What do you base this on?
Typical EFoil rider cruises at 30 km/h, probably not much different that typical wingfoiler.
World record wingfoiler is 77 km/h
World record Efoil is 66 km/h
Either of these records is insanely fast on any foil
I base this on my experience with radio controlled planes: As soon as the motor is powerful enough, aerodynamics become less important.
Or as Enzo Ferrari said: âAerodynamics is for those who canât build enginesâ.
This is certainly only true for efoilers like me that still have a lot to learn.
This is the resume of âThe Bearâ. A lifelong passion spent in watersports so the things you are attempting to decode he has likely already figured out.
Itâs great that you are passionate about the science of all of this but important to remember the practical real life data thatâs already out theređ
No, basic foils seem pretty simple, at least the first 90% as you wrote.
All my foils worked well enough and yours does look well designed.
I was trying to say, how it is really hard to attach the way a foil rides exactly to any one of its attributes, because they mostly influence each other.
Did you compare your foil to any other âknownâ foils?
From looking at your layup, I would expect the wing is not nearly rigid enough.
I stopped doing my own foils, when I noticed how even with 18 layers of uni directional carbon the wings were too soft to know if the instabilities in flight were due to my design or simply due to the layup.
Most brands did switch to ultra high modulus carbon layup, which is really hard to get your hand on.
In the beginning of mass market foils, many wings used winglets.
At this point, no company uses them anymore, as far as I know.
I just want to have fun designing and riding my own hydrofoils. I am 30 years too late to this, but still having a lot of fun thinking about all this!
I only have one commercial beginner foil from waydoo that I can compare to. The rest is a bit too expensive at the moment.
I am surprised that my wing seems to be rigid enough up to now. The core itself (PLA+) is very stiff compared to foam. I have only a single layer of 160 g/m² glass + some carbon rovings. It is probably stiff enough because it is pretty small and has low AR and 9% thickness. The next wing I am making will have higher AR and will be laminated with 160 g/m² carbon. I will try to use vacuum bagging.
How would I notice that it is not stiff enough? It feels very good up to 35 km/h. I didnât try more at the moment.
If you have access rent a Fliteboard or Lift for an hour and try that. You will know what a good efoil - foil should feel like.
To me Waydoo has a reason why they are less expensive than these other brands who have been at it longer so perhaps their foils are not quite as good. I have never ridden any of these myself only Slingshot for a short while before I went with Gong so want to qualify my âguidanceâ 
Guess it is hard to explain, if you do not have a reference.
Speed in a straight line will not be a problem.
If you turn hard or have some turbulent water, a soft foil will feel increasingly unreliable, making it pretty hard to turn in an efficient way.
Small size and low AR will help.
9% is less than most foils I measured.
F-One, Axis and Duotone all were in the range of 11-12% last I checked.
Probably also to get them strong enough. Many of the newer wings have like 100mm chord at 1000mm span and going from 9% to 12% get stiffness to 175%.
Thanks for the info. I think I will just buy a used sabfoil leviathan and make an adapter. Then I can compare and play around. Do these also work at approx 3 deg angle of incidence?
Or maybe this one? Looks like a square adapter would be easier to manufacture:
I do not think many release info like that.
All the newer Axis foils have 1° angle of attack of the frontwing to fuselage and 1,5° stabi to fuselage, so 2,5° total.
If you can get used Axis wings for a good price, that also might be a good option.
There has been a guy, who did a 3D printed fuselage for those (including 3D model), so it could be easy to adapt. But I did not try it.
I did some research and may have a lead for you to explore. My intuition about the fence changing the handling characteristics told me to think about the spanwise flow on the wing. After all, that is really what the tip controls. So if the span wise flow on the top vs bottom is affected, how could that change the performance?
From my preliminary research, it seems like the roll stability is coming from the vortex on the wing tip. Because water is so viscous and dense, a vortex which is âattachedâ to the wing tip will damp the roll rate significantly. Think about basically a balloon which is trying to move water out of its way as you roll the board, that is what the vortex can do.
Notice how on aircraft which prioritize efficiency, the tips are facing up? Upward pointing tips works to minimize the vortices much better. Reducing the size of the attached vortex allows for quicker roll rate.
In summary, the tips down creates much more span wise flow on the top of the wing and a larger induced vortex on the tip. This vortex is attached to the wing and becomes a factor in the roll rate or stability of the wing.
I would check the power efficiency of the wing with tips up vs down at a lower speed near stall where the AoA is high to validate this theory.
Fun topic, thanks for sharing! Great to see your creativity and motivation to test new ideas!
Experimenting is fun AF, hope you keep at it! I think of it as a car or bike on a banked track being similar to front wing tips down (or edges on a snowboard), and the inside tip grabs or digs in. Upward tips allow the wing to slide or slip and not bite into a turn (like soft rounded rails on a surfboard). I have found the opposite on the tail and upward winglets seems to lock in the feel more. Trying popular brand designs quickly adds to ones knowledge of what works, and I needed to reach a level or proficiency to really understand and feel what a foil is actually doing.