Definition
VY is the airspeed that produces the greatest gain in altitude per unit of time. At VY, the aircraft has the largest excess power available, meaning the difference between the power the engine is producing and the power required to maintain level flight is at its maximum. Flown at full climb power, VY delivers the fastest possible climb measured in feet per minute.
Plain English
VY is the speed that gets you the most altitude in the shortest amount of time. If you want to be high quickly, fly VY.
Context Anchor
You will see VY in climb performance discussions, aircraft operating handbooks, and during normal climbout after takeoff when the goal is to gain altitude efficiently.
Derivation
The 'V' in V-speeds comes from the French word vitesse, meaning speed. The subscript 'Y' is simply a label the FAA and ICAO use to distinguish this particular climb speed from others like VX (best angle of climb). Knowing the V stands for 'speed' helps make sense of the whole family of V-speeds you will meet.
Why Pilots Care
Maintaining VY allows the fastest possible altitude gain, which helps clear obstacles, avoid traffic, and reach a safe altitude quickly.
Analogy
Think of VY as the elevator setting that gets you to a higher floor in the least time, not the path that moves you away from the building at the steepest angle.
Intuition Check
Best rate means most altitude gained per minute. It does not mean the steepest climb path over the ground; that is a different climb speed.
Example Sentence 1
After liftoff and once clear of any obstacles, the pilot pitched for VY to climb efficiently to cruise altitude.
Example Sentence 2
The performance chart showed that holding VY produced a 900 feet-per-minute climb rate.