Actually it depends if the goal is to accommodate one or two seated persons that need to travel in a horizontal position.
What is true for a weight shift controlled craft (standing position, Evolo Project even a Moth) is not true for a craft using a seated rider looking for flight stability without possibility to move one’s weight. Imagine the Evolo project with a seat : possible but not comfortable at all. Worst still with two seats.
The stability of N-seated boats can only be got by spreading the lifting surfaces apart on the corners of a triangle (Tri-foiler, Hydroptere, Project Dared, …) or on the corners of a square (https://quadrofoil.com/ Slovenia) or two lifting planes with two pair of masts (Seabubbles, …).
IMHO a fuse is not suited for a N-seated craft.
Yes, three or four masts is less efficient than one but each can be 10mm-thick, and they won’t bent since two is always better than one
I don’t mind that you disagree, you are entitled to.
I don’t understand why you’ve added a second person though as from what’s been built they seem to be happy with one person on the board (plus a gokart can’t fit 2 anyway).
I’m also not talking about having the foil set up for weight shifted use (you assumed that). With this project you could use a mast in the front for a high aspect wing (they are super stable) and then a separate mast at the back with a large stabiliser that controls turning and pitch. That would already reduce drag.
You’re right but I don’t see the sales taking off without a two seater in the range to share the stoke
I mentioned the abandon of the fuselage for seated riders because:
1- Toto44 was suggesting the use of a fuselage that is not compatible with a seated riding position.
2- you didn’t mention two T"s in your post but nothing and a front wing and a big stab so implying a fuselage.
That’s a long lifting surface (2+m ?) not easy to transport
Two T"s are of course compatible (Moth’s, FoilKayak, Kotaro Horiuchi project as early as 2007 here below … and have often been used for one or two seats plus the strong bending forces on the single masts in the turns. That’s also why the J foil solutions have emerged (see quadrofoil example above).
That implies nothing about a fuselage, you made that assumption. If you read my initial post, I simply said Toto44 was right about the drag from "3 masts in the water and then I proposed a different wing setup.
That would be a lot easier to transport than a Quatrofoil (which is huge). Especially if it was cleverly designed and removable.
The 20mm Axis foil masts would be a great platform for a dual mast setup and strong.
While some of the other designs use J-foils and other types of foils, you cannot argue that the T-foil is much simpler and just as effective if you look at the new AC75 boats which only use 2 T-foils at a time when sailing.
I have some experience with this concept as well, focused on Big foil at the back and tiny foil in the front:
I have been a participant in the TU delft team in 2014 ( two foil concept ) :
And I am now in the Dutch Solar Boat team ( 3 foil concept, large rectangular black boat @2:10 below ) :
In my / our experience, where the small/big foil is placed depends on the weight shift contribution due to the acceleration / acceleration. In electric high powered boats such as solar boats in this example with about 7kW of engine power, the desire was for the two foil concept to have the small foil in the front. This was also practical for the weight distribution in combination with the hull shape ( large in the back → battery in the back ).
Ah coowl! This was probably still in the development / test phase, the PV panels seem to be missing. But they have switched back to 3 foils. I don’t know the exact motivation but from what I understood is was mainly for roll stability ( especially for side winds ).
TU Delft actually has electronically controlled foils which is very fancy and allow for super low drag racing. We still have a mechanical systems which has the advantage of being easy to repair when you are drunk .
They used it to race last week. The official races were cancelled so they did a one day session on the Ketelmeer with 3 other boats I believe. The foils and struts which hold the gears with an engine in the hull is pretty cool!
I knew it wasn’t recent but didn’t bother determining the exact date.
@Jezza, in this article, you also have the explanation why double T-foil (or line) setups would work but however would not be a commercial success unless you limit the max speed to 15kmph. AI has obviously a role to play.
there’s no video so we can all watch as the Yamaha team struggles to balance this thing and stop it from toppling in the turns. Without a wide track, or the ability to use your bodyweight to balance, driving the OU-32 might be a bit like the first time you try to take your training wheels off a bike. And that’s the kind of kinetic problem the tends to get the mind ticking over.
x x x
While the OU-32 never made it to production in the 1980s and isn’t likely to in the 2020s either, it could inspire future vehicles – at least, that’s what the Yamaha team will be telling management.
@FriFoil should be interested. @JTAG Would you describe your control system ?
1- in short radius turns (less than 5 m), what is the max speed allowed with two / three / four T foils, repectively line / triangle / square setups?
2 - Is Artificial Intelligence involved or a classic height sensor / IMU and PID thing ?
3 - is it applicable to efoil with 2 T’s or with a fuselage ?
They are way too tiny and are obviously going to be unstable. There’s on obvious reason Yamaha ran into issues. I’m not even sure where you got the 15kph speed from…
I am proposing an HA foil wing which is much wider. The TU team has already proved this works well.
You connected the names? If you did some research you’d see they are different people running different organisations which are 68.8km away from one another…
Self-stabilisation is done thanks to the foil configuration, no electronic control !
Thank you for your proposition of @Flying_Rodeo we will check it out
For reverse we had to implement electronic relays (see image)
We chose this foil configuration because we already had a prototype that worked very well. We built it at HEIA-FR for the HydroContest event. At the end of the contest I tried getting on it (it was remote controlled) and it foiled pretty good. At this contest EPFL had a two T foil config and we beat them in final. They had a lot of stability problems when turning. So we prefered using our foil config for our 2 prototype.
I am not an expert in foil configurations and your questions are very interesting @SoEFoil. We are going to test our prototype 2 very soon and will be able to answer your questions than.
We are trying to build a seated foiler that doesn’t require any particular skills (equilibrum and piloting) and we believe are configuration is best adapted for this purpose. Check out our website www.fri-foil.ch and our instagram @frifoil if you want more information on our project
At slow speed, everything is possible. But turns at a higher speed with too long high aspect foil usually means breaching the water surface that could mean boat stall, which is the plague of passenger hydrofoil boats. This explains the small size of the OU-32: not to breach the water surface.
Little did I know that someone would bounce back from that with something other than a touch of humor. I am speechless by so much negativity.
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