Hey Brett, fusing the front and rear foil was how I planned to use only two struts also.
Looking good Brett.
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Many possibilities and variations for sure. Much to explore.
The call from the hydrofoil surfcraft guy sounds interesting Brett
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I like to see how the design shape changes with several different dimensions before I make a final selection.
I like template no. 4 !! That , 16-18" tip to tip , on an 8" deep spitfire base , with possibly a back one , dimensions maybe around ? 5" base , 12-14" tip to tip , and maybe ? 6" ‘chord’? …that , placed in a ‘spread apart inline fin setup’ , would be something I will try , at some stage . [There is a tentative test rider on the horizon , too !!]
If you mean the first eliptical foil (4th from the top), it has a 7" chord at the center. It has a flat surface area of 145 sq. in. and a wingspan (tip-to-tip) of 26.4". The last eliptical foil, no. 6 (8" center chord; 145 sq. in.), has a wingspan of 25.1". But the areas are adjusted (increased) to accomodate down-angled tips for all foil templates pictured.
This is why I like to look at scale templates first. You need to know how much surface area you want/need before you play with foil shape and dimensions.
Hows yours coming along FIns??
surfoils, what sort of product is this other guy selling? is it a hydrofoil for surfboards or what?
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Hi Brett, How’s everything??
I see what you mean about the different tip angles,I believe that trying to put them on the same wing will not work very well…
mostly because it complicates the flow so much, they will likley hinder each other.
I would think putting the downturned tip in the back and upturned in the front would be the way to go…(just my opinion though)
Here’s my latest line of thinking,
Guaranteed to give Ben nightmares…
Just kidding I’ve actually been building a new 12" straight strut this time with no flex,it should be ready for this weekend if there’s any surf…I will be trying it out on the bodyboard, My son is having a bithday party at the beach so there might even be some footage, but that’s wishfull thinking…
I thought I’d post this pic to show the different setups I’ve tried,what I learned from them is that simplicity is exremely important, the more consistent the foil is from the water’s perspective the fewer suprises you’ll have while at higher speeds.
That is one of the reasons I’m working on the monostrut it simplifies the flowpath even more…good luck
Till later,Dave
45 degree down-angled tips is what I am looking at Brett.
Interesting looking foil you have there Dave.
Just a quick response without elaborate discussion:
What I like most about the the 45 degree down-angled foils is that vertical and horizontal lift vectors are equal (have the same magnitude). They also can be surface-piercing, asymmetric foils with symmetrical outlines.
The greatest lift force is perpendicular to the bottom surface of the asymmetric foil.
With 45 degree lean angles (or greater), centrifugal/centripetal acceleration may be a more important consideration than gravitational acceleration.
“Earth’s gravitational acceleration is 32 ft/second per second. Times 3 = 96. So if my calculations are correct, a turn with a fixed radius of 10 feet at 21 mph will produce a centripetal acceleration of 96 feet/second per second.”
On hiatus for a while…
did I miss something?
hey Surffoils, you're not on holiday are you? You've got fans to entertain!
Since these days 4 years ago in 2013. things have moved forward with Go Foil making a business of foils for SUPs and paddle in shortboards.
But Ive got a new idea to recycle old surfboards into foil boards with just a few attachments.
Bring it, Surfoils. Ready.
All the best
Will do Greg !
First off I love what Go Foil has done, theyve put a foil on a board, got Kai to ride it and now … Foiling is more acceptable to the surfing public. It really is available to everyone.
Years ago I did it with a custom board , custom struts and foil , so theres 3 basic parts to getting foiling.
The foil and strut has to be custom made for the purpose and foiling deep water crumblers is different to surfing mainstream shallow reefs and hollow beach breaks. Sure you can go looking for specific wave types to ride but I wanted to make foils that work in everyday waves too.
Foils arent skimming, they sit inside the wave and are subject to the internal maelstrom, one of the first lessons I learnt was that you need to keep the struts short for several reasons…
1 beack waves often break in shallow water
2 the forces IN the wave create a rotation thats too strong to fight, especially in the tube, so keeping the foil closer to the board lessens the leverage the wave has and makes it easier to control. When Ive pulled into even small tubes and the board/strut and foil are straining to spin out from under me and chew me up like a steel bladed turbine, you want to put the physics back in your favour.
3 from ‘paddling speed to full lift’ on a foil takes just a second, if your strut is 3 or 2 feet long youre very quickly a lot taller. When you pull into a head high barrel and rise up 3 feet its now only a waist high barrel.
Ive tried single struts, inline doubles and 3 and 4 strut arrangements, with more struts you get stabilty and you dont need a specialised connection like a tuttle box.
With multiple stuts you could use simple ‘off the shelf’ connectors and spread the physical load.
With ‘off the shelf’ connectors you could recycle any old surfboard, as long as it floats and paddles so theres no need to buy a specialised foil board.
On any morning you can put in a few connectors, attach you struts and foil and youre in the game at minimum cost.
Interested ?
more, more!
Excellent idea Brett.
Question, though. The videos we’ve seen of Kia show him pumping the foil back out to the line up. It looks like as hard as that is it would be harder still with multiple attachments.
Dang it !