Delta Hydrofoil Pro Tip: Why angle of attack is important

[@SparD4029]

I don't have too much front foot pressure on my Spotz 3...

[@werdasliest]

I always wonder if the front wings are at 0° AoA (in line with the fuselage) and the lift will be greated by the Naco profil itself. Or is it usefull to give the frontwing already an 2-4° AoA ? I am more interesstet in an foil for pumping . Would be also great if someone has experiance what kind of Naca will work out. Hearing a lot of diferent things at the moment. Naca 63 210 or 6412

[@thefoildesigner]

Most thread I have read were not very convincing. Has to do with the back ground of writers/shapers/foilers I think, most are purely experimenting and interpretation are not always accurate IMO. You often see that on how folks interpret the role of bottom contours on surfboards. Regarding your questions, I have been wondering the same for a while but some facts make me think that wing profile has little to do with the lift, or at least not as much as the angle of incidence (AoI: the angle of the front wing relative to the fuselage, AoA is what YOU control with the board pitch). Fact 1 is that planes can fly up-side down by compensating the down ward lift (if any) of the wing with the AoA. Fact 2, which is more telling for what we do, is that Naish moved away from asymmetric profiles few years back and are now using only symmetric profiles. If lift was indeed primarily governed by the profile, then you would expect NO lift on these wings, and as far as I know, Naish sells them by the metric ton so they work. At the end of the day, you as rider will adjust you board level (the AoA) to optimize the speed. If your AoI is off by several degrees, you may ended up having to pitch the board more than you should to correct it, which may not be comfortable, but theoretically doable. I recently built a large aspect ratio for a wing surfer with only 0.5 degree AoI. The goal was to be able to go fast and reduce drag and he loves it! For pumping, since speeds are rather low, I would thing a larger AoI is required, maybe 3 degrees. Finally, the thickness of the wing will most-likely affect the drag, so fast wings (like for kite or tow-in) are usually very thin and have (I assume) a low AoI. XXL wings for SUP are usually thinker, thus slower and easier to control and presumably have larger AoI.

[@SaulOhio]

If the hydrofoil is used on a windsurfer, is there any difference in how much angle of attack is needed?

[@aldenhaverly]

The angle should be between 2 to 3 degrees +SaulOhio

[@rikardwildare1714]

Hi! I am working on a electric hydrofoil board and I would love to hear your thoughts on the AOA of the rear wing when the forward force is coming from a propeller placed just above the rear wing. One would think that the angle would be the opposite from when a kite is used to "propel" the foil. What do you think? You can se the build on Instagram @wildtech.eu. Thank you.

[@junuhunuproductions]

Wow, your build is awesome. I love seeing the process of making :)