UK-Cherub Forum
Cherub Chat => Tech Chat => Topic started by: Team Slatter on March 20, 2014, 04:29:53 PM
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Hiya ,
Just wondering what the 97 rules are on sail sizes
Alex
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http://www.uk-cherub.org/doku.php/rules
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cheers, do you know what the ratio is fom min to jib
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it's up to you. Tim will be able to tell you a few typical numbers from the measurement files.
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Hi Alex (team slatter)
in Sweet Dreamzz we have 3 options, 8.5 main - 4 jib. 9.5 main - 3 jib for the '97 set up.
Our spinny is 29r or xenon (which I think is a only a fraction too big for the 97 kite measurement). For '05 set up we use the 9.5 main - 4 jib and use an old 800 kite but are really quite underpowered for twin wire but really enjoy the blasting!
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These are from an old spreadsheet...
Sail No 2641 2685 2637
Mainsail
From the spars
Luff Length a 5.97 6.07 5.5
Foot Length b 1.78 1.83 1.87
From the sail laid on a flat surface
Leech Length c 5.95 5.75 5.45
Luff Round Offset g 0.155 0.19 0.175
Luff Round length AY 5.76 5.81 5.35
Leech Round Offsets d 0.32 0.285 0.35
e 0.59 0.565 0.62
f 0.77 0.79 0.725
Foot Round Offset h 0 0 0.05
Foot Round length CX 1.78 1.785 1.15
Any Other adjustments units^2 0
Area of main triangle 5.244 5.260 5.042
Area of Luff Round 0.5952 0.7359 0.6242
Area of Leech round 2.75842 2.60475 2.5437
Area of Foot round 0 0 0.038
Total Mainsail Area 8.5982 8.6008 8.2484
Jib
Luff Length a 4.375 4.43 4.4
Foot Length b 1.69 1.67 1.51
Leech Length c 3.78 3.87 3.92
Luff Round g 0.05 0.045 0.05
Leech Round offsets d
(if large leech) e
f
Leech round offset
(if small) e 0.16 0.15 0.172
Foot Round h 0.18 0.205 0.195
Any other adjustments units^2
Area of main triangle 3.1549 3.1979 2.9284
Area of Luff Round 0.1458 0.1329 0.1467
Area of Leech round (method 1) 0 0 0
Area of Leech round (method 2) 0.4032 0.387 0.4494
Area of Foot round 0.2028 0.2282 0.1963
Total Jib Area 3.90 3.94 3.72
Total White Sail Area 12.50 12.55 11.96
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Cheers Guys, Is there a limit to the Kite, I know it originaly was 15m2 however the ones at the inlands looked certainly bigger.
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The 1997 Rules state - "The area of spinnaker may not exceed 15m2."
If you want to use a bigger kite then you will fall under the current 2011 rules (or more commonly known as 2005 rules as that is when the sail area size was changed) to which the rules state "The area of spinnaker may not exceed 21m2".
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Kite measurement rule can be "worked" to make the best of the 15m2. A long thin kite where the luff and leach approach similar lengths can result in a surprisingly big kite.
Born Slippy's at the Inlands was made to the rules and is 14.999m2. It took only a small cut to reduce this from a 18m2 kite made for Evo.
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We still have a full set of 97 rules sails. (Madge 2646)
the Kite is new from North last year and i asked them to change the proportions a bit so it might look bigger and fuller but it's still a 15m2 sail.
there are guys in the 97 rules boats that are sailing with larger kites for most events and may only go full 97 rules at the nationals. this is sometimes more fun in the blasts but we had more than enough fun on Sunday when it was super windy.
cheers
Nick
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I am looking at a pinnel and bax kite or a suffolk sails kite as they are quite close