Manoeuvring Envelope (V-n Diagram)
The V-n Diagram
A graph plotting Load Factor (n) on the Y-axis vs Airspeed (V) on the X-axis.
Boundaries
- Stall Limit (High Lift Limit): The curved line on the left. The aircraft creates maximum lift at $C_{Lmax}$. You cannot pull more gs than this line allows (the wing will stall).
- Structural Limit (Limit Load): The flat top/bottom lines (e.g., +2.5g or +3.8g). Exceeding this causes permanent deformation.
- Ultimate Load: Usually 1.5x the Limit Load. The point of structural failure.
Corner Speed (Va)
The intersection of the Stall Limit line and the Structural Limit line.
- At $V_A$, the aircraft stalls just as it hits the limit load factor.
- It is the fastest speed at which the aircraft will stall before it breaks.
- Formula: $V_A = V_{S1} \sqrt{n_{limit}}$
High Speed Limits
- Vne / Vd: The vertical line on the right defining the maximum speed.