Overview
This lecture introduces fundamental aviation terminology essential for understanding the basic principles in the theory of flight.
Basic Airfoil Concepts
- An airfoil is a curved structure designed to produce lift, including both wings and propellers.
- Wings create upward lift; propellers generate thrust (forward lift).
Key Structural Terms
- The leading edge is the front of the airfoil.
- The trailing edge is the rear of the airfoil.
- The chord line is an imaginary straight line from the leading edge to the trailing edge.
- Camber refers to the airfoil’s curvature; upper and lower cambers describe the top and bottom curves, and the mean camber is their average.
Wing Dimensions and Shapes
- Wingspan is the distance from one wingtip to the other.
- Wing area is calculated by multiplying the average length by the average width (like a rectangle).
- Plan form is the shape of the wing as seen from above.
- Aspect ratio is the ratio of wingspan to average wing chord; high aspect ratios reduce drag (common in gliders), low ratios improve maneuverability (common in fighter jets).
Wing Angles and Airflow
- Angle of incidence is the angle between the chord line and the aircraft’s longitudinal (lengthwise) axis; it is usually fixed.
- Relative airflow is the direction of airflow relative to the wing, opposing the aircraft’s motion and can change with maneuvers.
- Angle of attack is the angle between the chord line and the relative airflow, critical for aircraft performance and safety.
Key Terms & Definitions
- Airfoil — A curved surface designed to generate lift when moving through air.
- Leading edge — The front edge of an airfoil.
- Trailing edge — The rear edge of an airfoil.
- Chord line — A straight line joining the leading and trailing edges.
- Camber — Curvature of the airfoil’s upper or lower surface.
- Wingspan — Distance from one wingtip to the other.
- Wing area — The surface area of the wing.
- Plan form — The outline shape of a wing viewed from above.
- Aspect ratio — Wingspan divided by average wing chord.
- Angle of incidence — Angle between chord line and longitudinal axis.
- Relative airflow — Air movement direction relative to the wing.
- Angle of attack — Angle between chord line and relative airflow.
Action Items / Next Steps
- Review and memorize these basic terms before moving on to more complex topics in aviation theory.