[Illustration: Aircraft over the Wright memorial shaft.] _Administration_ Wright Brothers National Memorial is administered by the National Park Service, U.S. Department of the Interior. A superintendent, whose address is Kill Devil Hills, N.C., is in immediate charge. _Glossary_ _Aileron_—A control surface set into or near the trailing edge of an airplane wing, extending, when in the wing, toward the tip and usually within the contour of the wing, and used to control the longitudinal axis of an airplane. _Airborne_—Of an airplane or other winged craft: Supported entirely by aerodynamic forces, flying. _Airfoil_—A surface or body, as a wing, propeller blade, rudder, or the like, especially designed to obtain a reaction, as lift or thrust, from the air through which it moves. _Angle of attack_—The acute angle between the chord of an airfoil, and a line representing the undisturbed relative airflow. Any other acute angle between two reference lines designating the cant of an airfoil relative to oncoming air. _Aspect ratio_—The ratio between the span of an airfoil and its chord. _Camber_—The curve of an airfoil section from the leading edge to the trailing edge. Camber is usually expressed as the distance from the chord line to the upper or lower surface of an airfoil. _Center-of-pressure travel_—The movement, or the amount of movement, of the center of pressure along a chord of an airfoil as the latter is inclined through its normal angles of attack. _Chord_—An assumed straight-line tangent to the lower surface of an airfoil section at two points, or a straight line between the leading and trailing edges of an airfoil section, or between the ends of the mean line of an airfoil section; the distance between the leading and trailing edges of an airfoil section. _Drag_—A resistant force exerted in a direction opposite to the direction of motion and parallel to the relative gas or air Stream. _Dynamic lift_—The lift given an airplane by the aerodynamic force produced from an adequately designed airfoil. _Glider_—A fixed-wing aircraft having no power plant and constructed so as to glide and soar. _Gliding_—The art, science, and activity of moving through the air in a glider. _Heavier-than-air aircraft_—Any aircraft weighing more than the air it displaces. _Lift_—That component of the total aerodynamic forces acting on an airfoil or on an entire aircraft or winged missile, perpendicular to the relative wind, and exerted, normally, in an upward direction opposing the pull of gravity. _Lighter-than-air aircraft_—An aircraft that rises and is supported in air by virtue of a contained gas weighing less than the air displaced by the gas. _Nose dive_—A steep dive by, or in, an aircraft.