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  1. #43
    The thing with anything new is you do have to let it find its own feet.

    As we know, kiting started off as a light wind alternative to windsurfing – and it's certainly simpler and easier to learn. But good kiters nowadays tend to wait for stronger wind. It's clearly a different sport with its own following.

    In foiling, there's the theory and then there's a lot of variation in rider experience – and then the diversity of the kit available.

    I have yet to see anything in kiting that would give me more than a big slalom board would give, but, hey. Give it time.

    The kiters went down the foiling development route earlier, and their foils are now pretty efficient. They do get going in lighter winds but in choppy/rough water and in strong wind the skilled foilers still do well on their foil boards, being clear of the water.

    So only time will tell where the optimum windsurfing/windfoiling set-up will lie.
    The PWA foil racing scene should help optimise the gear over the next season or two. I enjoyed watching they live coverage of the exhibition races held last season.


    I still think the benefit for the average sailor will be in no longer needing a huge rig in relatively light wind. Once up on the foils, most say they like the feeling of flying silently above the water.



    On topic, I suspect that adding horizontal mini foils to an existing single fin, will just add a load of drag, and make most boards plane later, and slower. I predict they would also be slower to turn, and crap for jumping.
    Last edited by basher; 22nd January 2018 at 09:44 PM.
    Now back in the UK.

  2. #44
    Senior Member tooold2dance's Avatar
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    Quote Originally Posted by tooold2dance View Post
    Their are other companies making the mini foil. Seabreeze forum has had several threads on these mini foils. It inspired me to make one, I used K4s , Fang as the fin and a set of quad fronts as the wing, 36 and 15 Leons stiff.
    I installed the wing with 1 degree angle of attack, rather than fit at the bottom , which I consider too fragile ,with obvious bottom contact, the wing it fitted about 1/3 down from the base, powerbox. This I used on a Tabou Rocket 140 which I have a lot of time on. Day 1 showed a lot of promise, the wind was near 12kts, the rear seemed to lift some, not near out of the water, their were no adverse reaction, a fast turn wasn’t possible to judge. I considered a slight improvement over a single fin. Day 2 with wind more like 13 + it’s right at the planing threashold for single or tri fin, the mini foil was draggy, hard to plane.
    Change to a single, performance much better. My conclusion is in lower winds the mini foil ‘could’ increase some quality time, at normal planing conditions its not an improvement. If one is already on their largest sail, to suggest go larger is a mute point.

    The construction was to run a carbon batten through the fin into the base of the wing, epoxy with SGlass as support once set. Minimumal use but no structural issues thus far. Will get tested more in April ‘18.

    The claims by the companies who are producing these IMO are far fetched, using % of this and that over, what.

    This mini foil is one of 3, that I have made, the other 2 are for a windsup, with much smaller wings, that like to catch weeds.
    think it’s covered here bbbbBasher


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  3. #45
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    Quote Originally Posted by tooold2dance View Post
    Their are other companies making the mini foil. Seabreeze forum has had several threads on these mini foils. It inspired me to make one, I used K4s , Fang as the fin and a set of quad fronts as the wing, 36 and 15 Leons stiff.
    I installed the wing with 1 degree angle of attack, rather than fit at the bottom , which I consider too fragile ,with obvious bottom contact, the wing it fitted about 1/3 down from the base, powerbox. This I used on a Tabou Rocket 140 which I have a lot of time on. Day 1 showed a lot of promise, the wind was near 12kts, the rear seemed to lift some, not near out of the water, their were no adverse reaction, a fast turn wasn’t possible to judge. I considered a slight improvement over a single fin. Day 2 with wind more like 13 + it’s right at the planing threashold for single or tri fin, the mini foil was draggy, hard to plane.
    Change to a single, performance much better. My conclusion is in lower winds the mini foil ‘could’ increase some quality time, at normal planing conditions its not an improvement. If one is already on their largest sail, to suggest go larger is a mute point.

    The construction was to run a carbon batten through the fin into the base of the wing, epoxy with SGlass as support once set. Minimumal use but no structural issues thus far. Will get tested more in April ‘18.

    The claims by the companies who are producing these IMO are far fetched, using % of this and that over, what.

    This mini foil is one of 3, that I have made, the other 2 are for a windsup, with much smaller wings, that like to catch weeds.
    Tooold, I appreciate the experimentation and planned to do something similar myself if i had time. However, whilst I know nothing about hydrodynamics, but extrapolating from my foils front wing, I guess the shaping of the horizontal fin is critical and needs to be asymmetric (top to bottom) in order to generate lift. Doesnt it need to be curved on the top and flattish on the bottom like a plane wing? A retro fitted normal fin thats designed to be vertical, and therefore symmetrical left to right, isnt going to work properly when turned 90 degrees, even with some angle of attack. How about sanding them to shape them a bit?

  4. #46
    Senior Member tooold2dance's Avatar
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    Smidge:
    When I investigated this mini foil, I asked Steve of K4, which fins he felt to use.
    K4 do make the Ezzy fins asymmetrical , they do have toe which could effect things like angle of attack. FCS , surf fins have some very sophicated inside foils.
    The wing geometry airfoil thinking is but one on many considerations.
    I dont think myself that asymmetrical is a distinct requirement . The AOA , shape of the wing,the. placement are all primary concerns. Given the limited time on this my thoughts, far from conclusions, are the right combination may increase lift, thus performance, to enhance light wind non planing is not something for me to be excited about, I would much rather windsup. It is easy enough to sand the fins, but they are far harder to shape than imagined. I often see reference to our fins to the shape of aircraft wing shapes, the hydro dynamic forces to me are much different than air.

    • ^ "The cause of the aerodynamic lifting force is the downward acceleration of air by the airfoil..." Weltner, Klaus; Ingelman-Sundberg, Martin, Physics of Flight – reviewed, archived from the original on 2011-07-The study of this lot makes my head ache.


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  5. #47
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    Makes sense. Ezzy's asymmetric profile would be interesting to play with in this context now that I have looked it up. My brain shuts off as soon as I see any forum comments about toe in and asymmetric fins....... If this works though there will be a lot of up force on the attachment and I struggle to see how my DIY skills could fashion something that could take something over 100kgs of focused force. Dont tthink I will get around to it

  6. #48
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    Quote Originally Posted by smidge View Post
    Makes sense. Ezzy's asymmetric profile would be interesting to play with in this context now that I have looked it up. My brain shuts off as soon as I see any forum comments about toe in and asymmetric fins....... If this works though there will be a lot of up force on the attachment and I struggle to see how my DIY skills could fashion something that could take something over 100kgs of focused force. Dont tthink I will get around to it
    It will only generate 100kg plus force if it well exceeds design speed...I think its a good idea to effectively increase width of board...but if its going so fast you are having control issues...just remove it ?? I actually tried building one...but that's another story.

    Trouble with all T foils is they have a definite performance envelope...increased speed just gives more and more lift,at some point ( if foil is big enough to lift you at minimum planing speed) the T foil must generate more lift than you have load...will come out if water or you cant control it or produces massive drag...

    What is needed is a constant lift system/ foil...but that is really difficult with leeway ( it messes with angled foils lift direction, its proving even harder for boards/ kites because if lack of heeling force...In foiling cats foils are angled...down wind foil generates positive lift, upwind generates negative lift and counters heeling force.( bit of a simplification but principle is there)
    Then as foiler goes faster leeward foil lifts slightly, reducing its area, hence keeping lift fairly constant. ( they adjust buoyancy / weight to keep fine balance) Meanwhile windward foil counters increased heeling force...if you are lucky !!
    They do utilise T foils on rudders sometimes but only small ones so lift never exceeds load...All a massive balancing act..( I had a ride on Hydroptere a few years ago....absolutely incredible)
    Was doing 30kts in around 12...was quite eerie..
    Last edited by Alphie; 23rd January 2018 at 04:55 PM.

  7. #49
    Senior Member tooold2dance's Avatar
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    The serious design would incorporate a adjustment feature, saw one on Seabreeze forum. 3 of my creations have wings, this is the only large one. None have exhibited any negative character, bar collecting weeds.


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