Post by: jamallstar on October 15, 2019, 09:40:43 AM
Centre section is high density foam with the outboard sections polystyrene. (https://uploads.tapatalk-cdn.com/20191015/ee4a78f64023e62da790470083fbbcfb.jpg)(https://uploads.tapatalk-cdn.com/20191015/05a793d94a9eb4733f607e87ec1cc10b.jpg)(https://uploads.tapatalk-cdn.com/20191015/c0378263b52f000b70f0e8b509e66a48.jpg)(https://uploads.tapatalk-cdn.com/20191015/a9b1a052cceb14530b5126f284772a3e.jpg)(https://uploads.tapatalk-cdn.com/20191015/09b61b6e4f9aece4cd3215b80ae21bb0.jpg)(https://uploads.tapatalk-cdn.com/20191015/940ad8bf94034aee46d0b1efc66fe951.jpg)(https://uploads.tapatalk-cdn.com/20191015/0c90a04d281ee8c7f439f0ff63cd3749.jpg)
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Post by: JEG on October 15, 2019, 01:35:45 PM
Post by: kiwi on October 15, 2019, 02:53:22 PM
new account?
Post by: Admin on October 15, 2019, 03:07:52 PM
Post by: container on October 15, 2019, 05:38:58 PM
cheers theres still heaps of work to do yet but its turning out quiet a nice shape, the wing tip curve is slicccck. not the easiest thing in the world to shape out of cheap polystyrene
Post by: SUPeter on October 16, 2019, 10:30:55 AM
Post by: jamallstar on October 16, 2019, 12:00:17 PM
Here is the drawing for the polystyrene tips, but that is only a core so the finished dimensions will be slightly bigger. Not sure if i will keep the concave on the top surface yet, well see how it looks when shes all laminated and faired up(https://uploads.tapatalk-cdn.com/20191016/46e2bf86d8c2d2028279d2ac3f24fc37.jpg)
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Post by: surfcowboy on October 17, 2019, 01:57:45 AM
Post by: Wetstuff on October 17, 2019, 05:47:40 AM
Oooo, Jamall ...unless you are a certified genus whose brain automatically processes Reynolds numbers without knowing it, you may have made a very pretty sculpture. I am still rooting for you.
Jim
Post by: PonoBill on October 17, 2019, 07:28:45 AM
Wetstuff--I doubt any current builder making foil wings is paying attention to reynolds numbers. At best they might go to airfoiltools.com and plug in their foil measurements, but beyond that it's cut and try.
In my own case, the only time I tried to use foil calculations was when I designed the geezer foil, and I was off by a factor of four.
Post by: jamallstar on October 17, 2019, 10:06:33 AM
i have made 5 wings prior to this, all designed and shaped by eye and 2 of which i can flat water start on the sup which is no easy feat, i think this one will turn out just fine
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Post by: surfcowboy on October 17, 2019, 06:29:10 PM
Not his first rodeo. ;D
Post by: SUPeter on October 18, 2019, 05:14:55 AM
Post by: Wetstuff on October 18, 2019, 06:09:42 AM
Jim
Post by: PonoBill on October 18, 2019, 10:14:42 AM
http://airfoiltools.com/airfoil/details?airfoil=e817-il
Post by: Beasho on October 21, 2019, 02:32:28 AM
Eppler817. The characteristics look ideal for our low speed, wide range applications, especially given the big variations we use in angle of attack. Most hydrofoil watercraft don't pitch as much. I've never seen an airfoil like this in use. Could be worth a try.
http://airfoiltools.com/airfoil/details?airfoil=e817-il
What Reynolds numbers are we dealing with? I could dust off the calculations but are they 10,000 or 50,000 or 200,000 ???
Post by: jondrums on October 21, 2019, 10:23:41 AM
I expect Reynolds number of 1e6 - 2e6 depending on chord and speed of course
http://airfoiltools.com/calculator/reynoldsnumber?MReNumForm%5Bvel%5D=5&MReNumForm%5Bchord%5D=0.28&MReNumForm%5Bkvisc%5D=1E-6&yt0=Calculate
Post by: SUPeter on October 21, 2019, 01:02:39 PM
Post by: jamallstar on November 09, 2019, 02:18:04 PM
Ive finally got around to shaping the underside of the gull wing. Not quite there yet but not far off, next will be rebates for uni reinforcing. (https://uploads.tapatalk-cdn.com/20191109/be287a653595ee1067ce6cf187cc5889.jpg)(https://uploads.tapatalk-cdn.com/20191109/43501858f8fa1cc50c2ace7a0f422887.jpg)(https://uploads.tapatalk-cdn.com/20191109/49f7050e4b08988c8a3f12042ddeb0ec.jpg)
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Post by: jamallstar on November 11, 2019, 09:47:46 AM
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Post by: Wetstuff on November 11, 2019, 11:49:34 AM
https://scx1.b-cdn.net/csz/news/800/2017/engineerside.jpg
Jim
Post by: jamallstar on November 13, 2019, 01:28:55 PM
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Post by: jamallstar on November 16, 2019, 11:44:32 AM
2x 300g DB patches over the mounting plate, 1× strip 300g unis spanning 3/4 of the wing, 1x 300g unis at 45 degrees and 2x 200g twill over the whole lot.
Once that was dry i dug out the leading edge and filled it with some individual strips of unis and then bog.
Next i filled in the trailing edge and wing tips where i had dug all the foam out before laminating to get carbon on carbon contact, now the fun part. Sand it all!
(https://uploads.tapatalk-cdn.com/20191116/71c21730963d0beca54161feab77f6c9.jpg)(https://uploads.tapatalk-cdn.com/20191116/ada9a29ecda963ed12de4bac380d101a.jpg)(https://uploads.tapatalk-cdn.com/20191116/41f0fcdbb0cab26c129935831366b1eb.jpg)
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Post by: jamallstar on November 16, 2019, 11:46:03 AM
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Post by: jamallstar on November 16, 2019, 11:55:34 AM
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Post by: surfcowboy on November 16, 2019, 02:39:59 PM
Post by: kiwi on November 16, 2019, 04:37:07 PM
Post by: jamallstar on November 16, 2019, 08:42:44 PM
Kiwi theres 2x 3 or 400g DB patches 200mm square + 2x 200g twill on the top, and the same on the bottom but with a layer of 300g unis on the 45* and a 100mm strip about 3/4 of the span. Feels pretty stiff
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Post by: jamallstar on November 25, 2019, 08:03:15 AM
The gull wing is super easy to flat water sup start, easier than the axis 102 and much easier than the axis 1000 high aspect to get going, fairly similar once up and pumping to the 1000, maybe a little bit slower owing to its size and leading edge shape but it turns like a wing half its size.
Few pics from my second dock start session on it. Ive got the tail wing at zero right now but ill try a few different angles later in the week when we get some onshore breeze for upwind/downwindera
(https://uploads.tapatalk-cdn.com/20191125/842882c6911716018c0d3eba28a40d70.jpg)(https://uploads.tapatalk-cdn.com/20191125/6e36edebdcd02ca75f428cef8b9beccf.jpg)(https://uploads.tapatalk-cdn.com/20191125/7a160f5b6ecf5b01b117005b7ff5f2d9.jpg)
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Post by: jamallstar on November 25, 2019, 08:06:06 AM
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Post by: JEG on November 25, 2019, 02:21:25 PM
Post by: jamallstar on November 26, 2019, 09:28:02 AM
I have a maliko tail for this foil, chopped about 70mm off each tip. I havent really tried it surfing since the chop but downwinding it is faster and alot looser to turn but also lost alot of pumping power. I would just buy a new tail wing if it were me
This is my second session on the gull, still cant quite figure out the pumping cadence it feels alot different to anything ive tried so far. Seems to really like short sharp pumps
https://www.instagram.com/p/B5T0xNVAPKl/?igshid=1ith3ef203v4g
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Post by: Piros on November 26, 2019, 02:56:47 PM
Post by: HBsups on December 01, 2019, 12:32:40 AM
Do you mind posting a bit on how you made the actual board (ie the choped surfboard)? I'm particularly interested in how you got strength and water seal in the connection to the foil base plate and how you sealed the cut section...
Thanks in anticipation, and apologies if I have missed the description elsewhere.
Cheers HB
Post by: container on December 12, 2019, 09:39:45 AM
ive done a couple of 10 mile downwinders on the gull recently, super happy with how it performs. really fast and turns easily for its size. i havent played round with the tail wing angle at all, not until im fluent in riding it as is. it seems to get quite pitch sensitive at high speed probably due to the leading edge shape and neutral tail angle. still feels really good for pumping tho so maybe it will just have to be a bit of a trade off
https://www.instagram.com/p/B53UyRHgE_1/
Post by: JEG on December 12, 2019, 12:31:35 PM