•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

•Apr 7, 2023 33

AIM

•Apr 7, 2023 44

Tyre classification

Tyre construction

Radial Vs Cross ply

Aircraft tyre operating characteristics

Design criteria

SCOPE

•Apr 7, 2023 55

Tyre manufacturing techniques

Tyre testing

Tyre storage

Maintenance practices

Conclusion

SCOPE

•Apr 7, 2023 66

TYRE CLASSIFICATION

•Apr 7, 2023 77

Type I

Type II

Type III

Type IV

Type V

AIRCRAFT TYRE CLASSIFICATION

•Apr 7, 2023 88

Type V

Type VI

Type VII

Type VIII

New design

AIRCRAFT TYRE CLASSIFICATION

•Apr 7, 2023 99

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%

•Apr 7, 2023 1010

TYRE CONSTRUCTION

•Apr 7, 2023 1111

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

•Apr 7, 2023 1313

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

•Apr 7, 2023 1414

TYRE CONSTRUCTION

Side wallSide wall

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

ContaminationContaminationCutsCutsFlexing Flexing

•Apr 7, 2023 1515

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

•Apr 7, 2023 1616

TYRE CONSTRUCTION

•Apr 7, 2023 1717

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

•Apr 7, 2023 1818

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

2121

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

2222

TYRE OPERATING CHARACTERISTICS

Tread wearTread wear

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

2323

TYRE OPERATING CHARACTERISTICS

•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

2525

TYRE OPERATING CHARACTERISTICS

Number of TyresNumber of Tyres

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

2626

TYRE OPERATING CHARACTERISTICS

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

2727

CHOICE OF MAIN WHEEL

•Apr 7, 2023 2828

TYRE DESIGN

CHOICE OF MAIN CHOICE OF MAIN WHEELWHEEL

2929

CHOICE OF MAIN CHOICE OF MAIN WHEELWHEEL

3030

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

•Apr 7, 2023 3131

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 %%

•Apr 7, 2023 3232

ADDITIONAL DESIGN CRITERIA

•Apr 7, 2023 3333

AIR CRAFT TYRE

MANUFACTURING PROCESS

3434

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

•Apr 7, 2023 3535

MANUFACTURING PROCESS

•Apr 7, 2023 3636

MANUFACTURING PROCESS

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%

•Apr 7, 2023 3838

MANUFACTURING PROCESS

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

•Apr 7, 2023 3939

MANUFACTURING PROCESS

•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

•Apr 7, 2023 4141

MANUFACTURING PROCESS

•Apr 7, 2023 4242

MANUFACTURING PROCESS

Component preparationComponent preparation

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

•Apr 7, 2023 4444

Component preparationComponent preparation

Bead buildingBead building Single Strand Single Strand Multi StrandMulti Strand

MANUFACTURING PROCESS

•BEAD PRODUCTION

•STEEL CALENDERING

•Apr 7, 2023 4747

Tyre Building

Assembling process

Manual or Automatic

“Green Tyre”

Robot employment

MANUFACTURING PROCESS

•Inner Liner •Body Ply: Mounting

•Tread Mounting

•TYRE ASSEMBLING PROCESS

•Green Tyre

•Apr 7, 2023 4949

Curing

Final shape

Tread patter and engraving

Typical curing time

Car tyre 15min

Air craft tyre 10 – 20 Hrs

MANUFACTURING PROCESS

•CURING PRESS/MOULD

•Tyre Mould •Tyre Press

•TYRE MOULD & PRESS

•Apr 7, 2023 5252

Final product

Operations performed

Uniformity measurement

Balance measurement

X-ray inspection

Visual inspection

MANUFACTURING PROCESS

•Tyre Balance •Visual Inspection

•TYRE MANUFACTURING

•Apr 7, 2023 5454

AIR CRAFT TYRE TESTING

•Apr 7, 2023 5555

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

•Apr 7, 2023 5757

Dynamic Testing on Dynamometers

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

AIRCRAFT TYRE TESTING

•Apr 7, 2023 5858

Tread Wear Testing

Taxi Takeoff

Landing Taxi

Camber Taxi

µ-slip with braking

Runway Simulation

AIRCRAFT TYRE TESTING

•Apr 7, 2023 5959

Physical Properties Testing

Vertical Load Deflection

Lateral Load Deflection

Fore/Aft Load Deflection

Tread Force Measurement

Tread Pressure Measurement

Tread Slip Measurement

AIRCRAFT TYRE TESTING

•Apr 7, 2023 6060

Non-Destructive evaluation

Separations

Looseness (Fatigue)

Low Inter ply Adhesion

Porosity and Voids

Trapped Air and Bubbles

Poor Cord Adhesion

Broken Cords

AIRCRAFT TYRE TESTING

•Apr 7, 2023 6161

Hydrostatic Burst Testing

10,000 psi Maximum Capacity

Variable Pressure Rate

Computer Generated Plots

AIRCRAFT TYRE TESTING

•Apr 7, 2023 6262

Static Testing

Vertical Load Deflection

Lateral Load Deflection

Torsional Load Deflection

Combined Load

Bead Break Resistance

Bottoming Load Deflection

AIRCRAFT TYRE TESTING

•Apr 7, 2023 6363

AIR CRAFT TYRE STORAGE

•Apr 7, 2023 6464

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

6666

AIRCRAFT TYRE STORAGE

Ozone EffectOzone Effect

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

•OZONE EFFECT

•Apr 7, 2023 6868

AIRCRAFT TYRE STORAGE

Avoiding OzoneAvoiding Ozone

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

•Apr 7, 2023 6969

AIRCRAFT TYRE STORAGE

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

•Apr 7, 2023 7070

AIRCRAFT TYRE STORAGE

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

•Apr 7, 2023 7373

AIRCRAFT TYRE STORAGE

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

•Apr 7, 2023 7474

AIRCRAFT TYRE

MAINTENANCE PRACTICES

7575

INFLATION PRESSURE MAINTENANCE

Under inflated Tyre

External Heat

Internal Heat

Over inflated Tyre

PERIODICITYPERIODICITY OF PRESSURE CHECKOF PRESSURE CHECK

•Apr 7, 2023 7676

Every 24 HoursEvery 24 Hours

Before every flightBefore every flight

IDEAL WAY TO CHECK TYRE PRESSUREIDEAL WAY TO CHECK TYRE PRESSURE

•Apr 7, 2023 7777

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

•Apr 7, 2023 7878

RECOMMENDED TYRE PRESSURES

WEAR LIMITSWEAR LIMITS

•Apr 7, 2023 7979

Retreadable Tyres

Non Retreadable Tyres

Wet Surfaces

Dimpled Tyres

•Apr 7, 2023 8080

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

8282

HAPPY LANDINGS !