Messages in AirborneWindEnergy group.                          AWES 23742 to 23793 Page 367 of 440.

Group: AirborneWindEnergy Message: 23742 From: Peter A. Sharp Date: 8/16/2018
Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

Group: AirborneWindEnergy Message: 23743 From: benhaiemp Date: 8/16/2018
Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

Group: AirborneWindEnergy Message: 23744 From: benhaiemp Date: 8/17/2018
Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

Group: AirborneWindEnergy Message: 23745 From: Joe Faust Date: 8/17/2018
Subject: KGM1 - GHIVA / NEWS August 18, 2018

Group: AirborneWindEnergy Message: 23746 From: Peter A. Sharp Date: 8/17/2018
Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

Group: AirborneWindEnergy Message: 23747 From: Peter A. Sharp Date: 8/17/2018
Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

Group: AirborneWindEnergy Message: 23748 From: Pierre BENHAIEM Date: 8/17/2018
Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

Group: AirborneWindEnergy Message: 23749 From: Peter A. Sharp Date: 8/17/2018
Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

Group: AirborneWindEnergy Message: 23750 From: joe_f_90032 Date: 8/17/2018
Subject: Re: KGM1 - GHIVA / NEWS August 18, 2018

Group: AirborneWindEnergy Message: 23751 From: Pierre BENHAIEM Date: 8/17/2018
Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

Group: AirborneWindEnergy Message: 23752 From: Peter A. Sharp Date: 8/18/2018
Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

Group: AirborneWindEnergy Message: 23753 From: Pierre BENHAIEM Date: 8/18/2018
Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

Group: AirborneWindEnergy Message: 23754 From: joe_f_90032 Date: 8/18/2018
Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

Group: AirborneWindEnergy Message: 23755 From: Pierre BENHAIEM Date: 8/18/2018
Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

Group: AirborneWindEnergy Message: 23756 From: Joe Faust Date: 8/18/2018
Subject: 2017 ACK Graduation Project - Airborne Wind-turbine

Group: AirborneWindEnergy Message: 23757 From: Pierre BENHAIEM Date: 8/18/2018
Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

Group: AirborneWindEnergy Message: 23758 From: joe_f_90032 Date: 8/18/2018
Subject: Re: AWES Anchoring

Group: AirborneWindEnergy Message: 23759 From: dave santos Date: 8/20/2018
Subject: Re: 2017 ACK Graduation Project - Airborne Wind-turbine

Group: AirborneWindEnergy Message: 23760 From: Peter A. Sharp Date: 8/21/2018
Subject: Re: 2017 ACK Graduation Project - Airborne Wind-turbine

Group: AirborneWindEnergy Message: 23761 From: dave santos Date: 8/22/2018
Subject: Re: 2017 ACK Graduation Project - Airborne Wind-turbine

Group: AirborneWindEnergy Message: 23763 From: joe_f_90032 Date: 8/22/2018
Subject: Re: Sky Serpent under a Pilot-Lifter Kite

Group: AirborneWindEnergy Message: 23764 From: Joe Faust Date: 8/23/2018
Subject: Re: Sky Serpent under a Pilot-Lifter Kite

Group: AirborneWindEnergy Message: 23765 From: benhaiemp Date: 8/23/2018
Subject: Re: Sky Serpent under a Pilot-Lifter Kite

Group: AirborneWindEnergy Message: 23766 From: dougselsam Date: 8/23/2018
Subject: A working tidal-power system

Group: AirborneWindEnergy Message: 23767 From: Joe Faust Date: 8/23/2018
Subject: Re: A working tidal-power system

Group: AirborneWindEnergy Message: 23768 From: benhaiemp Date: 8/23/2018
Subject: Re: A working tidal-power system

Group: AirborneWindEnergy Message: 23769 From: benhaiemp Date: 8/23/2018
Subject: Re: A working tidal-power system

Group: AirborneWindEnergy Message: 23770 From: Peter A. Sharp Date: 8/24/2018
Subject: Re: A working tidal-power system

Group: AirborneWindEnergy Message: 23771 From: Doug Selsam Date: 8/24/2018
Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

Group: AirborneWindEnergy Message: 23772 From: dougselsam Date: 8/24/2018
Subject: Kite-reeling concrete blocks "are really" "kites"

Group: AirborneWindEnergy Message: 23773 From: Pierre BENHAIEM Date: 8/24/2018
Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

Group: AirborneWindEnergy Message: 23774 From: joe_f_90032 Date: 8/24/2018
Subject: Re: Skypower100 Website

Group: AirborneWindEnergy Message: 23775 From: dave santos Date: 8/24/2018
Subject: More SkySails100 AWES Buzz

Group: AirborneWindEnergy Message: 23777 From: dave santos Date: 8/24/2018
Subject: Correction- [AWES] More SkySails100 AWES Buzz

Group: AirborneWindEnergy Message: 23778 From: dave santos Date: 8/25/2018
Subject: TUDelft Further Documents Launching Mast Challenges (video)

Group: AirborneWindEnergy Message: 23779 From: dave santos Date: 8/25/2018
Subject: Re: TUDelft Further Documents Launching Mast Challenges (video)

Group: AirborneWindEnergy Message: 23780 From: joe_f_90032 Date: 8/25/2018
Subject: Re: TUDelft Further Documents Launching Mast Challenges (video)

Group: AirborneWindEnergy Message: 23781 From: joe_f_90032 Date: 8/25/2018
Subject: 25 m2 LEI V3

Group: AirborneWindEnergy Message: 23782 From: dave santos Date: 8/25/2018
Subject: Singing Sands as Dynamical Similarity-case with AWES Networks (?)

Group: AirborneWindEnergy Message: 23783 From: gordon_sp Date: 8/26/2018
Subject: Re: Sky Serpent under a Pilot-Lifter Kite

Group: AirborneWindEnergy Message: 23784 From: dave santos Date: 8/26/2018
Subject: Re: Sky Serpent under a Pilot-Lifter Kite

Group: AirborneWindEnergy Message: 23785 From: dave santos Date: 8/27/2018
Subject: Dr. Anders Ansar on Power Kites

Group: AirborneWindEnergy Message: 23786 From: joe_f_90032 Date: 8/27/2018
Subject: Makani news

Group: AirborneWindEnergy Message: 23787 From: joe_f_90032 Date: 8/27/2018
Subject: Re: Makani news

Group: AirborneWindEnergy Message: 23788 From: joe_f_90032 Date: 8/27/2018
Subject: Re: Makani news

Group: AirborneWindEnergy Message: 23789 From: andrew@airhes.com Date: 8/28/2018
Subject: Re: Dr. Anders Ansar on Power Kites

Group: AirborneWindEnergy Message: 23790 From: dougselsam Date: 8/28/2018
Subject: Selsam awarded new U.S. Patent for offshore wind

Group: AirborneWindEnergy Message: 23791 From: joe_f_90032 Date: 8/28/2018
Subject: Re: Selsam awarded new U.S. Patent for offshore wind

Group: AirborneWindEnergy Message: 23792 From: joe_f_90032 Date: 8/28/2018
Subject: Re: Selsam awarded new U.S. Patent for offshore wind

Group: AirborneWindEnergy Message: 23793 From: gordon_sp Date: 8/28/2018
Subject: LEVER-ARM LAUNCH




Group: AirborneWindEnergy Message: 23742 From: Peter A. Sharp Date: 8/16/2018
Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig
Attachments :

    Hi Pierre,

              Yes, Flettner rotors (L/D = 3 to 4) used as pull-kites should be able to fly at a high elevation angle. So the tethers should be shorter for reaching a given altitude, as compared to a cross-wind moving kite.

              An SRVK will have a L/D that may only be 1 to 1, and a tether angle of 45 degrees. That it because it produces torque, and torque creates high drag. So an SRVK or an FRVK will not have a high elevation angle – as you noted.

    PeterS

     

     

    From: AirborneWindEnergy@yahoogroups.com [mailto:AirborneWindEnergy@yahoogroups.com]
    Sent: Wednesday, August 15, 2018 10:06 PM
    To: AirborneWindEnergy@yahoogroups.com
    Subject: RE: [AWES] Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a high elevation angle.

     

     

     

    Hi Peter,

     

    I quoted an extract from authors including Michael Traut. Apparently you don't agree with their statements. Indeed some other papers can provide other values. There is a lack of reliable information about flying Flettner rotors with high spin ratio as 4, in defect 3, in defect 2.

     

    Even if the approximations you give are correct, a L/D ratio of 3 or 4 leads to an elevation angle of respectively 72° and 76° as shown on http://2e5.com/kite/ld/ . And as Flettner (and also self-rotating) rotors are not subject to cosine loss by themselves their elevation angle (72° or 76°) can be quite high by using pumping mode.

     

     

    I have also to precise that some FRVK (and SRVK) could have an elevation angle lesser than 72°, considering they can fly.

     

    The center of the eight or loop path of current crosswind kites is generally about 30° elevation angle, as the low part of the flight window is more powerful. It is thus a curious paradox that AWES would be more effective at lower elevation angle, leading to an implementation of a very long tether in order to reach high altitude, leading to huge space and land use.

     

     

    So I opened this topic to present an alternative solution for a higher elevation angle.

     

     

    PierreB

     

     

     

     

     

     

    Group: AirborneWindEnergy Message: 23743 From: benhaiemp Date: 8/16/2018
    Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

    Hi Peter,


    I quoted an extract from authors including Michael Traut. Apparently you don't agree with their statements. Indeed some other papers can provide other values. There is a lack of reliable information about flying Flettner rotors with high spin ratio as 4, in defect 3, in defect 2.

    Even if the approximations you give are correct, a L/D ratio of 3 or 4 leads to an elevation angle of respectively 72° and 76° as shown on http://2e5.com/kite/ld/. And as Flettner (and also self-rotating) rotors are not subject to cosine loss by themselves their elevation angle (72° or 76°) can be quite high by using pumping mode.

    I have also to precise that some FRVK (and SRVK) could have an elevation angle lesser than 72°, considering they can fly.

    The center of the eight or loop path of current crosswind kites is generally about 30° elevation angle, as the low part of the flight window is more powerful. It is thus a curious paradox that AWES would be more effective at lower elevation angle, leading to an implementation of a very long tether in order to reach high altitude, leading to huge space and land use.

    So I opened this topic to present an alternative solution for a higher elevation angle.


    PierreB



     



      

    Group: AirborneWindEnergy Message: 23744 From: benhaiemp Date: 8/17/2018
    Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig





    Hi Peter,

    The elevation angle leads to several concerns. The best known is the cubed cosine loss.

    The current crosswind kites and some rotating kites like Rod's Daisy or my Rotating Reel have an elevation angle of about 30° or 35° in the central axis. With an elevation angle of 30° the efficiency becomes 0.65 due to cubed cosine loss. With an elevation angle of 45° the efficiency becomes 0.35. With an elevation angle of 60° the efficiency becomes 0.125.

    The second concern, in my opinion, is the land and space used by taking account of all possible wind directions. The more the elevation angle is high, the less the wind changes modify its location.

    The configuration you propose as the Sharp Rotor VAWT Kite is not subject to cosine loss. Considering it flies with an elevation angle of 45°, it is an important advantage. The same for a Flettner Rotor VAWT Kite. And also the same for a Variable Pitch Blade VAWT Kite. But as you mention the used torque lowers the elevation angle.

    In the end a pull-kite using a Flettner rotor or even a Sharp rotor can have a higher elevation angle and also without cosine loss.

    PierreB












    Group: AirborneWindEnergy Message: 23745 From: Joe Faust Date: 8/17/2018
    Subject: KGM1 - GHIVA / NEWS August 18, 2018
    ... ,I will send you a brief update on the KGM1 research project:we completed on July the first configuration of the prototype generator  - which is now 100% manual - and carried out a very first flight test at Acqui Terme, aimed at testing the mechanical functioning of the generator, some design parameters but above all assessing the synchrony between the mechanical movements and flight trajectories (object of one of the most important patents). I am very satisfied with the results obtained among other things in weather conditions at the limit of non-volatility, I expect to organize another test always in manual, but with a minimum of telemetry on board, and I hope be able to raise the necessary funds to further push the project (so far we have done everything with just over 10 k € and some help from one of the old lenders of the Kite-Gen!!!!), with the aim of powering the generator in order to measure the producible powers (5 kW in this configuration) and dissipated in the "passive" phases. There are also other important parameters to test that I consider extremely interesting for the entire high altitude wind sector, but without doubt we will have to start an initiative that now requires an operational team and a minimum of structure. At the same time, a master thesis on the modeling and control of trajectories by a graduate student in the Milan Polytechnic - managed by Prof. Fagiano - has begun, thus a further expression of interest on the part of the academic world.We will try to merge the first information from the tests with the relevant theoretical aspects.
    Finally, contacts with a company that already deals with the production and sale of electricity are continuing and in September a technical evaluation phase of the initiative will be launched.

    And from America, does you will finally have some good news?  A cordial greeting from Turin. 
    Marco Ghivarello
     
    https://www.linkedin.com/showcase/kgm1/
      GHIVA Progettaz. CAD   Sede Legale:  Via Orbetello, 36 - 10148 Torino Sede Operat:  P.za Comunale, 6 - 10090 Rivalba (To) mail: ghiva@ghiprog.it - Web: www.ghiprog.it Cell. 338.8005595  -  Tel. 011.2205774  -   P.ta Iva 09402900014 
    Group: AirborneWindEnergy Message: 23746 From: Peter A. Sharp Date: 8/17/2018
    Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig
    Attachments :

      Hi Pierre,

                Yes, as far as I know, which isn’t much, the longer the tether, the greater the land use. But using a tether angle greater than 45 degrees doesn’t substantially shorten the tether, so I’m not clear on why you want to achieve a higher tether angle than 45 degrees.

                There would be no advantage, as far as I can tell, to fly an SRVK at a tether angle greater than 45 degrees. To do so, it would be necessary to sacrifice a lot of torque and power. Yes, the wind speed will be a little stronger higher up, but that won’t be enough to compensate for the reduction in power required to lower the L/D ratio of the SRVK. A higher tether angle than 45 degrees would mean a loss of power because, as far as I can tell, some torque would need to be sacrificed in order to create more lift. Torque increases VAWT kite drag, and drag lowers the L/D ratio

                If I were trying to design a pull kite using a Flettner rotor or a Sharp Rotor, I would start by assuming a conservative L/D ratio of 2 to 3 rather than an optimistic 3 to 4.

                Many published papers contain typos. So it’s hard to know if an author has actually made a mistake. If I disagree, I may be disagreeing with a typo. Or, I may be wrong. So I try to consider the preponderance of evidence.

      PeterS

               

       

      From: AirborneWindEnergy@yahoogroups.com [mailto:AirborneWindEnergy@yahoogroups.com]
      Sent: Wednesday, August 15, 2018 9:33 PM
      To: AirborneWindEnergy@yahoogroups.com
      Subject: RE: [AWES] Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a high elevation angle.

       

       

      Hi Peter,

       

      I quoted an extract from authors including Michael Traut. Apparently you don't agree with their statements. Indeed some other papers can provide other values. There is a lack of reliable information about flying Flettner rotors with high spin ratio as 4, in defect 3, in defect 2.

      Even if the approximations you give are correct, a L/D ratio of 3 or 4 leads to an elevation angle of respectively 72° and 76° as shown on http://2e5.com/kite/ld/. And as Flettner (and also self-rotating) rotors are not subject to cosine loss by themselves their elevation angle (72° or 76°) can be quite high by using pumping mode.

      I have also to precise that some FRVK (and SRVK) could have an elevation angle lesser than 72°, considering they can fly.

      The center of the eight or loop path of current crosswind kites is generally about 30° elevation angle, as the low part of the flight window is more powerful. It is thus a curious paradox that AWES would be more effective at lower elevation angle, leading to an implementation of a very long tether in order to reach high altitude, leading to huge space and land use.

      So I opened this topic to present an alternative solution for a higher elevation angle.

       

      PierreB

       

       

       



        

      Group: AirborneWindEnergy Message: 23747 From: Peter A. Sharp Date: 8/17/2018
      Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig
      Attachments :

        Hi Pierre,

                  That all sounds right to me.

                  A HAWT type rotor that is tipped to the wind reduces its swept area. And if the blades are fixed, then the angle of attack cannot be optimum during a full revolution. But variable pitch might be able to partially compensate. If the blades were Sharp Rotors, that would keep the blades at their optimum “angle of attack” during a full revolution.  That should be the case for the Sharp Rotor HAWT Long-Pull Kite.

        PeterS

         

        From: AirborneWindEnergy@yahoogroups.com [mailto:AirborneWindEnergy@yahoogroups.com]
        Sent: Friday, August 17, 2018 12:56 AM
        To: AirborneWindEnergy@yahoogroups.com
        Subject: RE: [AWES] Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a high elevation angle.

         

         

         

         

         

         

        Hi Peter,

        The elevation angle leads to several concerns. The best known is the cubed cosine loss.

        The current crosswind kites and some rotating kites like Rod's Daisy or my Rotating Reel have an elevation angle of about 30° or 35° in the central axis. With an elevation angle of 30° the efficiency becomes 0.65 due to cubed cosine loss. With an elevation angle of 45° the efficiency becomes 0.35. With an elevation angle of 60° the efficiency becomes 0.125.

        The second concern, in my opinion, is the land and space used by taking account of all possible wind directions. The more the elevation angle is high, the less the wind changes modify its location.

        The configuration you propose as the Sharp Rotor VAWT Kite is not subject to cosine loss. Considering it flies with an elevation angle of 45°, it is an important advantage. The same for a Flettner Rotor VAWT Kite. And also the same for a Variable Pitch Blade VAWT Kite. But as you mention the used torque lowers the elevation angle.

        In the end a pull-kite using a Flettner rotor or even a Sharp rotor can have a higher elevation angle and also without cosine loss.

        PierreB

         

         

         

         

         

         

         

         

         

         

         

        Group: AirborneWindEnergy Message: 23748 From: Pierre BENHAIEM Date: 8/17/2018
        Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig
        Attachments :

          Hi Peter,

           

          Joined scheme:


           

          PierreB

           

           

          Group: AirborneWindEnergy Message: 23749 From: Peter A. Sharp Date: 8/17/2018
          Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

          Hi Pierre,

                    The attachment didn’t open.

          PeterS

           

          From: AirborneWindEnergy@yahoogroups.com [mailto:AirborneWindEnergy@yahoogroups.com]
          Sent: Friday, August 17, 2018 4:46 PM
          To: AirborneWindEnergy@yahoogroups.com
          Subject: RE: [AWES] Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a high elevation angle. [1 Attachment]

           

           

          [Attachment(s) from Pierre BENHAIEM included below]

          Hi Peter,

           

          Joined scheme:

           

          PierreB

           

           

          Group: AirborneWindEnergy Message: 23750 From: joe_f_90032 Date: 8/17/2018
          Subject: Re: KGM1 - GHIVA / NEWS August 18, 2018
          Group: AirborneWindEnergy Message: 23751 From: Pierre BENHAIEM Date: 8/17/2018
          Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig
          Attachments :

            Hi Peter,

            I think the attachment is on the website. I join now a more complete sketch of the space and land use with different elevation angles.

             

            PierreB

             

             

             

             

             

              @@attachment@@
            Group: AirborneWindEnergy Message: 23752 From: Peter A. Sharp Date: 8/18/2018
            Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig
            Attachments :

              Hi Pierre,

                        The attachment is quite helpful. I can see that a tether angle greater than 45 degrees does in fact significantly reduce the land area.

                        The website wouldn’t open for me. Don’t know why.

                        In any case, now I do appreciate why you want to use a higher tether angle. Thanks for explaining.

              PeterS

               

              From: Pierre BENHAIEM [mailto:pierre-benhaiem@orange.fr]
              Sent: Saturday, August 18, 2018 12:00 AM
              To: AirborneWindEnergy@yahoogroups.com
              Cc: Peter A. Sharp <sharpencil@sbcglobal.net

              Group: AirborneWindEnergy Message: 23753 From: Pierre BENHAIEM Date: 8/18/2018
              Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig
              Attachments :

                Hi Peter,

                 

                Thanks for your comment.

                Concerning the space and land use*, the difference between 30° and 45° is quite huge, the difference between 45° and 60° is still important but lesser.

                Most projects using crosswind kites are studied for an average 30° elevation angle in order to avoid a very important cosine loss. With 30° elevation angle the efficiency is 0.65 and with higher angles the efficiency drops drastically. And this leads to several concerns as a high space and land use and also a tether moving in high speed in a low angle, preventing any secondary use, that with a lack of passive safety if the automated control management is failing. Also wind changes lead to a (too) large travel of the kites for positioning in the new window of flight. Risks of serious collisions or tangle are increased within a kite-farm. It is the high price to pay for their very high power/weight ratio.

                 

                PierreB

                *I sent again the filr in another format.

                 

                 

                 

                 

                 

                  @@attachment@@
                Group: AirborneWindEnergy Message: 23754 From: joe_f_90032 Date: 8/18/2018
                Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

                Group: AirborneWindEnergy Message: 23755 From: Pierre BENHAIEM Date: 8/18/2018
                Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

                I agree.

                 

                 

                 

                 

                Group: AirborneWindEnergy Message: 23756 From: Joe Faust Date: 8/18/2018
                Subject: 2017 ACK Graduation Project - Airborne Wind-turbine
                Group: AirborneWindEnergy Message: 23757 From: Pierre BENHAIEM Date: 8/18/2018
                Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig

                I included a crash zone (= tether length) that occurs when the tether does not break. But if the tether breaks, the kite can fly with the tether on kms, far out of the zones, causing extensive damage.

                 

                 

                 

                 

                  @@attachment@@
                Group: AirborneWindEnergy Message: 23758 From: joe_f_90032 Date: 8/18/2018
                Subject: Re: AWES Anchoring

                Showing a soft anchor method: 


                Group: AirborneWindEnergy Message: 23759 From: dave santos Date: 8/20/2018
                Subject: Re: 2017 ACK Graduation Project - Airborne Wind-turbine
                This is a good example of a student project that if it did not succeeded as wished, surely worked as an educational experience. A complaint off-forum is that cheap emotionally insensitive ridicule, was not indulged here (under moderation principles).
                Group: AirborneWindEnergy Message: 23760 From: Peter A. Sharp Date: 8/21/2018
                Subject: Re: 2017 ACK Graduation Project - Airborne Wind-turbine
                Attachments :

                  Hi DaveS,

                            My reaction to the ACK project is different from yours. I read a lot of research papers and many of them are done as senior thesis papers. There are usually a number of authors. The quality tends to be low, most often because the students have not adequately searched the available literature, so they tend to duplicate what has already been done, often without realizing it. Such groups typically have a faculty advisor. What bothers me is that, although doing most any project will be an “educational experience”, the students too often learn poor research methodology. And research methodology is the most important thing for them to learn at that stage of their education.

                            With respect to their results, the ACK project was a high school level project, or maybe a first year college engineering project. As part of a senior project, if that is what it was, it was an inadequate demonstration of competence for professional engineers about to enter the work force. They should have been held to a higher standard. They demonstrated sloppy work, which implies that their faculty advisor condoned sloppy work. So I fault their faculty advisor for not doing his or her job.

                  PeterS

                   

                   

                  From: AirborneWindEnergy@yahoogroups.com [mailto:AirborneWindEnergy@yahoogroups.com]
                  Sent: Monday, August 20, 2018 3:22 PM
                  To: AirborneWindEnergy@yahoogroups.com
                  Subject: Re: [AWES] 2017 ACK Graduation Project - Airborne Wind-turbine

                   

                   


                  This is a good example of a student project that if it did not succeeded as wished, surely worked as an educational experience. A complaint off-forum is that cheap emotionally insensitive ridicule, was not indulged here (under moderation principles).

                  Group: AirborneWindEnergy Message: 23761 From: dave santos Date: 8/22/2018
                  Subject: Re: 2017 ACK Graduation Project - Airborne Wind-turbine
                  PeterS,

                  "Sloppy work" is how beginners develop creativity. The main idea is to encourage students at whatever level they are at, and who knows how far some will go. Lets leave sterile complaining over marginal student engineering projects to the trolls off-Forum. One might as well blame the inequitable educational outcomes on the lack of compassion for the less advantaged. This is also why your understanding of rotor phase-space, as "gobbledygook" is ok, rather than a moral flaw. Those students tried hard with what they had, as do us all,

                  daveS
                  Group: AirborneWindEnergy Message: 23763 From: joe_f_90032 Date: 8/22/2018
                  Subject: Re: Sky Serpent under a Pilot-Lifter Kite
                  Another contemporary version. Lifter wing is not balloons this time; a blue tarp is used for tail. Wake from working blades may not reach the lifter wing except in certain angles of flight. 

                  Rebuilt Sky Serpent Hits 1100 Watts

                  Doug Selsam sent us the link. 


                  Group: AirborneWindEnergy Message: 23764 From: Joe Faust Date: 8/23/2018
                  Subject: Re: Sky Serpent under a Pilot-Lifter Kite
                  I am not sure how the attached photo will show or be available at forum 

                    @@attachment@@
                  Group: AirborneWindEnergy Message: 23765 From: benhaiemp Date: 8/23/2018
                  Subject: Re: Sky Serpent under a Pilot-Lifter Kite

                  Hi Doug,


                  This is a stimulating realization. All is perfect: straighter Sky Serpent (tm), stability, smoothed power.  Congratulations.


                  PierreB

                  Group: AirborneWindEnergy Message: 23766 From: dougselsam Date: 8/23/2018
                  Subject: A working tidal-power system
                  What took the energy sector so long to hang a turbine from a boat?

                  "Scotrenewables Tidal Power has announced that its 2 MW floating tidal stream turbine prototype has managed to generate more than 3 GWh of renewable electricity during its first year of continuous operation, which is reported to be more than the entire wave and tidal energy sector has notched up in the 12 years before the launch of the SR2000 in 2016."

                  ================================================================

                  Moderator note: 
                  The SR2000 gets tethered and may qualify as a paravane system. Such places the system within the water-kite realm.   
                  Group: AirborneWindEnergy Message: 23767 From: Joe Faust Date: 8/23/2018
                  Subject: Re: A working tidal-power system
                  Related tech: 
                  Note: many diagrams of tethered paravane energy systems neglect to show involved tethers to the systems' anchors. The systems are not just free-floating hulls or boats, but the hulls and wings are being kited to some sort of anchor system. The general paravane energy sector is not new, but is being continually freshly developed. 

                  Some tethered kite systems using water as the media:

                    @@attachment@@
                  Group: AirborneWindEnergy Message: 23768 From: benhaiemp Date: 8/23/2018
                  Subject: Re: A working tidal-power system

                  Another project with a turbine that is hanged to a boat http://www.hydro-gen.fr/. The project creator David Adrian explains that "the currents are generally stronger near the surface than in the bottom."


                  PierreB

                  =========================

                  Moderator:  One must study their presentation carefully; finally they note and barely show about:  "As soon as it is anchored, we can start to output power".   Hence this is a kite system where the flygen is mostly in water and the rotor is in the water.  


                  Group: AirborneWindEnergy Message: 23769 From: benhaiemp Date: 8/23/2018
                  Subject: Re: A working tidal-power system

                  http://www.ltawind.com/Tech.php?lang=en&part=The_Airship could be an AWES version of the SR2000.


                  PierreB

                  Group: AirborneWindEnergy Message: 23770 From: Peter A. Sharp Date: 8/24/2018
                  Subject: Re: A working tidal-power system
                  Attachments :

                    Hi Pierre,

                              Thanks for posting this information.

                    My reaction to the LTA blimp kite is that it is too heavy and too expensive and could be improved by using a different design. For this  design, saving weight is critical for minimizing costs.

                    I would use the huge blimp body as a type of wind speed enhancer (shroud). Mount a single, small HAWT inside of the nose of the blimp. The opening in the nose would be considerably larger than the HAWT diameter. Then use slanted, radial channels behind the rotor that extend out to where the blimp diameter is the largest. That creates a Bernoulli effect speed up of the air passing through the rotor.

                    The air flowing around the blimp will be speeded up considerably at that maximum diameter, and so will provide a strong suction effect due to its lowered pressure. That will suck additional air through the rotor, thus further multiplying its RPM and its power. So the generator could be small and light.

                    It should be possible for one small, high RPM HAWT in the nose to produce as much power as the two, large, low RPM HAWT mounted on the wing tips. The total weight would be greatly reduced. And the total drag should be greatly reduced as well by eliminating the large, external HAWT. So the L/D ratio of the blimp as a whole should be much higher.

                    Mounting large rotors at the tip of the short wings has the effect of reducing airflow over part of the wings which are in front of the HAWT rotors. So eliminating those rotors will increase the lift of the wings, thus further increasing the L/D ratio of the blimp kite as a whole.

                    By feeding air to the slots around the largest diameter of the blimp, the boundary layer on the rear portion of the blimp should stay attached longer and be less turbulent. That should lower the drag of the blimp and further enhance the L/D ratio of the blimp as a whole.

                    PeterS

                             

                     

                    From: AirborneWindEnergy@yahoogroups.com [mailto:AirborneWindEnergy@yahoogroups.com]
                    Sent: Thursday, August 23, 2018 4:18 PM
                    To: AirborneWindEnergy@yahoogroups.com
                    Subject: [AWES] Re: A working tidal-power system

                     

                     

                    http://www.ltawind.com/Tech.php?lang=en&part=The_Airship could be an AWES version of the SR2000.

                     

                    PierreB

                    Group: AirborneWindEnergy Message: 23771 From: Doug Selsam Date: 8/24/2018
                    Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig
                    Wind Energy Installations require sufficient space that they could fall and stay within that space,
                    according to current codes..
                    Looks like the 62 degree one would fall outside the 45 degree zone,
                    the 45 degree one would fall outside the 30 degree zone,
                    and the 30-degree one would fall outside its own designated zone as shown in the diagram
                    The zones need to be large enough for crashes, not just the hoped-for normal operation.


                    Group: AirborneWindEnergy Message: 23772 From: dougselsam Date: 8/24/2018
                    Subject: Kite-reeling concrete blocks "are really" "kites"

                    https://qz.com/1355672/stacking-concrete-blocks-is-a-surprisingly-efficient-way-to-store-energy/

                    OK Guys, another "breakthrough".

                    The article says "no maintenance".

                    Cranes need no maintenance?

                    I note quite a similarity to kite-reeling.

                    Seems to me that if one is an economic solution,

                    the other one might also be.

                    and vice-versa.

                    One thing I notice is these "press-release breakthroughs" promote "advantages"

                    but seldom acknowledge disadvantages.



                    Group: AirborneWindEnergy Message: 23773 From: Pierre BENHAIEM Date: 8/24/2018
                    Subject: Re: Flettner and Sharp Rotor VAWT Kite (FRVK and SRVK) towards a hig
                    Attachments :

                      Hi Doug,

                       

                      The second diagram comprises 30, 45, and 60 degree zones respectively in red, orange, green, and crash zones that are indicated with - - - -. 

                      A crash zone is delimited with the respective tether length as radius, and is valid as long as the tether does not break.

                       

                      PierreB

                       

                       

                       

                        @@attachment@@
                      Group: AirborneWindEnergy Message: 23774 From: joe_f_90032 Date: 8/24/2018
                      Subject: Re: Skypower100 Website

                      The SkyPower100 project plans to create a kite-based system able to operate automatically and continuously
                      By Jonny Bairstow
                      Thursday 23 August 2018
                      ============================================================
                      See article linked above.

                      Group: AirborneWindEnergy Message: 23775 From: dave santos Date: 8/24/2018
                      Subject: More SkySails100 AWES Buzz
                      A reminder of SkySails' current R&D with partners, EnBW Energie Baden-Württemberg AG, Leibniz Universität Hannover and EWE Offshore Service & Solutions-

                      https://www.energylivenews.com/2018/08/23/innovative-collaboration-to-see-airborne-wind-power-soar-to-new-heights/
                      Group: AirborneWindEnergy Message: 23777 From: dave santos Date: 8/24/2018
                      Subject: Correction- [AWES] More SkySails100 AWES Buzz
                      Correcting: SKYPOWER100 not SkySails100

                      *sigh*

                      SkySails has two supposed soft-kite advantages over its rivals in the ~100kW AWES class; lowest capital cost and relative crash resistance. At least for now, a fabric kite likely has a considerably longer life than a rigid wing, if both are prone to crash.
                      Group: AirborneWindEnergy Message: 23778 From: dave santos Date: 8/25/2018
                      Subject: TUDelft Further Documents Launching Mast Challenges (video)
                      Evident in this short video are specific mast-launching trade-offs that caused KiteLab Ilwaco and kPower a decade ago to reject land-based launching masts (mobile ship-based masts avoid some shortcomings). Recalling several players, like KiteGen and its Stem, who prematurely down-selected land-based masts. KiteLab found the quickest cheapest way to deeply explore the mast-launch design space was to fly a small short-lined kite by hand while reeling out, one's own body acting as a scale-model mast, under dynamic similarity principle.

                      In summary, launching from a land mast (especially dangling v mast-head placed) leaves the kite often stranded in weakest most-turbulent surface wind, even as good wind wind aloft passes overhead. A kite on short-lines has a very high orbit frequency in gusts that easily saturates control actuation. We see in this video TUDelft's kite experiencing the full mix of unstable effects, and its no surprise the action jumps from a shakey start short-lined to a later state reeled-out. One can hear wild forces on the mast, and the pod's actuation limits exceeded during uncontrolled looping.

                      TUDelft's intent here seems to be to show a single successful launch, rather than formally confirm a long-supposed AWES design trap ( that kPower argued with KiteGen). Compare this chaotic TUDelft mast launch with standard HG/PG winch-tow launch model long advocated as the Open-AWE baseline launch design. TUDelft in fact launches long-lined most of time, by necessity.
                      https://www.youtube.com/watch?time_continue=13&v=k50HvzitpzQ

                      Once again, lacking best-practice comparative testing by the larger R&D players, we rely on empiric heuristics across test cases, but look forward to eventual optimal experimental design in future major R&D. Open_AWE IP shared here over the years includes winch-tow optimization ideas (like down-range "kite-buddy" mobile launch vehicles) to someday fully automate winch-tow.
                      Group: AirborneWindEnergy Message: 23779 From: dave santos Date: 8/25/2018
                      Subject: Re: TUDelft Further Documents Launching Mast Challenges (video)
                      Whoops, link provided did not start at 0:00. Try this one-


                      https://www.youtube.com/watch?v=k50HvzitpzQ
                      Group: AirborneWindEnergy Message: 23780 From: joe_f_90032 Date: 8/25/2018
                      Subject: Re: TUDelft Further Documents Launching Mast Challenges (video)
                      Group: AirborneWindEnergy Message: 23781 From: joe_f_90032 Date: 8/25/2018
                      Subject: 25 m2 LEI V3

                      Video 7: 25 m2 LEI V3 tube kite transitioning to traction phase, flying figure eight manoeuvres


                      [ ] examine the ribbon tether dynamics
                      [ ] listen to control pod operating


                      Published on Aug 3, 2018
                      SUBSCRIBED 261
                      25 m2 LEI V3 tube kite transitioning to traction phase and starting to fly figure eight manoeuvres (30 March 2017, former naval airbase Valkenburg, Leiden, Netherlands). The footage is recorded by a GoPro video camera mounted on the suspended kite control unit, looking at the kite. At t = 10 s the kite is powered (indicated by the noise from the winch motor) which takes around Δt = 6 s. The powering tensions the rear bridle lines, which can be recognized from the knots moving towards the line of sight to the rear edge of the wing. The wing slightly flattens, increasing its projected span. Once powered, at t = 17 s, the kite dives into crosswind manoeuvres and as a result picks up speed. This is indicated by the increasing flutter noise from the canopy. Video courtesy of Kitepower B.V. This video is supplementary material to the scientific paper by Rolf van der Vlugt, Anna Bley, Michael Noom and Roland Schmehl about “Quasi-steady model of a pumping kite power system”, Renewable Energy, 131, pp. 83-99, 2019. https://doi.org/10.1016/j.renene.2018...


                      Group: AirborneWindEnergy Message: 23782 From: dave santos Date: 8/25/2018
                      Subject: Singing Sands as Dynamical Similarity-case with AWES Networks (?)
                      We call AWES multi-kite architectures "Kite Networks" or "Networked Kites", especially to explore "planetary-scale" periodic kite arrays designed as energy-harvesting metamaterials. Most of our theoretic similarity cases are small-scale or even microscopic, like vibrating crystal-lattice models. We have learned to see a few macroscopic similarity cases, like gravity waves in marine, seismic, and atmospheric physics. For example, consider an ordinary ocean wave in the strictest topological kite physics terms; the wave is wind-powered, its lower body acts as anchor/tether for the part lifted above the horizon. We extend the wave unit into consideration of coherent large-number wave fields, like ocean wave fields. We hope to create Kite Networks of similar dynamics, that transfer harvested wind energy as bulk waves.

                      Have you ever heard of Singing Sands? Its a phenomenon so remote from ordinary experience as to seem mythical, but a natural property of large sand dunes, of wind and sand basically, that perhaps will help us better envision novel kite networks. Before singing, wind first forms rounded sand into a periodic wave field, and these waves are unstable, storing potential energy toward their crests. In hot conditions, with a super-dry surface sand layer over a firmer moister core, sufficient disturbance triggers a self-sustaining resonance that can sound just like an airplane, as the loose dry surface layer acts phonon-anyonically. The sound level has been measured at up 105db, centering around 400Hz. The consistent sand particle size and mass predicts coherent wave behavior and the grains avalanche in a thin surface layer, releasing vibrational energy. Trapped air is considered to add elasticity into the dynamics. The vibrations build as the stored potential energy slowly drains downslope. Like ocean capillary waves, the small initial waves combine into larger waves, eventually mimicking the drone of a classic aircraft, as this NG video reveals-

                      https://www.bing.com/videos/search?q=singing+sands&view=detail&mid=8068C5B596FCC6383CE48068C5B596FCC6383CE4&FORM=VIRE

                      https://en.wikipedia.org/wiki/Singing_sand

                      We also duly note stark differences of the sand model (metaphor and analogy are never exact), that sand grains of themselves are not exactly kites in wind, even if gravity grain flows are somewhat wind-like. Beyond the shared anionic metamaterial aspects, what new principle can sands teach us to apply to our Kite Networks? It may be that our kite formations someday store considerable mass aloft, and upon demand this mass can be worked downward in aero-oscillating modes, generating waves that speed down the lines at c (internal Mach1). If that's too tricky, it would be fantastic enough if a vast sand-like vibrating kite network layer drove a surface PTO layer. That's been the goal, Singing Sands seem to offer new clues to the designer of what's physically possible. There are always unhappy objectors to the grandest historical adventures of the imagination. Even a theoretic misunderstanding might create a path forward. While no better AWES model is yet validated, even with so many trying, open curiosity and imagination is a wise side-bet on the future.
                      Group: AirborneWindEnergy Message: 23783 From: gordon_sp Date: 8/26/2018
                      Subject: Re: Sky Serpent under a Pilot-Lifter Kite

                      I have many questions about the system

                      1.    Why are all the turbines in phase?   Should we not stagger alternate turbines for improved efficiency?

                      2.    Would three bladed turbines be more efficient?  They are the standard of the industry.

                      3.    Since all turbines turn at the same speed, is the torque on each interconnecting shaft small?  Is the torque on the shaft below the bottom turbine much greater than the other torques?

                      If we could elevate the generator to a higher elevation we could take advantage of higher winds and convert the system into a true HAWE system.  This could be achieved by lifting the generator with some LTA system or a secondary lifter kite.  The train of turbines can operate almost horizontally which would negate the elevation angle and improve efficiency.  The only problem is that the generator will tend to spin due to the torque of the turbines and must be anchored to the ground by multiple diagonal tethers.  Alternately we could have two opposing trains of turbines which will neutralize the torque.  This is the system I propose with the difference that we convert to a groundgen by using a cable drive and eliminating the secondary lifting device.

                      Group: AirborneWindEnergy Message: 23784 From: dave santos Date: 8/26/2018
                      Subject: Re: Sky Serpent under a Pilot-Lifter Kite
                      Hi Gordon,

                      JoeF and I got to see the Sky Serpent in flight at HAWPcon09.

                      Lets tackle your questions:

                      1.   
                      Why are all the turbines in phase?   Should we not
                      stagger alternate turbines for
                      improved efficiency?

                      turbine phase, but the in-phase ST seems to run very smoothly.
                      No proof-of-concept is expected to be optimally detailed.
                      The major ST efficiency question is scaling-up rigid
                      structure v. multi-power-kite (soft-kite) scaling.

                      2.   
                      Would three bladed turbines be more
                      efficient?  They are the standard of the
                      industry.

                      have as high a power-to-weight for flight. Two blades are generally
                      favored for aircraft propellers, as more efficient rotors by specific power.
                      Props with more than two blades seek maximized thrust within operational
                      disc-diameter limits, like landing gear clearance constraint.

                      3.   
                      Since all turbines turn at the same speed, is
                      the torque on each interconnecting shaft small? 
                      Is the torque on the shaft below the bottom turbine much
                      greater than the other torques?

                      would increase lower structure accordingly. Again, no proof-of-concept
                      is expected to be optimally detailed.

                      but need to be prototyped to move forward. They are considered workable,
                      but to really catch on will have to beat out every other scheme in
                      eventual comparative simulation and fly-off. Meanwhile, anyone who first
                      tries out any AWES concept, good or bad, contributes value to
                      pioneering experience.

                      daveS

                      ===== you wrote ====

                      If we could
                      elevate the generator to a higher elevation we could take
                      advantage of higher
                      winds and convert the system into a true HAWE system.  This
                      could be achieved by lifting the
                      generator with some LTA system or a secondary lifter kite. 
                      The train of turbines can operate almost
                      horizontally which would negate the elevation angle and
                      improve efficiency.  The only problem is that the generator
                      will
                      tend to spin due to the torque of the turbines and must be
                      anchored to the
                      ground by multiple diagonal tethers. 
                      Alternately we could have two opposing trains of turbines
                      which will
                      neutralize the torque.  This is the
                      system I propose with the difference that we convert to a
                      groundgen by using a
                      cable drive and eliminating the secondary lifting
                      device.
                      Group: AirborneWindEnergy Message: 23785 From: dave santos Date: 8/27/2018
                      Subject: Dr. Anders Ansar on Power Kites
                      Anders has long been a most perceptive and creative kite scientist who makes and flys his own often-amazing experiments, including revolutionizing speed-skating and doing DUW (direct-upwind) with a SS (single-skin) kite-arch and two cyclists. We have occasionally corresponded for over twenty years. On the page linked below, he displays his fresh thinking with a variety of novel insights. For example, he predicts kite surfing can achieve even higher speeds if the kite traction force is conveyed to the board rather than at surfer's waist (I'll be drawing up designs for my landboard after this is posted).

                      An interesting theoretic conjecture is the potentially high lift coefficient of a Magnus Effect wing, which he notes might do well a kite contest of limited projected-area. I suspect the Magnus Effect fails to achieve theoretic potential by some still unaccounted real-world flaw, or we would see more evidence of potential. Of course typical power kites currently win by all other measures (L/D, P/W, practicality, etc), since there is plenty of room in the sky for added kite area, and maintaining cylinder rotation is a design complication and drag factor. Anders generously admits his efforts to improve on the standard power kite-as-Darwinian-winner have not succeeded, but he keeps at it.

                      Standard power kite performance remains the AWES baseline for everyone to measure against, not just Swedish aerospace savants-

                      https://sites.google.com/site/iwkitebeatsall/
                      Group: AirborneWindEnergy Message: 23786 From: joe_f_90032 Date: 8/27/2018
                      Subject: Makani news

                      Ride like the wind: Makani energy kite test flights in the works, lift off later this year

                      By Landry Fuller Special to West Hawaii Today | Monday, August 27, 2018, 1:15 a.m.

                      ====================================================================


                      Notice firm new tower design.

                      Group: AirborneWindEnergy Message: 23787 From: joe_f_90032 Date: 8/27/2018
                      Subject: Re: Makani news
                      Group: AirborneWindEnergy Message: 23788 From: joe_f_90032 Date: 8/27/2018
                      Subject: Re: Makani news
                      Some fresh text and photos: 

                      Makani kites
                      is one phrase that is fresh for them. They have well used 
                      energy kite and energy kites
                      as well as 
                      airborne wind energy


                      Group: AirborneWindEnergy Message: 23789 From: andrew@airhes.com Date: 8/28/2018
                      Subject: Re: Dr. Anders Ansar on Power Kites
                      Group: AirborneWindEnergy Message: 23790 From: dougselsam Date: 8/28/2018
                      Subject: Selsam awarded new U.S. Patent for offshore wind
                      Attachments :
                        On July 17, 2018, The USPTO published U.S. Patent 10,024,307 Floating Marine Wind Turbine.
                        Based on a previous disclosure, the pictures look the same, but the claims are new.
                        This patent covers, for example, floating deep-water offshore wind turbine installations
                        similar to Equinor/Masdar's currently-successful "Hywind" project, off the coast of Scotland,
                        in U.S. Waters.
                        Applicable to a variety of wind turbine configurations, including airborne, as well as more traditional wind turbines.


                          @@attachment@@
                        Group: AirborneWindEnergy Message: 23791 From: joe_f_90032 Date: 8/28/2018
                        Subject: Re: Selsam awarded new U.S. Patent for offshore wind

                        Selsam, Douglas Spriggs Floating marine wind turbine 10024307 Cl. F03D 15/20


                        We look for AWES applications in your new claims. 


                        Group: AirborneWindEnergy Message: 23792 From: joe_f_90032 Date: 8/28/2018
                        Subject: Re: Selsam awarded new U.S. Patent for offshore wind

                        There are probably many ways to involve his ideas in some kite applications:


                        https://patents.justia.com/inventor/douglas-spriggs-selsam


                        Group: AirborneWindEnergy Message: 23793 From: gordon_sp Date: 8/28/2018
                        Subject: LEVER-ARM LAUNCH
                        Attachments :

                        In order to scale up HAWE systems we require an automatic launch and landing system which is reproducible and safe.  With my concept of continuously restraining the lifter kite with diagonal stays, it is possible to launch and land the kite from the same location.  With this system a single skin (SS) kite is spread over a frame and restrained in place by the diagonal stays.  The frame is attached to a lever arm system which can be hoisted by reeling in the main tether(s).  When the lifted frame reaches an adequate height, the wind will catch the kite and continue with the launch.  Landing the system reverses this process except that the frame is located on the ground and the kite is spread out on top of it, ready for the next launch.  If the winds are inadequate then the lever-arm can be lowered to the ground by extending the tether.  The weight of a SS kite is minimal so the frame and arm can be of light weight construction.  It may be possible to launch very large kites with this system.


                          @@attachment@@