First the width of the craft.
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<br>Take a look at page
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<br>http://www.geocities.com/F16HTclass/F16HT_to_F18_equality.html
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<br>It has been severly updated, you will be familiar with large parts of the text but there are some big parts newly added.
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<br>Some due to my friend here blowing the wissle. Okay width :
<br>Another lucky guess gentlemen for it appears that 2,5 mtr. as a maximum width coincides perfectly with a 83 % thrust in the stronger winds. Calculation goes as follows :
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<br>ratio righting moment doubled trapezed F16HP/F18= (150 *3,5 + 100*1,25) / (150 *3,6 + 180 *1,3) = 650 / 774 = 0,8398 % = 84 %. The sailarea ratio F16HP/F18 = also 84 % and both masts are equally high. So both crews will be double trapped in the same windstrength and depower at the same time thus the max thrust ratio will be fixed 84 % too ! So if the high speed drag is 84 % too than an F16HP at 2,5 mtr. width will be perfectly equal to the F18's. When the platform isn't then wings providing extra width can raise the thrust ratio in these conditions. Example : Width goes to 2,7 (0,2 mtr, wings on both sides)
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<br>150 * (2,7+1) + 100 * 1,35 = 690 kgm
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<br>then
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<br>690 / 650 = 1.0615 = 106 % more heeling resistance this leads to the F16HP rig being able to produce 6 % more thrust than it would at 650 kgm anti-heeling moment. And this is produced at 103 % the windstrength at which a F18 starts to depower. Which is nearly nothing, hardly noticable, but the 6 % increase in Thrust isn't so small !! And best thing about this setup is that it leaves light and medium air characteristics unaffeacted. Make the platform wider only boost heavy air performance and nothing else.
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<br>So we have :
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<br>1 Genaker to finetune downwind performance
<br>2 Jib to fine tune upwind performance
<br>3 Width to finetune heavy air upwind performance
<br>4 Rather long upwind beats and short downwind tracks making any heavy air downwind performance difference to have a rather small impact on the overall result. Less impact time thus speed differences on this course are relatively unimportant ; analogue to cat-skiff paradox.
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<br>And we already had equality in the light air due to the lightweight and 83 % wetted surface area. Seems to me that we've got all the finetune mechanismes we want to make the F16HP equal to the F18 class. And max width 2.5 mtr. is a very good starting point.
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<br>Wouter
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