SF, cool to see the new foil set-up assembled. I’m looking forward to video of it in action.
Hang Loose
bodyboard.
[IMG]http://i153.photobucket.com/albums/all the bolts and screws sticking out.
A basic in, just time c and a"Hang Loose"…s expression !!
This was a great foil but some components need to change.
the front corners have to be rounded for safety and smoother intro into turns.
and the central beam needs to be shortened into a ‘pod’, keeping all the area up front.
The next foil is built around this front aluminium frame.
With side arms and centre pod made from ply and glass.
the arms are 2 layers of ply with 2X 6 oz inside and 1 X 6 oz wrap.
Centre pod.
under construction…
Fascinating…
Wow - captivating stuff here. Can I place my order now? I want to fly too!
These are the voyages of the starship Enterprise… to explore strange new worlds…
Here’s a few pics of Terry Hendricks doing his hydrofoil bodyboard/paipo thing last year.
First pic with the board we’ve all seen with the classic adjustable foil arrangement.
and then this pic dated 9 months ago in July with a totally new design, looks like an in-line version.
Its looks awesome ! I wonder how it rides. …?
I’d love to know what he’s up to.
Picked up an old bodyboard to make into a foilboard.
i screwed a dozen white plastic drywall anchors into the underside…
And then put screws thru a 10 in wide ply strip into the anchors.
The struts for the foil are then screwed into the ply.
I keep coming back to this foil…
The length gives it smooth lift and the down turned tips give great hold in the face when it gets hollow.
but the rolled tips were too far back.
looking at some pics makes me think I need to put a more lateral foil at the front so it can penetrate for hold like the front of this foil.
so the plan is to keep a longitudinal planing section at the back and make a lateral foil for the front.
Something like this for the front lateral foil…
It’s a double Spitfire fin with a 40mm concave. Heavily foiled with a maximum thickness of 5 mm. (3/16ths I think )
Most of the riders weight is on the back submerged foil (green)
while the front lateral foil will be a surface piercing foil (black) that controls the pitch angle.
I found a test pilot who’s ridden the prone foils with a view to jumping on the shortboard version. He’s riding an earlier foil thats stable and easy while I work on the more technical possibilities.
i'm trying a extreme low aspect foil on a windsurfer. After I asked you about the profile I decided to use a profile. Stops accelerating at a veryveryvery low speed, so maybe I'll follow your example and make it flat.
Surffoils, saw your post above w/ Terry Henricks pics and photos caught my eye first, before reading text. First thought was, “Wow, Surffoils is getting so hydronamically experimental he is starting to look a lot like Terry Hendricks!”
Nick, thats cool to put a foil on a windsurfer, what sort of arrangement are you doing and what length strut/s ?
I hope I answered you earlier question ?
Looking at Terry’s foils…
it appears hes gone for a low aspect too and also given it a foil, but I ask anyone trying a low aspect foil to ditch any foiling and go with a flat plate and just taper the edges, that’s all that’s needed. I’m sure a flat plate doesnt perform wonderfully as a vertical fin but as a horizontal hydrofoil a flat plate is magically simple.
The double Spitfire is 2 layers of 1.8mm ply with a layer of 6 and Innegra sandwiched between.
And then a layer of 6 over the outside.
DrStrange, I’m just amazed that Terry’s still working on the foils and developing new designs. Hopefully he will jump in on this thread at some stage…
Glassed 6 top and bottom.
and ready to go into a new configuration, one longitudinal foil at the back and this double spitfire lateral foil at the front.
Longitudinal foils are gentle, sweeping and easy to control but Ive interpreted some feedback that leads me to try a single lateral foil at the front to look for better high speed performance.
At low speeds, sufficient area gives lift, but at higher speeds when the wave face is vertical, a more pentrating foil is needed, with a more sensitive AOA.
Trimming at angle A the foil tip is almost horizontal.
turning into the wave at angle B, the tip presents a greater angle of resistance to the upward flow.
If the effect is too strong I wouldnt reduce the overall width of the foil as the penetration is how hydrofoils function but i would increase the taper at the tip or reduce the overall side to side roll/ concave.
See what happens huh ?
Now youve gone back to the sideways foils, isnt that what the experts said would work?
When it comes to paddle-in “low profile hydrofoil” surfing, surffoils has pioneered many different prototypes, including tests with traditional foil configurations.
Hi Clint, yes, lateral foils are ubiquitous in the history of hydrofoils but those foils are based on straight line forward speed on flat water and not surfing waves as we know them.
At low speeds, it all Newton, morphing to Bernoullian theory at higher speeds. And that’s great for designing foils for surfing. Most of surfing is done at low speeds, not just takeoffs but during and after turns the forward speed can drop significantly ( think stalls and snaps) irrespective of the rotational speed. Lateral Hydrofoils don’t respond to rotational speed, but ‘long’ (itudinal) foils are great at low speeds.
Thats why Ive had such great performance with ‘long’ foils so far. Most of my foil-surfing has been at low to medium speed on average waves.
However… As i got better at riding the foils and I took bigger waves and as the speeds increased, I didn’t think the ‘long’ foils were keeping pace, something wasn’t as good as I thought it should be, so a change was in order to see how far or fast things can go.
‘Long’ foils are good up to a moderate speed and then a different foil design is needed to make the Quantum Leap up in speed, and I think its going to need ultra thin high aspect lateral foils to make that jump, but the ‘long’ foils need to be retained for all the low speed lift.
It’s just a matter of how and where to blend two different foil shapes to get the best result.
Clint , hang in there, I’m doing my best to keep you entertained.
Hi guys, I'm the test pilot for SurfFoils chiming in to talk a little about how it rides.
I've been riding the square yellow aluminium foil on a bodyboard to get started, mainly to get my head around the dynamics of foil surfing versus regular surfing.
Its been a pretty amazing experience so far and I'm very thankful to SurfFoils for having me on board.
I won't comment too much this early on, but its a very different type of surfing to what we are all used to. Its very different to "surface planing" which we are all more than familiar with in surfing, such as getting the speed from the drop in your fall line, and then pressuring a rail into a bottom turn creating lift and speed around the water surface area to project along the wave. Connecting turns "cutting" into the waters surface.
Its more like surfmat riding, or maybe even bodysurfing, where you are actually surfing the power WITHIN the wave, underneath the surface of the water (at low to moderate riding speeds that is).
Once you get a nice angle with the foil at takeoff and pressure the foil into that energy under the water, you immediately lift up and takeoff with a buttery smooth speed and feel. The power seems to be closer to the upper area of the wave in a medium to soft wave, and once you have it on tap you just glide along with an amazingly smooth speed that stays very constant provided you keep the angle okay. You can turn left and right, and perform swooping cutbacks, trim along the wave, etc. Seeing as it rides the power IN the wave, I've even ridden a wave than ended up in the channel still surfing behind the unbroken lip on just the swell (not broken wave) for a long way. Its very intuitive surfing where you're trying to feel out the power under the water to get up and running, and once you have it, where a surfboard or even mal would start to fail you just keep humming along at a constant speed until the wave is well and truly dead.
The hard part is trying to find the angles early on to get that energy on tap, and when you don't get it right funny things can happen. It can just immediately "power down" and stop/flop/throw you right off the front like a skateboard hitting a kerb. It can also be effected by sideways power, losing stability and throwing you off sideways. Its pretty funny when things go wrong, its like theres an eject button.
Nevertheless, basic dynamics and feel are in place now and step two is to surf the standup version and learn how pumping, pressuring, shoulder torque, etc. effect the ride. The very least we'll have is a video of it being surfed, being surfed well first surf is another matter. It may be all good from the get-go, but it may require a little practice before any decent waves are linked! :)
Ill chime back in later with more ride reports.
CC,
I found your account interesting. One of the things I liked about Jack McCoys’s recent movie was the foil surfing - just the speed and gliding across swells before they starting breaking.
I spoke to Brett a while back and one of his comments that particularly interested me was the capacity to slice through white water.
As you say, I look forward to seeing how these boards ride in decent sized waves.
Bob
Alex, thank you for the review.
Its great to read an independant assessment and work out how I can make it a better experience for you, but it appears you’ve enjoyed your first few weeks with a hydrofoil.
Bob, its certainly a different way to surf, as Alex said…
"you immediately lift up and takeoff with a buttery smooth speed and feel. "
On Thursday Alex is picking up the shortboard hydrofoil and then its up to him to choose when he wants to be the first shortboard hydrofoiler. On the day I will be taking video from the water and within 2 weeks Ben Chipper will be in Sydney ready to photograph anything that moves.
Onward and UPward !
Only just saw your message
Your project caught my intrest because you also need sideways resistance (you need it in the pocket, I need it because of the wind in my sail).
I made an inverted V with a mostly straight leading edge, no struts, only a horizontal beam made of wood in which I put the finbase (to connect the foil to the board).
The test was in too much wind and now the connecting beam looks like it exploded!
It wasn't meant to fly,only create lift to put the board on the water with less wind then is needed with a normal fin.
Next step is to make a stronger beam and get rid of the profile on the foil.
Unfortunately, Lots of idea's but no place to work, so it may take a while.
Here’s the setup I rode today in 3 to 6 foot face.
It was an absolute blast, needs to go into DOH waves to check its high speed handling but the double spitfires front and back were a lot of fun… slidey, fast, grippy, great swooping cutbacks totally clear of the water, but not perfect though.
For the moment I’ve converted to a lateral foil at the front but a longitudinal foil at the back gives more consistent control. Sadly my GoPro sd card was full after a few waves today so Ive handed the card over to my tame IT guy to put together a highlights video from the past few sessions.
Here’s tomorrow’s setup…
you can see the different orientation of the foils…
And the specialised front strut…
And the different heights of the foils…
I prefer a twin foil setup because the foils can be moved further apart or closer together to alter the performance.
hang in there for the new video…
I’m loving this. !!!