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Sneak peek new Kook 2 piece foil

Forum for hydrofoil builders.


Mossy 757
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Re: Sneak peek new Kook 2 piece foil

Postby Mossy 757 » Sun Nov 13, 2016 1:59 am

plummet wrote:Ahh yes I remember that now.

But what if you had a short fuse and small stab. Wouldn't that be even faster again? albeit with loosing some stability?
It would just be out of tune/balance...you'd either need more AoA on the stab in the form of a shim or it'd need to be ridden uber fast to create enough lift on the stab to feel balanced.

tahoedirk
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Local Beach: Kings beach, CA
Favorite Beaches: All clean beaches
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Re: Sneak peek new Kook 2 piece foil

Postby tahoedirk » Sun Nov 13, 2016 5:17 am

hmmmmm.
The more I learn the less I know.
It blew today and it was over 50 degrees. I took 1/2 inch off one rear stab , reprofiled it and tried it out... Better. Moved the front strap 3" forward :o .... beter, fast, smooth, still not perfect, periodic, annoying, slurping like, non terminal cavitation . Came it bolted other foil, thick wing full, stab, less pitch in it's place without issue :D Difficult to ride downwind , bouncy ; maybe more pitch and smaller stab.
Maybe I should have taken less than a half inch, that was a bit drastic , but maybe not. I might take a bit off the span and ponder the profile more . Also, I added a bit of pitch while re profiling so I still think it might be a bit much
Still no go pro documentation to see where the slurps happens. duhh..
At least it's fun to kite in freezing water , Gotta buy a goofy ski area pass before the prices go up , again. Yay winter.
My new mast looks real good. Still moving forward . Dirk

tkettlepoint
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Re: Sneak peek new Kook 2 piece foil

Postby tkettlepoint » Sun Nov 13, 2016 1:45 pm

1/3 surface area of front wing is a good starting point for most stab. until you really want to tune it. then 10% higher or lower anything over that you need to mess with the front wing profile

tahoedirk
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Local Beach: Kings beach, CA
Favorite Beaches: All clean beaches
Style: out of control
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Re: Sneak peek new Kook 2 piece foil

Postby tahoedirk » Sun Nov 13, 2016 6:19 pm

Yeah 1/3 was my initial guideline but after making 6 or 7 front and rear wings this was the best combo that I had the patience to pair together, tune and ride in objective coditions. Now that I "know" about the various effects of pitch and I still don't know about the position of the mast location, I'm still humbly baffled.

I guess I need to make another foil with the strut directly behind the TE(where I had it in my previous model) and another at 2" back. These are 1" back How else can I know? I'm not exactly sure what my next move should be. I think i should still be satisfied if 1 out of 5 modifications are improvements. On a good note I love feeling no drag...yeeehaawww.
1479056394131.jpg
This one is 1 3/4" back and with a different wing it rode like magic
20161113_083821.jpg
Lots more work!
Made some bags and got a massive chunk of 2.0 lbs/ft foam instead of the 2.4 I've been using. Not sure, I don't mind heel dents from massive hucking but ... hot cold hot cold, sea level 8000ft sea level 8000ft . I may have to use gore tex vent plugs...... any thoughts?

tkettlepoint
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Re: Sneak peek new Kook 2 piece foil

Postby tkettlepoint » Sun Nov 13, 2016 10:31 pm

mast .5 to 1" behind is what I found worked the best for me. for the board I use 2lbs all everyday this summer was the first time I ever had a board balloon up ( good thing it was the prototype board and my r&d guys has it) I have always said all boards should have a vent plug in them. And carbon board even more. So from now on the 15 dollar plug will go in all my boards.

terrie
www.jellyfishboards.com

Mossy 757
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Local Beach: First Landing State Park, Virginia Beach Oceanfront
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Gear: Delta Hydrofoil and board. Cabrinha Velocity 9m, Flysurfer Sonic2 11m, Elf Joker-7 15m

Re: Sneak peek new Kook 2 piece foil

Postby Mossy 757 » Mon Jan 16, 2017 7:37 pm

Any updates from the last few months Dirk?

tahoedirk
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Re: Sneak peek new Kook 2 piece foil

Postby tahoedirk » Tue Jan 24, 2017 9:20 pm

My progress has been almost non existent. I moved one mast forward an inch, made a new mast, I am moving another rearward an inch. I cut some new wing profiles but the weather has taken a bit of my motivation away for the moment.
I'm not sure why I need 2 full size pickup trucks, a car and a 2 axle trailer right now.
I am still looking forward to spring and summer.

The skiing is very good however!
20170124_120823.jpg

tahoedirk
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New Kook 2 piece foil

Postby tahoedirk » Tue Mar 07, 2017 12:48 am

Hi there, happy winter people!

I got the shop warmed up and I put in a few days this week. I am a little challenged for motivation since it's still winter, but more challenged to continue my craft because of the introduction of numerous quality production models for less than 1500$ I have stayed motivated since I believe my foils have been arguably good as almost anything available, that is becoming a very ambitious claim to maintain. As a father of 2 living in the mountains, I am lucky to have 6 months a year to be in the water, lake Tahoe is not that reliable either. On top of that I am 1 of 2 most proficient riders on my 10 ish foils and boards out ther so the outside feedback is good, but limited. I am just one guy, yeah I'm the CEO , head designer, production manager, quality control, and especially test rider, so I am indeed living the dream. BUT, so many "improvements" are not actually improvements. It is nearly impossible to only change one thing at a time. In general , this shit is hard and challenging.

I'm going to stick with it this season. I left off with some new , carefully selected profiles cut. On a suggestion from Billie, I am trying to simplify the mold making by using the wing beds themselves, so far so good. I am building up the mold halves and the wing plug together, alternately glassing one and then the other and finishing with thickened epoxy ,gel coat. I think it's going to work fine. I have had numerous creative mold release challenges using packing tape, waxed paper, pva ,frekote and more .

I was also thinking I need an adjustable modular fuselage for effective R&D with multiple options for mast location, length and pitch.

In concept I love my 1 piece foil but it is not perfect and there is little that I can alter. I took one model, 3 degree small stab, and moved the mast forward an inch, on the other 2.5 degree larger stab, I moved it back an inch. I really hope this will reveal something.

The new wing seems like it has way too much negative camber on the lower surface , that's where it goes concave. It's very pronounced at the curved parts. Last summer I spent hours trying to add and subtract negative camber in my main foil, I ended up with a little, but not at the wingtips. When I put the anhedral curve in this wing, it accentuated the camber near the tips..... we'll see.
2 more feet of snow this morning.

Cmon warm weather
Attachments
20170306_141859.jpg
Seems like a lot of lower surface negative camber to me.
20170306_141646.jpg
2 new masts, 3 different lpositions
20170306_141739.jpg
Molds and foils coming along well

Mossy 757
Very Frequent Poster
Posts: 1245
Joined: Fri Sep 11, 2015 5:10 pm
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Local Beach: First Landing State Park, Virginia Beach Oceanfront
Style: Kitefoil
Gear: Delta Hydrofoil and board. Cabrinha Velocity 9m, Flysurfer Sonic2 11m, Elf Joker-7 15m

Re: Sneak peek new Kook 2 piece foil

Postby Mossy 757 » Fri Sep 08, 2017 2:53 pm

How's it going, bud, any updates? Heard it's been warm out your way recently...

tahoedirk
Medium Poster
Posts: 173
Joined: Sun Aug 31, 2014 5:02 pm
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Local Beach: Kings beach, CA
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Style: out of control
Gear: Homemade gear
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Re: Sneak peek new Kook 2 piece foil

Postby tahoedirk » Fri Sep 08, 2017 6:53 pm

Thamks for the interest Mossy,

I started windsurfing again with my kids. Windsurfing is a lot of work but if my 10 and 12 year old kids can do it so can I .....

I made a fuselage with mounting holes all over for quick fuselage length change and mast locations, After testing 15- 20 or so variations of wings , angles and mast locations and fuselage lengths, I have been unable to improve the all around nature, speed, stability and maneuverability of my foil. I really think I got lucky a couple years ago.

I have learned to ride with my own style , I turn every 50 feet going fast or slow. Foiling transitions will keep me busy forever! My current favorite is a toeside to heelside tack without switching my feet. My goal is right now is fluid tacks and gybes both directions switching stance both before and after the turn, I'm close!

I left my foil on the beach at Sherman island for days this summer and the few who rode it liked it a lot . A few people want one of their own.
So.... I like my two mast profiles, I will use them. I like my t-bar strut/fuse, it simply could not be stronger or sleeker. I suspect my 2 piece design will not handle a log or a big fish or rock without failing .
I am going to make a couple foils with the t-bar style again. I am still playing with the positive camber on the lower surface of both wings(I had the - part wrong) , I believe this is key to balancing stability and maneuverability. It is very challenging to change only one slight variable at a time.

I am looking into building windsurfing foils, SUP foils, electric foils and foils for pumping. There is an absolute foil frenzy going on in parts of the world. Too bad it's almost winter again in my world.

My boards have been coming out very nicely and holding up very well with 2 @ 6 oz on the hull and 3@ oz on the deck, = 4 @6 oz wrapping the rails completely , 5 layers under foot. I shaved a pound with 2lb foam and slightly smaller size.
I got to ride Mikes new foil and it felt surprisingly similar except the stance made me feel that I need to learn to ride with my back foot in the strap , about a foot rearward!! I think that's why I couldn't break 33mph last year when I was trying.
What a great summer! I wish there was more warm weather in store. Even though my kids fly kites very well, they choose windsurfing for now, they both just learned to waterstart!!

Parenting has seriously got in the way of Hydrofoil design but I did just get another 500$ of cool , sexy carbon fiber.
If your are in Tahoe (no beach) or Sherman(no beach) gimme a call 530 546 WIND before it gets cold
Dirk


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