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How J E Gordon might build an inflated ring of kites

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  • roderickjosephread
    Use a cell of cells, with glueing between layers, containment of bubble cells with cross woven structures and a wet glue to provide adhesion and flexion.
    Message 1 of 20 , Jun 24 11:54 PM
      Use a cell of cells, with glueing between layers, containment of bubble cells with cross woven structures and a wet glue to provide adhesion and flexion.

      Starting at the very inside of the torus..
      use a fish tank bleed pipe, tie the free end in a large loop. The other end is connected to a non porous flexible pipe. This will be our artery to supply the correct density gas to our ring.
      Next a layer of fine bubble wrap is wound like a toroidal coil onto the ring. As bubble wrap overlaps itself it is glued to itself.
      A few layers of Cling film are pulled as a flat layer around the outside of the ring then a layer of cling film toroidal coil wound onto the ring.
      Now larger scale bubble wrap is woven onto the ring. clockwise coil layers, anti clockwise layers, flat layer outside, flat layer inside. with wet spray on photo mounting glue between the layers.

      As you build up the ring it will be necessary to burst bubbles on the inside to keep the volume down. Bursting the top skin of the bubbles is not a problem. (alternatively custom made bubble wrap would have bubble size diameters matched to the weaving process)

      Another layer or two of dry bubble wrap.
      A good Dusting of talcum powder.
      Now compress the ring with your doughnut shaped bag.
      A bag made of stiff, light cross weave, uv stopping rip stop.
      Mount your kites on the bag.
      keep pumping lighter than air gas in the artery.
      fly and gather some energy.

      Bubble wrap has some excellent properties to recommend it.

      Daisy funding on pleasefund.us was very slow and didn't make the target... more as a product of my marketing manner I suspect.
    • roderickjosephread
      It would be good if custom built bubble wrap not only had adaptable bubble size profiles but also a range of fluid filling and wrap material options. Also if
      Message 2 of 20 , Jun 25 12:53 AM
        It would be good if custom built bubble wrap not only had adaptable bubble size profiles but also a range of fluid filling and wrap material options.
        Also if your bleed pipe was set inside sticky gel, as repair gas is emitted it helps push repair fluid around.
      • Bob Stuart
        Well, maybe, except when J.E. Gordon describes something, I know what he is talking about. Bob Stuart
        Message 3 of 20 , Jun 25 4:09 AM
          Well, maybe, except when J.E. Gordon describes something, I know what he is talking about.

          Bob Stuart

          On 25-Jun-12, at 12:54 AM, roderickjosephread wrote:

          Use a cell of cells, with glueing between layers, containment of bubble cells with cross woven structures and a wet glue to provide adhesion and flexion.

          Starting at the very inside of the torus..
          use a fish tank bleed pipe, tie the free end in a large loop. The other end is connected to a non porous flexible pipe. This will be our artery to supply the correct density gas to our ring.
          Next a layer of fine bubble wrap is wound like a toroidal coil onto the ring. As bubble wrap overlaps itself it is glued to itself.
          A few layers of Cling film are pulled as a flat layer around the outside of the ring then a layer of cling film toroidal coil wound onto the ring.
          Now larger scale bubble wrap is woven onto the ring. clockwise coil layers, anti clockwise layers, flat layer outside, flat layer inside. with wet spray on photo mounting glue between the layers. 

          As you build up the ring it will be necessary to burst bubbles on the inside to keep the volume down. Bursting the top skin of the bubbles is not a problem. (alternatively custom made bubble wrap would have bubble size diameters matched to the weaving process)

          Another layer or two of dry bubble wrap.
          A good Dusting of talcum powder.
          Now compress the ring with your doughnut shaped bag.
          A bag made of stiff, light cross weave, uv stopping rip stop.
          Mount your kites on the bag.
          keep pumping lighter than air gas in the artery.
          fly and gather some energy.

          Bubble wrap has some excellent properties to recommend it.

          Daisy funding on pleasefund.us was very slow and didn't make the target... more as a product of my marketing manner I suspect.


        • roderickjosephread
          And if you want to see just how robots could make custom form plastic bubble structures..
          Message 4 of 20 , Jun 25 4:16 AM
          • Bob Stuart
            Still not getting your image. What is fish-tank tubing? Perforated? Periodically, or generally? The picture probably also needs more words, or pictures,
            Message 5 of 20 , Jun 25 4:32 AM
              Still not getting your image.  What is "fish-tank tubing?"  Perforated?  Periodically, or generally?  The picture probably also needs more words, or pictures, for transfer.

              Bob Stuart

              On 25-Jun-12, at 5:16 AM, roderickjosephread wrote:


            • roderickjosephread
              Apologies for my poor description skills Bob. I bet J E Gordon had a good editor and time on his side. Advice: technical descriptions, written whilst preparing
              Message 6 of 20 , Jun 25 6:25 AM

                Apologies for my poor description skills Bob. 

                I bet J E Gordon had a good editor and time on his side.

                 

                Advice: technical descriptions, written whilst preparing child's lunches & preschoolers windsurfing lessons in Gaelic is not a good idea.

                 

                I was trying to describe a novel construction method for my torus based kite rings.

                In particular I was describing the torus ring component.

                I'm aiming to create a product with a useful mix of rigidity, flexibility and durability. And ideally the component is lighter than air, can be made from off-the-shelf parts, and repair itself too. 

                 

                We previously discussed the strength, lightness and durability benefits of inflated multi cellular structures. I have tried to evolve this architecture into my torus designs. 

                 

                The description I gave previously, built the torus from the inside out. 

                 

                Dissecting the structure:

                From the outside in, you would observe a tightly inflated ring shaped bag.

                 

                The bag has tether points around its circumference, front and back.

                At one point a small flexible hose enters the bag through a gland. 

                 

                The bag is woven from crossed fibres. Long fibres reach around the ring circumference. Shorter fibres cross the longer fibres, and reach around the ring sectional circumference.

                 

                Underneath the tightly inflated external skin, a layer of talcum powder allows the skin to slip over a non-permeable membrane.

                 

                Underneath the non-permeable membrane, tightly wound and glued layers of bubblewrap.  The compression from the external skin keeps gaps between the bubble cells to a minimum.

                 

                Cutting further into the bubblewrap layers, a layer of sticky gel encases the hose.

                 

                The hose has continued through the layers, to inside the sectional centre of the ring. The hose runs all the way around inside centre of the ring. Here in the very centre of the ring, the hose has small perforations.

                 

                The hose acts as a feed line pumping lighter than air bubbles into the sticky gel. This way, small amounts of gel are pushed under gas pressure toward leaks. Almost like sap from heartwood protecting exterior layers of a tree.

                 

                Bubblewrap filled with lighter than air gas would be a bonus.

                 

                I hope that description makes more sense. Please critique it. I'll try and supply a drawing soon.

                 

                Roddy.

              • Bob Stuart
                Perhaps you are writing underneath where within would be more appropriate. And does middle refer to the center of the hole, or the circle defining the
                Message 7 of 20 , Jun 25 9:50 AM
                  Perhaps you are writing "underneath" where "within" would be more appropriate.  And does "middle" refer to the center of the hole, or the circle defining the primary dimension of the torus?  

                  In any event, I think that any shapes we put up should be reasonably efficient as wings.  It was the bulk of just the wires and struts that doomed the biplane, as much as the interference between the wings.  The higher the percentage of wind resistance you incur for the sake of a light-weight structure, the lower your practical wind speed.  Hang  gliders, being slow, reverted to the use of rigging.  Can't you maintain a ring of kites using directed aerodynamic reactions?  Spinners seem to manage it.

                  Bob Stuart

                  On 25-Jun-12, at 7:25 AM, roderickjosephread wrote:



                  Apologies for my poor description skills Bob. 

                  I bet J E Gordon had a good editor and time on his side.

                   

                  Advice: technical descriptions, written whilst preparing child's lunches & preschoolers windsurfing lessons in Gaelic is not a good idea.

                   

                  I was trying to describe a novel construction method for my torus based kite rings.

                  In particular I was describing the torus ring component.

                  I'm aiming to create a product with a useful mix of rigidity, flexibility and durability. And ideally the component is lighter than air, can be made from off-the-shelf parts, and repair itself too. 

                   

                  We previously discussed the strength, lightness and durability benefits of inflated multi cellular structures. I have tried to evolve this architecture into my torus designs. 

                   

                  The description I gave previously, built the torus from the inside out. 

                   

                  Dissecting the structure:

                  From the outside in, you would observe a tightly inflated ring shaped bag.

                   

                  The bag has tether points around its circumference, front and back.

                  At one point a small flexible hose enters the bag through a gland. 

                   

                  The bag is woven from crossed fibres. Long fibres reach around the ring circumference. Shorter fibres cross the longer fibres, and reach around the ring sectional circumference.

                   

                  Underneath the tightly inflated external skin, a layer of talcum powder allows the skin to slip over a non-permeable membrane.

                   

                  Underneath the non-permeable membrane, tightly wound and glued layers of bubblewrap.  The compression from the external skin keeps gaps between the bubble cells to a minimum.

                   

                  Cutting further into the bubblewrap layers, a layer of sticky gel encases the hose.

                   

                  The hose has continued through the layers, to inside the sectional centre of the ring. The hose runs all the way around inside centre of the ring. Here in the very centre of the ring, the hose has small perforations.

                   

                  The hose acts as a feed line pumping lighter than air bubbles into the sticky gel. This way, small amounts of gel are pushed under gas pressure toward leaks. Almost like sap from heartwood protecting exterior layers of a tree.

                   

                  Bubblewrap filled with lighter than air gas would be a bonus.

                   

                  I hope that description makes more sense. Please critique it. I'll try and supply a drawing soon.

                   

                  Roddy.




                • roderickjosephread
                  good tips on efficient accurate writing thanks Bob. that any shapes we put up should be reasonably efficient as wings. I mostly agree,but in
                  Message 8 of 20 , Jun 25 2:06 PM
                    good tips on efficient accurate writing thanks Bob.

                    "that any shapes we put up should be reasonably efficient as wings. "
                    I mostly agree,
                    but in considering
                    "Can't you maintain a ring of kites using directed aerodynamic reactions?"
                    We all want it and yes,
                     purely soft structures can reliably inflate and rotate.
                    Maintaining an ability to taking power from them. I think that makes the problem a bit more complex.

                    If kites are set to drive a soft band around, the band still has to be held across the wind at the extents of the kite travel.

                    Scaling and lifting  spinners becomes complex.

                    The power dynamics of an arched ribbon are too hard for me to see how they will drive large powers.

                    I don't think a pure ring of kites will be able to drive power as reliably as kites driving a stiffened ring component.

                    If the stiffened ring component is buoyant enough to lift the kites and tether it carries;
                    Then a stack of ring components can reach vertically upward in calm weather.
                    The stack of components will always be in tension ready to transfer torque.

                    A balance will exist between factors of torus dimensions, filling buoyancy, bag weight, ring stiffness, diameter needed for torque. 
                    The ring will tend to be compressed as torque is sent downward. The whole tower will bend over in strong winds. kites will rip off.

                    I have no idea where the balance is. I'm keen to find out.
                    Limited resources force me to try and guess before experimenting.
                    I'll let you know as soon as I do.
                  • dave santos
                    I think Roddy s versions of giant inflated rings have considerable potential in AWES design. The ring acts as a furling aid for the parafoil extensions, and
                    Message 9 of 20 , Jun 28 9:02 AM
                      I think Roddy's versions of giant inflated rings have considerable potential in AWES design. The ring acts as a furling aid for the parafoil extensions, and may even provide suitable structure for a novel giant annular generator as Beaujeans envisions. Such a radical generator avoids a lot of the mass-scaling penalty of giant conventional generators.

                      Having given long pondered inflated rings as kite structure, plus decades of study and practice of ring wings, it seems to me that an optimal configuration is a concentric ring structure so as to end up with a pierced or open disc in over all geometry. Such a "flying saucer" disc is then able to act as a decent wing, not too thick in proportion to chord. The simplest instance of this is an inflated ring with membrane infill, but a number of nestled rings could make a nice Aerobie style flying ring on a grand scale. Various throwing toys suggest the viability of this form factor.

                      A "tube wing" made of tandem inflated rings, a la Altaeros, also has interesting uses, but the flying angle of the tube disc plane, for aerodynamic lift, cancels HAWT autogyro-lift  usage.

                      coolIP
                    • Pierre BENHAIEM
                      Indeed good perspectives.But for keeping a good profile high pressure is needed.Do you think it is possible for soft or inflatable wings to compete with rigid
                      Message 10 of 20 , Jun 28 2:50 PM

                        Indeed good perspectives.But for keeping a good profile high pressure is needed.Do you think it is possible for soft or inflatable wings to compete with rigid blades?

                         

                        PierreB




                        > Message du 28/06/12 18:03
                        > De : "dave santos"
                        > A : "AirborneWindEnergy@yahoogroups.com"
                        > Copie à :
                        > Objet : [AWES] Inflated rings as kites
                        >
                        >  

                        >

                        I think Roddy's versions of giant inflated rings have considerable potential in AWES design. The ring acts as a furling aid for the parafoil extensions, and may even provide suitable structure for a novel giant annular generator as Beaujeans envisions. Such a radical generator avoids a lot of the mass-scaling penalty of giant conventional generators.

                        >
                        Having given long pondered inflated rings as kite structure, plus decades of study and practice of ring wings, it seems to me that an optimal configuration is a concentric ring structure so as to end up with a pierced or open disc in over all geometry. Such a "flying saucer" disc is then able to act as a decent wing, not too thick in proportion to chord. The simplest instance of this is an inflated ring with membrane infill, but a number of nestled rings could make a nice Aerobie style flying ring on a grand scale. Various throwing toys suggest the viability of this form factor.

                        >
                        A "tube wing" made of tandem inflated rings, a la Altaeros, also has interesting uses, but the flying angle of the tube disc plane, for aerodynamic lift, cancels HAWT autogyro-lift  usage.

                        >
                        coolIP
                      • Robert Copcutt
                        ... Dave, It is not clear what you were trying to say there. It seems to me inflated tubular wings are the best way to make a large light wing. Inflated
                        Message 11 of 20 , Jun 28 3:29 PM
                          On Thu, 2012-06-28 at 09:02 -0700, dave santos wrote:
                          >

                          > A "tube wing" made of tandem inflated rings, a la Altaeros, also has
                          > interesting uses, but the flying angle of the tube disc plane, for
                          > aerodynamic lift, cancels HAWT autogyro-lift usage.
                          >
                          >

                          Dave,

                          It is not clear what you were trying to say there. It seems to me
                          inflated tubular wings are the best way to make a large light wing.
                          Inflated toroids can be very stiff for a given mass. Consider a bicycle
                          tire. The aerodynamic wing is made from a series of toroids behind each
                          other (in tandem as you say).

                          Hargrave found that 2 tubes (or boxes) 1 behind the other was more
                          stable. A kite with 4 tubes in a square arrangement, and 3 tethers,
                          could be adjusted to provide lift in almost any situation. That is what
                          I was talking about in my post on 17th May.

                          By the way, some video of the kite tests we did has now been added to
                          http://visventis.org/

                          Robert.
                        • dave santos
                          Robert, sorry for the confusion, but there are two major kinds of ring wings- (1) those with the center-axis along the apparent wind direction (shaped like a
                          Message 12 of 20 , Jun 28 7:16 PM
                            Robert, sorry for the confusion, but there are two major kinds of ring wings- (1) those with the center-axis along the apparent wind direction (shaped like a napkin ring much like Altaeros' duct, a Circoflex, or Reinhart's ring kite) and (2) flat disc wings with the axis set vertical (like Aerobie throwing ring). Both work well in specific applications. A vast almost flat wing made of concentric inflated rings is proposed as an optimization of Rod's single ring torus.

                            Pierre, Adequate high pressure inflation of wings is easy for Ram-Air; as ram pressure increases proportionally to velocity. Only a slight overpressure of a small fraction of an atmosphere is enough to make a firm enough wing for high speed flight. Ordinary blimps travel "fairly fast" (~50kts) with less than .01 ATM of Helium pressure.

                            I still think the ram-air wing is the greatest advance in megascale weight-to-lift in our time, with the singleskin wing second, and the closed-cell inflated wing third, owing to the need for active inflation pumping. Hard wings will be long limited to mere jumbo-jet scale, far smaller than future soft wings. I think future ram parafoils will fly rather faster than Dave Culp conservatively imagines, even beyond 150kts, after seeing so much advancement in new race kites in just a few years. Nothing scales like a soft wing.
                          • Bob Stuart
                            If ram air is not of sufficient pressure for some parts, it should be simple to use a ram-air turbine to put out any pressure desired, with the same benefits
                            Message 13 of 20 , Jun 28 7:38 PM
                              If ram air is not of sufficient pressure for some parts, it should be simple to use a ram-air turbine to put out any pressure desired, with the same benefits of pressure available always matching the pressure needed.  Inflated parts are not subject to the same square-cube scaling laws as other structures, being still essentially all-tension construction.  This makes their adoption quite beneficial for large, light, rugged construction.   Rapid "assembly" from compact storage is a further benefit.  Members can even be extended or retracted to change the kite area, keeping tether power constant.  

                              Bob Stuart

                              On 28-Jun-12, at 8:16 PM, dave santos wrote:


                              Robert, sorry for the confusion, but there are two major kinds of ring wings- (1) those with the center-axis along the apparent wind direction (shaped like a napkin ring much like Altaeros' duct, a Circoflex, or Reinhart's ring kite) and (2) flat disc wings with the axis set vertical (like Aerobie throwing ring). Both work well in specific applications. A vast almost flat wing made of concentric inflated rings is proposed as an optimization of Rod's single ring torus.

                              Pierre, Adequate high pressure inflation of wings is easy for Ram-Air; as ram pressure increases proportionally to velocity. Only a slight overpressure of a small fraction of an atmosphere is enough to make a firm enough wing for high speed flight. Ordinary blimps travel "fairly fast" (~50kts) with less than .01 ATM of Helium pressure.

                              I still think the ram-air wing is the greatest advance in megascale weight-to-lift in our time, with the singleskin wing second, and the closed-cell inflated wing third, owing to the need for active inflation pumping. Hard wings will be long limited to mere jumbo-jet scale, far smaller than future soft wings. I think future ram parafoils will fly rather faster than Dave Culp conservatively imagines, even beyond 150kts, after seeing so much advancement in new race kites in just a few years. Nothing scales like a soft wing.


                            • dbmurr@ymail.com
                              Hello all, great topic. I found your group from a link and recommendation on Roderick Read s kitepowercoop.org site. Soft, inflated, milticellular kite parts
                              Message 14 of 20 , Jun 28 9:35 PM
                                Hello all, great topic. I found your group from a link and recommendation on Roderick Read's kitepowercoop.org site.
                                Soft, inflated, milticellular kite parts with variable pressure control to individual groups of cells can greatly simplify the flight controls of larger kite structures.
                                I have worked on several inflated ring/rotor kite designs that may help forward this discussion. I've posted two of my early sketches of designs that relate somewhat to Roderick's ring kites & some of Dave Santos' comments at flyinground.com
                                I hope this helps the development of this kite type.
                                Regards, db murray


                                --- In AirborneWindEnergy@yahoogroups.com, Bob Stuart <bobstuart@...> wrote:
                                >
                                > If ram air is not of sufficient pressure for some parts, it should be
                                > simple to use a ram-air turbine to put out any pressure desired, with
                                > the same benefits of pressure available always matching the pressure
                                > needed. Inflated parts are not subject to the same square-cube
                                > scaling laws as other structures, being still essentially all-tension
                                > construction. This makes their adoption quite beneficial for large,
                                > light, rugged construction. Rapid "assembly" from compact storage
                                > is a further benefit. Members can even be extended or retracted to
                                > change the kite area, keeping tether power constant.
                                >
                                > Bob Stuart
                                >
                                > On 28-Jun-12, at 8:16 PM, dave santos wrote:
                                >
                                > >
                                > > Robert, sorry for the confusion, but there are two major kinds of
                                > > ring wings- (1) those with the center-axis along the apparent wind
                                > > direction (shaped like a napkin ring much like Altaeros' duct, a
                                > > Circoflex, or Reinhart's ring kite) and (2) flat disc wings with
                                > > the axis set vertical (like Aerobie throwing ring). Both work well
                                > > in specific applications. A vast almost flat wing made of
                                > > concentric inflated rings is proposed as an optimization of Rod's
                                > > single ring torus.
                                > >
                                > > Pierre, Adequate high pressure inflation of wings is easy for Ram-
                                > > Air; as ram pressure increases proportionally to velocity. Only a
                                > > slight overpressure of a small fraction of an atmosphere is enough
                                > > to make a firm enough wing for high speed flight. Ordinary blimps
                                > > travel "fairly fast" (~50kts) with less than .01 ATM of Helium
                                > > pressure.
                                > >
                                > > I still think the ram-air wing is the greatest advance in megascale
                                > > weight-to-lift in our time, with the singleskin wing second, and
                                > > the closed-cell inflated wing third, owing to the need for active
                                > > inflation pumping. Hard wings will be long limited to mere jumbo-
                                > > jet scale, far smaller than future soft wings. I think future ram
                                > > parafoils will fly rather faster than Dave Culp conservatively
                                > > imagines, even beyond 150kts, after seeing so much advancement in
                                > > new race kites in just a few years. Nothing scales like a soft wing.
                                > >
                                > >
                                >
                              • John Oyebanji
                                Thanks, Murray. You are most welcomed. Quite a fascinating introduction of your person. JohnO John Adeoye Oyebanji; CEO, Hardensoft International
                                Message 15 of 20 , Jun 28 11:48 PM
                                  Thanks, Murray. You are most welcomed. Quite a fascinating introduction of your person.
                                  JohnO
                                  John Adeoye Oyebanji;
                                  CEO, Hardensoft International
                                  President-protem, Airborne Wind Energy Industry Association - AWEIA International

                                  From: "dbmurr@..." <dbmurr@...>
                                  Sender: AirborneWindEnergy@yahoogroups.com
                                  Date: Fri, 29 Jun 2012 04:35:20 -0000
                                  To: <AirborneWindEnergy@yahoogroups.com>
                                  ReplyTo: AirborneWindEnergy@yahoogroups.com
                                  Subject: [AWES] Re: Inflated rings as kites

                                   

                                  Hello all, great topic. I found your group from a link and recommendation on Roderick Read's kitepowercoop.org site.
                                  Soft, inflated, milticellular kite parts with variable pressure control to individual groups of cells can greatly simplify the flight controls of larger kite structures.
                                  I have worked on several inflated ring/rotor kite designs that may help forward this discussion. I've posted two of my early sketches of designs that relate somewhat to Roderick's ring kites & some of Dave Santos' comments at flyinground.com
                                  I hope this helps the development of this kite type.
                                  Regards, db murray


                                  --- In AirborneWindEnergy@yahoogroups.com, Bob Stuart <bobstuart@...> wrote:
                                  >
                                  > If ram air is not of sufficient pressure for some parts, it should be
                                  > simple to use a ram-air turbine to put out any pressure desired, with
                                  > the same benefits of pressure available always matching the pressure
                                  > needed. Inflated parts are not subject to the same square-cube
                                  > scaling laws as other structures, being still essentially all-tension
                                  > construction. This makes their adoption quite beneficial for large,
                                  > light, rugged construction. Rapid "assembly" from compact storage
                                  > is a further benefit. Members can even be extended or retracted to
                                  > change the kite area, keeping tether power constant.
                                  >
                                  > Bob Stuart
                                  >
                                  > On 28-Jun-12, at 8:16 PM, dave santos wrote:
                                  >
                                  > >
                                  > > Robert, sorry for the confusion, but there are two major kinds of
                                  > > ring wings- (1) those with the center-axis along the apparent wind
                                  > > direction (shaped like a napkin ring much like Altaeros' duct, a
                                  > > Circoflex, or Reinhart's ring kite) and (2) flat disc wings with
                                  > > the axis set vertical (like Aerobie throwing ring). Both work well
                                  > > in specific applications. A vast almost flat wing made of
                                  > > concentric inflated rings is proposed as an optimization of Rod's
                                  > > single ring torus.
                                  > >
                                  > > Pierre, Adequate high pressure inflation of wings is easy for Ram-
                                  > > Air; as ram pressure increases proportionally to velocity. Only a
                                  > > slight overpressure of a small fraction of an atmosphere is enough
                                  > > to make a firm enough wing for high speed flight. Ordinary blimps
                                  > > travel "fairly fast" (~50kts) with less than .01 ATM of Helium
                                  > > pressure.
                                  > >
                                  > > I still think the ram-air wing is the greatest advance in megascale
                                  > > weight-to-lift in our time, with the singleskin wing second, and
                                  > > the closed-cell inflated wing third, owing to the need for active
                                  > > inflation pumping. Hard wings will be long limited to mere jumbo-
                                  > > jet scale, far smaller than future soft wings. I think future ram
                                  > > parafoils will fly rather faster than Dave Culp conservatively
                                  > > imagines, even beyond 150kts, after seeing so much advancement in
                                  > > new race kites in just a few years. Nothing scales like a soft wing.
                                  > >
                                  > >
                                  >

                                • roderickjosephread
                                  Today, I tried compressing a cellular sausage in a section of my torus bag.The sausage was made from rolled up, large cell, bubble wrap. The resultant
                                  Message 16 of 20 , Jun 29 5:33 AM
                                    Today, I tried compressing a cellular sausage in a section of my torus bag.
                                    The sausage was made from rolled up, large cell, bubble wrap.

                                    The resultant structure was moderately firm.
                                    I'd say firm enough to hold a balanced array of kites around the torus in a moderate+ wind.
                                    The sausage was too small a diameter to be well compressed... video to follow. I'll redo the test with a thicker sausage too.

                                    I could sit and jump on the bag without any bubbles bursting.
                                    With a foot on the front of the bag and a hand pulling one end up...
                                    The bag would bend progressively with effort. 5kg ish at 1m ish gave about 10cm. Still no popping.

                                    I'm going to order some larger cell air cushions... commonly used as packaging void fill and available everywhere.
                                    I do approve of this brand name.

                                    Typically LEI kite bladders are inflated around 6psi. 
                                    Could a ram air kite approach that pressure internally as it went faster?
                                    If so an open cell construction for the mounting torus rings is feasible. 
                                    There is a way to make an interlinking cell structure where some cells inside the torus could inflate with ram air kite pressure ... the other (earlier inflation) cell set would inflate with torus leading edge vented pressure.

                                    hmmmm

                                  • dbmurr@ymail.com
                                    Thanks John, Good to meet you here. I see your work on the web. We share similar interests. I am also working on energy, food & water issues, and will post
                                    Message 17 of 20 , Jun 29 12:44 PM
                                      Thanks John,
                                      Good to meet you here. I see your work on the web. We share similar interests. I am also working on energy, food & water issues, and will post over time at agronautics.com if you wish to look sometime in the future.
                                      For the AWE group I plan on further related kite/energy postings at flyinground.com & look forward to more discussions.
                                      Regards, db murray


                                      --- In AirborneWindEnergy@yahoogroups.com, "John Oyebanji" <hardensoftintl@...> wrote:
                                      >
                                      > Thanks, Murray. You are most welcomed. Quite a fascinating introduction of your person.
                                      > JohnO
                                      >
                                      > John Adeoye Oyebanji;
                                      > CEO, Hardensoft International
                                      > President-protem, Airborne Wind Energy Industry Association - AWEIA International
                                      >
                                      > -----Original Message-----
                                      > From: "dbmurr@..." <dbmurr@...>
                                      > Sender: AirborneWindEnergy@yahoogroups.com
                                      > Date: Fri, 29 Jun 2012 04:35:20
                                      > To: <AirborneWindEnergy@yahoogroups.com>
                                      > Reply-To: AirborneWindEnergy@yahoogroups.com
                                      > Subject: [AWES] Re: Inflated rings as kites
                                      >
                                      > Hello all, great topic. I found your group from a link and recommendation on Roderick Read's kitepowercoop.org site.
                                      > Soft, inflated, milticellular kite parts with variable pressure control to individual groups of cells can greatly simplify the flight controls of larger kite structures.
                                      > I have worked on several inflated ring/rotor kite designs that may help forward this discussion. I've posted two of my early sketches of designs that relate somewhat to Roderick's ring kites & some of Dave Santos' comments at flyinground.com
                                      > I hope this helps the development of this kite type.
                                      > Regards, db murray
                                      >
                                      >
                                      > --- In AirborneWindEnergy@yahoogroups.com, Bob Stuart <bobstuart@> wrote:
                                      > >
                                      > > If ram air is not of sufficient pressure for some parts, it should be
                                      > > simple to use a ram-air turbine to put out any pressure desired, with
                                      > > the same benefits of pressure available always matching the pressure
                                      > > needed. Inflated parts are not subject to the same square-cube
                                      > > scaling laws as other structures, being still essentially all-tension
                                      > > construction. This makes their adoption quite beneficial for large,
                                      > > light, rugged construction. Rapid "assembly" from compact storage
                                      > > is a further benefit. Members can even be extended or retracted to
                                      > > change the kite area, keeping tether power constant.
                                      > >
                                      > > Bob Stuart
                                      > >
                                      > > On 28-Jun-12, at 8:16 PM, dave santos wrote:
                                      > >
                                      > > >
                                      > > > Robert, sorry for the confusion, but there are two major kinds of
                                      > > > ring wings- (1) those with the center-axis along the apparent wind
                                      > > > direction (shaped like a napkin ring much like Altaeros' duct, a
                                      > > > Circoflex, or Reinhart's ring kite) and (2) flat disc wings with
                                      > > > the axis set vertical (like Aerobie throwing ring). Both work well
                                      > > > in specific applications. A vast almost flat wing made of
                                      > > > concentric inflated rings is proposed as an optimization of Rod's
                                      > > > single ring torus.
                                      > > >
                                      > > > Pierre, Adequate high pressure inflation of wings is easy for Ram-
                                      > > > Air; as ram pressure increases proportionally to velocity. Only a
                                      > > > slight overpressure of a small fraction of an atmosphere is enough
                                      > > > to make a firm enough wing for high speed flight. Ordinary blimps
                                      > > > travel "fairly fast" (~50kts) with less than .01 ATM of Helium
                                      > > > pressure.
                                      > > >
                                      > > > I still think the ram-air wing is the greatest advance in megascale
                                      > > > weight-to-lift in our time, with the singleskin wing second, and
                                      > > > the closed-cell inflated wing third, owing to the need for active
                                      > > > inflation pumping. Hard wings will be long limited to mere jumbo-
                                      > > > jet scale, far smaller than future soft wings. I think future ram
                                      > > > parafoils will fly rather faster than Dave Culp conservatively
                                      > > > imagines, even beyond 150kts, after seeing so much advancement in
                                      > > > new race kites in just a few years. Nothing scales like a soft wing.
                                      > > >
                                      > > >
                                      > >
                                      >
                                    • Robert Copcutt
                                      Dave, It was clear the first time that you were talking about 2 different ring wing concepts. What is still not clear is why you think the tubular wing concept
                                      Message 18 of 20 , Jun 29 3:15 PM
                                        Dave,

                                        It was clear the first time that you were talking about 2 different
                                        ring wing concepts. What is still not clear is why you think the tubular
                                        wing concept has a problem with its flying angle.

                                        It seems to me that the tubular type will need fewer tethers than the
                                        disc type, and have better directional stability.

                                        Ram-air can only provide limited pressure (for a given air velocity).
                                        For manually piloted kites, where a large drag coefficient has
                                        advantages, that is OK. When we finally manage to make automated AWE
                                        systems we will need lower drag coefficients. To achieve that the
                                        inflated support structures will need to be at much higher pressures.
                                        Probably several bar.

                                        To inflate a bladder energy is needed. With ram-air it comes from the
                                        wind. When higher pressures are needed the only option is to do the
                                        pumping on the ground. Doing any active pumping in the air would require
                                        extra airborne mass which cuts performance and adds cost. As Joe's
                                        cheering sticks clearly illustrate, we have the technology to make light
                                        bladders that leak at a negligible rate.

                                        Robert.


                                        On Thu, 2012-06-28 at 19:16 -0700, dave santos wrote:
                                        >
                                        > Robert, sorry for the confusion, but there are two major kinds of ring
                                        > wings- (1) those with the center-axis along the apparent wind
                                        > direction (shaped like a napkin ring much like Altaeros' duct, a
                                        > Circoflex, or Reinhart's ring kite) and (2) flat disc wings with the
                                        > axis set vertical (like Aerobie throwing ring). Both work well in
                                        > specific applications. A vast almost flat wing made of concentric
                                        > inflated rings is proposed as an optimization of Rod's single ring
                                        > torus.
                                        >
                                        >
                                        > Pierre, Adequate high pressure inflation of wings is easy for Ram-Air;
                                        > as ram pressure increases proportionally to velocity. Only a slight
                                        > overpressure of a small fraction of an atmosphere is enough to make a
                                        > firm enough wing for high speed flight. Ordinary blimps travel "fairly
                                        > fast" (~50kts) with less than .01 ATM of Helium pressure.
                                        >
                                        >
                                        > I still think the ram-air wing is the greatest advance in megascale
                                        > weight-to-lift in our time, with the singleskin wing second, and the
                                        > closed-cell inflated wing third, owing to the need for active
                                        > inflation pumping. Hard wings will be long limited to mere jumbo-jet
                                        > scale, far smaller than future soft wings. I think future ram
                                        > parafoils will fly rather faster than Dave Culp conservatively
                                        > imagines, even beyond 150kts, after seeing so much advancement in new
                                        > race kites in just a few years. Nothing scales like a soft wing.
                                      • dave santos
                                        Robert, The problem with the tube type of ring wing is that added turbine blades create negative lift. The disc type, on the other hand has its AoA matched
                                        Message 19 of 20 , Jun 29 3:27 PM
                                          Robert,

                                          The problem with the "tube" type of ring wing is that added turbine blades create negative lift. The "disc" type, on the other hand has its AoA matched to added turbine blades creating positive autogyro lift.

                                          The problems with inflated structures are with lifting gas and/or thick-wall construction. Joe's stick sadly happen's to represent the easiest case of inflation retention.

                                          Ram-air parafoils create static over-pressure at a very small energetic cost, as only a fraction of the foil's stagnation zone is tapped. Once inflated, there is very little loss from small valved ram-air inlets.

                                          daveS
                                        • Robert Copcutt
                                          ... Your reference to Roderick s post made me suspect that you were thinking of putting the generator outside the tube (a groundgen maybe). The Altaeros tube
                                          Message 20 of 20 , Jun 29 4:51 PM
                                            On Fri, 2012-06-29 at 15:27 -0700, dave santos wrote:
                                            >

                                            > The problem with the "tube" type of ring wing is that added turbine
                                            > blades create negative lift. The "disc" type, on the other hand has
                                            > its AoA matched to added turbine blades creating positive autogyro
                                            > lift.

                                            Your reference to Roderick's post made me suspect that you were thinking
                                            of putting the generator outside the tube (a groundgen maybe). The
                                            Altaeros tube is filled with helium and my understanding is that they
                                            use this buoyancy to keep the tube almost horizontal. The drag caused by
                                            the huge lighter than air (LTA) structure will far exceed the drag from
                                            the turbine. Maybe they angle their tube to try to gain extra lift, but
                                            the thing can only support a small turbine anyway, so I cannot see it
                                            making much difference to the it.

                                            Both LTA and pure flygen are concepts I have completely discarded as
                                            impractical. Practical inflated wing kites will be for groundgens and be
                                            filled with air. My concept is like the basic Altaeros shape but far
                                            slimmer. If there is a turbine inside it will be tiny - sufficient only
                                            to power airborne control systems. The advantage of the inflated toroid
                                            is that a wing with a large area can be made without relying on dozens
                                            of tethers.

                                            >
                                            >
                                            > The problems with inflated structures are with lifting gas and/or
                                            > thick-wall construction. Joe's stick sadly happen's to represent the
                                            > easiest case of inflation retention.

                                            The gas inside will be air so I see nothing sad about what Joe's stick
                                            represents.


                                            > Ram-air parafoils create static over-pressure at a very small
                                            > energetic cost, as only a fraction of the foil's stagnation zone is
                                            > tapped. Once inflated, there is very little loss from small valved
                                            > ram-air inlets.
                                            >

                                            Sure, but ultimately we will need much more aerodynamic kites.

                                            Robert.
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