Subsonic

Parasite Drag

All drag that is not associated with the production of lift.

Induced Drag

The portion of total drag associated with the production of lift.

Airfoil

A streamline body that produces more lift than drag when set at a suitable angle of attack.

Mean Camber Line

The line joining the midpoints between the upper and lower surfaces of an airfoil.

Chord Line

The line joining the endpoints of the mean camber line.

Maximum Thickness

The largest distance between the upper and lower surfaces of the airfoil, measured perpendicular to the chord line.

Thickness Ratio

The maximum thickness to the chord ratio; determines the aerodynamic efficiency of an airfoil.

Maximum Chamber

The maximum distance of the mean camber line from the chord line.

Leading Edge Radius

The radius of a circle tangent to the upper and lower surfaces at the leading edge.

Pressure Coefficient

A dimensionless number that describes the relative pressures throughout a flow field.

Critical Pressure

Vapor pressure of a fluid at the critical temperature, where distinct liquid and gas phases do not exist.

Critical Pressure Coefficient

The pressure coefficient of the point of minimum pressure on an airfoil section.

Critical Velocity

The velocity at which the liquid flow changes from streamlined to turbulent.

Geometric Wingspan

The distance between tip to tip of the wing, measured perpendicular to the airplane wing centerline.

Wing Area

The projection of the planform on a plane of reference, usually the chord plane.

Aspect Ratio

A measure of how long and slender a wing is, defined as the square of the span divided by the wing area.

Low Aspect Ratio Advantages

High maneuverability, compact design, better for high-speed flight, and structural strength.

Low Aspect Ratio Disadvantages

Low lift to drag ratio, increased fuel consumption, poor glide performance, and less stability at low speeds.

High Aspect Ratio Advantages

High lift to drag ratio, efficient for cruise and glide, improved stability, and good for soaring.

High Aspect Ratio Disadvantages

Structural challenges, reduced maneuverability, limited low-speed applications, and operational limitations.

Taper Ratio (λ)

The ratio of the tip chord (ct) to the root chord (cr).

Mean Aerodynamics Chord

The average chord length of a tapered, swept wing.

Total Drag Coefficient (CD)

The sum of all individual drag components acting on an aircraft or object.

Oswald Efficiency Factor

A factor that reduces the estimated induced drag for real-world wings, improving fuel efficiency and reducing drag.

Compressibility Effect (Va)

The effects of compressibility that influence aerodynamic forces at high speeds.

Dynamic Viscosity (μ)

The coefficient of dynamic viscosity that affects fluid flow characteristics.

Air Density (ρ)

A factor affecting the aerodynamic forces, representing the mass per unit volume of air.

Velocity of air (V)

Speed of the air relative to the aircraft, a critical factor in determining lift and drag.

Maximum Thickness Ratio

Max thickness divided by the chord length; important for aerodynamic efficiency.

Leading Edge Design

The design of the leading edge affects the airflow and lift generation across the wing.

Stability at Low Speeds

Ability of the aircraft to maintain control without excessive input; varies with aspect ratio.

Fuel Efficiency

How effectively an aircraft uses fuel, closely linked to lift-to-drag ratios.

Lift-to-Drag Ratio

A measure of the efficiency of the wing, comparing the lift produced to the drag experienced.

Structural Efficiency

The effectiveness of the wing design in providing structural integrity while minimizing drag.

Aerodynamic Resistance

The overall resistance experienced by an object moving through a fluid.

Flow Field Pressure Distribution

Variation of pressure in the fluid surrounding an airfoil during operation.

Transonic Flight

Flight conditions where airflow around an object reaches transonic speeds, affecting pressure distribution.

Wing Design Impact

The influence of wing shape and configuration on the overall performance and efficiency of flight.

Dynamic Stability

The capability of an aircraft to return to its original flight path after a disturbance.