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Fw: [solarballoons] ULDB pumpkin test in Elizabeth City NC

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  • Ralph Wallio, W0RPK
    ... From: fairchild_24 To: Sent: Thursday, August 09, 2007 12:51 PM Subject: [solarballoons] ULDB
    Message 1 of 1 , Aug 9, 2007
      ----- Original Message -----
      From: "fairchild_24" <fairchild_24@...>
      To: <solarballoons@yahoogroups.com>
      Sent: Thursday, August 09, 2007 12:51 PM
      Subject: [solarballoons] ULDB pumpkin test in Elizabeth City NC

      This was a very successful series of tests. There were 2 test
      articles, one being a new build scaled 27m diameter pumpkin with a max
      bulge angle of 55 degrees and the next tested being the original 27m
      pumpkin first tested last March, but with 10 out of its 200 gores
      trussed-up by sewing the fin-flanges together. They both deployed
      beautifully in a simulated ascent to 100000 ft by injecting only the
      scaled amount of lift and then back-filling with air to simulate
      expansion of the helium.
      Large super-pressure pumpkin balloons have been plagued with a
      peculiar type of buckled shape that we have called an s-cleft. It is
      caused by having too much bulge material for the given number of gores.
      Last March, we tested a scaled version of the Sweden pumpkin (flt 555)
      in order to produce and study the s-cleft phenomenon. It successfully
      reproduced the s-cleft in captivity. We determined that the
      shape was not the result of tendon locking or friction, but an actual
      low-potential energy alternate shape that evolved from the wrinkled
      and clefted low pressure ascent shapes.
      These tests have proven that we can scale the large size balloons
      properly to a testable size to indicate whether or not a particular
      design will properly deploy. See the group photo of the team in front
      of the deployed pumpkin under the photos section. That's me in the
      red shirt, far left

      Rodger Farley, NASA/Goddard Space Flight Center
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