What does planform refer to in aviation?

Planform refers to the shape or outline of an aircraft wing when viewed from above, on a horizontal plane. This characteristic is crucial in aerodynamics as it influences the lift and drag properties of the aircraft. The planform shape can vary significantly between different aircraft designs, impacting the aircraft's performance characteristics, including stability and maneuverability.

Understanding the planform is essential in aircraft design and performance analysis, as it directly affects how the air flows over the wing. Factors such as wing area, aspect ratio, and taper are all components of the wing's planform that designers consider to ensure optimal aerodynamic efficiency.

The other aspects mentioned, like the thickness and material of the wing, though important for structural integrity and performance, do not define the planform itself. Similarly, cruising speed and landing trajectory relate to flight dynamics but do not pertain to the visual and geometric attributes of the wing's outline as seen from above.