An aircraft’s ability to defy gravity relies on the design of its wings. These components are shaped to interact with airflow, generating lift. The curvature of the wing, known as camber, plays a significant role in flight.
Defining Wing Camber
Camber refers to the curvature of an airfoil, the cross-sectional shape of an aircraft wing. This curvature can be visualized by imagining a line from the leading (front) edge to the trailing (back) edge. The mean camber line is an imaginary line equidistant from the upper and lower surfaces.
The shape of this mean camber line defines the airfoil’s characteristics. Airfoils can exhibit positive, negative, or zero camber. Positive camber, where the upper surface is more convex, is most common for generating lift. Zero camber describes a symmetrical airfoil, where upper and lower surfaces are identical, and the mean camber line aligns with the chord line, a straight line connecting the leading and trailing edges. Negative camber means the mean camber line curves downwards.
Camber’s Contribution to Lift
Camber influences how a wing generates lift by affecting airflow and pressure distribution. As air flows over a cambered wing, the curved upper surface forces the air to travel a greater distance than air moving along the flatter lower surface. This difference causes air above the wing to accelerate, resulting in lower pressure, while air below the wing slows, leading to higher pressure. This pressure differential creates an upward force.
This phenomenon is explained by Bernoulli’s principle: an increase in fluid velocity corresponds to a decrease in static pressure. The lower pressure above and higher pressure below the wing pushes the airfoil upward, generating lift. Even at a zero angle of attack, a cambered airfoil can produce lift due to its shape, unlike a symmetrical airfoil which requires an angle of attack. Wings with greater camber produce more lift.
Camber in Aircraft Design
The application of camber in aircraft design is tailored to an aircraft’s purpose and operational speeds. Aircraft designed for slower flight, such as gliders or cargo planes, feature pronounced camber to maximize lift at lower speeds. This allows them to generate substantial lift without high forward velocities. High-speed aircraft, like fighter jets, use airfoils with minimal or zero camber and sharp leading edges to reduce drag and maintain speed.
Modern aircraft utilize adjustable camber to optimize performance. Leading-edge slats and trailing-edge flaps are devices that can extend and pivot to change the wing’s curvature during flight. Deploying these devices increases the wing’s camber and surface area, enhancing lift for takeoff and landing, allowing for slower approach speeds and shorter runway requirements. Retracting them for cruise flight minimizes drag. This variable camber technology allows aircraft to achieve optimal aerodynamic performance across flight conditions.