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Catnewbie

Member Since 18 Feb 2011
Offline Last Active Aug 23 2014 08:16 AM
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Posts I've Made

In Topic: A Class Fail? The Future of the A's

03 August 2014 - 07:51 AM

Simon,

 

By full load I mean (full vertcal lift)=1480 Newtons lift from the leeward foil + 120 lift Newtons from the T foil, both =1600N

It also means full righting moment (lateral lift around 600 Newtons for the leeward foil + 60 Newtons for the rudder blade= 660N

 

The optimum angle 68° comes from cooking trigonometry formula with 1480N and 600N regardless of area, foil section or aspect ratio

 

I do not consider windward foil & T-rudder.

 

Cheers

 

W


In Topic: A Class Fail? The Future of the A's

31 July 2014 - 10:26 AM

In the above message I implictly consider the flex is "manageable" and that's probably another story, only composite specialist could answer on this point.

 

Cheers

 

W


In Topic: A Class Fail? The Future of the A's

31 July 2014 - 10:22 AM

Thank you PJD for your crystal clear answer,

and thank you everybody for fuelling the discussion with sound arguments.

 

My purpose was not to focuse on a potential loophole of rule 8, instead it's about measuring the "gap" between a theorical optimum solution (mimimun drag @ a design speed) and the best existing solution.

 

My theorical optimum solution would be (if computations are not stupid) a surface piercing foil at 67° from vertical, with a 56cm span.

 

If the board with no load has a 45° angle, and if it can flex under full load at 67° then we have already the optimal solution which meets perfectly rules 8.

 

In other words, with the flex, insertion from below is no more necessary to get the optimum.

 

That's all I wanted to enlight, I m not proficient with measurement or fair interpretation of the rules, so I stick to  what I believe I understand better.

 

Cheers

 

Wolfgang


In Topic: A Class Fail? The Future of the A's

30 July 2014 - 08:32 AM

Please I would have question PJD,

 

Do the new Z foil flex under load ?

 

Thanks

 

W


In Topic: A Class Fail? The Future of the A's

26 July 2014 - 07:46 AM

Thanks Ozcrisb,

 

3 points foiling will be the next point, according to Paradox team. I believe so and we might see huge gap in performance when full righting moment will be put at full use.

 

Cheers

 

W