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  • Pierre Benhaiem
    Hi, After some difficulties of which translate for French terms ( démultiplication du levier ) previnting for enough understanding. AWE traction kites like
    Message 1 of 1 , Oct 26, 2009
      After some difficulties of which translate for French terms ("démultiplication du levier") previnting for enough understanding. 
      AWE traction kites like kite surf or KiteShip perfectly work.Rotation for AWE kite generators raises different problems with identical aerodynamic features of kites.
      From linear AWE:good transmission between tether and generator,but dispersed swept area.So its economical interest is limited because of the too important ratio used aerial space/power.
      From some cyclic AWE with kites:low ratio used ground and aerial space/power but problems of transmission:the useful tangential force (which creates torque) is limited and there are important axial and radial forces (which not creates torque,but damages to the structure).
      Mechanical characteristics are the base of OrthoKite system studying.
      Double lever systems theoretical allow to use the complete window of fly,left and right.However on known devices left and right levers like Fig.1b
      on http://www.energykitesystems.net/index.html simultaneously are pull,that to assure left and right motion.So radial force is high,since transmission is + - 180°:radial force is necessary to put the device in oscillating power motion:so tangential force is low.The benefit of magnitude of the torque of the lever arm  is weak (perhaps it is the reason why there are few descriptions of this point).OrthoKite system transmission is about 90°,so radial force is low,and tangential force is high.
      Axial force is a common problem for all vertical axis:more high is the angle of fly,more high is axial force.  
      It is the reason why a OrthoKite variant describes jacks under the swivelling tray for an adapted oblic axis to the angle of fly of kites.With such a device trajectories of kites are light curves on a vertical plan (instead horizontal trajectories).
      On OrthoKite system the magnitude of the torque of the lever arm  is such that its length corresponds to power/angular speed,and is dependent of the ratio LD of the kites.
      For Kitegen carousel it is identical,but angular speed being lower (no direct drive of kites) the length of the arm lever is higher.
      The first easy experiment (without kite) with a salad spinner with a scotched ruler:pull on thethered on one end = high torque:pull on tethered on two ends = high radial force (high traction,low torque).
      The next experiment with a kite:an OrthoKite variant with a wagon putting in motion the 2 lines of the kite one end to the other end of the double lever.
      The following step:a complete prototype with a storing device smoothing generator production,sensors,automation.The storing device is an hydraulic installation with hydraulic actuating,hydropneumatic accumulator,hydraulic motor.For this step at least a firm is necessary. 
      I would be happy scientifics and searchers develop and precise the points on tangential,axial,radial forces:it is one key for some AWE projects.
      Pierre Benhaïem

      1 of 1 Photo(s)

      double lever systems.JPG
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