Aerodynamics of the slot

Discussion in 'Sailboats' started by chabrenas, Feb 4, 2009.

  1. sailor2
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    sailor2 Senior Member

    If area is reduced going for higher Cl without changing Lift_force, it doesn't necessarily chance L/D much. As a result C-cats don't have less L/D downwind as they would have if they were allowed to have more area with same mast height & less Cl. That means high Cl max can work in high performance boats as well just fine. Would be much harder to have the same situation on iceboats as that would require so short chords that low Re-number would prevent it from working.
    Yes, because going for max L/D with high mast also means less force for same heeling moment. So even for upwind, max L/D isn't optimum for best performance. Even more so in practise as mast height can't be increased just as one wants it to be meaning one must sail with less heeling moment if trying to get better L/D and drop in lift force is even more dramatic.
     
  2. sailor2
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    sailor2 Senior Member

    Did you meant to say would be ?
    If not, could you provide examples of such boats with telescoping spars.
     
  3. Tcubed
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    Tcubed Boat Designer

    <<<<<<If area is reduced going for higher Cl without changing Lift_force, it doesn't necessarily chance L/D much. As a result C-cats don't have less L/D downwind as they would have if they were allowed to have more area with same mast height & less Cl. That means high Cl max can work in high performance boats as well just fine. Would be much harder to have the same situation on iceboats as that would require so short chords that low Re-number would prevent it from working.>>>>>>

    I'm not quite sure what you mean here but the first point is not very clear as the induced drag penalty must be weighed against the wetted area penalty.

    Also c cats work within the restricted area rule which always favors high AR.
    ***
    No, it is are. Just read the references (post #14) for well established examples.

    And Chabrenas, time has not changed anything, reducing weight and windage aloft (hollow spars or not) remains just as relevant as always.

    Bottom line for light wind ; Lots of sail area , as in lots.
     

  4. Tcubed
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    Tcubed Boat Designer

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