Weight and Balance


Xicoy CG Machine blue tooth to iPad works well for measuring and adjusting CG. The lines on the table are where I use a T-square to mark location of landing gear and CG locations relative to the gear. (There have been lots of jets measured on this table.) The distance between the mains and nose gear and the distance the desired CG is forward of the main gear are entered into the system. The system then gets weight on each gear and calculates the actual CG relative to the desired CG. Then you can move stuff around and try to get the desired CG. Once I get the desired CG I always fill the tanks to get the take off weight and CG. Then I defuel and make sure the CG is still acceptable as fuel is removed. When the tank is not exactly on the CG it is valuable to know how the CG shifts with fuel burn.


This is the empty weight with full air trap, all external ordinance, and 1.25oz or 35g of lead weight in the nose cone. The factory CG marked on the bottom of the bottom of the wings is 90mm forward of the mains. The CG here shows 60mm forward of the main gear which is my desired CG. This CG is 30mm behind the marks which is where I will start based on multiple reports in other forums. Some of the EDF guys are flying at 40-50mm behind the factory marks so I will fly first and probably remove some of the nose weight after that.


This is take off weight with all tanks full. CG moves forward 4mm which is completely acceptable. As the aft tank empties the CG shifts 6mm forward when the front tank is full. As the front tank empties the CG moves back to toward 60mm. I expect landing CG will be 61-63mm forward of the mains. Looks good to me for a safe flight. After the first flight CG can be adjusted as necessary.