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Thread: Elevator spring

  1. #1

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    Elevator spring

    My supercub, which was rebuilt ground up in 1999, has a spring on the elevator which holds the elevator up above the horizontal stabilizer while in a resting state. This spring requires a lot of force for full forward and full aft stick, making it difficult to finesse aileron input while applying forward or aft stick. Is this spring tension normal for super cubs, or is it an aftermarket STC addition? Would spring tension be adjustable?

    My super cub requires an extreme amount of trimming in the pattern; with full flaps and full nose down trim, I still have to apply a fair bit of forward stick to maintain airspeed on final approach!
    Last edited by womblesd; 09-29-2019 at 04:30 PM.

  2. #2
    www.SkupTech.com mike mcs repair's Avatar
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    Spring is controlled by stabilizer position. Heavy cubs might do better without it. You can adjust cable length.


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  3. #3

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    I don't get why aft stick requires more force.Does it have 1 spring or 2 back there?
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  4. #4

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    I have not opened it up to view spring(s). The spring tension increases significantly the further stick is pushed or pulled.

  5. #5
    Jonnyo's Avatar
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    What is the purpose of the spring ?

  6. #6
    PerryB's Avatar
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    They were required to get the airplane to meet the pitch stability/ oscillation requirements for certification.
    After Monday and Tuesday, even the calendar says WTF !

  7. #7

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    You can see pictures of the spring and cable in the Javron cub post pictures.Look at the elevator control horn.
    I installed it for the purpose of relieving stick pressure at slow speeds.It should make up elevator easier but you say yours is harder both ways.I don't see how that can be.
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  8. #8
    Steve Pierce's Avatar
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    Those pictures should help. I suspect something is not installed or rigged correctly.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  9. #9

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    I have flown Super Cubs with very weak springs. A sheer delight, not having to trim all the time. I am with Mike above.
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  10. #10
    Steve Pierce's Avatar
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    The spring has nothing to do with having to trim the airplane in my opinion. My Super Cub only required trim for the load when leveled off and two turns of nose down trim when entering the pattern and pulling flaps. Installed the Thrustline mod and all I do is trim the load. Slow down in the pattern and have stick pressure until I pull flaps and then neutral. I think you have a rigging issue or something is installed wrong. I have flown to many Super Cubs that were like mine.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  11. #11
    cubdriver2's Avatar
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    You'll find that pilots that cut their teeth on J3 don't like the spring on Pa11 or Pa18, J3 doesn't have a spring

    Glenn
    "Optimism is going after Moby Dick in a rowboat and taking the tartar sauce with you!"
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  12. #12
    supercrow's Avatar
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    I never used the spring on any of mine. Just fine without it, even on oversize tailfeathers.
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