wing loading as I had with this heavier boat. It worked great, and with 6 HP it may be fast.

[@user-eb4qk9lx3m]

Слишком здоровенные крылья.

[@michalczarnecki3521]

How did you calculate the size of the foils as well as the balance?

[@bjofuruh]

I made a spreadsheet with all variable parameters for the boat, so I could calculate weight, weight distribution, lift, drag, engine power and so on. If you are interested in designing your own, you should purchase Ray Vellingas book on hydrofoil design.

[@Vintabilly]

@@bjofuruh Ray's book is the key!

[@sangtsang7936]

👍👍👍！😲

[@AaronBrand]

Does it turn?

[@bjofuruh]

Yes! It can turn at full speed. Not shown here because the aileron mechanism was not yet fully adjusted, so it was still a bit unstable in roll.

[@kevintravis1807]

Wow I can fire myself. Tell the boss to shove his job.