t1callahan
I think your logic comparing to the GP balancer is flawed. Unless you place the plane exactly on the same spot of the GP balancer every time you will get different readings. At least i always did. I build with magnets so I have a sheet of metal on my building table. I drew a line across the width of the metal and the main gear and scales always go on that line. I also draw another line down the center of the entire length of the table, The nose wheel or tail wheel scales always go on that line. So with the main gear on that line that goes across the table I drop a line at the LE of the wing at the side of the fuse and make a mark on the table. I then measure from that LE mark at the fuse back to where the CG is and make a mark there. So this is also at the side of the fuse. Then I measure the distance from that CG mark back or forward depending on the gear location to the center line across the table that the main gear sits on.
I measure the distance from the mains to the nose or tail wheel by starting at the center line the main gear is on along the center line that goes lengthwise on the table either back for the tail wheel or forward to the nose gear. The same thing is done for the weight placement. But in short every measurement is along with the center line for the main gear of the center line for the nose/tail wheel.
Hope this all make sense. But every plane I ever balanced with that GP CG machine never came out the same. Every plane I balanced before and then used the Xicoy, I had to take weight out. I have used the Xicoy to balance 40 size to 1/4 scale planes. So it works...
Good luck
Bill
Last edited by thebluemax; 03-13-2017 at 11:12 AM.