Definition
VX is the airspeed that produces the greatest gain in altitude over the shortest horizontal distance. It is flown when the priority is clearing an obstacle in the climb path rather than reaching altitude in the least time. VX is slower than VY (best rate of climb speed) and yields a steeper climb angle but a lower rate of climb in feet per minute.
Plain English
VX is the speed that gets you the most height for the least ground distance covered. You use it when you need to climb steeply, like getting over trees or a building at the end of the runway.
Context Anchor
You will see VX in the airplane’s handbook, takeoff planning, obstacle-clearance discussions, and initial climb procedures.
Derivation
The 'V' stands for velocity (speed), and the 'X' is simply a letter chosen by convention to designate this particular speed in the V-speed system. Knowing 'V' means speed helps you read the whole family of V-speeds (VX, VY, VS, VNE, etc.) as different specific airspeeds.
Why Pilots Care
It gives the steepest climb path, allowing an airplane to clear nearby obstacles such as trees or power lines after takeoff.
Analogy
VX is like choosing a steep hiking trail to gain height quickly over a short distance. It gets you upward in less ground distance, but it is not the fastest way to cover the whole climb.
Intuition Check
“Best angle” does not mean best overall climb. It means the steepest climb path over the ground; “best rate” is the speed for gaining altitude fastest over time.
Example Sentence 1
After rotation on the short runway, the pilot pitched for VX to clear the trees off the departure end before lowering the nose to VY.
Example Sentence 2
On a short-field takeoff with obstacles, the pilot maintained VX until all terrain was cleared.