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Old 18th January 2011, 09:02 PM   #11
pfaffi
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Hi Guys!
True but....
If you like to ad +/- 5knts wind range take an adjustable outhaul!!
Thats answer enoubgh or?!
pfaffi
(sorry to tell but 7,0 we use in competition > 30knts and I would like to see one of you with -4cm in these conditions)
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Old 18th January 2011, 10:03 PM   #12
Erik Loots
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@pfaffi

> 30knts and I would like to see one of you with -4cm in these conditions

Yeah, difference in discipline, I would do full downwind with 30kn wind in my 7.0 with -4cm . There is downwind much less apparent windspeed in the sail with good speed, but I agree if slalom or match racing (competition) its better to pull the outhaul to boost speed.

I do have an adjustable outhaul on all booms even for the 5.6/5.1, because I can't go all day downwind and end again at the place I started .
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Old 19th January 2011, 12:09 AM   #13
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OK my question was not clear. I guess many sails will get extra wind range with an adjustable outhaul (though +/- 5 knts seem huge). One would expect the Reflex system to adjust automatically to wind variations, short and long wavelengths. Downwind/upwind is another story but the sail should never become backhanded, by design. Otherwise why is it superior to traditional cutaways?
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Old 19th January 2011, 02:46 PM   #14
pfaffi
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not to be to technical but:
Deep Downwind like Erik told is a lower apparent wind and you can go with deep profile. Upwind (go back after downwind) is a higher apparent wind and less twist in apparent wind direction. Therefore upwind a deep profile is contra productive and will force you to open very much your boom/sail and go slowly and less angel. You will win with outhaul for all circumstances. But it is also true that the Reflex System will lock the force in a wide outhaul range but don't over-stress it.
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Old 27th January 2011, 12:08 AM   #15
BelSkorpio
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Hi guys,

if you want to read a little bit more theory about how a sail (or a wing for that matter) is supposed to work:
http://www.sailtheory.com/sail.html

It shows with pictures, why you need a big belly in front of your sail while reaching, even more curve while going downwind and why you need a flatter profile when pointing.

I found it very interesting.
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Old 27th January 2011, 03:38 PM   #16
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Hi BelSkorpio, It is a nice article indeed. A flat profile has better lift/drag ratio and works with smaller AoA, to some extend. So I fully understand the use of adjustable outhaul for that purpose. My question was about wind strength, not direction. But I can understand that even the best sail in the world may become backhanded and require some trimming. BTW aren't all sails like that?
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Old 27th January 2011, 05:59 PM   #17
BelSkorpio
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Hi Farlo,

Yes I understand what you're saying.
Regardless of the wind direction and corresponding outhaul adjustments, the sail should handle a wide wind force range.
That was also the reason why I brought up the topic.

If we discuss only 1 wind direction, say reaching,I think that the reflex system with the reflex batten tensioners could improve 2 important issues:
- give more twist and better release of overpowered windpressure by means of an increased S-profile
- tunnel more power to the front of the sail, resulting in less backhand power, more comfortable handling and better performance


So with the reflex batten tensioners, they improve two issues at the same time.

Not that bad, I think.

I haven't seen this yet with the other sail brands.
The other sail brands all tension their battens from the leech, and rely on the "dynamic or integrated" compact clew (NP terminology, let's just call it reduced boom length) to create more twist and S-Profile.
To improve the forward tunneling of the wind power, they only rely on the cambers.

Severne Reflex has of course also the cambers and reduced boom length, but add the reflex batten tensioner technology as a surplus.


Again, I have no experience with these sails, but would like to try them out.
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Old 28th January 2011, 02:30 PM   #18
Farlo
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Hi BelSkorpio,

Recently I've heard a few guys saying that batten tension is not that important (seen that written on this forum as well). It shall be strong enough to remove wrinkles and that's it. In my shop they even advise to keep them slightly loose. Therefore I wonder if the position of the tensioner makes a big difference, moreover close to the boom. OK maybe the Reflex is designed to work with big tension but I guess the foot of the batten is so stiff that most of the S-shape is given by the cutaway. Does anyone know what the rigging instructions tell about battens?
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Old 28th January 2011, 06:06 PM   #19
BelSkorpio
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Tension is not that import. Just remove the wrinkles. True. I even wrote that myself somewhere on this forum, I think.
But you always create tension when you bend battens, else they would remain straight in their natural form. And this tension will now be applied to an end-point further away from the leech, more to the front of the sail, resulting in a curvature a little bit more to the front of the sail. Again, every camber has the same goal, but the reflex tensioner will help with this, I think.
And then last but not least, there will be no tension at all in the batten at the end between reflex tensioner and leech, allowing better twist and more S-shape according to me. I would like to see those reflex tensioners more in detail to see how easily they allow the negative bending during overpowered conditions.
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Old 31st January 2011, 04:16 PM   #20
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Hi BelSkorpio, IMHO the batten tension has little effect on bend curve. Most of it comes from the sail shape and wind pressure, I believe. But it brings some tension in the sail body which may affect responsiveness. Just read in test reports that NP integrated clew also require outhaul adjustments for max wind range. Nothing magic, seemingly...
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