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1
Foil SUP / Re: NL Wingtips
« on: November 26, 2020, 09:23:49 AM »
Jondrums you could be on to something there, in my experience from putting tell tales on foils, when you do a sharp turn (while towing, so as sharp a turn as physically possible as you can lean against the low line) the flow on the inboard tip bends in to nearly 90 i.e. it is almost 100% spanwise flow towards the centre of the wing, while the tip on the outside of the turn sees around 45 but flowing towards tje tip. Of course this will be entirely foil dependant but i would say it would be roughly similar on all foils. The wings may change but the water certainly does not. There is an easy way to see whats going on down there- chuck some tell tales on and send it past a gopro

2
Foil SUP / Re: NL Wingtips
« on: November 19, 2020, 02:05:55 PM »
Fascinating stuff.

I remember hearing or seeing people try attaching wake board fins on various parts of the wing.

Has anyone tried putting wing tips like the NL on their high aspect wing?

I think Alex Auguera has. You can see them on his GL in this video
https://www.youtube.com/watch?v=f6BWBE9pFrc

those are called fences, theyre there to minimize spanwise flow. its a budget fix for a wing that hasnt been designed prtoperly in the first place. a bit like the russians putting them on their mig wings when trying to break the sound barrier.

3
Random / Re: Moving to NZ because of the virus
« on: October 08, 2020, 12:10:19 PM »
stay where ya are thanks

4
Foil SUP / Re: Foil broke away - lost.
« on: August 22, 2020, 10:41:18 AM »
could use a mounting system that doesnt rely on thin plastic tracks and only the peel strength of the bottom skin keeping it in there?

5
Foil SUP / Re: Foil Videos
« on: August 21, 2020, 11:19:08 AM »
Haha didnt everyone start on one of those?

6
Foil SUP / Re: Can We Talk Stabilizer Geometry?
« on: August 18, 2020, 02:58:02 PM »
Yeah with my usual tail setup.  It wasnt designed with positive pitch stability in mind so it was really the worst of both worlds, drag from a tail wing and downforce from the tips in line with the centre of lift. Still went great, and gave a brutally effective answer to my question

7
Also when i built that foil i was working next to the team new zealand americas cup base, The designers would walk past our workshop everyday on their way to get coffee. When they saw this wing they took photos of it and laughed. i think if they were in anyway beneficial we would have seen them on AC foils by now, even test foils. Nope

8
Marketing gimmick. I did a lot of research on humpback whale tubercules a few years ago when i first started building foils. At face value they seem like a good idea but when you look at the math, science and how the whales actually benefit from tubercules you will see there is almost no use for them in a surf foil enviroment. Chevalier-taglang did an excellent article on them and their use on racing yacht rudders.

The only benefit i can see is maintaining tip flow during extremely tight turns when flow on the inside wingtip is almost perpendicular to the centre line, which doesnt seem like much of a trade off. Performance on these wings may still be great, but i would be looking at the qualities other than tubercules (foil section, aspect ratio, the fact that these guys shred regardless of how good the foil is)

Spoiler- they only work at huge (post stall) angles of attack, 20- 90 degrees. Pre stall they actually increase drag..

9
Foil SUP / Re: Can We Talk Stabilizer Geometry?
« on: August 18, 2020, 11:59:31 AM »
Its awesome, feels completely different to an elliptically loaded foil but well and truely served its purpose. It was designed and built to answer one question- will a very small(area), very high aspect, very highly loaded foil with bell shaped lift distribution and a shitload of wing twist behave in a predictable and satisfactory way.  YUP.  Mk.2 flying wing tuna tail is going to be a fkn WMD

10
Foil SUP / Re: GoFoil NL 190
« on: August 17, 2020, 01:44:02 PM »
That looks pretty standard for a (true) high aspect wing, its fast but i think the main point is just how slow everything else is! Really everything we have been riding thats thicker than 12% and has an AR of less than 5 is a fkn dog.

11
Foil SUP / Re: Can We Talk Stabilizer Geometry?
« on: August 16, 2020, 10:58:19 AM »
 11 degrees of twist from root to tip and no fuselage to act as a datum!?

12
Foil SUP / Re: Can We Talk Stabilizer Geometry?
« on: August 16, 2020, 10:44:17 AM »
hold on to ya zimmer frames. why dont we move the stabilizing down force out to the main wing tips, sweep the wing tips aft so the stabilizing force is aft of the centre of gravity- the red mast in this case- and chop the fuselage off all together. problemo solvo.

13
Foil SUP / Re: What do people want in a foil?
« on: July 14, 2020, 11:23:33 AM »
Nope you nailed it! Stabs are all of your stability, and most of your (speed limiting) drag.
In a few weeks you will see some very interesting developments in this area  ;) ;)

14
Foil SUP / Re: Axis 1150
« on: July 09, 2020, 07:57:38 PM »
And dont give up! I tried for a solid year or 2 before i could nail it every time

15
Foil SUP / Re: Axis 1150
« on: July 09, 2020, 07:51:04 PM »
I have flat water started the 1150, 1020, and even the 82! (Just barely, and only once. But im still claiming it)  my weight is about 78kg.
Basically the bigger and fatter the leading edge, the easier it will be to take off. There is less of a pressure peak on a rounded LE which means it can handle a higher angle of attack with less water flow before stalling. The s series axis foils use a 15% thick raf48 section which you will see has a very thick entry.

You have to know what youre doing to flat water a high aspect, theyre very pedantic when it comes to pump motion and frequency.

My advice would be to start off on the 1020, standard fuse (long fuse= more positive pitch stability= more up) 440 tail and a 750 or 500 mast, in 20 odd knots of wind with short steep chop. Not on shore ocean swells coming across from peru. Once you figure out the motions you can then try in less and less wind until eventually you will do it in flat water

P.s also you have to paddle and pump like you wouldnt believe, you have to be in very good shape and have excellent paddle technique

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