What does MAC stand for in the context of CG measurements?

• A. Mean Aerodynamic Chord
• B. Maximum Airfoil Coefficient
• C. Mechanical Airframe Constant
• D. Magnetic Alignment Constant

Answer: (A)

Mean Aerodynamic Chord is the reference length used to describe where the center of gravity sits relative to the wing. It’s a single representative chord length that captures the overall aerodynamic effect of the wing’s shape and lift distribution. In CG measurements, you express the CG position as a percentage of this MAC, so comparisons and stability assessments stay consistent across different aircraft and wing geometries. The MAC is derived from the wing’s planform and how lift would be distributed along the span, making it the natural standard for tying together wing geometry and balance. The other terms don’t fit CG measurements because they refer to different concepts (like maximum lift per blade, a generic mechanical constant, or a magnetic reference), not to a wing reference length used for CG.