For a single foil, I would highly suggest a delta-type shape or something with sweep-back or rake. Although it generates more induced drag, it is much more forgiving in terms of stall angle.
In the video, you can see that the foil has a larger, lift generating and load bearing front foil, and a smaller, stabilizing rear foil, to impart pitch stability. If the rear foil’s angle were adjustable, pitch stability could be adjusted.
although it is about RC aircraft, RC aircraft have the incredible similarity to surf craft of operating in the same Reynolds number range, so many parallels can be made.
All the resin and glass work is done, about 17 layers of 6oz and innegra with the 3ply inside. Its a hydrofoil but it looks like a big V shaped fin. Not as heavy as I thought it might be.
I just covered it in a thin slurry with micro balloons and I’ll start foiling it tomorrow.
I mentioned to Roy a few days ago that I got the idea to do this foil after I tried a tunnel fin.
Hi Clint, Im just making some broad conceptual strokes and hopefully some forward steps in foil design.
** If **I have a plan its to make a shortboard foil that works in everyday waves.
Heres a bit of foil design theory Im working on…
Looking at the standard foil for skiing, its mainly a flat plate designed for use at a controlled range of speeds…
But some boats and ships have Vee shaped foils where as the speed increases the boat rises and less foil area is required. So thats a shape i am going to use.
For everyday surfing its impractical to have a long strut where the rider is 3 foot above the water surface.
It looks cool but theres a lot of weight in the vertical strut so it makes sense to me that the board is a maximum of around a foot above the waves surface.
SO a short strut ( ~12 inches ) is the way to go and my previous prototypes have shown that a foil with a length (chord) of about 24 inches is suitably stable for surfing speeds.
Another prarmeter to work with is the area. So far Ive found that a foil, or a pair of foils , can easily plane on a knee-high wave with a combined area of around 250 square inches.
Doesnt seem too hard really? … to design a 12in X 24in foil with an area of 250 sq inches ?
3 ply and it will get a few layers of glass either side.
It’s one of two foils that I’ll make into a V-shaped surface piercing setup.
Ive gone away from the elongated ‘fin’ look as they flex under use and would need to be a lot thicker to maintain a stable and reliable shape under pressure. I’ve found out that concaves don’t work either.
The numbers are right on this setup to plane at a range of speeds but my hunch would be that the next generation will be even smaller, more compact foils.
Hey Surffoils you are still running with the patronising tag at the bottom of your page, is there a good reason why you continue to want to cause tension amoungst forum members?
Hi Marsh, here I am pushing the boundaries of experimental design, discarding conventions of hydrofoil design to build a unique surfcraft steampunked from scraps and sweat, and you focus on my tag.
But you’re tag comes up on everything you post, it is repeated constantly across 11 pages of this epic ecapade and every other thing you post on the forum. It is a constant reminder that you have a personal grudge against someone, monotonously repeating this insulting and obnoxious nuisance of a tag.
The importance of a hydrofoil boogieboard looses all credibility when you finish your post with an offensive tag, which you were personally asked to remove and declined. I don’t read your posts, I just see your tag and think you’re being a dick head.
Maybe the ‘Way To The Future’ is to forgive the past and move on.
Maybe “The way to the future” could start with the issuing of a sincere and open apology from the actual author of “this insulting and obnoxious” quote…
With it directed at the many “boring amature” members of this group that it directly offends…
Politics? I think I’m too honest for that game ha!!
I just thought that maybe it was time to let it go and move on, it’s a tension that the forum doesn’t need, but keep living in the past and carrying that baggage into the future if you want??
Surfoils if someone is telling you to keep the tag up they are obviously too weak to get on here and post how they really feel, you couldn’t get much lower than that, to that person I say grow some balls.
And the quoting people thing? If I wanted to stoop to your level I could go back through your posts and tag something you said to constantly patronise you, apart from making me look pathetic how would you feel about looking at the tag all the time, what would it do to the forum and where would that shit slinging mind game end?
Vanhelsing, 6 months on here, 109 posts, a lot of talking and no evidence that you can actually make anything with your two hands. You’ve been asked before to show something but you sucked your head right in and provided nothing. When are you going to debut to sways one of your boards?? A while back you gave some detailed info on vac bagging techniques, coff it up, swaylocks would be stoked to see what you can produce, it must be good??, or are you just a trolling bullsh!t artist?
..... the "mad science" continues ..... yeehaawww !
happy birthday / new year , mate ! ...
...so ....
.....when are waves due , on your side of the desert ?
On another note ...
good ol' Marty lent me his Canon EOS , while I'm recuperating . So , "maybe" I can [hopefully ] some better quality surfing shots soon , hopefully ...we shall see . As I always say ..."wait ...and see !"
he has some chip's fins to try out now , too .... :)
oh , and ...you might not want to have those exposed sharp screw tips in YOUR foot , by the way , Brett ....
