I get the feeling that there are plenty of people that would be able to build beautiful hydrofoil wings, but might just be held up by the doubt of wing profile selection.
You often see topics pop up discussing one or two random profiles, that got grabbed from somewhere. Well I would like to see more people making good (and beautiful) backyard wings. So if you let me know a few design parameters I can run a optimisation program that will select the best wing profile for your specific hydrofoil (NACA 4 and NACA 5 series only included at the moment, plans to expand in the future). I have had a lot of fun building and riding my own wings. It is a great feeling riding your handmade design that also rips.
Here is a example for a typical kite surf wing. Designed for:
Velocity range 20-40 Km/hr
Wing span: 650 mm
Area: 1200 cm²
Required lift (Rider weight): 85 Kg
Results show that the NACA1505 would be the best selection, with a weighted average drag of only 1.5Kg. However NACA1706 could also be a good choice, with slightly higher average drag, but a slightly lower stall speed of 14.1 Km/h instead of 16.4 Km/hr.
Notes:
The program assumes a elliptical wing profile will be used. Optimisation is based on the average chord, calculated from the Surface area and Wing span.
(Edit: from version 3, Apr 2021, Elliptical, Tapered or custom plan can be calculated accurately and average chord is no longer used. Wing is calculated for various chord lengths along its width)
This only looks at a ideal front wing, additional inefficiencies due to tip losses, tip washout and extra losses due to fuse, mast , stab is not considered here. Take it into account separately if needed.
NACA 4 and NACA 5 series only included at the moment, plans to expand in the future
(Edit: fron Version 2, Sep 2020, added basically all the airfoils one can find on Airfoils.com, so up to around 2500 airfoils. Lift induced drag was also added.)
The results are weighted a bit to give more importance to performance in the middle of the selected Velocity range and less importance near the ends.
(Edit: from version 2, Sep 2020, results show a balanced selection (weighted more to look at the middle of speed range. As well as a High speed and Low speed weighted selection for consideration.)
Xfoil is used for the basis of calculations.
Again, this is just to help DIY'ers.