Aircraft Structure General Concepts

MTP Dornier

Primary Structure

Types of Frames or Structure (Fuselage, Wings, Bulkhead,Empenage,Landing Gear)

Secondary Structure

Only Air, Mostly Aerodynamics (Fairings,Interior,Panel,Winglets,Control Surfaces)

Safe Life

Repair after a fix number if Flight.( LIFE CYCLE)

Fail Safe

Redundancy, Backup,( If one fail another one takes over)

Damage tolerance

Is the aircraft still flyable after repair.(Corrosion)

100

Lower Fuselage

200

Upper Fuselage

300

Empennage

400

Powerplant

500

Left Wing

600

Right Wing

700

Landing Gear

800

Doors

Three Axis

Vertical Axis, Lateral Axis, Longitudinal Axis

Body Station

From Bulkhead to Aft

Body Buttock Line

Wingtip to Wingtip ( Parallel to the body Centerline)

Body Waterline

Cross Section Horizontal Planes

Tension Load

Pulling Force

Compression Load

Pushing Force

Shear Load

Pulling force But Hinahati (that acts parallel to a surface, causing internal sliding. )

Torsion Load

(Twisting FORCE)A force that tries to twist a structural member about its longitudinal axis

Bending Load

A combination of tension on one side and compression on the other

Drain Ports

Always open, and to remove unwanted fluid, Prevent corrosion

Drain Valve

Have a spring (Spring loaded),Used during scheduled checks to sample fluids

Ventilation Provision

Drain holes to direct the flow of fluid towards external drain points. An example of this is the holes drilled in stringers to allow fluids

Aluminum

Used to provide a conductive path for the dissipation of the electrical energy.

Aluminium Structure

the electricity will flow through the skin and discharge out to the static discharger

Composite Structure

Carbon components are shielded by Copper or Stainless Steel Plates.( Dont conduct Electricity)

Electromagnetic Fields

Related to the lightning attachment can cause unwanted transient currents and currents in the aircraft wiring and systems.

Zone 1

Surfaces where there is a high probability of initial lightning attachment (entry or exit)(Damage where damage probable)

Zone 2

Surfaces where there is a high probability of a swept stroke zone. The lightning strike has its initial point of attachment in Zone 1 and moves into Zone 2( Areas where damage probable

Zone 3

This zone includes all of the aircraft surfaces that are not in Zone 1 and 2. A low probability of attachment of a lightning strike. However, high lightning currents can go through Zone 3 by direct conduction between 2 attachment points( Least probable damage)

TRUSS TYPE

An older, lighter, and simpler form of aircraft construction that uses rigid framework

Semi Monocoque

(Stressed Skin) Good Strength to Weight Ratio. Common type of construction used in modern aircraft

Monocoque

(Single Shell) External skin carries all the flight loads, with minimal or no internal support structure

Frames

Help to maintain the shape of the fuselage and reduce the column length of the stringer,

Stringers

Give shape to the fuselage shell and they are located on the inner side of the aircraft skin panel.

LONGERONS

Hold the bulkheads and formers, and these, in turn, hold the stringers.

Bulkheads

Forms of boundary of Pressurized Structure

Skin

Forms the external surface of the fuselage.

Riveting

Are metal pin–type fasteners designed primarily for shear–type loads.

SOLID RIVETS

A permanent mechanical fastener consisting of a smooth cylindrical shaft

Blind Rivets

(Also known as a pop rivet) is a tubular mechanical fastener designed to be installed completely from one side of a structure

Special Rivets

a broad term referring to any rivet type designed for specific, non-standard applications

Bolting

Maintenance accesses, replaceable and movable structural parts(Non permanent fasteners)

Metal to Metal Bonding

Bonded structures, which are locally reinforced by bonded doubler-plates,

Sandwich Structure

The second category of adhesive-bonded structures is that which contains bonded joints between skin sheets and low density core material,

CHROMIC ACID ANODIZING (CAA)

Process uses a weak chromic acid solution, which is less corrosive than sulphuric acid

Primer

Increases the corrosion resistance properties because it contains corrosion inhibitors.

Top coat

Protect the Primes(gives the aircraft the necessary appearance.)

A320 Main entry doors

4

A320 Cargo doors

2

A320 Service door

2

A320 Emergency Exit Door

4

Spar

Main Structure ( Primary Structure)

Spar

Carry the load during flight

Landing Gear

Carry Flight during on the Ground

Divider

Use to avoid flushing of Fuel

Center Tank

Gets filled with first and also gets consumed First in a Tank

Stringers

Support the skin

Pylon

Support the Engine and Transfer the load

Clips

Are usually found on the inner surface of the skin and are attached to the frame and also to the stringer.

Doors

Main Entry Door,Service Doors, Cargo Doors, Emergency Exit doors

Service Doors

Provide access to internal Components for Maintenance

Cargo Doors

Enable Fast and safe loading and loading of Freight

Cockpit Windows

6

Sliding Windows

2

Fixed Windows

3

Wing Three Main Structure

Left Wing Box, Center Wing Box

Left And Right Boxes

Have the Rear Spar and Front Spar Which are fuel tank walls design to contain Fuel

Spar

The most single important structural member of an Aircraft wing (Resist Bending and Shear Stress) Carry main flights

Ribs

Carry Torsion, Compression and Shear loads and also gives shape to the wing and provide walls to the Fuel tanks

Leading Edge

Flaps or Slats

Trailing Edge

Supports Flight Controls (Winglet-Boeing) (Wingtip-Airbus)

Nacelles

strut assembly includes a torque box, firewall and fireseal, fairings, strut drains, fan cowl support beam, and engine attach fittings.

Pylons

Support the ENGINE and transfer load to the Torque Box

Vertical Stabalizer or Fin

Located at the Top of the Tail Section and provides directional Stability

Surface Hinges

attach flight control surfaces to the aircraft structure.

5

How many Hinges have the wing does

Static Balancing

Uses balance Weight