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Spontaneous Launch Risk and "Killability"

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  • dave santos
    A weird paradox of classic kite methods applied to megascale AWE is that keeping large kites down, or bringing them down on demand, can be a major
    Message 1 of 8 , Oct 12, 2011
      A weird paradox of classic kite methods applied to megascale AWE is that keeping large kites down, or bringing them down on demand, can be a major headache.  The Eideken Prize, kiting's highest honor, is named after a kite pilot dragged aloft by the spontaneous launch of the largest wing ever made (Osborne's 17000ft parafoil). Many kite sport accidents occur when a kite "fires" unexpectedly. In a rising wind, large single-line kites easily surprise the novice flier by pulling too hard to pull down (a case of actuation saturation). "Walking down"  the line, hand over hand or with a pulley, is easier than hauling in, but still has definite limits. Only the tendency of high wind to crash the kite or pull out the anchor ends many such nightmare sessions.
       
      A kite is not dangerous until it is attached to a tether. A tether is not fully "armed" until anchored. The combination of kite, tether, and anchor, including accidental anchors, sets up a devastating potential to drag cross-country indefinitely. Multi-lines to multi-anchors is the best precaution against breakaway kites.
       
      Kite killers are special cutters, releases, tag-lines, or even automatic or remote-controlled devices that disable a kite. Its predicted that kite-killers will be required safety features of self-stable AWE systems. An ideal kite-killer is easily reversible for quick relaunch. It should not add much weight, fuss, or cost. Kites are secured on the ground temporarily by varied methods. One can use a back-stop behind the kite, throw sand on the leading edge, or use a special stake to hold full brakes on a multi-line kite. Large kites are kept in bags or as a bundle until flight.
       
      Large kite arrays face special challenges. How do we keep big arrays safely grounded when any part of it that catches air could cascade-launch the whole? How do we kill a large Hyda-like monster like the Spider-Mill? These are open questions.
       
      =================
       
       
      Latest Corrections: 1) Wubbo said "fantastic", not "fabulous". 2) Rod spells "spiralling" with more class than Yahoo's spell-checker.
    • Joe Faust
      Brainstorm to stop Mega-Array Kite * Triggered melting of key parts * Triggered porosity control * Triggered inversion lines in wing elements * Triggered
      Message 2 of 8 , Oct 12, 2011
        Brainstorm to stop Mega-Array Kite 
        • Triggered melting of key parts
        • Triggered porosity control
        • Triggered inversion lines in wing elements
        • Triggered reefing aloft
        • Triggered splintering
        • Triggered rip seams
        • Trigger line reversals
        • ?
        ... your turn
      • Bob Stuart
        Deflation of essential inflated spars. Inflated parts are very good at limiting loads, and then recovering elastically. We can also use members with a
        Message 3 of 8 , Oct 12, 2011
          Deflation of essential inflated spars.  Inflated parts are very good at limiting loads, and then recovering elastically.  We can also use members with a section like a tape measure, which can be stiff in one direction, fail catastrophically on overload, and still recover 100% when the load is entirely removed.  Pairs of such structures can be stiff in two directions.
          Overload limiters can also be made with rubber in tension inside a tube, holding segments together.  If the structure is pulled hard enough to stretch the rubber more, something else happens - something buckles, or gets released, or cut.  

          Bob Stuart

          On 12-Oct-11, at 11:14 PM, Joe Faust wrote:

          Brainstorm to stop Mega-Array Kite 

          • Triggered melting of key parts
          • Triggered porosity control
          • Triggered inversion lines in wing elements
          • Triggered reefing aloft
          • Triggered splintering
          • Triggered rip seams
          • Trigger line reversals
          • ?
          ... your turn


        • Doug
          Substitute the word flogiston for kite .
          Message 4 of 8 , Oct 13, 2011
            Substitute the word "flogiston" for "kite".
            :)

            --- In AirborneWindEnergy@yahoogroups.com, dave santos <santos137@...> wrote:
            >
            > A�weird paradox of�classic kite methods applied to megascale AWE�is that keeping large kites�down, or bringing them down on demand, can be a major headache.� The�Eideken Prize,�kiting's highest honor, is named after a kite pilot dragged aloft by the spontaneous launch of�the largest wing ever made (Osborne's 17000ft parafoil). Many kite sport accidents occur when a kite "fires" unexpectedly. In a rising wind, large single-line kites�easily surprise the novice�flier by pulling too hard to pull down (a case of actuation saturation). "Walking down"� the line, hand over hand or with a pulley, is easier than hauling in, but still has definite limits. Only the tendency of high wind to crash the kite or pull out the anchor�ends many such nightmare sessions.
            > �
            > A kite is not dangerous until it is attached to a tether. A tether is not fully "armed" until anchored. The combination of kite, tether, and anchor, including accidental anchors, sets up a devastating potential to drag cross-country indefinitely. Multi-lines to multi-anchors is the best precaution against breakaway kites.
            > �
            > Kite killers are special cutters,�releases,�tag-lines, or even automatic or remote-controlled devices that disable�a kite. Its predicted that kite-killers will be required safety features�of�self-stable AWE systems. An ideal kite-killer is easily reversible for quick relaunch. It should not add much weight, fuss,�or cost. Kites are secured on the ground�temporarily�by varied methods. One can use a back-stop behind the kite, throw sand on�the leading edge, or use�a special stake to hold full brakes on a multi-line kite. Large kites are kept in bags or�as a bundle until flight.
            > �
            > Large kite arrays face special challenges. How�do we�keep big arrays safely grounded when any part of it that catches air could cascade-launch the whole? How do we kill a large Hyda-like�monster like the Spider-Mill? These are open questions.
            > �
            > =================
            > �
            > �
            > Latest Corrections: 1) Wubbo said "fantastic",�not "fabulous". 2) Rod spells "spiralling"�with more class�than Yahoo's spell-checker.
            >
          • dave santos
            Bob s idea of deflating airbeams is great, as the mechanism to initiate deflation can be a just a tiny low-power valve. Blowing a seam, as Joe
            Message 5 of 8 , Oct 13, 2011
              Bob's idea of deflating airbeams is great, as the mechanism to initiate deflation can be a just a tiny low-power valve. Blowing a seam, as Joe suggests, would be faster, but not so easily reversible maybe still not fast enough for "sense and avoid" aviation standard. Reinfaltion would require a blower/pump at each airbeam and take some time.
               
              The optimal "kill" capability is for an array to fly down under positive control (as a MetaKite) and have it able to stay there by its own downforce. Negative AoA of one part of a flying array could lead a chain-reaction as a "cascaded landing". Passive self furling of wings (like delta kites) in high wind can keep tether forces within winch ratings, an example of smart load-case engineering. A MetaKite might have "kill-ganglines" or cascading kill-lines. If these lines are rigged as loops, the kill could reverse for quick relaunch. A redundant non-reversible system might be the failsafe. NASA uses explosive-bolts to part spacecraft modules. An AWE equivalent could be a spring-loaded line-guillotine device, which probably exists as COTS.
               
              Tragically, Doug knows more about phlogiston than kites (except how to spell it). Large kites have been around for thousands of years, and dousing them in high-wind is a REAL problem. On the other hand the SuperTurbine's proposed giant rotating carbon towers are "unobtainium". We all looked the other way when Doug confused Trade Wind with Jet Stream. The fastest way to kill a SuperTurbine is to harangue NREL and lecture NASA ;^)
               
               
            • Bob Stuart
              Re: regulating air beams. You may have noticed that when you blow up a party balloon, the resistance is highest initially. Then, what surgeons call an
              Message 6 of 8 , Oct 13, 2011
                Re: regulating air beams.  You may have noticed that when you blow up a party balloon, the resistance is highest initially.   Then, what surgeons call an aneurism appears, and the inflation pressure goes down for a long period.  This effect might be used to trip small components into collapse with automatic recovery, but it is probably sufficient to just keep a long beam at a constant internal pressure.  Most large inflated structures have constant air supplies in the expectation of minor leaks, or at least permeability.   It is probably smart to use a special material where they are most likely to buckle, to take repeated  folding.

                Bob Stuart

                On 13-Oct-11, at 10:50 AM, dave santos wrote:


                Bob's idea of deflating airbeams is great, as the mechanism to initiate deflation can be a just a tiny low-power valve. Blowing a seam, as Joe suggests, would be faster, but not so easily reversible maybe still not fast enough for "sense and avoid" aviation standard. Reinfaltion would require a blower/pump at each airbeam and take some time.
                 
                The optimal "kill" capability is for an array to fly down under positive control (as a MetaKite) and have it able to stay there by its own downforce. Negative AoA of one part of a flying array could lead a chain-reaction as a "cascaded landing". Passive self furling of wings (like delta kites) in high wind can keep tether forces within winch ratings, an example of smart load-case engineering. A MetaKite might have "kill-ganglines" or cascading kill-lines. If these lines are rigged as loops, the kill could reverse for quick relaunch. A redundant non-reversible system might be the failsafe. NASA uses explosive-bolts to part spacecraft modules. An AWE equivalent could be a spring-loaded line-guillotine device, which probably exists as COTS.
                 
                Tragically, Doug knows more about phlogiston than kites (except how to spell it). Large kites have been around for thousands of years, and dousing them in high-wind is a REAL problem. On the other hand the SuperTurbine's proposed giant rotating carbon towers are "unobtainium". We all looked the other way when Doug confused Trade Wind with Jet Stream. The fastest way to kill a SuperTurbine is to harangue NREL and lecture NASA ;^)
                 
                 


              • dave santos
                Bob,   That s good Kite Jujitsu (like the two-line Push-Turn or reeling-out in hard gusts), in an emergency to easily loose a lace or belt to make a
                Message 7 of 8 , Oct 13, 2011
                  Bob,
                   
                  That's good Kite Jujitsu (like the two-line Push-Turn or reeling-out in hard gusts), in an emergency to easily loose a lace or belt to make a rigid air beam quickly go soft, and conversely, to repressurize with just a tiny servo-winch. This is also a great slow-actuation method for trimming giant "air-bag actuators" within a soft kite, according to conditions.
                   
                  The standard reflex for many giant soft-kites and arrays will be default depower or downforce when load limits or emergency self-powered release occurs.
                   
                  We are running out of problems...
                   
                  daveS

                   
                • Doug
                  ... ***I guess that IS like misspelling Flogiston - 4 miles vs 6 miles, sorry Dave I saw your machine up there in my telescope and mis-under-estimated the
                  Message 8 of 8 , Oct 14, 2011
                    --- In AirborneWindEnergy@yahoogroups.com, dave santos <santos137@...> wrote:

                    > Tragically,�Doug knows more about phlogiston than kites (except how to spell it).

                    ***I must be slipping! How could I misspell kite? er um I mean Phlogiston? Hello it is a Greek concept: PH! Good call Dave S.!

                    >We all looked the other way when Doug confused Trade Wind with Jet Stream.

                    ***I guess that IS like misspelling Flogiston - 4 miles vs 6 miles, sorry Dave I saw your machine up there in my telescope and mis-under-estimated the altitude! :)

                    Even spellcheck says I misspelled flogiston, and Superturbine!

                    >The fastest way to kill a SuperTurbine is to harangue NREL and lecture NASA ;^)

                    *** Well the fastest way really is to have a 70 mph wind, as we did here the other day. We lost some concrete roof tiles. You had to lean into it to walk. The steel pole holding up a SuperTwin(TM) bent over 20 degrees (the SuperTwin(TM) itself was still operating and is fine - no damage, re-installed yesterday).

                    ***The Firefly(TM), a 2-rotor downwind machine, exploded in a (100% predicted) failure mode, that nobody (including (especially?) the above 4-letter tagging crews) knows about, having no experience running or even observing multi-rotor turbines. (They are too busy)

                    Maboomba!

                    (Maboomba is another invention of mine. An unknown word when I registered the domain maboomba.com a couple years ago, (3 hits on google) that today gets 130,000 hits when you google it. Who said I never invented anything useful? :)

                    Could maboomba be the 22nd century version of Phlogiston?

                    What IS Maboomba?

                    Ever get an e-mail offering 20 million dollars from a deceased uncle and they need someone they can trust, like you, to handle it? Maboomba!

                    :O... ... ... ... ... ... ...
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