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BYRAVI

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PARTS OF AN AIRCRAFT

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Customer RequirementsPayload, Range, Endurance, Speed,

Research, Development and Marketanalysis

Requirements Satisfied ?

Final Evaluation

Flight Test

Detailed Design

ConceptualDesign

Preliminary Design

Test Article Fabrication

DESIGN PROCESS

No

Yes

Stop

Go

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CONCEPTUAL DESIGN

Preliminary Estimate of Take-off Weight Wing Loading Selection Main Wing Design Fuselage Design Horizontal and Vertical Tail Design

Engine Selection Take-off and Landing Enhanced Lift Design Structure Design and Material Selection Refined Weight Analysis

Static Stability and Control Cost Estimate Design Summary and Trade Study

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More weight

More lift needed

More wing area

More profile drag

More induced drag

More thrust

More fuel for a givenrange/mission

Larger fuel tank volume

Larger fuselage and/or wings

Larger engines

Heavier supporting structure

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FUEL FRACTION ESTIMATES

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FUEL FRACTION ESTIMATES

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3 VIEW

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PRELIMINARY DESIGN

Freeze The Configuration

Develop Lofting

Develop Test and Analytical Base

Design Major Items

Develop Actual Cost Estimate

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INBOARDS

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VISION REQUIREMENT

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DETAILED DESIGN

Design The Actual Pieces To Be Built

Design The Tooling and Fabrication Process

Test Major Item Structure, Landing Gear

Finalize Weight and Performance Estimates

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A/C STRUCTURES & SYSTEMS

AIRCRAFT CONSISTS OF:

1. STRUCTURES

* FUSELAGE

* WING

* EMPENNAGE

* LANDING GEAR

2. SYSTEMS

* POWER PLANT & FUEL SYSTEM

* FLIGHT CONTROL SYSTEM

* HYDRAULICS

* ECS

* ELECTRICAL & AVIONICS

PRIMARY FACTORS TO CONSIDER FOR AIRCRAFT STRUCTURES ARE:

STRENGTH

WEIGHT

RELIABILITY

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STRUCTURES

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FACTORS OF LOADS:

AIR LOADS :Pressure, lift, drag duringmaneour, gust load.

LANDING LOADS :On ground, water & arrestedlanding ( on ships).

POWER PLANT LOADS :Thrust, Torque.

Loads acting on each element of the structure are to be considered for design .

SPECIAL LOADS:

seat jettisoning, bird strike, cabinpressurization etc.

WT. & INERTIA LOADS :

component weight & inertia

LOADS ON AN AIRCRAFT

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MAIN STRUCTURE OR BODY OF THE AIRCRAFT

PROVIDES SPACE FOR1. PERSONNEL2. CARGO3. CONTROLS & ACCESSORIES

PROVIDES ATTACHMENT FOR1. NOSE CONE2. WIND SCREEN & CANOPY3. WING4. EMPENNAGE

5. NOSE & MAIN LANDING GEAR6. AIR INTAKE7. POWER PLANT

FUSELAGE

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3 MAJOR ASSEMBLIES:

FRONT FUSELAGE CENTRE FUSELAGE REAR FUSELAGE

FRONT FUSELAGE:

CONSISTS OF: NOSE CONE - Radar Antenna RADAR EQUIPMENT BAY Multi Mode Radar WIND SCREEN & CANOPY NOSE U/C BAY & ATTACHMENT

EQUIPMENT BAY AIR INTAKE STUB WING extension of Fuselage in Wing Shape DOORS COVERS

FUSELAGE MAJOR ASSEMBLIES

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INTERFACE

INTERFACES:

FRONT FUS. TO CENTER FUS.

CENTER FUS. TO REAR FUS.

WING TO FUSELAGE

FIN TO FUSELAGE

H.STABILIZER TO FUSELAGE

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STRUCTURAL ELEMENTS OF FUSELAGE

FRAMES / BULK HEADS

SKINS LONGERONS /STRINGERS

FLOORS

WALLS

AIR DUCT

DOORS & COVERS

Frame:

Maintains shape of fuselage

Reduces column length of the stringer

to prevent in-stability of the structureand for panel breaking.

* Light in construction

Bulkhead:

Heavier Transverse members locatedat intervals

Transfers concentrated loads to theshell of the A/C.

* Machined / Sheet metal built-up

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FRAME TYPES:

PRIMARY FRAMES : TransferConcentrated / Inclined Load(Machined Or Built-up )Eg: WING FUS, FIN FUS , U/C SEAT.

SECONDARY FRAMES: Totransfer air loads

(sheet metals)

STRUCTURAL ELEMENTS OF FUSELAGE

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BULKHEAD TYPES:

Open ring type

Close ring type

Full web type

STRUCTURAL ELEMENTS OF FUSELAGE

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STRUCTURAL ELEMENTS OF FUSELAGE

Skin:

Fabric Skin:

* Truss Type

* Slow speed A/C

* Takes only Air Loads & cannot resist shear / bending load.

Stressed skins:* Sheet metal/composites

* Riveted or bonded to the Frames & Stringers.

* Takes Air Loads, Shear, Bending Loads and Torsional Loads

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TOP

SHEET

BOTTOMSHEET

CORE

Engine

Cowling

STRUCTURAL ELEMENTS OF FUSELAGEComposites:

Composite Al.

Density(gm/cc) 1.8 2.4

Strength(Mpa) 1200 400

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Stringer / Longeron:

* A longitudinal stiffener attached toskin

* Increases effectiveness of skin

* Increases Compressive and shearcritical stress.

TYPICAL SKIN & STRINGERASSEMBLY

STRUCTURAL ELEMENTS OF FUSELAGE

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STRUCTURAL ELEMENTS OF FUSELAGE

WALLS & FLOORS:

Transfer the shear load Side walls for fuel tanks

Side walls for landing gear bay.

Tank floors and ceilings

Equipment bay floors

Cockpit floors

TYPICAL FLOOR ASSEMBLY

TYPICAL WALL ASSEMBLY

FLOOR

STRINGERSWALL

LONGERON

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Most important lift-producing part of the aircraft.

Wings vary in design depending upon the aircraft type and its purpose.

The shape of a wing greatly influences the performance of an airplane, Speed ofan airplane, its maneuverability & its handling qualities

Wings also carry the fuel for the airplane.

Types:1. Straight2. Sweep (forward and back)3. Delta

4. Swing-wing.

W I N G

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Straight Wing:* for small, low-speed airplanes

* General Aviation airplanes often of this type* Provides good lift at low speeds & Stable flight* Not suitable for high speeds.

W I N G

Delta Wing:

* Looks like a large triangle from top.

* Can reach high speeds (supersonic aairplanes LCA, Concorde)

* Landing speeds are very fast.

SimpleDelta

ComplexDelta

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Sweep-back Wing:* for most high-speed airplanes.* Creates less drag* More unstable at low speeds.* Take off and Landing at a high rate of speed.

Forward-sweep wing:* Yet to make it into mass production.* Highly maneuverable & highly unstable (X-29).

* Computer-based control system is a must to helpthe pilot fly.

Swing Wing:* Has high lift characteristics of a primarily straight

wing with the ability of the sweepback wing to

enable high speeds. During landing and takeoff, the wing swings into analmost straight position.

During cruise, the wing swings into a sweepbackposition.

W I N G

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ELEMENTS OF WING

Spar: It is a primary beam, which extends tothe full length of the wing.

Rib: a light structure conforming to the shapeof the airfoil over which the skin is attached

and transfers the air load to the spars.Nose rib: Rib between front spar and theleading edge of the airfoil.

Inter-Spar rib: Rib between the adjacentspars.

Nose Rib

Inter sparRib

LighteningHoles

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Spoilers: Located on top of the wings. Opposite effect of flaps and slats.

Reduces lift and increases the drag. Helps the airplane to slow down sooner.

Slats: Located on the leading edge of the wings.

Flaps: Located on the trailing edge of the wings.

Aileron: Hinged on the trailing edge of the wing. Helps in rolling motion of theairplane.

ELEMENTS OF WING

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EMPENNAGE

Commonly called as Tail of A/c.

Consists of Vertical stabilizer(Fin) and horizontal stabilizer(Tail Plane). Stabilizers help the aircraft maintain a straight path through the air as it flies.

Stabilizers act like the feathers on an arrow.

EFFECTS OF CONTROL SURFACES

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EFFECTS OF CONTROL SURFACES

Elevator

AileronRudder

Rudder

Elevator

Aileron

Flap

Slats Spoilers

LANDING GEAR

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LANDING GEAR

MAIN LANDING GEARNOSE LANDING GEAR

Actuated by

Hydraulic System

Absorbs the forcesimposed on the A/c by

take-offs & landings.

NLG can be steeredfrom the cockpit.

MLG is equipped withbrakes for stopping theA/c & steering the A/con the ground.

AIRCRAFT STRUCTURE JOINTS

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AIRCRAFT STRUCTURE - JOINTS

JOINTS:

Structural Elements are joined together to form sub-assembly

Sub-assemblies are joined together to form major assemblies (Fuselage,Wing, Empennage, Canopy & Wind Shield etc.)

TYPES OF JOINTS:

Temporary / Removable joints : Bolted (shear / tension).

Permanent Joints : Riveted and Welded joints.

IMPORTANT JOINTS : Engine mount

Landing gear attachment

Fin attachment

Canopy & wind shield

Wing attachment

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AIRCRAFT STRUCTURE - JOINTS

Landing Gear attachment

AIRCRAFT STRUCTURE JOINTS

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FASTENERS:

AIRCRAFT STRUCTURE - JOINTS

1. Permanent Fasteners(Standard):

Rivets : HS 1005, HS 1006, HS 1014, HUCK MLGPL

Blind Rivets: NAS 1919B, NAS 1921B

(Used where there is no access on the other side)

2. Removable Fasteners (Standard):

Bolts : HS 1001, HS 1002Nuts : 3373A

Anchor Nuts: 3381A, 155H940, 155H942

3. Special Fasteners:

Wing Fuselage Attachment Bolts

MATERIALS

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Aircraft Materials should have:

* Good strength

* Good Stiffness* Less Weight

* High Reliability

Material consideration for selection: Strength to weight ratio (Ultimate tensile strength to Density

) higher the ratio is better.

Stiffness to Weight ratio ( Young's modulus to Density )

Availability

Ease of manufacturing

Cost Effective

MATERIALS

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