How long is your NAR payload?

Discussion in 'Competition Rocketry' started by vcp, Aug 23, 2018.

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  1. Aug 23, 2018 #1

    vcp

    vcp

    vcp

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    I hadn't thought about it much before NARAM - the fine sand I got at Hobby Lobby required a tube of 78mm to get 28 gm. But the minimum length of 60 mm sort of implies that payloads exist that are much shorter. Is there a denser sand? If so what is it and where can a mere mortal obtain it. How short can you get a payload?
     
  2. Aug 23, 2018 #2

    Buzzard

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    Gary - Mine came in at 69mm. I seem to recall it sandbox sand. Chris Flanigan mentioned that he found some high-density sand. I will see if I can find that text.

    Chas
     
  3. Aug 24, 2018 #3

    vcp

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    I must have 'fluffy' sand.
     
  4. Aug 24, 2018 #4

    dhbarr

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    It should be possible to mix different grain sizes to increase density. Maybe not -reasonable- but doable.
     
  5. Aug 24, 2018 #5

    MClark

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    For filling sand bags for shooting sometimes zircon sand is used.
    Black sand, magnetite, can be had from regular river sand.
     
  6. Aug 24, 2018 #6

    dhbarr

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    Huh. I had no idea about Zircon or Chromite sand. TIL.

    On a related note I thought they had changed the payload dimensions to be 18-mm-couplery, but I see NAR still says the larger OD.

    Maybe I'm just misremembering?
     
  7. Aug 24, 2018 #7

    Buzzard

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  8. Aug 24, 2018 #8

    Buzzard

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    From the US Model Rocketry Sporting Code 2017.2:

    22.3 Payload Specifications The standard NAR payload is a sealed non-metallic cylinder containing fine sand, with a mass of no less than 28.0 grams. This cylinder must be a minimum of 17.0 millimeters in diameter, and a minimum of 60.0 millimeters in length. No holes may be drilled into it, no changes made in its shape, and no material may be affixed to it.

    Chas
     
  9. Aug 24, 2018 #9

    dhbarr

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    Interesting, http://www.nar.org/contest-flying/us-model-rocket-sporting-code/payload-events/payload/ still says:

    "
    25.2 Payload Specifications
    The standard NAR model rocket payload is a non-metallic cylinder containing fine sand, with a mass of no less than 28.0 grams. This cylinder shall be 19.1 +/- 0.5 millimeters in diameter, and 70.0 +/- 10.0 millimeters in length. The payload may be permanently sealed to prevent the loss of the sand. No holes may be drilled into it, no changes made in its shape, and no other material may be affixed to it.
    "
     
  10. Aug 24, 2018 #10

    vcp

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    Guess I need to find some depleted uranium 'sand'.
     
  11. Aug 24, 2018 #11

    vcp

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    Last edited by a moderator: Oct 24, 2018
  12. Aug 25, 2018 #12

    Buzzard

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    Guess the volunteer that updates the website hasn't made the change to the latest USMRSC, aka Pink Book.

    C
     

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