This is what I was trying to explain. Every magazine seems to have an article on the MAC calculation every couple of years. But if you understand the principle -- the point on the wing where there will be equal areas on both sides, then and it's easy to estimate. In fact, for most planes it is completely unnecessary because they have constant chord wings.

But if you do the MAC calculation, then you STILL have to decide where the CG should be. So then after all the measuring and calculation...people tell you to guess! I'm not trying to be critical of anyone posting here. It's something I have seen over and over.

Of course, guessing works well enough, especially a conservative guess -- the airplane will fly. But the CG is likely to be well forward of the optimal point. Then you've got to start experimenting with moving the CG back. Why not calculate a reasonable CG in the first place and set up your plane that way? It saves a lot of effort later on.

Jim