Aircraft tyre technology

•Apr 7, 2023 11

AIR CRAFT TYRE TECHNOLOGY

Presented By GN Sanga

An Aircraft tyre carries 250 to 1,000 times its mass An Aircraft tyre carries 250 to 1,000 times its mass

compared to 50 times for a passenger car tyre, compared to 50 times for a passenger car tyre,

while aircraft tyre temperatures can fall to -50 ˚ while aircraft tyre temperatures can fall to -50 ˚

during flight and reach + 60 ˚ on the runwayduring flight and reach + 60 ˚ on the runway

22

To bring out the salient To bring out the salient features of aircraft tyre features of aircraft tyre technologytechnology

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AIM

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Tyre classification

Tyre construction

Radial Vs Cross ply

Aircraft tyre operating characteristics

Design criteria

SCOPE

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Tyre manufacturing techniques

Tyre testing

Tyre storage

Maintenance practices

Conclusion

SCOPE

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TYRE CLASSIFICATION

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Type I

Type II

Type III

Type IV

Type V

AIRCRAFT TYRE CLASSIFICATION

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Type V

Type VI

Type VII

Type VIII

New design

AIRCRAFT TYRE CLASSIFICATION

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TYRE CONSTRUCTION

Automobile and truck tyreAutomobile and truck tyre

Long operationLong operation Relatively large loadRelatively large load Reasonably high Reasonably high speedspeed Deflection 12-14%Deflection 12-14%

Aircraft tyreAircraft tyre

Tremendous loadTremendous load Very high speedsVery high speeds Deflection 32-35%Deflection 32-35%

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TYRE CONSTRUCTION

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TreadTread

Removes waterRemoves water Increases tractionIncreases traction

Inter Tread FabricInter Tread Fabric

Reinforcement Reinforcement layerlayer Stable and Stable and distortion freedistortion free Protection to Protection to casing pliescasing plies

TYRE CONSTRUCTION

•TYRE CONSTRUCTION

CasingCasing

Layer of high modulus cordLayer of high modulus cord Installed around bed coilsInstalled around bed coils

BreakersBreakers

Added layer of fabricAdded layer of fabric Part of tyre casingPart of tyre casing

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TYRE CONSTRUCTION

BeadsBeads

Holds tyre on wheelHolds tyre on wheel High tensile wireHigh tensile wire Held by apexHeld by apex Filler gives strengthFiller gives strength

ChaffersChaffers

Prevents chaffing damagePrevents chaffing damage Reduces brake heatReduces brake heat Nylon material coated with rubberNylon material coated with rubber

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TYRE CONSTRUCTION

Side wallSide wall

Special rubber with anti oxidantsSpecial rubber with anti oxidants Protection against weatheringProtection against weathering Resistant toResistant to

ContaminationContaminationCutsCutsFlexing Flexing

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TYRE CONSTRUCTION

Inner linerInner liner

Inner face of tyreInner face of tyre Attached to first casing plyAttached to first casing ply Prevents leakage of inflation gasPrevents leakage of inflation gas

Chined tyresChined tyres

Type of nose wheel tyreType of nose wheel tyre Deflects water awayDeflects water away

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TYRE CONSTRUCTION

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Breaker packageBreaker package

For radial tyresFor radial tyres Below treadBelow tread Gives stiffnessGives stiffness Keep circumference constantKeep circumference constant

CasingCasing

Ply of fabric with rubber coated cordPly of fabric with rubber coated cord Cord direction 90 degree to bed directionCord direction 90 degree to bed direction

TYRE CONSTRUCTION

PROPERTIESPROPERTIES Cross-ply Radial

Cut Resistance - Tread NONO YESYESCut Resistance - Sidewall YESYES NONORepairability YESYES NONOTraction NONO YESYESHeat Resistance NONO YESYESWear Resistance NONO YESYESFlotation NONO YESYES

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CROSS-PLY Vs RADIAL

•CROSS PLY / BIAS TYRE

•RADIAL TYRE

2020

TYRE

OPERATING CHARACTERISTICSOPERATING CHARACTERISTICS

Heat GenerationHeat Generation

Heavy loads cause heat generation Heavy loads cause heat generation Heat DissipationHeat Dissipation Internal Heat generationInternal Heat generation

Centrifugal ForcesCentrifugal Forces

Heavy load and high speedHeavy load and high speed Onset of traction waveOnset of traction wave Traction wave lead to groove crackingTraction wave lead to groove cracking

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TYRE OPERATING CHARACTERISTICS

Tensile, compression and Shear forceTensile, compression and Shear force

Internal Tensile ForceInternal Tensile Force Tensile force on outer layer / Inner layerTensile force on outer layer / Inner layer Shear force are developed Shear force are developed Under inflationUnder inflation

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Tread wearTread wear

High operation temperatureHigh operation temperature High Speed BrakingHigh Speed Braking Sharp and Fast turnsSharp and Fast turns

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•TYRE OPERATING CHARACTERISTICS

Tyre Size selectionTyre Size selection

Main wheelMain wheel Loading capability Loading capability Most aft Centre of Gravity Most aft Centre of Gravity

Nose WheelNose Wheel Static LoadStatic Load Dynamic Braking conditionDynamic Braking condition Most forward aft Centre of Most forward aft Centre of GravityGravity

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Number of TyresNumber of Tyres

Tyre Size Tyre Size Inflation Pressure of the TyreInflation Pressure of the Tyre

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Based on static loading Based on static loading Total main gear load Fm is calculated Total main gear load Fm is calculated

Fm = Fm = ln * Wln * W lm+ ln lm+ ln Where lm & ln = distance measured Where lm & ln = distance measured from the aircraft Cg at from the aircraft Cg at its aft limit its aft limit W= Weight of AircraftW= Weight of Aircraft

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CHOICE OF MAIN WHEEL

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TYRE DESIGN

CHOICE OF MAIN CHOICE OF MAIN WHEELWHEEL

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CHOICE OF MAIN CHOICE OF MAIN WHEELWHEEL

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CHOICE OF NOSE CHOICE OF NOSE WHEELWHEEL

Based on Nose wheel load Fn during braking at Based on Nose wheel load Fn during braking at maximum effortmaximum effortFn = Fn = lm lm (W-L) + (W-L) + h hcg cg ( ( axax W - D+T) W - D+T)

lm+lnlm+ln lm+ln g lm+ln g

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CHOICE OF NOSE WHEEL

Where Where L = lift L = liftD = DragD = DragT = ThrustT = ThrustHcg = Height of Hcg = Height of

aircraft cgaircraft cgax ax = Constant = Constantgg

Factor of safety Factor of safety - 7%- 7% Future weight increase Future weight increase - 25 - 25 %%

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ADDITIONAL DESIGN CRITERIA

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AIR CRAFT TYRE

MANUFACTURING PROCESS

Raw materialsRaw materials

Natural rubber or polyisopreneNatural rubber or polyisoprene Styrene-butadiene co-polymerStyrene-butadiene co-polymer PolybutadienePolybutadiene Halobutyl rubberHalobutyl rubber Carbon blackCarbon black SilicaSilica

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Raw materialsRaw materials

SulphurSulphur Complex organic Complex organic compoundscompounds Activators Activators Anti oxidantsAnti oxidants Textile fabricTextile fabric

•STEPS IN MANUFACTURING PROCESS

Rubber (natural or synthetic)Rubber (natural or synthetic) -- 38%38% Filler Filler (carbon black, silica, (carbon black, silica,

carbon chalk)carbon chalk) -- 30%30% Reinforcement materialsReinforcement materials -- 16%16% PlasticizersPlasticizers -- 10%10% ChemicalsChemicals -- 4%4% Anti-oxidantsAnti-oxidants -- 1%1% MiscMisc -- 1%1%

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Typical tyre

Compounding & MixingCompounding & Mixing

Homogeneous mixtureHomogeneous mixtureTwo counter rotating rotors employedTwo counter rotating rotors employedSheet comes out in the form of stripSheet comes out in the form of stripNon-uniform distribution of carbon blackNon-uniform distribution of carbon black

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•BANBURY MIXING

Component preparationComponent preparation

CalenderingCalendering Produce body pliesProduce body plies Large dia rolls squeeze Large dia rolls squeeze rubber into rubber into thin sheetthin sheet Fabric (Textile) CalenderFabric (Textile) Calender Steel Calender Steel Calender

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ExtrusionExtrusion Contains a screw , barrel, drive Contains a screw , barrel, drive heater & dieheater & die Compound is pushed thro’ a die Compound is pushed thro’ a die Can be rolled on spool or cut thro’ Can be rolled on spool or cut thro’ lengthlength

•EXTRUSION – PREPARATION •OF TREADS AND SIDEWALLS

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Bead buildingBead building Single Strand Single Strand Multi StrandMulti Strand


•BEAD PRODUCTION

•STEEL CALENDERING

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Tyre Building

Assembling process

Manual or Automatic

“Green Tyre”

Robot employment


•Inner Liner •Body Ply: Mounting

•Tread Mounting

•TYRE ASSEMBLING PROCESS

•Green Tyre

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Curing

Final shape

Tread patter and engraving

Typical curing time

Car tyre 15min

Air craft tyre 10 – 20 Hrs


•CURING PRESS/MOULD

•Tyre Mould •Tyre Press

•TYRE MOULD & PRESS

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Final product

Operations performed

Uniformity measurement

Balance measurement

X-ray inspection

Visual inspection


•Tyre Balance •Visual Inspection

•TYRE MANUFACTURING

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AIR CRAFT TYRE TESTING

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AIRCRAFT TYRE TESTING

Dynamic Testing on Dynamometers

Tread Wear Testing

Physical Properties Testing

Non-Destructive evaluation

Hydrostatic Burst Testing

Static Testing

AIRCRAFT TYRE TESTING MACHINE

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Dynamic Testing on Dynamometers

Taxi Takeoff Landing Taxi Cross-wind Landing Rejected Takeoff Taxi Durability Double Overload Takeoff Flat Spot Decay Cornering Force


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Tread Wear Testing

Taxi Takeoff

Landing Taxi

Camber Taxi

µ-slip with braking

Runway Simulation


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Physical Properties Testing

Vertical Load Deflection

Lateral Load Deflection

Fore/Aft Load Deflection

Tread Force Measurement

Tread Pressure Measurement

Tread Slip Measurement


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Non-Destructive evaluation

Separations

Looseness (Fatigue)

Low Inter ply Adhesion

Porosity and Voids

Trapped Air and Bubbles

Poor Cord Adhesion

Broken Cords


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Hydrostatic Burst Testing

10,000 psi Maximum Capacity

Variable Pressure Rate

Computer Generated Plots


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Static Testing

Vertical Load Deflection

Lateral Load Deflection

Torsional Load Deflection

Combined Load

Bead Break Resistance

Bottoming Load Deflection


•Apr 7, 2023 6363

AIR CRAFT TYRE STORAGE

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AIRCRAFT TYRE STORAGE

Handling of tyreHandling of tyre

Two prong fork/ sharp Two prong fork/ sharp equipmentsequipments

Wide & flat fork truckWide & flat fork truckRounded bar through centreRounded bar through centre

•TYRE HANDLING

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Ozone EffectOzone Effect

Atmosphere ozoneAtmosphere ozoneOzone by industriesOzone by industriesOzone and organic materialsOzone and organic materials

•OZONE EFFECT

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Avoiding OzoneAvoiding Ozone

Avoid strong air currentsAvoid strong air currentsAvoid electric devicesAvoid electric devicesProtective chemicals Protective chemicals

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Ideal StorageIdeal Storage

Cool, dry & no direct sunlightCool, dry & no direct sunlightNo fluorescent lamps, electric No fluorescent lamps, electric

devicesdevicesNo contact with POLNo contact with POL

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Ideal StorageIdeal Storage

Stored verticallyStored verticallyFlat and wide surfaceFlat and wide surfaceFirst in-first outFirst in-first out

Lightly lubricated with talc powderLightly lubricated with talc powder

•TYRE STORAGE

•TYRE STACKING

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StackingStacking

Stacking permissibleStacking permissible Up to 40 Inches Up to 40 Inches - 5 - 5 Between 40 and Between 40 and 49 inches - 449 inches - 4 Over 49 inches Over 49 inches - 3 - 3

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AIRCRAFT TYRE

MAINTENANCE PRACTICES

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INFLATION PRESSURE MAINTENANCE

Under inflated Tyre

External Heat

Internal Heat

Over inflated Tyre

PERIODICITYPERIODICITY OF PRESSURE CHECKOF PRESSURE CHECK

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Every 24 HoursEvery 24 Hours

Before every flightBefore every flight

IDEAL WAY TO CHECK TYRE PRESSUREIDEAL WAY TO CHECK TYRE PRESSURE

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Use of calibrated pressure gauge

Ambient Temperature

Sl No.

Measured pressure range(% of Operational pr.)

Tyre status

01 More than 105 % Over inflated02 From 105 to 100 % Correct pressure

03 From 100 to 95 % Permitted pressure decrease per day

04 From 95 to 80 % Under inflated05 Less than 80 % Flat tyre

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RECOMMENDED TYRE PRESSURES

WEAR LIMITSWEAR LIMITS

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Retreadable Tyres

Non Retreadable Tyres

Wet Surfaces

Dimpled Tyres

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DAMAGE LIMITS

Chevron cutting

Tread chunking

Cut damage

Casing plies cut

Tread Cut more than 50% deep

Tread Cut more than 50% across

Shoulder wear

Side Wall Cracking

•CHEVRON CUTTING

•TREAD CHUNKING

•SIDE WALL WEAR

•TIRE BURST

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HAPPY LANDINGS !

Aircraft tyre technology

Technology

Transcript of Aircraft tyre technology