Japanese paper craft model rocket

Discussion in 'Low Power Rocketry (LPR)' started by hakudoh, Jun 16, 2019.

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  1. Jun 16, 2019 #1

    hakudoh

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  2. Jun 16, 2019 #2

    kuririn

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  3. Jun 16, 2019 #3

    hakudoh

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  4. Jun 19, 2019 #4

    kuririn

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    I thought I was done with paper rockets for a while after doing three recently. But my curiosity got the better of me and so I built the first one:
    0619190606.jpg
    This is the 1904 rocket. Some observations:
    1. Instructions are in Japanese, but if you've done cardstock rockets or models before, you can just follow the illustrations and figure it out.
    2. Print in landscape mode, actual size, and use A4 or legal cardstock. I used letter sized cardstock, fit to paper and it seems to print slightly underscale. So I subbed a bt-20 tube for the paper engine tube and enlarged the hole in the centering rings using a circle cutter.
    3. The instructions include making an engine hook out of wire. I just subbed one from my parts stash.
    4. The interlocking glue tabs are interesting. Haven't seen that before.
    5. The fins are open on the bottom, and I'm concerned about landing damage. So I used a generic "choose your size" chute kit and chose 24". the largest size. Slowest descent, but the most wind drift. Will fly on calm days only.
    6. No mention of nose weight, but my mindsim tells me that it might need some. Will see where the CG is after finishing.

    Haven't decided yet whether to print the Camui on letter cardstock or look for some legal sized sheets. I may also redo the 1904 on legal paper. Hey, for a few cents of paper I can afford a redo, right?
    The C75B rocket however is big. The actual size printout won't even fit on legal paper. You need ledger size (11X17). 24mm motor mount. Don't know if I'm gonna do that one.
    There is also a .pdf for a paper launch controller. Interesting. Laters.
     
    Last edited: Jun 19, 2019
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  5. Jun 19, 2019 #5

    K'Tesh

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    Going to have to try these...
     
  6. Jun 20, 2019 #6

    GlenP

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    Very cool “airfoiled” fins on the camui. Also has a neat graphical instructions on how to cut a parachute from a grocery bag, very clever. Thank you for sharing these designs.

    The body tube patterns are in landscape mode, so you have to curl the paper across the natural grain, which may crease unless you steam the paper. I usually make body tube patterns in portrait layout on cardstock paper, but this limits the max dia you can get from a single sheet to 8.5/pi or about 2.7”
     
  7. Jun 22, 2019 #7

    kuririn

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    OK, here's the Camui:
    0622190951.jpg

    It's big! So big that it can hide the 1904 behind it:

    0622190950.jpg
    Even though I printed it underscale with letter size instead of legal cardstock.
    Approx. 2.25" dia. and about 36" tall.

    I might check if Office Depot can print the C75B... rocket on 11x17 cardstock. I think I may have some 11x17 poster board paper but my printers can only go 8.5" max wide.

    We have a launch scheduled for tomorrow. These two are going up, weather permitting. Laters.
     
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  8. Jun 22, 2019 #8

    Rktman

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    Impressive and very very cool!
     
  9. Jun 23, 2019 #9

    GlenP

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    I really like the fins on that one, will have to give it a try. That is bigger than the Estes Mercury Redstone, for relative comparison, but is probably much lighter and would totally scream on a C6-5
     
  10. Jun 23, 2019 #10

    Rktman

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    Since I've never tried cardstock rocketry, I'm still amazed that a single unlaminated layer of paper can withstand the acceleration and windforce of an 18mm motor, even if it is 100lb cardstock.
     
  11. Jun 23, 2019 #11

    GlenP

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    Portions of it are more than a single layer, the seams have a layer of glue that dries like hard plastic laminated in between two layers of paper. And additional glue can be spread on the inside for reinforcement. Those nose cones can be pretty rigid when built properly, and the body tube seams can be as well. Still have to handle it carefully if holding the tube in between couplers, but just a thin layer of white glue spread around the inside of the paper gives it a little bit of extra support.
     
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  12. Jun 23, 2019 #12

    Rktman

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    Eric Noguchi

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    Thanks for clarifying. Knowing those details, it makes a whole lot more sense.
     
  13. Jun 24, 2019 #13

    Nytrunner

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    How heavy are those? I' certainly interested
     
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  14. Jun 24, 2019 #14

    kuririn

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    The 1904 is .95 oz.
    The Camui is 2.5 oz.
    Both w/o motor. Also these were printed slightly underscale.
    Was unable to send these up yesterday due to breezy conditions. Lost two other rockets.
     
  15. Jun 24, 2019 #15

    GlenP

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    again for comparison with a more familiar rocket, while slightly smaller in dia and length the Estes Mercury Redstone is slightly heavier at 3.7 oz, per Estes estimate, as built mine is 4 oz.
     
  16. Jun 25, 2019 #16

    OverTheTop

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