Understanding Aerodynamics and Aircraft Flight

Aerodynamics

The study of the properties of moving air, and especially of the interaction between the air and solid bodies moving through it.

Airfoil

A structure with curved surfaces designed to give the most favorable ratio of lift to drag in flight, used as the basic form of the wings, fins, and horizontal stabilizer of most aircraft.

Angle of Attack

Is the angle between the oncoming air or relative wind and a reference line on the airplane or wing.

Angle of Incidence

The acute angle the wing chord makes with the longitudinal axis of the aircraft is called the angle of incidence, or the angle of wing setting. A Chord Line is a line depicting the chord which extends forward of the leading edge.

Boundary Layer

On an aircraft wing the boundary layer is the part of the flow close to the wing, where viscous forces distort the surrounding non-viscous flow.

Chord

The width of the wing from the leading edge apex to the trailing edge.

Drag

The force that exerts a braking action to hold the aircraft back. Drag is a backward deterrent force and is caused by the disruption of the airflow by the wings, fuselage, and protruding objects.

Dutch Roll

A type of aircraft motion, consisting of an out-of-phase combination of 'tailwagging' and rocking from side to side.

Glide Ratio

The distance the airplane will, with power off, travel forward in relation to the altitude it loses.

Glide Angle

The angle between the plane of the horizon and the path of a glider or airplane; especially: the least angle at which a glider or airplane which glide to earth in still air.

Lift Coefficient

Is a ratio between lift pressure and dynamic pressure and is a function of the shape of the wing and angle of attack.

Mach Number

The ratio of the true airspeed of the aircraft to the speed of sound in the same atmospheric conditions.

Shock Wave

Typically associated with supersonic aircraft, however, they also form on an aircraft traveling at less than the speed of sound.

Stall

Results from a rapid decrease in lift caused by the separation of airflow from the wing’s surface brought on by exceeding the critical AOA. A stall can occur at any pitch attitude or airspeed.

Subsonic

The term describes an aircraft that flies below its critical Mach number.

Supersonic

The term describes an aircraft that flies above its critical Mach number.

Vortex Generators

Is an aerodynamic device, consisting of a small vane usually attached to a lifting surface, such as an aircraft wing.

Vortex

A mass of whirling fluid or air, especially a whirlpool or whirlwind.

Wave Drag

Is a force, or drag that retards the forward movement of an airplane, in both supersonic and transonic flight, as a consequence of the formation of shock waves.

Winglet

A small vertical surface at the tips of the wings. They help direct the turbulent airflow that all wings have at the tips. They make the wings more efficient.

Yawing

Movement nose of a/c deflecting rudder.