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Thread: a question for those that have built a Black Pearl

  1. #1
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    Default a question for those that have built a Black Pearl

    I have a black pearl ver. 8.7 m50 measuring the motor mount position its 12.5 inches from the transom and I ran against a different ver. whose motor was 14 inches from the transom.
    I noticed his boat wasn't as loose as mine. I have added weight to the front and i still balance about 1.5 inches back of the sponson. To get closer to 1 inch I have to add another 91/2 oz
    to the front. With all the extra weight my boat just over 10 pounds is that to heavy for a P-hydro?
    :canada

  2. #2
    Join Date
    Jun 2009
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    Hi! 10lbs is certainly getting up there! I am considered heavy, and am running just over 8lb. IMO, once the boat is balanced and riding right, all the additional weight should be placed at the CG to keep her down.

    We've made several improvements over the years, both to performance and cosmetics. The motor mount position was one of them. Yours happens to be the furthest the motor mount was back. Also, the boat is much lower profile now. Below is my set-up for Ver12 (don't tell anyone ). Hopefully others will chime in as well.

    CG: 42mm from rear of sponsons.

    Strut: Neutral angle, Neutral height (strut height at which the center of the prop shaft is at the same height as the bottom of the sponson ride pads with a level afterplane). 18.5mm from bottom of strut to bottom of boat.

    Batteries: (2) 5000mah 4S

    RTR Weight (includes batteries, motor, esc, additional weight, etc..): 8lb, 3.6oz

    Battery Weight: 2lb, 5oz

    Additional Weight added at CG: 4.6oz
    Attached Images Attached Images

  3. #3
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    Thanks Pete for your input.I will try the cg at 42 mm and see if I need the extra weight. I have about 2 degrees negative in the strut running a ABC 1815 prop.
    :canada

  4. #4
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    No problem. And just to be clear, those parameters are all for the V12 version. It's much different than the V8.7. Plus, you are running a low lift prop. I run an H5, so I'm getting a lot more lift on the strut. Hopefully some folks running low lift props will chime in.

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