Yep , this guy is a super seriously fit feller !
He needs to be , the stuff he does in Hawaii and elsewhere , it seems....
I found some old surfing foils from 2006, starting with a few Twin lateral wing foils.
Made of polycarbonate, 2 Wings @ 24" x 8" on an 18" high Aluminium frame with the front wing set higher so it didn't ruin the clear flow for the back wing. And if the front wing broke the surface at speed then the rear wing would still lift from further back for stability.
The idea was that the poly would be indestructible and the Aluminium would be light and easy to weld and change.
The result was that with 400 square inches of lift it floated up off the wave at almost paddling speed. The lift from a foil quadruples as the speed doubles so this one wanted to fly so easily but the Aluminium frame buckled going into a tube.
I remember rolling with the board and then on the next wave it lifted but at an odd angle, looking under the board the whole frame had been pushed sideways in the last tube and was at 45 degrees off centre.
Lessons learned were that 400 sq in is way too much and 18 inches allows for a lot of lateral forces.
The poly wings were crudely foiled with a sander at the TE and LE topside only and as it's been proven, the foil profile isn't as important as expected.
But as expected, things are easily overthought and the basics are here to be found.
Highlights of years of experimentation. Golden. Thank you.
"Let the day's own troubles be sufficient for the day". - JC
So Greg, are you going to post up your theories and foils ?
Well, firstly, I'm not worthy. You and StoneBurner, are way out in front on this thing and I've just been a parasite. But, I'm about to take the plunge
A while back, when I was more optimistic about my knowledge and skills, I had some foils cut from HD foam by one on the RC airplane guys. I don't recall his name, but could easily find him again. Pic below. My intention was to build a mini-airplane foil in the "GO-foil" style. However, After digesting some of what has been discussed above, I think I want to go a different direction.
The key is to reduce the wetted foil area in proportion to the speed of the board. Several shapes come to mind, but I keep coming back the the oval or elipse. The problem with this is that there would be four surface penetrations to attach. And that is holding me back.
But on the plus side, the foil area needed is small and could retain the philosophy that Brett is following of having an easy retrofit to existing boards using fin box attachments. And compared to the mini-airplane approach the load is quartered. Also the with a proper oval shape the board would go rail to rail easily.
I'm reminded of that FarSide cartoon with the two professors at the white board with two gobs of equations separated in parenthesis by "And then a miracle happens". I need to bridge the miracle part.
Working on it, though. We'll see.
All the best, boys
One of my foil designs a week or two ago was an asymmetric ellipse.
At the moment, I have branched off in a new direction for maintaining proper lift at varying speeds.
My gestalt is I may have found my grand unification design. At least I hope. Lots of tedious (but not too complex) math based design left to do before a prototype is possible.
Swaylocks Surfboard Design Forum: thoughts & theories ... practical & theoretical
RAIL PROFILE http://bgboard.blogspot.com/2014/03/march-82014-afterr-seeing-recent.html
I like math. I'm reading "The Math Book, 250 Milestones in the history of Mathematices" C Pickover. You would like it.
all the best
The Grand Unification sounds good. Can't wait to see it.