The leading edge is the part of the wing that first contacts the air;Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 305. Aviation Supplies & Academics, 1997. alternatively it is the foremost edge of an
airfoil
An airfoil (American English) or aerofoil (British English) is a streamlined body that is capable of generating significantly more Lift (force), lift than Drag (physics), drag. Wings, sails and propeller blades are examples of airfoils. Foil (fl ...
section. The first is an aerodynamic definition, the second a structural one.
As an example of the distinction, during a
tailslide
The tailslide is an aerobatic maneuver that starts from level flight with a loop up into a straight vertical climb (at full power) until the aircraft loses momentum. When the aircraft's speed reaches zero and it stops climbing, the Pilot (aerona ...
, from an aerodynamic point of view, the
trailing edge
The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge meets.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 521. Aviation Supplies & Academics, 1997. ...
becomes the leading edge and vice versa but from a structural point of view the leading edge remains unchanged.
Leading edge extension
A leading-edge extension (LEX) is a small extension to an aircraft wing surface, forward of the leading edge. The primary reason for adding an extension is to improve the airflow at high angle of attack, angles of attack and low airspeeds, to im ...
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Leading edge slats
A slat is an aerodynamic surface on the leading edge of the wing of a fixed-wing aircraft. When retracted, the slat lies flush with the rest of the wing. A slat is deployed by sliding forward, opening a slot between the wing and the slat. Air from ...
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Leading edge slot
A leading-edge slot is a fixed aerodynamics, aerodynamic feature of the wing of some aircraft to reduce the Stall (flight), stall speed and promote good low-speed handling qualities. A leading-edge slot is a spanwise gap in each wing, allowing ai ...
Vortex generator
A vortex generator (VG) is an aerodynamic device, consisting of a small wikt:vane, vane usually attached to a lifting surface (or airfoil, such as an aircraft, aircraft wing) or a rotor blade of a wind turbine.leading edge radius and leading edge stagnation point.
Seen in plan the leading edge may be straight or curved. A straight leading edge may be swept or unswept, the latter meaning that it is perpendicular to the longitudinal axis of the aircraft. As wing sweep is conventionally measured at the 25% chord line an unswept wing may have a swept or tapered leading edge. Some aircraft, like the General Dynamics F-111, have swing-wings where the sweep of both wing and leading edge can be varied.
In high-speed aircraft, compression heating of the air ahead of the wings can cause extreme heating of the leading edge. Heating was a major contributor to the destruction of the
Space Shuttle Columbia
Space Shuttle ''Columbia'' (OV-102) was a Space Shuttle orbiter manufactured by Rockwell International and operated by NASA. Named after the Columbia Rediviva, first American ship to circumnavigate the globe, and the Columbia (personification) ...
during re-entry on February 1, 2003.
Sail boats
When sailing into the wind, the dynamics that propel a
sailboat
A sailboat or sailing boat is a boat propelled partly or entirely by sails and is smaller than a sailing ship. Distinctions in what constitutes a sailing boat and ship vary by region and maritime culture.
Types
Although sailboat terminology ...
forward are the same that create lift for an airplane. The term leading edge refers to the part of the sail that first contacts the wind. A fine tapered leading edge that does not disturb the flow is desirable since 90% of the drag on a sailboat owing to sails is a result of vortex shedding from the edges of the sail. Sailboats utilize a mast to support the sail. To help reduce the drag and poor net sail performance, designers have experimented with masts that are more aerodynamically shaped, rotating masts, wing masts, or placed the mast behind the sails as in the mast aft rig.