Definition
VY is the airspeed that produces the greatest gain in altitude per unit of time. At VY, the airplane has the maximum excess power available — the difference between the power the engine is producing and the power required for level flight is at its greatest — which the airplane converts into climb rate measured in feet per minute.
Plain English
VY is the speed that gets you the most altitude in the shortest amount of time. Fly at VY when you want to climb up as fast as possible measured by the clock.
Context Anchor
You will see VY in climb performance discussions, takeoff procedures, and the airplane’s handbook when choosing the right climb speed after liftoff.
Derivation
The 'V' stands for velocity, the standard aviation symbol for a defined airspeed. The 'Y' is simply a letter assigned by convention to distinguish this speed from others like VX (best angle of climb) or VS (stall speed). The subscript letters do not stand for words — they are labels.
Why Pilots Care
Selecting VY allows the airplane to reach a safe altitude as quickly as possible, which improves obstacle clearance margins and overall departure efficiency.
Grounding Statement
At VY, the airplane is gaining altitude as fast as it can per minute under the current conditions.
Intuition Check
Best rate does not mean the steepest climb path. It means the most altitude gained per minute.
Example Sentence 1
After takeoff and once clear of obstacles, the pilot lowered the nose slightly and accelerated to VY for the climb to cruise altitude.
Example Sentence 2
With a high density altitude the pilot verified the correct VY speed in the performance section before beginning the climb.