myiW Current Conditions and Forecasts Community Forums Buy and Sell Services
 
Hi guest · myAccount · Log in
 SearchSearch   ProfileProfile   Log in to check your private messagesLog in to check your private messages   RegisterRegister 
RS-X Uphaul use while sailing?
Goto page Previous  1, 2, 3  Next
 
Post new topic   Reply to topic    iWindsurf Community Forum Index -> Windsurfing Discussion
View previous topic :: View next topic  
Author Message
pete1111



Joined: 16 Apr 2005
Posts: 193
Location: The Dude

PostPosted: Tue Aug 09, 2016 5:51 pm    Post subject: Reply with quote

From what I heard it was 15kts with some holes so more than enough to get going on a 9.5 but pushing hard up wind you try to get the most out of your gear.
Back to top
View user's profile Send private message
konajoe



Joined: 28 Feb 2010
Posts: 496

PostPosted: Thu Aug 11, 2016 9:08 am    Post subject: Reply with quote

If you watch the RS:X sailors for a while, you'll notice that they have the sails rigged with twist, but they're not dumped at the top like modern formula and slalom sails. The center of effort of their rigs is much higher up. On modern formula and slalom rigs it is much lower. So I wonder if the 'rope trick' translates well into Formula racing and gps sailing?
Back to top
View user's profile Send private message
dllee



Joined: 03 Jul 2009
Posts: 3960
Location: East Bay

PostPosted: Thu Aug 11, 2016 1:22 pm    Post subject: Reply with quote

Could the lesser twist have something to do with the max sizing of the sails?
If you don't have unlimited sizing of sails for really light winds, you rig your smaller sail with less downhaul, so it twists less, to give more low end power, and it dumps away less wind, making your sail more powerful.
I seem to have a upper limit in sail size around 6 meters, even if the winds are 11-17 mph here in Berkeley. Planes up just fine, slacking the downhaul until the head just barely twists when I pump the sail. Other sailors my size on equal boards are barely planing on 6.5's, while I"m powered on a 6 with very little downhaul.
Of course, there are limits to what you can do with less downhaul. About 1/2 meter is all you can gain on a 6 meter sail with almost no downhaul.
Back to top
View user's profile Send private message
CoreAS



Joined: 23 Oct 2015
Posts: 45
Location: Dallas, TX

PostPosted: Thu Aug 11, 2016 2:35 pm    Post subject: Reply with quote

Think Steve Allen the Aussie sailor started this technique on the PWA a few years ago, and he said he did it to create better upwind/distance from the rig air flow etc.

Phil Mcgain once said on Maui sails forum that the uphaul rope created bad air flow over the sail and made you slower! and that some racers take off the uphaul rope even on 10m sails etc. Never could tell if he was being serious or not Shocked

..did see a video once of a formula sailor uphauling without a rope, so it is possible!

_________________
Facebook: North Texas Foiling
Instagram: northtexasfoiling
https://www.facebook.com/coreadventuresports
Back to top
View user's profile Send private message Visit poster's website
dllee



Joined: 03 Jul 2009
Posts: 3960
Location: East Bay

PostPosted: Thu Aug 11, 2016 2:43 pm    Post subject: Reply with quote

Actually, little Teddy Huang and Mike Gebhardt did that on D-2 rigs back in the early '90's.
Before that, Bernard, one of the local Larkspur and Berkeley sailors, used to hold the uphaul when he was training for the Olympic for Argentina, back another decade.
Back to top
View user's profile Send private message
snyd1437elZA



Joined: 11 Aug 2016
Posts: 2

PostPosted: Thu Aug 11, 2016 8:58 pm    Post subject: Reply with quote

It's definitely the uphaul. They use very thin uphauls, probably to reduce the air disturbance at the leading edge. I was experimenting with downhaul and outhaul on my RS:X tonight, trying to get a similar profile, having the luff touching the boom, but I couldn't get it to touch the boom much past the harness lines. Any ideas? Would batten tension affect it?

Here's what it looked like a couple months ago when I had 15-25mph winds:
https://www.youtube.com/watch?v=jXICAsNKzy0
Back to top
View user's profile Send private message
dllee



Joined: 03 Jul 2009
Posts: 3960
Location: East Bay

PostPosted: Thu Aug 11, 2016 10:13 pm    Post subject: Reply with quote

Looser outhaul? To get the deepest pocket.
Back to top
View user's profile Send private message
Sailboarder



Joined: 10 Apr 2011
Posts: 656

PostPosted: Fri Aug 12, 2016 7:08 am    Post subject: Reply with quote

When pinching upwind with my large sail, I need to bring the sail back and my body weight forward. If I try to keep the sail parallel to the board, I find my front arm is not long enough! I have yet to master it while planing, but using the uphaul makes a lot of sense when trying to gain a few degrees upwind.

Also, if the RS:X sails are a bit like the Kona ones, I would say you can add a lot of batten tension to create more belly in the sail. Outhaul, downhaul and batten tension are used together. In low wind, to get the most of the limited size, you reduce downhaul to get no twist and a tight leech, you reduce outhaul to get a bigger belly, and you increase tension in the battens, at least in the top ones to create a small belly up there too.
Back to top
View user's profile Send private message
DanWeiss



Joined: 24 Jun 2008
Posts: 2246
Location: Connecticut, USA

PostPosted: Fri Aug 19, 2016 12:02 am    Post subject: Reply with quote

The line being held is the uphal, not the adj. downhaul.

Holding the line increases leverage over the rig by increasing the distance of sailor's center of mass from the sail's center of effort. In other words, the sailor's righting moment is increased.

Remember that the RS:X sail was developed in days of heavy Formula Windsurfing popularity but before the FW sails and boards developed to sail fast and free. The RS:X sail is a highly modified version of the old NP RS 2. You may recall that the FW sails if those days required around 600 lb of DH tension. They snapped masts regularly. That would be unacceptable for Olympic gear so the sail could not use such massive luff curve and such high tension. The sail lost stability as a result.

Remember also that the RS:X is a "hybrid" board that must be driven upwind on the centerboard as well as flying on only the fin. This requires a further compromise in sail shaping compared to a FW sail of 12 years ago. Planing upwind on an RS:X will entail doing so on a sail with less stability. The draft moves back more.

Hanging off the uohaul will move the sailor's center of mass out and aft to match. We saw this in the very early days of FW, too.

The technique also works well on Bic Techno 293 as well as Kona One in big blows.

_________________
Support Your Sport. Join US Windsurfing!
www.USWindsurfing.org
Back to top
View user's profile Send private message
DanWeiss



Joined: 24 Jun 2008
Posts: 2246
Location: Connecticut, USA

PostPosted: Fri Oct 12, 2018 12:40 pm    Post subject: Reply with quote

The reason this works is it increases the distance of the sailors center of mass from vertical. Doing this allows a sailor to use more power or at least tune to it. Speed increases or stays more even over time. It is one part of the physics of windsurfing.

Not all boards benefit or will support this method. FW, RS:X, hybrids and even Kona One can be sailed better on the fin when holding the uphall. It does require a different tuning to reap its benefits and rarely supplies added performance simply by grabbing it upwind without changing your tuning.

_________________
Support Your Sport. Join US Windsurfing!
www.USWindsurfing.org
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    iWindsurf Community Forum Index -> Windsurfing Discussion All times are GMT - 5 Hours
Goto page Previous  1, 2, 3  Next
Page 2 of 3

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You can attach files in this forum
You can download files in this forum

myiW | Weather | Community | Membership | Support | Log in
like us on facebook
© Copyright 1999-2007 WeatherFlow, Inc Contact Us Ad Marketplace

Powered by phpBB © 2001, 2005 phpBB Group