Contra rotating propellers

Discussion in 'General Experimental Aviation Questions' started by Dave Hodges, May 6, 2019.

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  1. May 6, 2019 #1

    Dave Hodges

    Dave Hodges

    Dave Hodges

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    Does anyone know where I can find a contra rotating propeller mechanism? This is a setup that has two propellers on the same axis. One drive shaft is inside the main pipe. The other drive shaft is outside the main pipe. The drive shafts are coaxial and each has its own pulley and propeller. Each pulley has its own engine.
     
  2. May 6, 2019 #2

    blane.c

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    ENGINES FACING EACH OTHER.PNG Wouldn't it be simpler to just mount the two engines with the propellers facing each other?
     
    Last edited: May 6, 2019
  3. May 6, 2019 #3

    Dana

    Dana

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    For what size engines?

    The old Paraplanes had a setup like that with two 15HP Solo engines. It's not a popular setup because the complication usually isn't worth the advantages, if any.
     
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  4. May 6, 2019 #4

    blane.c

    blane.c

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    Also it is being done electrically. You could mount engine/generators anywhere and then supply power to the electric motors.

    https://www.contraelectric.com/
     
  5. May 6, 2019 #5

    henryk

    henryk

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    + CR flight...

    +differential CR gear=
    ( 80 kG thrust from 20 HP engine)

    20190422_181852.jpg 20190503_132256.jpg
     
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  6. May 6, 2019 #6

    blane.c

    blane.c

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    That looks like one engine with counter rotating props.
     
  7. May 6, 2019 #7

    henryk

    henryk

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    Last edited: May 6, 2019
  8. May 6, 2019 #8

    henryk

    henryk

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  9. May 7, 2019 #9

    pictsidhe

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    Has anyone actually flown a series electric HBA?
     
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  10. May 7, 2019 #10

    Dave Hodges

    Dave Hodges

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    It would be for a couple of Suzuki 993 cc engines.
     
  11. May 7, 2019 #11

    blane.c

    blane.c

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    Good question.
     
  12. May 7, 2019 #12

    blane.c

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    COUNTER ROTATING PROPS.PNG
     
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  13. May 7, 2019 #13

    pictsidhe

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    You'll likely have to build your own. That won't be an easy task
     
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  14. May 7, 2019 #14

    henryk

    henryk

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  15. May 8, 2019 #15

    Tiger Tim

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    I don’t know what you’re building, but I sure hope it’s a 3/4 scale M.C.72!
     
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  16. May 8, 2019 #16

    Dave Hodges

    Dave Hodges

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  17. May 8, 2019 #17

    Dave Hodges

    Dave Hodges

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    No, it's our own design.
     
  18. May 9, 2019 #18

    henryk

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    =not CONTER, not ROTATING,
    but OSCILLATING,very effective !

    IFF to made proper size to air flying ???
     
    Last edited: May 9, 2019
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  19. May 10, 2019 #19

    Jimstix

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    Why? The added weight and complexity will overcome any performance advantages of a dual-rotation propeller. Simplicate and add lightness.
     
  20. May 26, 2019 #20

    Dave Hodges

    Dave Hodges

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    That's the plan. Of course the advantages of contra-rotating propellers aren't justified with just one engine. But with two, as in your drawing, the thrust line doesn't change when an engine quits.
     

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