Definition
The airspeed at which an aircraft stalls in straight, level flight at a load factor of 1G, with no turning, pull-up, or other maneuver that would increase the apparent weight on the wings. It is the baseline stall speed published in the aircraft's performance data and serves as the reference from which stall speeds at higher load factors are calculated.
Plain English
The slowest speed at which the airplane will keep flying when it is going straight and level, not turning or pulling up. It is the standard stall speed shown in the aircraft manual.
Context Anchor
Seen in load factor discussions, especially when comparing straight, steady flight with turns, pull-ups, or other maneuvers that increase the force on the wings.
Derivation
Unaccelerated here does not mean the aircraft is not moving or not changing speed. In aerodynamics, acceleration refers to any change in the wing's load — typically from turning or pulling up. Unaccelerated simply means the wings are carrying their normal 1G load: the aircraft's actual weight, nothing more.
Why Pilots Care
It gives the baseline stall speed used to calculate safe speeds for normal flight; any maneuver that raises load factor above 1G increases the actual stall speed.
Analogy
Think of unaccelerated stalling speed as the starting reference mark on a ruler. Once the airplane is made to carry extra force in a maneuver, the stall-speed mark moves higher.
Grounding Statement
In straight, steady flight the wings only need to support the airplane’s normal weight, but in a hard turn or pull-up they must support more force, so the stall can happen at a higher speed.
Intuition Check
Do not read “unaccelerated” as only “not speeding up.” In this context, it also means not changing direction or being maneuvered in a way that adds extra load to the wings.
Example Sentence 1
The pilot referenced the unaccelerated stalling speed in the POH before calculating how much margin to add for a steep turn.
Example Sentence 2
In calm air the airplane’s unaccelerated stalling speed stayed constant until the pilot entered a turn and load factor rose.