2 fins and a nose cone...and it flies.

Discussion in 'Low Power Rocketry (LPR)' started by sl98, Feb 10, 2020.

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  1. Feb 10, 2020 #1

    sl98

    sl98

    sl98

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    The recent Apogee Peak of Flight contained a free plan for a 2 fin spin stabilized rocket. The rocket is designed by Kevin Cronwell and is in issue 514. The rocket only requires 6 parts, which I had on hand. The longest part of the build was waiting for glue to dry. Total build time was about 1 hour. I was a little skeptical whether it would fly. I launched today on an A8-3 and it flew straight and true. I don't think I would use a larger motor because you may never find it again. This little guy earned its paint.

    Cygnus - on pad.jpg Cygnus - lift off 1.jpg Cygnus - lift off 2.jpg Cygnus - lift off 3.jpg Cygnus - lift off 4.jpg
     
  2. Feb 10, 2020 #2

    mbeels

    mbeels

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    Neat! That's a fun idea.
     
  3. Feb 10, 2020 #3

    kuririn

    kuririn

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    Cool!
    First thought: wonder if it can be upscaled?:D
     
  4. Feb 10, 2020 #4

    gna

    gna

    gna

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    Nice! I saw that design, too, and thought about building one. I have everything but a coupling laying around here.
     
  5. Feb 10, 2020 #5

    sl98

    sl98

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    If you have a shorter coupler, you could use a thrust ring and glue the shorter coupler above the thrust ring. You could also try one of the yellow tubes Estes provides for placing thrust rings as your coupler. It might be a little bit of a loose fit but a wrap of tissue paper and soaking in thin CA might make a good fit.
     
  6. Feb 10, 2020 #6
  7. Feb 12, 2020 #7

    gna

    gna

    gna

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    Just curious--they list 1/8 balsa. Did you use 1/8 or 3/32 balsa?
    I'll have to dig through the bin with all my parts and see what's in there. I looked the other day for BT20 and didn't see any couplings, but I wasn't really looking for them.
     
  8. Feb 12, 2020 #8

    sl98

    sl98

    sl98

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    I did use 1/8 but it sure is overkill. I think 3/32 would be just fine. I would even try 1/16 basswood if I made another one.
     
  9. Feb 12, 2020 #9

    SDramstad

    SDramstad

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    Hmmmmmmmm..........:rolleyes::rolleyes::rolleyes::rolleyes:
     
  10. Feb 12, 2020 #10

    Alan15578

    Alan15578

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    Certainly.

    I had an old NACA report that explained it all, but I lost it. I think it dated back to the WWW I era. They wanted to stabilize dropped bombs with planar fins (two fins canted) because they could be packed and dropped more efficiently. NACA figured out how to size and cant the fins, but then fond that such stabilization was unsuitable because the bombs had a larger dispersion pattern. This type of stabilization was most often seen on the Parks water rockets. For sport rockets, it is just a novelty, but I still want to find the report number and the report itself. I think all the old NACA reports are available on line, but there are too many to search through.
     
  11. Feb 17, 2020 at 10:10 PM #11

    sl98

    sl98

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    Painted after maiden flight and made one fin black to make it easier to visualize the spin. You can see almost 1 full rotation in first two pictures as it is leaving the launch rod. Another perfect flight with an A8-3. Time to upscale.


    Cygnus painted (0).jpg Cygnus painted (1).jpg Cygnus painted (2).jpg Cygnus painted (3).jpg Cygnus painted (4).jpg Cygnus painted (5).jpg Cygnus painted (6).jpg
     
    gna, GlenP, BABAR and 1 other person like this.
  12. Feb 20, 2020 at 1:02 AM #12

    sl98

    sl98

    sl98

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    Started a 223% upscale using BT-60. Fins are cut. Working on 24mm motor mount. Initially I was thinking rear deploy. I am going to try MM that ejects with a streamer and still breaks rocket in 2 for tumble recovery. If that doesn’t work a switch to rear deploy should be easy.
    0C5AFA9A-60C1-4282-B43B-21D552FD3DE0.jpeg
     
  13. Feb 21, 2020 at 6:20 AM #13

    gna

    gna

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    Here’s mine:
    37B2FBCD-576B-4C71-BFFC-0BC7BB9A12FE.jpeg I papered the fins for a bit more strength. Of course, there’s no green grass here, so it’ll be a while before it flies, or gets painted...
     

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