CG help

[iceman]

just about ready to start adding the hardware to my scratch built rigger. what i need to know is how to get CG right. my thoughts are to put everything in place except the motor and stuffing tube and then move motor in hull to get CG then mount motor and install drive line. what method do y'all use for this? thanks in advance for any info given.

GARY

[iceman]

also the motor im using is a Leopard 3674 will i need a rear mount for this?

[martin]

I use 60% - 40%, sitting the running edges of the sponsons on scales & then the prop i get 60% on the sponson & 40% on the prop. Martin.

[iceman]

so if i measured from the pad on the front sponsons to the pad on the rear sponsons and divided it by 10 then come back 60 percent of that it should be cg of 60 front 40 rear right?

GARY

[martin]

I do mine 2 ways either by measurements or by weights, they both equate to 60/40% & both end up with the cg in the same place. If i do measurments then it length from the rear ski to the tips of the sponsons then 40% of that length,that gives cg point from the rear of the ski. Doing it by weight i measure the weight of the boat the & get 60/40% of that weight then sit the sponson ride pads on the scales supporting at the prop end, the weight you get should be the 60%, then i sit the ski on the scale supporting the sponson ride pad & you should have the 40% weight.

[JIM MARCUM]

Which ever CG you use, (I like 28-30% on my cats) you can easily change it by moving your LIPOs fore or aft. Asuming you have enough room in the hull to move the batts around. JIM

[martin]

What i would say & its how i do mine is the cg on a rigger is diff to cats or monos where around 30% is good for them, generally in a rigger where your pretty tight on space it dosnt leave to much room to move batteries fore & aft. So you need to get cg position sorted quite near final position during build.

[iceman]

Thanks for the help guys. think i got it now

GARY