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prude
Joined: 17 Oct 2013 Posts: 4
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Posted: Thu Oct 17, 2013 2:30 am Post subject: F2 sx tail cuts |
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Hi
I have a bad English, sorry
Adjust the depth of cut stern plates
Tell me why the wings?
Under what conditions govern?
http://savepic.su/3048776.jpg
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joe_windsurfxxx
Joined: 29 Jun 2008 Posts: 67
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U2U2U2
Joined: 06 Jul 2001 Posts: 5467 Location: Shipsterns Bluff, Tasmania. Colorado
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dllee
Joined: 03 Jul 2009 Posts: 5329 Location: East Bay
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Posted: Thu Oct 17, 2013 1:29 pm Post subject: |
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The more surface area you have under your feet, the earlier you will plane, the slower will be your top end speeds.
The less surface area you have under your feet, the later you will plane, the higher your top speed will be when fully or overpowered. |
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dllee
Joined: 03 Jul 2009 Posts: 5329 Location: East Bay
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Posted: Thu Oct 17, 2013 1:31 pm Post subject: |
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Pertaining to SX....
F-2's have very wide tails, and very wide area behind the widepoint.
They need the cutouts to get a higher top speed, as they plane up very early for their template and volume.
Other boards, like Sharks and Excocet/Tabou's, generally have narrower tails and narrower surface area under your feet, so cutouts are less necessary. |
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DanWeiss
Joined: 24 Jun 2008 Posts: 2296 Location: Connecticut, USA
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Posted: Thu Oct 17, 2013 2:05 pm Post subject: |
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zirtaeb wrote: | The more surface area you have under your feet, the earlier you will plane, the slower will be your top end speeds.
The less surface area you have under your feet, the later you will plane, the higher your top speed will be when fully or overpowered. |
Overstatement of the truth, I believe.
Aspect ratio of the planing surface can affect both early planing and top end quite positively given a certain range of wind speed. Just compare the 9'4" light wind slalom boards from 20 years ago (low aspect, little flat) to a FW board from ten years ago (high aspect, a bit more flat). The FW board will obviously plane earlier but also tends to have a higher top speed due to its stability.
We've both sailed those big slalom boards in 20 knots. They were simply out of control due to their low aspect rocker. I think you've experienced FW boards in 20. Certainly you know the blistering speeds that can happen on a FW board. _________________ Support Your Sport. Join US Windsurfing!
www.USWindsurfing.org |
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dllee
Joined: 03 Jul 2009 Posts: 5329 Location: East Bay
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Posted: Thu Oct 17, 2013 5:12 pm Post subject: |
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I sometimes ride a Formula162 Starboard.
I've logged over 30 days on a Kinetic 95cm wide Formula board.
I've ridden MikeZ's personal slab with his NP sail.
As for "20" year old light wind slalom boards, very few of us have them still around to try.
Can I compare a 1998 KineticFreeride 60cm with a 40 cm tail to any modern 70cm thru 80cm wide slalom board? My friends ride Excocets R's, Naish's Bullets, Starboards Isonics, Tabou Mantas, RRD black and whites, and slabs from 62 up thru 80......1
I have at my disposal a Warp Slalom 71cm.
NO DIFFERENCE in top speeds! Whoever has a bigger sail WILL plane up slightly earlier, whoever is correctly powered when up to speed will be faster, but it goes back and forth, irregardless of which board or sail is used, except the correct size for the wind and body weight is the key.
NO DIFFERENCE!
To compare Formula against light wind slalom is like comparing blondes to brunettes. Just not worth the effort, and it makes no difference.
Formula boards are NOT faster, but have better VMG. Difference in topspeeds between Formula and Slalom is around 2-4 mph. |
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jingebritsen
Joined: 21 Aug 2002 Posts: 3371
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Posted: Fri Oct 18, 2013 5:45 am Post subject: |
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exocet did these about 10 years ago. we discovered that the lighter the wind was, the deeper cut outs allowed for a early planing and glide thru lulls and corners. as the wind would get stronger, one could decrease the depth and gain a less detached feeling. the exocet adjustments allowed for a completely flush release.
friend of mine has an old FW exocet 99, no cut outs. he liked the board but sought out earlier planing. he dug out some of his own cut outs, and improved that aspect.
another friend of mine is not a very techy guy, he chronically under tensioned his down haul, and used a very soft fin and short harness lines. he had the exocet warp formula. he kept the tail adjusters flush. he was always fretting over a lack of control, AND he rarely took the extreme angles to get the most upwind/downwind performance. in other words he was free riding the board instead using it the way it was designed. all this lead him to switch to another board in the end. vicarious lessons watching him were aplenty. _________________ www.aerotechsails.com
www.exocet-original.com
www.iwindsurf.com
http://www.epicgearusa.com/ |
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dllee
Joined: 03 Jul 2009 Posts: 5329 Location: East Bay
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Posted: Fri Oct 18, 2013 3:30 pm Post subject: |
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As early as 2001, it was agreed universally that FORMULA boards needed cutouts, for top speeds, less wetted surface, downwind control, and trim control.
BUT, on slalom boards, the jury is still out. Certainly Excocet doesn't use them on 71cm and narrower slalom boards. Fanatic only uses cutouts on their widest boards. Tabou also.
Starboard and JP embrace the cutout idea down to their smaller boards. Naish is more in the fence.
So, cutouts are NOT universally needed. On narrower boards maybe not at all. On 80cm wide boards, it appears needed. |
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KevinDo
Joined: 02 Jul 2012 Posts: 426 Location: Cabrillo Inside
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Posted: Sat Oct 19, 2013 12:41 am Post subject: |
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zirtaeb wrote: | As early as 2001, it was agreed universally that FORMULA boards needed cutouts, for top speeds, less wetted surface, downwind control, and trim control.
BUT, on slalom boards, the jury is still out. Certainly Excocet doesn't use them on 71cm and narrower slalom boards. Fanatic only uses cutouts on their widest boards. Tabou also.
Starboard and JP embrace the cutout idea down to their smaller boards. Naish is more in the fence.
So, cutouts are NOT universally needed. On narrower boards maybe not at all. On 80cm wide boards, it appears needed. |
The speedsters in Australia tell me that they have successfully used cutouts on their speed needles but tell me that designing the cutout is incredibly difficult.
-Kevin _________________ 2014 Cabrillo Beach GPS CS (inside)
https://drive.google.com/folderview?id=0B1T3t6bAGX8AejJqTFg5empQNjQ&usp=sharing |
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