Airframe and Systems Flashcards
(17 cards)
What is :
1-Tension
2-Compression
3-Torsion
4-Shear
1-a stress that resists a force that tends to pull something apart
2-a stress that resists a crushing force
3-a stress that produces a twisting motion
4-a stress that resists the force tending to cause one layer of a material to slide over an adjacent layer
What is:
1-Hoop(Radial) Stress
2-Axial Stress
1-when an a/c is pressurized, a force is exerted on the walls causing the pressure hull to expand
2-stress along the length of an object (tension or compression)
What type of stress do the following experience:
1-fuselage
2-wing spars
3-landing gear
1-tensile stress from cabin pressurization
2-axial stress from generating lift
3-compressive stress
What are the main causes of Bending and torsion moments in the fuselage
Bending:
Weight
Lift from the tail
Torsion:
Fins and rudder
Cabin pressurization
What is a truss type fuselage
A rigid framework made of beams, struts and bars made to resist deformation by applied loads
What is:
1-A monocoque type fuselage
2-a semi-monocoque type fuselage
1-a single shell fuselage, relying largely on the strength of the skin to carry primary loads. Uses formers, frame assemblies and bulkheads to give shape to fuselage
2-also consists of formers, frame assemblies, bulkheads and stringers(longitudinal members placed between bulkheads) but the skin is reinforced by longerons
What is the difference between Cantilever and Semi Cantilever wings
Cantilever - no external bracing, supported internally
Semi Cantilever - external bracing using struts or wires
What components are wings made of
Spars: Primary load-bearing beams running lengthwise, resisting bending forces
Ribs: Perpendicular supports that shape the wing and distribute loads
Stringers: Longitudinal reinforcements that prevent buckling and add strength
Wing Box: Central structure housing fuel and connecting the wing to the fuselage
Skin: Outer covering for aerodynamic efficiency and additional strength
Fuel Tanks: Often integrated within the wing box (wet wing)
Fairings and Control Systems: Protect mechanisms like flaps and minimize drag
What is a:
1-mono spar wing
2-multi spar wing
3-box beam wing
1-wing that has only one main longitudinal member - ribs / bulkheads form the shape
2-more than one longitudinal member - ribs / bulkheads often included in forming shape
3-uses 2 main longitudinal members with connecting bulkheads to furnish additional strength and to give contour to wing. Corrugated sheet can be placed between bulkheads
What are the front, main and rear spars functions
Front - takes air load acting to bend wing backward. Where external loads like engines are mounted, front spar shares some of the load
Main - carries majority of load placed on wing
Rear - acts as mounting structure for TE flaps and ailerons. Resists upward twisting action of upwash at the TE
What is stressed skin, machined skin and torsion boxes in reference to an aircraft wing
Stressed - in subsonic a/c, the wings skeleton is covered by a light alloy skin that is designed to stiffen the wing by absorbing some of the load
Machined - a more rigid wing for faster flying a/c, consists of a skin that is manufactured from a solid billet of metal that is milled away to form the actual wing along with buttresses and ribs
Torsion boxes - the skin of the upper and lower surfaces of the wing joins the front and rear spars rigidly to form a box
What is a Nacelle
Streamlined enclosures used primarily to house the engine and its components
What is Safe-Life and Fail-Safe
Safe-Life - the minimum flying hours before structural failure starts to occur
Fail-Safe - a structure with duplicated primary structures allowing for an alternate path to be available for a load
With regards to the cockpit windows no 1 and 2:
1-What do the layers consist of
2-What are the qualities of the layers
3-What is put in place to prevent edge chipping of glass under differential expansion and contraction
4-What is used in the anti ice system
1-A glass pane laminated to each side of a vinyl interlayer/core
2-Glass pane - thicker than vinyl, primary load carrying member
Vinyl - acts as fail-safe load carrying member, preventing the window from shattering
Outer pane has no structural significance, provides rigidity, and scratches resistant surface
3-A thin strip of parting medium
4-Idium Oxide applied on inner face of outer glass pane, permitting for electrical heating,
1-What does cockpit window no 3 consist of
2-How is the spacer attached
3-What is the function of the spacer
1- Two stretched acrylic panes separated by a phenolic spacer
2- Attached to perimeter of the panes by pressure sensitive tape, acting as an air seal
3- To provide an insulation cavity preventing fogging on inner surface of windows
What are windows 4 and 5 made of, and what are their purposes
Both consist of a glass panel laminated to each side of a vinyl core(similar to 1 and 2)
A conductive film applied on outer face of inner glass permits electrical heating
No. 4 has additional vinyl laminated to inboard surface with a cast acrylic sheet laminated onto it, preventing glass shattering into cabin
What are the main functions of the outer, middle and inner cabin windows
An outer, middle and inner pane
Outer and middle designed to take full pressurization load
Failsafe structure insured by mid pane which is designed for 1.5× normal pressure at 70°F
Inner is non structural and mounted to sidewall lining
