How is constraint analysis used in aircraft sizing?

Constraint analysis determines acceptable design space by plotting thrust-to-weight ratio vs wing loading. Each performance requirement creates a boundary: Takeoff - T/W increases with W/S (higher loading needs more thrust for same field length); Landing - W/S upper limit (approach speed/field length); Climb - T/W lower limit for required climb gradient; Cruise - Achievable T/W and W/S combinations for required altitude and speed; Sustained turn - T/W required for specified g-load at altitude; and Ceiling - T/W required for specified climb rate at altitude. The feasible design space is bounded by all constraints. Optimum design typically minimizes weight at the intersection of most constraining requirements. Analysis is repeated for different design points (altitude, speed, weight) to find global optimum. Constraint diagrams guide initial sizing before detailed analysis.