11.2 B Airframe Structures Flashcards
Define longeron
Main longitudinal member of fuselage or nacelle
What’s the name given for a member that takes a tensile load?
Tie road
(Tension rod)
What load does a strut take?
Compression load
In a semi-monocoque stressed skin, what are the loads shared between?
Skin and framework
What is the purpose of the aircraft frame?
Gives cross- sectional shape, often circular
Maintains the contour of the covering, can be a stress bearing component, what is it?
Rib
Describe a spar
The main spa wise member of an aerofoil
What member assist sheet material in carrying loads along their length?
Stringer
What is a bulkhead?
A partition within the structure
What is a pressure bulkhead?
Forms the boundary of a pressurised structure
How do you know where certain components like frames and ribs are positioned?
Station numbers
Explain safe life
The period in which a component is extremely unlikely to fail
What is the purpose of using a crack stopper?
Placed at right angles to the crack, which reduces the rate of further cracking
What is the difference between aerodynamic and static loading?
Aerodynamic = when in flight
Static = when stationary
What are the two types of fuselage construction?
. Monocoque
. Truss
How does the truss type work?
Made of members like beams, struts etc then covered in fabric
What are the two sections of a monocoque classification?
. True monocoque
. Semi - monocoque
What are the main memebersin a true monocoque construction?
. Formers, frame, bulkheads and skin
What takes the primary stress in a true monocoque construction?
Skin
How is a semi- monocoque differ from a true- monocoque construction?
The skin is reinforced by longitudinal members, therefore both take the loads
What is the main advantage of a semi- monocoque structure?
Can withstand considerable damage and still be strong
What construction are floor boards?
Honeycomb composite construction
Floorboards have a foam tape on the underside where they contacts structure, what about in wet areas?
The edges are sealed up
How are the two wings attached to each others?
By the wing box
What is the wing box designed to do?
Provides support and rigidity to the wings
How is the horizontal stabiliser attached to the fuselage
Box section
How is the vertical stabiliser attached to the rear stabiliser?
By large machined fittings
The engine pylon is made of a frame and skin but how is it formed to make nacelle and strut?
Riveted and bonded together
What is the purpose of nacelles?
They are streamlined enclosures used to house engine and it’s components
Due to weight what is the preferred rivet type to join metal parts together?
Solid shank rivets
When would you use a blind rivet?
When access to joint is only available from one side
What marking do close tolerance bolt have on its head?
A raised or recessed triangle
What would you do if a bolt had no head markings?
Do NOT Use as probably a commercial grade bolt
What is the most effective assembly method?
Adhesive bonding
(Foam cores can also be used)
What are the three types of surface protection?
- Pretreatment
- Paint coatings
- Special coating
What 2 sections can paint coatings be subdivided into?
- Primers
- Top coat
For special coatings what is type 1 and type 2?
Type 1- water repellent (silicone free)
Type 2- heavy duty corrosion preventative
What are the two conditions for water used to clean an aircraft?
. Water between 7 and 8 PH
. Chloride level less than 100ppm
For an aircraft symmetry check what equipment would you use for small aircraft vs large aircraft?
Small aircraft = steel tale
Large aircraft = check the floor
