On a V-n (velocity versus load factor) diagram used to depict an airplane's structural and aerodynamic limits, the design maneuvering speed (Va) corresponds to which point on the chart?
- AThe point where the induced drag curve equals the parasite drag curve
- BThe intersection of the positive limit load factor line and the stall speed (CLmax) line
- CThe point where power available equals power required
- DThe intersection of the never-exceed speed line and the zero-load-factor line
Show answer & explanationAnswer & explanation
Correct answer: B. The intersection of the positive limit load factor line and the stall speed (CLmax) line
Maneuvering speed is defined on the V-n diagram as the lowest airspeed at which the airplane can develop enough lift to reach the positive limit load factor while also stalling at that exact load factor — i.e., where the CLmax (stall) curve intersects the positive limit load factor line. Above Va, the airplane can exceed limit load before stalling; below Va, it stalls before reaching limit load.
Why the other options are wrong
- A. This describes L/D max on a drag curve, unrelated to the V-n diagram's load factor limits.
- C. This describes an excess power/climb performance concept, not the V-n diagram.
- D. Vne relates to flutter/structural limits at high speed, not to maneuvering speed.
Va on the V-n Diagram
Maneuvering speed is the airspeed at which the airplane will stall exactly at the positive limit load factor, shown on the V-n diagram as the intersection of the CLmax stall curve and the limit load factor line.
- Below Va: airplane stalls before reaching limit load factor
- Above Va: airplane can exceed limit load factor before stalling
- Va decreases with decreasing weight
Memory trick: Where the stall curve meets the limit line — that's Va, your safety corner.