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Thread: Cg & all

  1. #11
    Senior Member HighWing's Avatar
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    Default Re: Cg & all

    Quote Originally Posted by HansLab View Post
    Does that much sound familiar to you? And some practical question: how do I get it there - and hold it there...?
    Hans,

    I made a box out of thins steel sheet and filled it sequentially with lead. I welded a piece of tubing over a drilled hole for the bolt and then added sides that fit within the fuselage structure. You can make the vertical height as tall as you think you may need. A thought on the lead: Another approach rather then melting and pouring would be to use some
    fine buckshot from the hunting supply store and after finding how much you need, pour some epoxy resin in to saturate it and bind it to the walls of the box.

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    Lowell Fitt
    Goodyear, AZ


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  2. #12
    Senior Member
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    Default Re: Cg & all

    I did exactly that (lead bird shot and epoxy adhesive) on my first homebuilt in 1974. I worked very well. Airplane was in service until 2011.

  3. #13
    Senior Member SkyPirate's Avatar
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    Default Re: Cg & all

    I did the same thing with lead buck shot but I put it in the aft vertical tube of the stabilizer
    Chase
    Model 5 OutBack
    912 UL

  4. #14

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    Default Re: Cg & all

    ItemWt. (Lbs.)Arm, (in.)MomentLeft Main, (- tare)355.0024.008520.00Right Main (- tare)338.0024.008112.00Tail Wheel (+ tare)0.000.000.00Nose Wheel (-tare)245.8038.509463.30TOTALS938.80 ^ ^ ^ ^ ^ ^ ^ ^26095.30 EMPTYWEIGHT CG, (in.) =27.80

    couple questions this is vixen 5.
    the wings are sweep 3 degrees foward, how do i add that factor in?
    if the cg are over the factory limit will it affect my airworthiness cert?
    do i need to make the added weight adjustment before inspection?

  5. #15
    Senior Member jiott's Avatar
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    Default Re: Cg & all

    I believe you must have a valid W&B document when you apply for your AW inspection.
    Jim Ott
    Portland, OR
    Kitfox SS7 flying
    Rotax 912ULS

  6. #16
    Senior Member t j's Avatar
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    Default Re: Cg & all

    vixenrookie, Just trying to double check your math. In can't figure out your nose wheel arm and moment. Did you forget the nose wheel arm and moment are negative numbers?

    The 3 degree foreward sweep will move both the foreward and rear cg limits foreward. You may need to contact the factory to find out how far forward they moved.
    Tom Jones
    Classic 4 builder

  7. #17

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    Default Re: Cg & all

    ItemWt. (Lbs.)Arm, (in.)Moment
    Left Main, (- tare)355.0024.008520.00
    Right Main (- tare)338.0024.008112.00
    Nose Wheel (-tare)245.8038.509463.30
    TOTALS938.80 ^ ^ ^ ^ ^ ^ ^ ^26095.30 EMPTYWEIGHT CG, (in.) =27.80

    see if thats easier to read, that factory sheet shows 1 degree, foward or backward.

  8. #18
    Senior Member t j's Avatar
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    Default Re: Cg & all

    I interpret it as:

    left main: 355 pounds X 24 inches = 8520
    Right main: 338 pounds X 24 inches = 8112
    Nose wheel: 245 pounds
    Total: 938 pounds

    The numbers for the nose wheel arm and moment are 8038 and 509463. Something's wrong there.
    Tom Jones
    Classic 4 builder

  9. #19
    Senior Member t j's Avatar
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    Default Re: Cg & all

    Okay, working the math backwards off the total moment I figure your nose wheel moment is 9463.

    I would do the math as (8520 + 8112 - 9463) divided by 938 = empty weight CG of 7.64 inches.
    Tom Jones
    Classic 4 builder

  10. #20

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    Default Re: Cg & all

    i got my numbers off the kitfox site where automates the numbers for you. im not real familar in understanding the weight and balance,

    heres where i measured and weight
    center of measurement was front of the wing to center front wheel was 38.5 inches
    front of the wing to center right and left wheel was 24"
    front of the wing to back of prop hub 53 5/8
    right 338 lb
    left 355 lb
    front 245.8 lb

    the wing sweep is 3 dregrees foward

    little history: my father-law gave this and learning as go ,getting to the point of finally assemble now the math comes in and its like teaching a rock to roll over. i greatly appciate the help on this.

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