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Dictionary Of Aeronautics


The new science of aeronautics has given rise to many new words, among

them some of awkward derivation, and even those properly formed and

worthy of preservation in the language are often erroneously used. The

following compact lexicon is therefore both interesting and instructive:



Aeroplane--A generic term applied in common use to all classes of

sustaining surfaces; strictly applicable only to flat surfaces.
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Adjusting Surfaces--Commonly a comparatively small surface, usually at

the end of a wing tip, used to adjust lateral balance; preferably

restricted to surfaces capable of variable adjustment, but not of

movement by controlling devices. See Stabilizer' and Wing tip and

compare Aileron.



Advancing Edge--The front edge of a sustaining or other surface.



Advancing Surface--A surface that precedes another through the air, as

in a double monoplane.



Aerocurve--A proposed substitute for aeroplane.



Aerodrome--A substitute proposed by Langley for aeroplane. Strictly

applicable to a course rather than to a vehicle.



Aileron (a'ler-on)--A small hinged or separated wing tip or surface

capable of independent manipulation for the purpose of maintaining

lateral balance.



Aviation (a-vi-a'shun)--Dynamic flight by means of heavier-than-air

mechanisms.



Aviator (a'vi-a-ter)--The operator or pilot of a heavier-than-air

machine.



Aerofoil--Term used to indicate lifting surface,



Angle of Incidence--The angle which a line drawn from the leading to the

trailing edge of the plane makes with the horizontal trailing angle

between the tangent to the trailing edge of the plane and the chord or a

line drawn from the leading to the trailing edge.



Arc--Any portion of a circle or other curve.



Aspect--The top or plan view of an aeroplane surface.



Automatic Stability--Applied to lateral or longitudinal stability

maintained by the action of suitable elements on mechanisms independent

of any control exercised by the operator. There is a tendency to

restrict the term to such stability secured by automatic manipulation of

controlling devices, rather than to systems in which balance is

maintained by the use of dihedral arrangements.



Biplane (bi'plane)--An aeroplane with two superposed main surfaces.



Balance--To maintain equilibrium by hand or automatic movement of

balancing surfaces, as opposed to equilibrium maintained by stabilizing.

See Stabilizer.



Body--The center part of an aeroplane or other aerial vehicle, in which

the motor, fuel tanks, passenger accommodation, etc., are placed.



Camber--The camber of the ribs is the amount of curvature which is

imparted to them in the same way that a motor car spring or a road has a

camber or curvature.



Chassis (shas-see)--That part of the main framework of a monoplane to

which the main planes and tail planes are fitted and which contains the

engine and aviators seat.



Center of Pressure--Really a line of pressure along the under side of a

wing or aeroplane surface, on either side of which the pressures are

equal.



Center of Gravity--The center of weight, about which the vehicle

balances in all directions.



Chord--A straight line drawn between the ends of the arc of a circle or

other curve.



Dirigible (dir'-igihle)--Steerable or navigable; applied to balloons.



Derrick--A tower in which a falling weight is dropped in starting an

aeroplane.



Diagonal--A diagonal brace or stay in a framework.



Dihedral (di-he'dral)--Said of wing pairs inclined at an upward angle to

each other.



Elevator--A principal supplementary surface, usually of a miniature form

of the main planes. Used for purpose of altering the vertical direction

of machine.



Gap--The distance between two main planes in a biplane.



Gliding--Flying down a slant of air without power.



Gyroscopic Effect--The property of any rotating mass whereby it tends to

maintain its plane of rotation against disturbing forces.



Gauchissement (or warping)--Applied to the main planes and produces the

same ultimate effect as the use of ailerons.



Hangar (hang'ar)--A shed for housing balloons or aeroplanes, generally

the latter.



Horsepower--A rate of work equivalent to the lifting of 33,000 ft.-lb. a

minute.



Head Resistance--The resistance of a surface to movement through the

air; closely proportionate to its projected area.



Heavier-than-air--Applied to dynamic flying machines weighing more than

the air they displace.



Horizontal Rudder--A horizontally placed rudder for steering in vertical

directions.



Lift--The sustaining effect, expressed in units of weight of an

aeroplane or wing surface.



Monoplane--An aeroplane with one or more main surfaces in the same

horizontal plane.



Main Plane--Usually the largest or lowest supporting surface of a

multi-surfaced aeroplane.



Mast--A spar or strut used for the attachment of wire or other stays to

stiffen the wings or other parts of a structure.



Main Spars--Lateral spars upon which the main planes are built.



Main Landing Wheels--In an alighting gear, the wheels that take the

chief shock in landing.



Ornithopter--A dynamic flying machine of the heavier-than-air type, in

which sustension is provided by the effect of reciprocating wing

surfaces.



Pylon--A tower to mark the course in aerial racing contests.



Ribs--Supports for the fabric, made of ash or spruce and bent to the

correct curves.



Rudder--One or more steering planes are invariably fitted to practical

machines to control the direction of flight.



Superposed Planes--Arrangement of one plane over the other, as in the

Wright, Voisin and Farman machines.



Supplementary Planes (or surfaces)--Additional surfaces which are used

for stabilization.



Stabilizer--Any surface for automatically maintaining lateral or

longitudinal balance.



Struts--Fixtures used in biplane construction to maintain an equal

distance between two planes.



Skids--Long skates on which the machine can land in safety.



Span--The distance from tip to tip of the main planes in a transverse

direction to that of flight.



Soaring Flight--The flight of certain large birds without wing flapping.

Its solution and imitation constitute one of the problems of aerial

navigation.



Sustaining Surface--Any surface placed in a horizontal or approximately

horizontal position, primarily for the purpose of affording sustension.



Triplane--An aeroplane with three main surfaces.



Webs--Small blocks of wood placed between the ribs which act as distance

pieces.



Wing Warping--A system of maintaining lateral balance by differential

twisting of wing tips in such manner as to increase the sustension on

one side and decrease it on the other.



--New York Tribune.



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