Lemming: While the Longacre method of CG determination is useful for a completed car, perhaps in your case with only a partially finished car another method may be more useful. This would consist of calculating the moments of various components about a chosen location relative to the car, and then resolving those into an average. For instance, choosing a convenient coordinate system reference point, perhaps at ground level, rear axle centerline and chassis centerline with x going forward, y going vertically, and z going laterally to the right side of the car, one can do the following: for each significant mass, identify its mass amount (or weight) and the coordinate position of its individual CG. If you are only concerned about the height of the composite CG, only y coordinates need be addressed, however, the same process can be used to find the longitudinal CG location by doing the same for x coordinates, etc. Once the ?masses? and locations are identified, the following calculation will yield the coordinate of the composite CG. Xe = (m1x1 + m2x2 + ...mnxn)/ (m1 + m2 + ...mn) Similarly for Ye and Ze.

This, of course, is easily incorporated into a spreadsheet so that as the build progresses and different items are added or accounted for or modified, the new numbers are easily produced.