S Aircraft Construction Flashcards
3 main aircraft sub assemblies
Fuselage
Wings
Empennage
5 attachment methods?
- Riveting
- Welding
- Bolting
- Pinning
- Adhesives
What is the name of a joint which connects 2 panels together using rivets?
Doubler joint
What is a method of ensuring bolts do not come loose?
Wire locking
Can composite materials be riveted?
No
How do we attach composite materials?
Composite fastener
What isa longeron?
Main longitudinal load bearing member of the fuselage
What are stringers?
Run longitudinally, bonded to the skin, help withstand buckling
What are formers/frames?
Define the shape and provide skin attachment points
What doos the aircraft skin do?
Provides aerodynamic shape as well as withstanding tension and compression stresses
What is a bulkhead?
Provide structural partitions inside the fuselage and give structural support
What is a firewall?
Fire resistant bulkhead installed between engine compartment and the rest of the airframe structure
What are intercostels?
When weaker areas around the windows and doors are reinforced with frames and stringers
What is a machined structure?
A single piece of material effectively carved with components included in its shape, removing the need for joints
Why are most fuselage sections circular?
Eliminating corners helps ensure laminar flow
Circular cross section can more easily withstand loads imposed by pressurisation
What is a double bubble structure?
Intersecting circles tied together by the fuselage floor
What shape are unpressurised aircraft?
Don’t have to be circular, can vary more widely
3 advantages of an oval fuselage?
- Lower manufacturing cost
- Greater capacity
- Better options for cargo
Where is the pressure hull located?
Between the forward and rear pressure bulkheads
What is the pressure bulkhead pressurised to?
Between 8 and 9psi
What is axial stress?
Stress acting along the longitudinal axis
What is hoop stress?
Stress that acts radially across the fuselage structure
When do axial and hoop stresses occur?
Cyclic stresses - every time the cabin is pressurised
What are 3 types of wing design?
Cantilever
Semi-cantilever
Externally braced
What are the 2 types of wing?
- Low wing
- High wing
What is the key disadvantage of a high wing?
Reduced visibility into the turns when banking
Where does a spar run from?
Root to tip
Where do ribs run from?
Leading edge to trailing edge
What do stringers do?
Combine with ribs to share loads and transfer loads to spars
What is the centre wing box?
Part of the fuselage which provides the attachment points for the wings
What is the wing box?
Main structural component of the wing
What does the wing box house?
Mounting points to support hinge points and actuators for control surfaces
How is the vertical stabiliser attached to the aircraft?
3 or 4 lugs and pins
What can cause catastrophic vertical stabiliser failure?
Excessive application/deflection of the rudder
The advantage and disadvantage of a T tail?
- Predictable flight characteristics
- Prone to deep stall
What does the pylon do?
Attaches the engine to the wing
How are weight/thrust forces carried?
Strut braces
What is a fuse pin?
A bolt designed to break at a given load
Why are fuse pins used for the engine pylon?
Allow the engine to separate without causing excess damage to the wing
