What is described as the angle between the chord line and the longitudinal axis of an aircraft?

The angle described as the angle between the chord line and the longitudinal axis of an aircraft is known as the angle of incidence. This angle is an important aerodynamic parameter because it affects the lift characteristics of the wing while the aircraft is in flight. The chord line of a wing is an imaginary straight line extending from the leading edge to the trailing edge, and the longitudinal axis of the aircraft is an imaginary line that runs from the nose to the tail.

When the angle of incidence is designed into an aircraft, it allows for a specific aerodynamic behavior at various speeds and configurations, which contributes to the overall stability and performance of the aircraft. This angle is typically set during the manufacturing of the aircraft and is meant to optimize the wing's ability to generate lift without causing excessive drag or stall at normal operating speeds.

In contrast to the angle of incidence, the angle of attack refers to the angle between the chord line of the wing and the oncoming airflow or relative wind during flight, and it can vary based on the flight conditions. The terms angle of elevation and angle of descent are related to the aircraft's flight path rather than its aerodynamic properties.