The following are the principal terms which have come into use in the development of aeronautics and are new and peculiar to the subject.
Aerofoil, a thin wing-like structure, flat or curved, designed to obtain reaction upon its surfaces from the air through which it moves.
Aeroplane, a form of aircraft heavier than air which has wing surfaces for sustentation, with stabilizing surfaces, rudders for steering, and power plant for propulsion through the air. The landing gear may be suited for either land or water use.
Pusher. A type of airplane with the propeller or propellers in rear of the wings.
Tractor. A type of airplane with the propeller or pro pellers in front of the wings.
Aileron, a movable auxiliary surface used for the control of rolling motion i. e., rotation about the fore and aft axis.
Air-Speed Metre, an instrument designed to measure the velocity of an aircraft with reference to the air through which it is moving.
Altimetre, an instrument mounted on an aircraft to con tinuously indicate its height above the surface of the earth. Ballonet, a small balloon within the interior of a balloon or dirigible for the purpose of controlling the ascent or descent, and for maintaining pressure on the outer envelope to prevent deformation. The Ballonet is kept inflated with air at the required pressure, under the control of a blower and valves.
Balloon, a form of aircraft comprising a gas bag and a car, whose sustentation depends on the buoyancy of the contained gas, which is lighter than air.
Captive. A balloon restrained from free flight by means of a cable attaching it to the earth.
Kite. An elongated form of captive balloon, fitted with tail appendages to keep it headed into the wind, and deriving increased lift due to its axis being inclined to the wind.
Bank, to incline an airplane laterally i. e., to rotate it about the fore and aft axis. Right bank is to incline the airplane with the right wing down.
Barograph, an instrument used to record variations in barometric pressure. In aeronautics the charts on which the records are made are prepared to indicate altitudes directly instead of barometric pressure.
Biplane, a form of airplane in which the main supporting surface is divided into two parts, one above the other.
Body of an Airplane, a structure, usually inclosed. which contains in a stream line housing the power plant, fuel, pas sengers, etc.
Cambre, the convexity or rise of a curve of an aerofoil from ita chord, usually expressed as the ratio of the maximum departure of the curve from the chord as a fraction thereof. " Top Cambre " refers to the to surface of an aerofoil, and " Bottom Cambre " to the bottom surface; " Mean Cambre " is the mean of these two.
Capacity, Lifting. The maximum flying load of an aircraft.
Carrying. Excess of the lifting capacity over the dead load of an aircraft, which latter includes structure, power plant, and essential accessories.
Centre, the point in which a set of effects is assumed to be accumulat, producing the same effect as if all were con centrated at this point.
Of buoyancy. The centre of gravity of the fluid dis placed by the floating body.
Of pressure of an aerofoil. The on the chord of an element of an aerofoil, prolonged if necessary, through which at any instant the line of action of the resultant air force passes.
Of pressure of a body. The point on the axis of a body longed if necessary, through which at any instant the line of action of the resultant air force passes.
Chord, Of an aerofoil section. A right line tangent to the under curve of the aerofoil section at the front and rear. Length. The length of the chord is the length of the aerofoil section projected on the chord, extended if neces sary.
Controls, a general term applying to the means provided for operating the devices used to control speed, direction of flight and altitude of an aircraft.
Dirigible, a form of balloon, the outer envelope of which is of elongated form, provided with a propelling system. car, rudders and stabilizing surfaces.