What does the V-n diagram primarily illustrate?

• A. The relationship between airspeed and load factor limits for structural safety.
• B. The relationship between airspeed and maximum thrust.
• C. The relationship between altitude and fuel burn.
• D. The relationship between airspeed and stall speed.

Answer: (D)

A V-n diagram maps the safe combinations of speed and load factor, showing how high you can pull the airplane without overstressing the structure and where stall will occur. The stall boundary on this diagram shifts with the required lift, so as you increase the load factor, you must fly faster to avoid stalling. That makes the diagram a direct illustration of how airspeed and stall speed relate to each other under different flight loads. While it also encodes structural limits, the key takeaway is how stall speed changes with airspeed (and load factor), which is why this option is the best description.