How is a Aircraft Load Balance Graph drawn or computed?

Balance Graph is a allowed Center of gravity range envelope plotted by Aircraft Weight in y-axis against the Center of Gravity in x-axis.





This is used to find whether the actual Center of gravity is within the allowed range as defined by the balance graph.|||You've asked a question that takes about a week to explain. I'll not get into the details but basically there is a center of gravity envelope that the cg must fall into before takeoff. This envelope has two axis as you suggest, weight and moment arm. You begin with the basic operating weight or for a light aircraft the empty weight and the BOW cg or empty weight cg. Then as you load things, passengers or cargo, they end up at some aircraft station which is a point measured in inches from the datum. The length of this station from the datum in inches is the arm. Multiply the weight of the object time this arm and you get a moment. You do this with each item or person you load. When you are loaded up, add up all of the moments that you calculated and add that total to the empty weight or BOW moment. Now you have the total moment to plot on the X axis. Next add up all of the weights of things that you loaded and add that to the BOW or empty weight and you now have the total weight of the aircraft with it's load. This is the zero fuel weight. Add in the weight of the fuel using the same principal and you now have the ramp weight and center of gravity. After taxiing out to the runway, you will now be at the takeoff weight and cg moment and hopefully that falls within the forward and aft limits of the cg envelope and ofcourse below the max takeoff weight. There's more to it but that's it in a nutshell. I don't have a week to kill.|||To be properly balanced an airplane's center of gravity must fall between the leading edge of the mean aerodynamic chord or LEMAC and the trailing edge of the mean aerodynamic chord or TEMAC. The mean aerodynamic chord or MAC being the center point where lift is generated.





A center of gravity graph defines what your LEMAC and TEMAC are. You just need to ensure that when you upload and download weight from any aircraft that your center of gravity remains within the aircraft's center of gravity design limitations|||for airplanes.. the closer is the center of gravity to the tail, the weaker is the turn momentum of tail controls. thus the craft is dumber. your test pilots state where is the limit to this.similarily moving the CoG towards the nose closes it to the aerodynamic lift acting point of the wing, thus destabilising the craft. /these work with the stabile plane, not unstable like f16/





helicopters state primarily the cabin loading, to keep the center of gravity within the range allowing the controlled flight. Out of these values the center of gravity is too apart from the lift from the main rotor thus even the full control inputs can not allow you to control the helicopter /having tail heavy heli results in inability to point the nose down and vice versa./