HULL OF AN AIRSHIP: The main structure of a rigid airship, consisting of a covered elongated framework which incloses the gas bags and which supports the nacelles and equipment. INCLINOMETER: An instrument for measuring the angle made by any axis of an aircraft with the horizontal, often called a clinometer. INSPECTION WINDOW: A small transparent window in the envelope of a balloon or in the wing of an airplane to allow inspection of the interior. KITE: A form of aircraft without other propelling means than the towline pull, whose support is derived from the force of the wind moving past its surface. LANDING GEAR: The understructure of an aircraft designed to carry the load when resting on or running on the surface of the land or water. LEADING EDGE: See Entering edge. LEEWAY: The angular deviation from a set course over the earth, due to cross currents of wind, also called drift; hence, “drift meter.” LIFT: The component of the total force due to the air resolved perpendicular to the relative wind and in the plane of symmetry. LIFT OF AN AIRSHIP: _Dynamic._—The component of the total force on an airship due to the air through which it moves, resolved perpendicular to the relative wind and in the plane including the direction of the relative wind and the longitudinal axis. _Static._—The vertical upward force on an airship when at rest in the air, due to buoyancy. LIFT BRACING: See Stay. LOAD: _Dead._—The structure, power plant, and essential accessories of an aircraft. Included in this are the water in the radiator, tachometer, thermometer, gauges, airspeed indicator, levels, altimeter, compass, watch, and hand starter. _Full._—The total weight of an aircraft when loaded to the maximum authorized loading of that particular type. _Useful._—The excess of the full load over the dead-weight of the aircraft itself. Therefore useful load includes the crew and passengers, oil and fuel, electric-light installation, chart board, gun mounts, bomb storage and releasing gear, wireless apparatus, etc. LOADING: See Wing loading. LOBES: Bags at the stern of an elongated balloon designed to give it directional stability. LONGERON: See Longitudinal. LONGITUDINAL: A fore-and-aft member of the framing of an airplane body or of the floats, usually continuous across a number of points of support. LOOP, A: An aerial maneuver in which the airplane describes an approximately circular path in the plane of the longitudinal and normal axes, the lateral axis remaining horizontal, and the upper side of the airplane remaining on the inside of the circle. MAROUFLAGE: The process of wrapping and winding wooden parts in cloth. MONOPLANE: A form of airplane which has but one main supporting surface extending equally on each side of the body. MOORING BAND: The band of tape over the top of a balloon to which are attached the mooring ropes.