AIRCRAFT STRUCTURES/ Design DEFINITIONS Flashcards
removable panel for inspection or
maintenance
Access panel
near of in the direction of the rear of the
aircraft
Aft
the study of how the moving body (aircraft)
interacts with air flowing around it, flies
Aerodynamics
the point of application for additional
aerodynamic loads
Aerodynamic centre
the study how to f ind measures against flutter
(undamped vibration in the structure due to
aerodynamic loads
Aeroelasticity
wing-section
Airfoil
extra injection of fuel in extra combustion
chamber between the turbine and the nozzle of
the engine; creates a higher thrust
Afterburner
strengthening at room temperature of a
quenched metal alloy by very small and
uniformly dispersed particles that precipitate
from supersaturated solution
Age hardening, ageing
decrease of mechanical properties of polymer
matrix composites or adhesives by exposure to
a wet environment
Ageing
control surface for aircraft rolling
Aileron
main components which carry all the loads
Airframe
passage in passenger cabin between rows of
chairs
Aisle
maximum stress level allowed in a structure
(so that it does not deform plastically or break)
Allowable stress
the combination of several metal components
Alloy
the angle between the chord line of a wing or
other aerodynamic surface and the oncoming
air
Angle of attack
Anhedral (negative Dihedral)
a wing in a reverse v-form
the ratio of wing span to average chord, an
indication of the slenderness of a wing
Aspect ratio
system to generate electric power when the
engines are not running
Auxiliary power unit
an extra beam in the root in the wing for
extra strength
Auxiliary spar
a structural member loaded at an angle (often
at a right angle) to its length
Beam
used for bolted or riveted joints – load/bolt
diameter times material thickness
Bearing stress
the product of a force and its moment arm
Bending moment
aircraft with an upper and lower wing on top
of each other
Biplane
an impact of a bird on the structure
Bird strike
one half of a propellor
Blade
joining member consisting of head and stem
using a nut to tighten it
Bolt
method of joining using adhesive material
(polymeric material with suff icient strength to
transfer load)
Bonding or adhesive bonding
strengthening wire to support a structure,
generally loaded in tension
Brace
small f itting or support to attach system parts
Bracket
system attached to the wheels to slow down
or stop the airplane when on the ground
Brake
out of plane bending, followed by crushing of
material under compressive loads
Buckling
a panel separating areas in the structure
Bulkhead
the curved line precisely between the upper
and lower skin of an airfoil
Camber
an arrangement of foreplanes and win, rather
than the conventional wing and horizontal
tailplane
Canard
a beam supported only at the end (wing root)
Cantilever (full cantilever)
point of balance of the mass of the aircraft
(component)
Centre of gravity
the centroid of the pressure distribution
Centre of pressure
line connecting geometric middle points of
cross sections of the aircraft structure
Centre-line of aircraft
line connecting geometric middle points of
cross sections of the aircraft structure
Centre wingbox
a resulting force by spinning a mass around
Centrifugal force
small angles or simple sheet metal parts for
(shear) connection of various parts
Clips and Cleats
the distance between the leading and trailing
edge of a wing section
Chord
the covers around the engine
Cowling
an imaginary line jointing the leading and
trailing edge of a wing section
Chord line
stress or force that tends to push material
together
Compression
part of the jet engine where the air coming
form the inlet is brought to a higher pressure
Compressor
attack of the material by an unwanted
chemical reaction (oxidation)
Corrosion
a wing in a triangular planform
Delta wing
structures that have different curvatures in
two directions of various directions
Double curvature
wing in a v-shape
Dihedral
holes in the structure to remove water
accumulated during flight
Drain holes
point where elastic elongation changes in
plastic elongation
Elastic limit
control surface for pitch
Elevator
control surface for pitch and roll
Elevons (Elevators- Aileron)
the rear section of the body of the airplane
with stabilisers
Empennage
principle of maintaining adequate performance
after some degree of damage or degradation
has occured
Fail safe
plastic deformation or breaking of a structure
Failure
non-structural transition part between
components to create an aerodynamic smooth
shape and low drag
Fairings
certif ication
procedures and airwothiness standards of the
US government (FAA)
FAR
means for mechanically joining parts (bolted
and riveted joints)
Fasteners
failure, at relatively low stress levels, of
structures that are subjected of fluctuating and
cyclic stress
Fatigue
vertical stabilizer, tailplane
fin
numerical method of calculation by
discretisation a continuum into a f inite number
of parts (elements)
Finite element method
generally heavily loaded part or f ixture to
attach system or other part to a structure
Fitting
the movable part at the trailing edge of the
wing which, when extended and / or deflected,
increase the lift
Flap
the surface which combines the control
function of flaps and ailerons
Flaperon
place where the pilots fly the airplane
Flight Deck
a horizontal stabilizing and control surface
forward of the wing (see canard)
Foreplane
Airloadson the skin distort the airframe, but the structure is said to be aero-elastic if it absorbs loads with out breakage and returns to its original shape when they are removed.
Aero-elasticity
a technique used mainly to reduce the aero-elastic bending of wings.
Bending relief
a fully equipped operational airplane, empty for example without crew, fuel or payload.
aircraft prepared for service weight (APS weight)
standard empty weight plus optional equipment.
Basic empty weight
weight of a standard aeroplane including unusable fuel, full operating fluids and full oil.
Standard empty weight
maximum power permissible for take-off
TOP
Actual atmospheric pressure at field elevation.
Station Pressure
a regular short period oscillation in yaw and roll
Dutch Roll
a high frequency oscillation usually caused by the interaction of aerodynamic forces and the natural frequencies of control surfaces and structure.
Flutter
the angle between the datum line of the aircraft from nose to tail, and the chord line of an aerofoil section
Angle of incidence
total pressure = static + dynamic pressure, p + q = C
Bernoulli’s Law
Shaking and thumping of the aircraft caused by turbulent lumps of agitated air left behind in the wake.
Buffet
Motion of the air or water along a curved path. Circulation produces lift.
Circulation
the angle subtended between the chord lines of biplane wings, and between wings and stabiliser
Decalage
the vertical distance between the wings of a biplane
Gap
the magnitude of the aerodynamic twisting effect exerted at the hinge of a control or flap surface.
Hinge moment
causes loss of power and mechanical shocks that can cause engine failure.
Detonation
Setting the blades of a stopped propeller at zero angle of attack, so as to reduce drag to the minimum by preventing windmilling.
Feathering
a form of pump which compresses the air supplied to the cylinders, to be mixed with fuel so as to maintain power to higher altitudes.
Supercharger and Turbo(super)charger
the relative airflow past an aircraft
Slipstream
the relationship between control surface movement and the movement of the control in the cockpit
Gearing
when it feels as if it is connected to a spring, which must be compressed or extended before the control surface begins to move.
Spongy
a regular short period oscillation in yaw and roll
Dutch Roll
the indicated of the aeroplane, corrected for position and instrument error.
calibrated airspeed (CAS)
flight with a component of airflow from the side
Sideslip
Controls are said to be well harmonisedwhen forces and deflections, and the response of the aircraft to them, are such that the pilot is not aware of having to use too much or too little effort.
Harmonisation
turbulence
Gust
the measure of material’s resistance to
deformations by surface indentation or by
abrasion
Hardness
treatment to improve the material properties
(mechanical properties, formability, corrosion
resistance)
Heat treatment of metals
device to create higher lift
High lift device
the core material, between face sheets of a
sandwich structure, with the shape of the six
sided wall shape made by the honeybee
Honeycomb
a movable joint with one (or more) degree(s)
of freedom
Hinge
the strain is equal to the stress divided by the
Young’s modulus
Hooke’s law
a body’s resistance to a change in its motion
as a result of an applied acceleration
Inertia
the main stringer in the fuselage or
longitudinal beam
Longeron
the high force which will be one time load the
structure at which no plastic deformation
should occur
Limit load
the front of the wing or tail plane
Leading edge
the forces which are caused by landing in the
landing gear and back-up structure
Landing loads
certification
procedures and airworthiness standards of the
European Joint Aviation Authorities (JAA)
Joint Aviation Regulations (JAR)
frame at which wing spar is connected to the
fuselage
Mainframe
to keep the plane in good condition for
continued operation
Maintenance
a structure with a cloes cross-section which
mainly consists of a thin skin
Monocoque
to fix on a support
Mount
stress level of a loaded material where next to
deformation starts to become plastic
Yield point
the increase in hardness and strength of a
ductile metal as it is plastically deformed below
its recrystallization temperature
Work hardening
the vertical aerodynamic plane at the end of
the wings
Winglet
the distance from wing-tip to wing-tip
Wing span
an aircraft’s weight (or effective weight if it
manoeuvring) divided by its gross wing area
Wing loading
a box in the wing to take torsion forces
Wing box
the plane to provide lift
Wing
a way of jointing two parts together by local
melting
Welding
a structural member mainly loaded in shear in
the plane of the member (part of the spar, and
sometimes in ribs and frames
Web
the system on which the airplane can land or
descent (also called landing gear)
Undercarriage
the load which will cause failure of the
structure
Ultimate load
structure which it’s made out of tubes, rods or
thin elements, each element only loaded in
tension or compression
Truss
balanced condition, an airplane that is flying
at an angle of attack such that its moment
about the centre of gravity is zero
Trim
This structures increases the rigidity of the wing and resist the twisting and bending motion without increasing the mass of used material used in construction
Torsion box
force that ( resists the movement of two contacting surfaces ) that slide relative to one another.
Friction
form of loading which tends to cause the
atoms or molecules of a material to slide over
each other
Shear
independent power driven adjustment or
shifting mechanism
Servo actuator
opening panels on upper surface of the wing
to disturb the airflow over the wing (spoils lift),
Spoilers
to give the aircraft stability during flight,
smaller wing (fixed horizontal and vertical) are
located at the tail of the plane
Stabilizer
the lowest speed of the aircraft in flight at
which the airflow over the wing separates and
becomes turbulent, so the lift will be lost
Stalling speed
a stiffening member which supports a section
of the load carrying skin,
Stringer
a slender (bar or tubular) structural member
which is loaded in compression
Strut
the angle between quart chord line of the
wing and centre line of fuselage, swept-back
has a positive sweep angle
Sweep angle
system of flaps or doors on the jet engine
that bends the jet forward, thus slowing down
the aircraft after landing
Thrust reverser
effect produced by two forces pulling against
each other
Tension
