Fuselage, Wings, and Stabilizing Surfaces Flashcards
ATA 01 to ATA 18
Aircraft General
ATA 20 to ATA 50
Airframe Systems
ATA 51 to ATA 57
Structure
ATA 61 to ATA 92
Powerplant
tends to stretch a structural member
Tension or Tensile
components designed to resist tensile loads
Ties
opposite of tensile loads and tend to shorten structural members
compression
components that are designed to resist compressive loads
struts
a force which tends to slide one face of the material over an adjacent face
shear
designed to resist shear forces
riveted joints
involves the three basic loadings
bending
three basic loadings
tension (outer), compression (inner), shear (across)
twisting force that produce tension, compression, and shear
torsion
occurs to thin sheet materials when they are subjected to end loads and to ties if subjected to compressive forces
buckling
internal force inside a structural member which resists an externally applied force
stress
defined as the force per unit area and is measured in units of N/mm^2 or MN/m^2
stress
ratio of the change in length to the original length
strain
a measure of the deformation of any loaded structure
strain
the maximum load that the designer would expect the airframe or component to experience in service
Design Limit Load
What is DLL?
Design Limit Load
Lift over weight is equal to
G
design limit load for utility aircrafts
3.4G 3.8G
design limit load for aerobatic aircrafts
6G
when it is applied the aircraft structure must not suffer any permanent deformation and all flying control and other systems must function normally
proof load
normally 1.125 x the DLL
proof load
it is the Design Limit Load multiplied by the safety factor
Design Ultimate Load (DUL)
What is DUL?
Design Ultimate Load
minimum safety factor required for a Design Ultimate Load
1.5
ratio of the ultimate load to the limit load
safety factor
defined as the minimum number of flying hours, landings, cycles, etc. which should elapse before a major structural failure occurs
safe life
this is a structure having multiple load paths which means that the loads are shared by adjacent members
fail safe structure
if one part fails, the load it carried will now be carried by the ________ member for a limited period
adjacent
eliminates the extra structural members by spreading the loading of a particular structure over a larger area
damage tolerant structure
a structure which is subjected to continual reversals of loading will fail at a load of less than would be the case for a steadily applied load
fatigue
a method of locating components on the aircraft must be established in order that maintenance and repairs can be carried out
station numbers
reference to a zero datum line at or near the forward portion of the aircraft
fuselage station lines
are given in inches forward (“-“) or aft (“+”) of the zero datum
station numbers
sign for inches forward and aft
-, +
are measured from the center line of the aircraft
wing stations
vertical position from a ground line or horizontal datum
water line (WL) or buttock line
What is WL?
water line
zoning of large aircraft is specified by the Air Transport Association of America in the ATA-100 Specification
Aircraft Structural Zoning System
Zones in Aircraft Structural Zoning System
Major Zone, Major Sub-zone, Simply a zone
lower half of the fuselage to the rear pressure bulkhead (below the main cabin deck)
Zone 100
upper half of the fuselage to the rear pressure bulkhead
Zone 200
Empennage, including fuselage aft of the rear pressure bulkhead
Zone 300
Power plants and struts or pylons
Zone 400
left wing
Zone 500
right wing
Zone 600
landing gear and landing gear doors
Zone 700
doors
Zone 800
reserved for uncommon differences between aircraft types not covered by standard series numbers
Zone 900
major zones divided to major sub-zones
2nd digit
major sub-zones are divided into zones
3rd digit
main structure or body of the aircraft and carries the aircraft payload in safe, comfortable conditions
fuselage
stresses are set up in the fuselage of aircraft when pressurized
axial stress (longitudinal)
tend to elongate the fuselage
axial stress (longitudinal)
set up in addition to axial stress
hoop stress (radial)
tend to expand fuselage cross section area
hoop stress (radial)
internal pressure of hoop stretch (radial) can reach ______
65.5 kN/m^2 or 9.5 psi
used for light, non-pressurized aircraft
truss type
a strong, easily constructed and relatively trouble free basic structure
truss type
covered by a lightweight aluminum alloy or fabric skin
truss type
more widely used fuselage construction
monocoque structure
all the loads are taken by the skin with just light internal frames or formers to give the required shape
monocoque structure
materials to provide rigidity and strength
sandwich construction, honeycomb core with a skin of composite material, glass fiber reinforced plastics (GFRP), carbon fiber reinforced plastics (CFRP), aluminum alloy
What is GFRP?
glass fiber reinforced plastics
What is CFRP?
carbon fiber reinforced plastics
pure monocoque structure with added stringers (stiffeners) and longerons to run lengthwise along the fuselage joining the frames together
semi-monocoque construction
What are the stiffeners of a semi-monocoque fuselage?
stringers
must withstand both the loads of pressurization and impact loads from bird strikes
flight deck windows
constructed from toughened glass panels attached to each side of a clear vinyl interlayer
flight deck windows
prevents ice from forming and makes the window more resilient and able to withstand bird strikes
electrically conducting coating
allow pilots to land the aircraft safely in the event of windscreen obscurity
direct vision windows
these are designed to be fail safe and normally have two panes of acrylic plastic mounted in an airtight rubber seal fitted into a metal window frame
passenger cabin windows
support the weight of the aircraft in the air and so must have sufficient strength and stiffness
wings
very few of this fly at more than 200 knots in level flight and so the air loads are low
bi-plane
biplanes flying at more than ___ knots are very few
200
this type of design is also used on low speed aircraft
braced monoplane
the mainplanes have to absorb the stresses due to lift and drag in flight and, if of cantilever design, their own weight when on the ground
cantilever monoplane
main load bearing members
spars
constructed so that they will absorb the downwards bending stresses when on the ground and the upwards, rearwards and twisting stresses when in flight
spars
generates direct stresses in a span wise direction as a response to bending moments and also reacts against twisting (torsion)
skin
these are span wise members that give the wing rigidity by stiffening the skin in compression
stringers
these maintain the airfoil shape if the wings support the spars, stringers, and skin against buckling and pass concentrated loads
ribs
What does MZFM stand for?
Maximum Zero Fuel Mass
maximum permissible mass of an airplane with no usable fuel
Maximum Zero Fuel Mass (MZFM)
the maximum permissible airplane mass at the start of the take-off run
Maximum Structural Take Off Mass (MSTOM)
What does MSTOM stand for?
Maximum Structural Take Off Mass
What does MSTM stand for?
Maximum Structural Taxi Mass
the maximum mass of the airplane at the commencement of the taxi
Maximum Structural Taxi Mass (MSTM)
the maximum permissible total airplane mass on landing in normal circumstances
Maximum Structural Landing Mass (MSLM)
What does MSLM stand for?
Maximum Structural Landing Mass
types of empennage
conventional, t-tail, h-tail, v-tail
provide the longitudinal and directional stability and the means of longitudinal control
tail
generally smaller versions of the mainplanes in that they use spars, ribs, stringers, and skin in their construction
tail
provides some aircraft their longitudinal stability and control
Foreplanes (canards)
What is another term for Foreplanes?
canards
what is another term for horizontal surfaces?
tailplane
provide longitudinal stability by generating upwards or downwards forces as required
horizontal surfaces (tailplane)
generates sideways forces as required
vertical surfaces (fin)
other term for vertical surfaces
fin
is the rapid and uncontrolled oscillation of a flight control which occurs as a result of an unbalanced surface
flutter
can prevent flutter
mass balancing
alter the moment of inertia of the surface and therefore the period of vibration
mass balancing
most widely used metals for structural use due to a good strength to weight ratio
aluminum
an aluminum and copper based alloy which has poor corrosion resistance except when clad with pure aluminum
duralumin
duralumin is an aluminum and copper based alloy which has poor corrosion resistance except when clad with ________
pure aluminum
has good conductivity and is difficult to weld
duralumin
only used where strength is vital and weight penalties can be ignored
steel
is much lighter than steel and can be used where fire protection is required
titanium
has good strength and retains this and its corrosion resistance up to 400 deg cel
titanium
Titanium retains strength and corrosion resistance up to temperatures of ______
400 deg cel
their principal advantage being their weight
magnesium
has an excellent strength to weight ratio because of its weight
magnesium
aluminum is ______ heavier than magnesium
1 1/2 times
have good resistance to corrosion and can easily be formed into complex shapes but their fatigue behavior is different to that of conventional metal alloys and is not generally a consideration at stress cycles below approximately ___ of ultimate stress
composite materials, 80%
suffering fatigue retain their design strength up to a critical point after which failure occurs rapidly whereas composites lose their properties gradually
metal structures
What is KFRP?
Kevlar Fiber Reinforced Plastics
outperform the commonly used aircraft structural materials
CFRP and KFRP
is designed to withstand landing at a particular aircraft weight and vertical descent velocity
aircraft landing gear
