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thombiz
Joined: 25 Jun 2007 Posts: 799 Location: Corpus Christi
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Posted: Sat Jul 20, 2019 7:49 pm Post subject: Thoughts on a size adjustable foil wing.... |
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We had family in for a visit two weeks ago and one of the toys the 4 year old brought to play with inspired some thoughts in me about foiling. The kid's toy was a metal jet fighter with wings that could be in numerous positions. It occurred to me that this concept could be used to make a front foil wing that could be adjusted to fit rider size. See the pics.
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dllee
Joined: 03 Jul 2009 Posts: 5329 Location: East Bay
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Posted: Sat Jul 20, 2019 8:22 pm Post subject: |
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Wouldn't surface area be the same?
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isobars
Joined: 12 Dec 1999 Posts: 20935
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Posted: Sat Jul 20, 2019 8:56 pm Post subject: |
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Yeah, but that MoFo would be faster'n hell.
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thombiz
Joined: 25 Jun 2007 Posts: 799 Location: Corpus Christi
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Posted: Sat Jul 20, 2019 10:04 pm Post subject: |
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It occurred to me, instead of the wing tips swinging, they could just telescope. That would simplify adjustment.
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dllee
Joined: 03 Jul 2009 Posts: 5329 Location: East Bay
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Posted: Sat Jul 20, 2019 10:10 pm Post subject: |
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There ya go, locking position, watersealed when extended, weight in control, stage adjustments, no insurmountable problems at all.
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grantmac017
Joined: 04 Aug 2016 Posts: 946
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Posted: Sun Jul 21, 2019 4:06 pm Post subject: |
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Last I checked the speed of sound in water is about 100× faster than any foil will reach. So a swept outline isn't going to gain anything.
If you want to have fun look up the 6 digit NACA profiles developed for low drag and stable center of lift. Specifically the ones used on the AC45 foiling cats. Then take a close look at the Slingshot Infinity wings.
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fathomfathom
Joined: 25 Jul 2005 Posts: 52
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Posted: Mon Jul 22, 2019 9:31 pm Post subject: |
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grantmac017 wrote: |
If you want to have fun look up the 6 digit NACA profiles developed for low drag and stable center of lift. Specifically the ones used on the AC45 foiling cats. Then take a close look at the Slingshot Infinity wings. |
Do you have a link to the theory /review of the NACA profile for those AC45?
I did a google but nothing of interest
Thanks
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grantmac017
Joined: 04 Aug 2016 Posts: 946
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Posted: Tue Jul 23, 2019 4:12 pm Post subject: |
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I can't seem to find the article, perhaps it was pulled?
Basically certain foil profiles have a fairly wide range of speeds before hitting a major drag wall and they can also offer a stable center of lift.
The early slingshot designs are very biased towards lift at the expense of drag and increased pitching moment. The later designs emphasize a stable center of lift and low drag. Because the drag is low they can use a larger wing which then increases lift at the bottom end.
If that makes any sense?
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dllee
Joined: 03 Jul 2009 Posts: 5329 Location: East Bay
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Posted: Wed Jul 24, 2019 1:38 pm Post subject: |
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So WE are paying for the R&D so the companies reap the profits.
Pretty normal.
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fathomfathom
Joined: 25 Jul 2005 Posts: 52
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Posted: Wed Jul 24, 2019 2:31 pm Post subject: |
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dllee wrote: | So WE are paying for the R&D so the companies reap the profits.
Pretty normal. |
Thats' rather negative
I think it's a win win.
Earlier adopters get to try new stuff and give feedback, the manufacturers take the cost of building new gear.
or if you prefer cheap, wait another 10-15yrs for mass production until us early adopters finish changing the products.
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