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Thread: Strut Angle

  1. #1
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    Strut Angle

    I have a new Traxxas Spartan and run it on 6s the thing flies . I have a problem with chine walk though. What is the best strut angle for stability? Any responses would be appreciated. Thanks





    E-Maxx and Spartan

  2. #2
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    Depends on weight placement. Slowly drop it until the chine walk goes away.

  3. #3
    RC Racer
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    I put a 5" rudder on and that eliminated my chine walk.

  4. #4
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    Let the strut down as needed? And what about trim tabs I have the adjustable ones?




    E-Maxx and Spartan

  5. #5
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    Yep. Back of the strut down. Dropping the tabs would help too but it tends to scrub more speed off than dropping the strut.

  6. #6
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    Every setup is slightly different, so the strut angle that works best for one person may not work well for another.

    Neutral strut angle is straight in line with the bottom of the hull, this is the best place to start.
    Negative strut angle (down) will push the bow down a bit, or, "make the boat run wetter" (more hull contacting the water)
    Positive strut angle (up) will lift the bow a bit, or, "make the boat run drier" (less hull contact with the water)

    Adjusting the trim tabs has more or less the same effect. adjusting them down will cause them to "push up" on the stern, which forces the bow down, or, "run wetter"

    Many RC boats are designed so the battery(s) can only be installed in one position, so trimming out the boat can only be achieved by adjusting strut angle and trim tabs. Because the Spartan has long battery trays trays that allow a wide range of battery positions, a considerable amount of "hull position" can be managed by adjusting battery position. The weight of the batteries can have a significant impact determining where the best position is, and, on how sensitive the adjustments are.

    I would offer the suggestion to start at neutral strut position, and experiment with battery positioning to achieve the best balance between speed and stability. Then fine tune the ride with strut position and trim tabs.

    I have found on both my Spartans, after finding best battery position, that a slightly positive (0.5-1.0mm) strut angle works best, and trim tabs close to neutral (trailing edge level with bottom of hull). But your best setup, and the setup that works best for others, may be slightly, or completely different.

    A few things to consider while experimenting:
    1. There is a general consensus the the steep and high rise of the V is what makes the Spartan hard to stabilize. In theory, the higher the stern rises in the water, the harder it is to stabilize the boat.
    2. The wetter you run the hull will tend to improve stability, but will sacrifice some speed due to increased drag
    3. The drive system is a "surface drive" so the prop is supposed to run only partially submerged. When adjusting the strut, negative trim will force the prop into the water which will in turn increase the load on components. Keep strut adjustments conservative and don't exceed the 2mm positive/negative limit recommended in the owners manual.

    I still haven't completely eliminated chine walk, but have it managed well enough to allow a fun time with our Spartans.

    hog

  7. #7
    RC Enthusiast
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    Nice write up Hog!

    Quick question : when you mention strut position and in reference to Negative and positive position.....Looking at the boat from the side profile (and upright) does Negative mean prop goes down ( as in if it was floating towards water) and positive means up ( as in if it was floating away from the water or towards the sky??

    Another dumb question by Jkerr sorry guys just getting up to speed

  8. #8
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    Positive would be like if you grabbed the prop and pulled it to the surface. Negative would be like if you pushed down on the prop. With positive trim, if you put a stick through the middle of the prop, it would point at the floor, negative would point at the ceiling. Bout time for somebody to make a tuning and setup video!

  9. #9
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    Yes, exactly right JKERR.

    There is a good illustration of strut angle and how to adjust it in the owners manual. For those that don't have a manual, it is available on-line here on the Traxxas site.

    hog

    PS. FR, I think you crossed up your positive negative description by accident. With a stick/rod extending out through the center of the prop, positive would point upward, negative downward.
    Last edited by hog; 08-15-2013 at 10:37 AM.

  10. #10
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    Agreed Hog thanks for clarifying,

    Anyone have a link to greasing the flex shaft,,,video is worth a million words haha

    and yes it someone could make a darn tune video there is enough demand for someone to be a hero

  11. #11
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    Yep. Sorry for adding to the confusion. It's opposite of what I said.

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