Apogee fin shape experiment build

Discussion in 'Low Power Rocketry (LPR)' started by bikefxr, Feb 17, 2019.

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  1. Feb 17, 2019 #1

    bikefxr

    bikefxr

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    My sons science fair project taking shape IMG_1550432948.102655.jpg
     
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  2. Feb 22, 2019 #2

    BABAR

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    looking good!
    Lots of balsa to finish!
     
  3. Feb 22, 2019 #3

    neil_w

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    Good stuff. Wouldn’t mind seeing the results when finished if you’re so inclined (after the fair of course)
     
  4. Feb 24, 2019 #4

    bikefxr

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    Sure I’ll post the results
     
  5. Feb 28, 2019 #5

    kkooch

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    If no airfoil on any....the fins with the least surface area will win out (ellipse).
    If a marginally stable model and/or wind and the model has to correct itself....the fins with the largest tip chord will win out.
    Overall, the model will go to a lower aoa (=lower overall drag) with larger fin tip chords to stable.
    Any of those with a good airfoil will win out vs. no air foil!

    A cool project no doubt!

    Kooch
     
  6. Mar 1, 2019 #6

    BABAR

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    Airfoiling vs not definitely a factor

    Also wondering how much "finishing" affects drag
    Rough balsa
    Sanded balsa
    Papered balsa
    Filled balsa
    Nathan-ized balsa.
     
  7. Mar 1, 2019 #7

    Zeus-cat

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    How are you measuring altitude? I recommend sticking to just a few variables and flying them multiple times on the same motor. Motors can be + or - 10% in thrust
     
  8. Mar 2, 2019 #8

    bikefxr

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    We are using a jolly logic altimeter two for speed and altitude and multiple flights
     
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  9. Mar 2, 2019 #9

    bjphoenix

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    I was curious about this too. I was wondering about square-edged fins vs. rounded edges vs. airfoils.
     
  10. Mar 2, 2019 #10

    Zeus-cat

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    Excellent.
     
  11. Mar 16, 2019 at 3:55 AM #11

    bikefxr

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    Ready for flights tomorrow IMG_1552708506.915499.jpg
     
  12. Mar 17, 2019 at 1:50 AM #12

    mjennings

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    Awesome that looks like a lot of fun! Don't forget your son can submit his project to NAR and potential get a year free junior membership
     
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  13. Mar 19, 2019 at 6:54 PM #13

    BABAR

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    Cool!
    With ten different flavors, how many flights are you doing on each to get statistically relevant data?

    I really like #10!
     
  14. Mar 19, 2019 at 6:55 PM #14

    BABAR

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    Be sure there is a vent hole so altimeter reads right
     
  15. Mar 19, 2019 at 7:58 PM #15

    bikefxr

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    Was doing 3 fights with each the vent holes were already in the payload bay
     
  16. Mar 19, 2019 at 8:00 PM #16

    bikefxr

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    #10 went the highest 424 feet fastest went 108mph pulled 9.8 gs at lift off used a Estes C 6-5
     
  17. Mar 19, 2019 at 8:01 PM #17

    bikefxr

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    I’ll post the rest of data later that’s all I could remember
     

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