Author Topic: A 1000 that has a lift of a 1600 - new Kujira Foil  (Read 2925 times)

winged surfer

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A 1000 that has a lift of a 1600 - new Kujira Foil
« on: August 18, 2020, 11:58:06 AM »
That’s what they say..
what do you think?

https://m.youtube.com/watch?v=MOrKRZ2z2L0
« Last Edit: August 18, 2020, 12:03:02 PM by winged surfer »

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Re: A 1000 that has a lift of a 1600 - new Kujira Foil
« Reply #1 on: August 18, 2020, 01:52:32 PM »
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..

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Re: A 1000 that has a lift of a 1600 - new Kujira Foil
« Reply #2 on: August 18, 2020, 02:01:14 PM »
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

bigmtn

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Re: A 1000 that has a lift of a 1600 - new Kujira Foil
« Reply #3 on: August 18, 2020, 02:19:53 PM »
any chance the foil whistles in a way that mimics a whale song?

PonoBill

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Re: A 1000 that has a lift of a 1600 - new Kujira Foil
« Reply #4 on: August 18, 2020, 04:44:50 PM »
I spent too much time in marketing. When I hear grave and important sounding pronouncements sprinkled with vast assertions at the beginning of a pitch my bullshit meter hits 11 and stays there until bedtime--tomorrow I'm going to wake up in the morning muttering "bullshit, bullshit...".

I read up on tubercles when Container did his wing design. I thought the idea had potential, but the more you read, the less likely a useful application appears. It's possible that a foil design that was having problems with stalling might be helped by tubercles, but while we obviously can stall our wings, being able to manage a few more degrees of stall angle and therefore do a shittier job of managing pitch doesn't seem like a design improvement. I'm sure someone will try one and be extremely enthusiastic about the performance, and I'm also certain they will do no testing or controlled comparison that supports their enthusiasm.

Here's one of the papers I read. Interesting, but probably irrelevant.  https://academic.oup.com/icb/article/51/1/203/636829
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exiled

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Re: A 1000 that has a lift of a 1600 - new Kujira Foil
« Reply #5 on: August 19, 2020, 01:39:01 AM »
I'll probably get one, but mostly because I already have an lol so I'm not committed to a whole new foil. They surprised me with that lol, its a blast to surf. I saw the wingtips and thought gimmick until James Casey commented on the Progression Project about how it was out running the Axis 900 on his downwind runs. I don't know if lighting will strike twice, but the lol was both gimmicky and effective, so I'm not gonna write this off yet.

Solent Foiler

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Re: A 1000 that has a lift of a 1600 - new Kujira Foil
« Reply #6 on: August 19, 2020, 01:53:34 AM »
Humpback whale tubercules have also been picked up by the marketing department at Zipp, manufactures of very expensive bicycle wheels...
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frenchfoiler

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Re: A 1000 that has a lift of a 1600 - new Kujira Foil
« Reply #7 on: August 19, 2020, 11:38:05 AM »
Marketing for sure but maybe that is not it, I guess we will have to try.

I like the look of this foil, more hight aspect, looks more performance than the lol which is already good.

 


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