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Last Weekend's ISU Flight

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  • paul.verhage@boiseschools.org
    Here s an update on the ISU launch last weekend. It was the best flight I ve seen in Idaho. No surface winds and a 20 mile flight that landed a few hundred
    Message 1 of 6 , Oct 5, 2004
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      Here's an update on the ISU launch last weekend. It was the best flight I've seen in
      Idaho. No surface winds and a 20 mile flight that landed a few hundred feet from the
      road in a plowed farm field. There were well placed roads for the entire flight. we
      spent lots of time with the farmer of the property we launched from and at a truck
      stop showing visitors the balloon and the UI View map.

      I ran out into the field as the balloon landed and missed grabbing it by about 3 feet.
      The plowed field was uneven and I couldn't change my running direction fast enough
      without tripping. I'll email a few photos when I get them from ISU. I'm attaching a
      spreadsheet of the science data my flight collected.

      Another topic. BalloonSats are popular with college students. The University of
      Idaho recommends using the plastic tube of a ball point pen to run the load line
      through. ISU says they saw metal pipe (from lamps) being used at Boulder. We lost
      three BalloonSats when the metal tube of one BalloonSats abradied the load line. I
      recommend using plastic tubing from hobby shops for the loal line and three cord
      suspension system. I'll post photos of the design shortly. I would also recommend
      using 1/2" thick styrofoam in place of the foam core. I'll write up an article on this for
      Nuts and Volts for early next year. I'm planning on getting Boise School District
      students to make a bunch of BalloonSats for launch.

      Paul
    • n9xtn@cox.net
      ... Very cool. We haven t quite been able to do that here yet, though we have had good luck being within a couple hundred yards as the payloads come down. ...
      Message 2 of 6 , Oct 5, 2004
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        > I ran out into the field as the balloon landed and missed grabbing
        > it by about 3 feet.
        > The plowed field was uneven and I couldn't change my running
        > direction fast enough
        > without tripping.

        Very cool. We haven't quite been able to do that here yet, though we have had good luck being within a couple hundred yards as the payloads come down.

        >
        > Another topic. BalloonSats are popular with college students.
        > The University of
        > Idaho recommends using the plastic tube of a ball point pen to run
        > the load line
        > through. ISU says they saw metal pipe (from lamps) being used at
        > Boulder. We lost
        > three BalloonSats when the metal tube of one BalloonSats abradied
        > the load line. I
        > recommend using plastic tubing from hobby shops for the loal line
        > and three cord
        > suspension system. I'll post photos of the design shortly. I
        > would also recommend
        > using 1/2" thick styrofoam in place of the foam core. I'll write
        > up an article on this for
        > Nuts and Volts for early next year. I'm planning on getting Boise
        > School District
        > students to make a bunch of BalloonSats for launch.

        For the UNO BalloonSat flight, I believe the students used plastic tubing used to run water to things like ice makers in refrigerators, etc. Easily obtained from a hardware or home improvement store. To keep the tubing from sliding through the cube, a metal retaining clip (looks like a "C" with flanges that grip the tube) was placed on both sides of the cube. This worked pretty well for us. The tube was flexible enough to keep the line from abrading. We also put a separate line from the top tracking payload to the bottom one so that if one of the BalloonSats did cut the load line, the tracking payloads would remain tied together. There were no cameras in our BalloonSats so there were no issues with obscuring their view with another line.

        Has there been an issue with foam core satellites? I think foam core mount board would be a lot easier for the students to cut cleanly than styrofoam.

        73 de Mark N9XTN
      • paul.verhage@boiseschools.org
        ... with flanges that grip the tube) was placed on both sides of the cube. This worked pretty well for us. The tube was flexible enough to keep the line from
        Message 3 of 6 , Oct 5, 2004
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          > For the UNO BalloonSat flight, I believe the students used plastic tubing used to run water to things like ice makers in refrigerators, etc. Easily obtained from a hardware or home improvement store. To keep the tubing from sliding through the cube, a metal retaining clip (looks like a "C"
          with flanges that grip the tube) was placed on both sides of the cube. This worked pretty well for us. The tube was flexible enough to keep the line from abrading. We also put a separate line from the top tracking payload to the bottom one so that if one of the BalloonSats did cut the load
          line, the tracking payloads would remain tied together. There were no cameras in our BalloonSats so there were no issues with obscuring their view with another line.
          >
          > Has there been an issue with foam core satellites? I think foam core mount board would be a lot easier for the students to cut cleanly than styrofoam.

          I'm using a polystyrene tube (3/8" diameter, I believe) for my BalloonSat tube. The
          tube is manufactured straight. I can hot glue it to the 1/2" styrofoam BalloonSat.

          I'm using 1/2" foam because it will be warmer and I believe easier to machine. As
          long as I use a sharp exacto knife, I get clean cuts on the foam. The BalloonSat
          should be stronger in foam than foamcore. I'll have some students make strenght
          tests on the stuff in the next week. Also, the BalloonSat will be more protected from
          water damage.

          I coat my BalloonSat with Uline tape, a tape made for styrofoam gliders. It comes in
          a variety of colors and is very lightweight. Especially when you compare it to the
          aluminum tape used on some BalloonSats. With uline tape and 1/2" foam, I believe
          my BalloonSat airframe is lighter.

          I'll have my students run some tests and report back the results.

          On using a three line suspension...
          Using the single line suspension risks abrading the line and dropping the lower
          BalloonSats, which is how my BalloonSat was lost. There are alternatives, as Mark
          said. But if you use a three line suspension, you also reduce the rocking and
          spinning experienced by the BalloonSats. The photos should be crisper as a result.
          The reduced rocking and spinning also cuts down on the abrasion.

          Paul
        • n9xtn@cox.net
          ... Our students used what appeared to be colored duct tape, but we weren t as concerned about weight. Is the Uline tape available at hobby stores? ... Can
          Message 4 of 6 , Oct 5, 2004
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            > I coat my BalloonSat with Uline tape, a tape made for styrofoam
            > gliders. It comes in
            > a variety of colors and is very lightweight. Especially when you
            > compare it to the
            > aluminum tape used on some BalloonSats. With uline tape and 1/2"
            > foam, I believe
            > my BalloonSat airframe is lighter.

            Our students used what appeared to be colored duct tape, but we weren't as concerned about weight. Is the Uline tape available at hobby stores?

            > On using a three line suspension...
            > Using the single line suspension risks abrading the line and
            > dropping the lower
            > BalloonSats, which is how my BalloonSat was lost. There are
            > alternatives, as Mark
            > said. But if you use a three line suspension, you also reduce the
            > rocking and
            > spinning experienced by the BalloonSats. The photos should be
            > crisper as a result.
            > The reduced rocking and spinning also cuts down on the abrasion.

            Can you describe (or post a photo) of your three-line suspension?

            - Mark
          • paul.verhage@boiseschools.org
            ... It is. HobbyTown in boise has part of a wall dedicated to the stuff. It s a very thin tape. ... I m working on it between classes. It s basically a
            Message 5 of 6 , Oct 5, 2004
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              > Our students used what appeared to be colored duct tape, but we weren't as concerned about weight. Is the Uline tape available at hobby stores?

              It is. HobbyTown in boise has part of a wall dedicated to the stuff. It's a very thin
              tape.

              > Can you describe (or post a photo) of your three-line suspension?

              I'm working on it between classes. It's basically a spreader ring for a parachute, but
              flipped upside down. I started with a bearing swivel and tied three 50 pound test
              spectra lines to it and sealed the knots in heat shrink tubing. I took a 6" diameter
              needle point ring and drilled three equally spaced holes in it. The lines from the
              bearing swivel drop through the needle point loop. I slid a bead on each line and
              then tied a large knot in the spectra. The knots keep the beads from sliding any
              farther down and the beads keep the needle point ring from sliding down. I'm now
              working on tying bearing swivels every 18 inches.

              A BalloonSat needs to have three tubes glued into it. The styrene tubes I'm using
              are very light weight. I cut grooves into the foam body of the BalloonSat for each
              tube before I assemble it. To make the grooves, I sharpened up a plastic tube and
              twisted it into the foam to cut a cylinderical groove the correct diameter. I also cut
              smaller diameter holes in the foam for 3/16" wooden dowel. The dowels protrude
              from the BalloonSat by about 3/4" so I can rubber band the hatch on the BalloonSat.

              After hot gluing the BalloonSat together, I cover it in tape (I used black for thermal
              concerns) and then punch out the holes in tape covering the BalloonSat airframe.
              Then I hot glue the tubes and dowels into place. I'm also making tape labels with my
              name and phone number.

              To fly the BalloonSats, I connect the swivel in the suspension to the bottom of the
              last module in the near spacecraft. The three lines from the suspension are dropped
              through the plastic tubes of each BalloonSat and the BalloonSats are pushed up to
              the level of a bearing swivel. I'll then run a jump ring through the bearing swivel so
              the BalloonSat can't slide off.

              I'll get a digital photo and send it this week.

              Paul
            • Mike Manes
              Hi Mark, Congrats on a near-bushel-basket recovery! Not sure whose email from U. Idaho that you were quoting (Paul V?), but I ran a post-mortem on the line
              Message 6 of 6 , Oct 5, 2004
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                Hi Mark,

                Congrats on a near-bushel-basket recovery!

                Not sure whose email from U. Idaho that you were quoting (Paul V?), but
                I ran a post-mortem on the line that separated above the six bottom
                payloads on EOSS-81. The line separated in the middle of the 2-ft open
                span between the knots separating the the two adjacent payloads. This
                span could never have come in contact with the ends of the thru tubes;
                so
                it appears that the 240# tensile dacron line separated due to excessive
                tension during post-burst chaos.

                Note that some of the separated payload housings had the aerodynamic
                characterisitics of a shoe box, thus exacerbating post-burst chaos. On
                most flights, we put a streamlined (fast-falling) beacon at the bottom.
                but on this one, I foolishly decided to move the beacon up the payload
                line and to let someone else's box take the parachute drag drubbing.

                EOSS has used this method successfully on many payloads, and we use
                threaded plastic dress caps drilled thru to prevent abrasion. Mating
                nuts make interior access to the clamshell housings fast and easy.

                We have also seen a number of student payloads using less robust
                attachments arrive at the recovery site with nothing but a plastic
                thru tube left on the line. The payload housing must be secured firmly
                to the thru tube, as this is all that is keeping it from solo flight.

                One EOSS payload uses a 0.38" diameter HDPE toilet fill tube as the
                thru tube. This tube has a molded-in flange at one end that provides
                a large-area surface to support the bottom of the housing. But it's
                very had to cut decent threads into this material to accept a nylon
                nut agt the top. I finally got it right using a very sharp lathe tool
                and the single-point threading method.

                Building-grade styofoam board can be useful for payload housings, but
                it is difficult to make precise cavities into, and nearly impossible
                to seal the air gap between the housing and a removable cover. And it
                doesn't tolerate a rough parachute drag without leaving gouged-off
                bits behind. The EOSS CW/cutdown beacon foamcore housing has endured
                well over 20 flights and recoveries; altho it's a bit "cosmetically
                compromised" from all the landing dings, it's still quite functional.
                Those poster paper shear layers are surprisingly robust, especially
                when treated with a couple of thin coats of Krylon.

                EOSS's first two Shuttles used a four-cord bridle attached to the
                corners and tied off a few feet above and below the housing. Although
                this scheme does support the package well while conferring some
                reducdancy, it also translates line tension into radial crushing forces
                that the walls of the housing must withstand. One Shuttle had to be
                re-built after a flight where it supported a 50# USAFA at the bottom
                of the line. And that flight did not incur post-burst chaos.
                The thru-tube method completely isolates the payload structure from the
                line tension, and that was our purpose in developing it.

                73 de Mike W5VSI
                EOSS

                n9xtn@... wrote:
                >
                > > I ran out into the field as the balloon landed and missed grabbing
                > > it by about 3 feet.
                > > The plowed field was uneven and I couldn't change my running
                > > direction fast enough
                > > without tripping.
                >
                > Very cool. We haven't quite been able to do that here yet, though we have had good luck being within a couple hundred yards as the payloads come down.
                >
                > >
                > > Another topic. BalloonSats are popular with college students.
                > > The University of
                > > Idaho recommends using the plastic tube of a ball point pen to run
                > > the load line
                > > through. ISU says they saw metal pipe (from lamps) being used at
                > > Boulder. We lost
                > > three BalloonSats when the metal tube of one BalloonSats abradied
                > > the load line. I
                > > recommend using plastic tubing from hobby shops for the loal line
                > > and three cord
                > > suspension system. I'll post photos of the design shortly. I
                > > would also recommend
                > > using 1/2" thick styrofoam in place of the foam core. I'll write
                > > up an article on this for
                > > Nuts and Volts for early next year. I'm planning on getting Boise
                > > School District
                > > students to make a bunch of BalloonSats for launch.
                >
                > For the UNO BalloonSat flight, I believe the students used plastic tubing used to run water to things like ice makers in refrigerators, etc. Easily obtained from a hardware or home improvement store. To keep the tubing from sliding through the cube, a metal retaining clip (looks like a "C" with flanges that grip the tube) was placed on both sides of the cube. This worked pretty well for us. The tube was flexible enough to keep the line from abrading. We also put a separate line from the top tracking payload to the bottom one so that if one of the BalloonSats did cut the load line, the tracking payloads would remain tied together. There were no cameras in our BalloonSats so there were no issues with obscuring their view with another line.
                >
                > Has there been an issue with foam core satellites? I think foam core mount board would be a lot easier for the students to cut cleanly than styrofoam.
                >
                > 73 de Mark N9XTN
                >
                >
                >
                > Yahoo! Groups Links
                >
                >
                >
                >

                --
                Mike Manes manes@... Tel: 303-979-4899
                "Things should be made as simple as possible, but not more so." A.
                Einstein
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