What is the stall speed in clean configuration referred to as?

The stall speed in clean configuration is referred to as VS1. This term specifically denotes the minimum speed at which an aircraft can maintain controlled flight in a straight line and level configuration, which typically means the aircraft is not in a landing or approach configuration with flaps extended or landing gear down.

Understanding VS1 is crucial for pilots since it provides essential data for safe flight operations, particularly when maneuvering in clean conditions. It informs pilots of the threshold speed at which the aircraft will stall, allowing them to maintain proper airspeed and avoid situations that could lead to a stall despite being in a clean configuration.

The other terms are distinct from VS1: VSO refers to stall speed in landing configuration, VLE indicates maximum landing gear extended speed, and VA signifies maneuvering speed, each serving different purposes in flight safety and aircraft performance.