NATIONAL UNIVERSITY OF SCIENCES & TECHNOLOGY

MS DESIGN AND MANUFACTURING 20112nd Semester

DESIGN, DEVELOPMENT AND PROCESS MAPPING OFAIRCRAFT RADIAL TYRE

Product Design and Development

ASSIGNMENT

Submitted to:

Prof. Dr. Liaquat Ali

Submitted by:

Arshad Chaudhry2011-NUST-MS-DME-28Waqas Saleem2011-NUST-MS-DME-21Sajjad Alam2011-NUST-MS-DME-05Yasir Anwar2011-NUST-MS-DME-06Imran Wattoo2011-NUST-MS-DME-04

Date of Submission: 31May, 2012

1.INTRODUCTIONAn aircraft tyre is as a ring shaped covering rubber covering that is installed on a wheel hub. The basic purpose is to protect the wheel and provide a flexible medium that allow absorbing of shocks. The wheel remains in close contact to the surface through the rubber tyre, where any damage to the tyre consequently results in damage to the main wheel hub.Synthetic, natural rubber, fabric and wire, along with other compound chemicals are used as main materials for manufacturing the rubber tyres. The aircraft tyres consist of two main parts i.e., tread and a body.

The purpose of tread is to provide the traction while the wheel body provides support to bear the load of aircraft. Prior to invention of rubber and mere strip of metal was attached to the outer circumference of the wheel hub to protect against wear and tear. Today, the vast majorities of tyres are pneumatic inflatable structures, comprising a doughnut-shaped body of cords and wires encased in rubber and generally filled with compressed air to form an inflatable cushion. Pneumatic tires are used on many types of vehicles, such as cars, bicycles, motorcycles, trucks, earthmovers, and aircraft.

2.CONCEPT DEVELOPMENTTyres are an integral and most essential part of the aircraft as they play a vital role during takeoff and landing phase. During these phases, these are subjected to enormous loading and momentum and thus are prone to much wear and tear as compared to wheels and tyres installed on ground transport vehicles.

We have recently come across with a problem of short life of aircraft wheels on Super-MU. In fact, life of an aircraft tyre and its wheel hub are measured separately and in number of landings and takeoffs. A shortened life of aircraft tyre would entail its replacement much frequently and incur increased cost.

Thus the design team thought of redesigning the tyre for aircraft Super-MU with an increased life and at competitive price as being offered by other manufacturers. It is important that the facilities for rubber production and subsequent processing are already held with Rubber Shops at Aviation Complex. This is mainly a reverse engineering approach while referencing to other aircraft tyre manufacturers and their best practices. The team would focus on manufacturing processes of the aircraft tyre and in this effort wheel hub would not be included as part of effort. The approach would be to make a design, develop manufacturing processes, develop prototype, and devise client acceptability and inspection criteria.

UNDERSTANDING THE OPPORTUNITY3.1MISSION STATEMENT

PRODUCT DESCRIPTIONThe product is an aircraft radial tyre.

BUSINESS CASEProduct would be used on commercial aircraft (Boeing 747).

GOALSTo capture 30% of market share by introducing better quality and durability and extended life of tyres at affordable cost than available in market.

PRIMARY MARKETAll Boeing 747 aircraft operating airlines

SECONDARY MARKETAll individual / private aircraft owners.

ASSUMPTIONS Low Cost Greater number of landings Less wear and tear Low premature failure rate Consistent quality Less care and maintenance requirements

COMPETITORS Good Year Michelin General Bridgestone

STAKE HOLDERS Users (Aircraft operators) Retailers / Distributors Sales & Marketing Service Centers Production Facility Aviation MROs Private aircraft owners

3.2GATHERING THE RAW DATA FROM CUSTOMERSThree methods for data collection were employed Interviews Focus groups Observing the product in useChoosing the customers (10-50 interviews)

The art of eliciting customer needs data Go with the flow Use visual stimuli Suppress preconceived hypothesis about the product technology Have the customer demonstrate the product and/ or typical tasks related to the product Be alert for surprises and the expression of latent needs Watch for non-verbal information

Documenting the interaction with the customers Audio tape recording Notes Video tape recording Still photography

3.2.2Interviews with Users

1. Number of Landings should be greater.2. Premature failure rate should be low.3. Installation/ removal easy.4. No extensive care and maintenance requirements.5. Not of a higher cost.6. Better quality.7. Protection against Weather effects8. Less wear and tear9. Should get fixed on existing wheel hub.10. Should support existing aircraft braking system.11. Should have adequate cooling mechanism after brake applications.12. Should operate in a wide range of temperatures even under extreme weather conditions.13. Should operate at varying nature of landing surfaces.14. Easy access to charge air pressure.15. Must retain the air pressure.

3.3INTERPRETING RAW DATA IN TERMS OF CUSTOMER NEEDS

Express the needs in terms of what the product has to do andnot in terms of how it will do Express the needs as specifically as the raw data Use positive and not negative phrasing Express the need as an attribute of the product Avoid the words must and should

3.3.1Data collection

About 10 to 15 users including technicians, pilots and maintenance engineers working in airlines and aviation MROs were interviewed for seeking customer needs. Additionally, maintenance facilities were visited for studying the existing tyres and the range provided by different manufacturers. All collected customer needs and interpreted needs are being summarized below :

CUSTOMERXYZADDRESSCHAKLALATELEPHONE05190990WILLING TO FOLLOW UPYESINTERVIEWERSPROJECT TEAMDATED15 APRIL, 2012CURRENT USEMICHELINTYPE OF USERCOMMERCIAL

CUSTOMER STATEMENTINTERPRETED NEEDS

Number of Landings should be greater.Tyre life is measured against the number of landings that should be higher enough to match aircraft inspections.

Premature failure rate should be low.Tyre should not fail before completion of assign life in terms of number of landings.

Installation/ removal easy.Procedure and access for removal/installation should be easy and less time consuming.

No extensive care and maintenance requirements.Reduced maintenance at operational and inspection level.

Not of a higher cost.Cost should be affordable vis--vis utility.

Better quality.Rubber of tyre should be of good quality to support described functions and usage.

Protection against Weather effectsWeather effects should have minimal or zero effect on tyre surfaces and rubber.

Less wear and tearCut marks, bruises, blisters and minimal frictional effects should be encountered during the operational life

Should get fixed on existing wheel hub.Tyre design and dimensions should allow it to get installed on existing wheel hub without requiring any modifications in hub assembly.

Should support existing aircraft braking system.Design, dimensions and weight loading capacity of tyre should be enough to support existing aircraft braking system without requiring any type of modification.

Should have adequate cooling mechanism after brake applications.Tyre design should allow instant cooling after brake application under high loading and momentum.

Should operate in a wide range of temperatures even under extreme weather conditions.Tyre should remain intact and in operational condition between temperature ranges from -25C to 60C.

Should operate at varying nature of landing surfaces.Should be able to support aircraft landing at rough surfaces, landing strips, ice and unpaved surfaces.

Easy access to charge air pressure.Charging of air pressure and its checking for inspection should have easy access.

Must retain the air pressureTyre should be able to retain maximum pressure for a longer period of time without requiring frequent charging of pressure.

3.4ORGANIZE THE NEEDS INTO HIERARCHY

Print or write each need statement on a separate card or self-stick note Eliminate redundant statements Group the cards according to the similarity of the needs they express Choose a label for each group Consider creating super groups consisting 2-5 groups Review and edit the organized needs statement

3.5HIERARICHAL NEEDS ARE AS GIVEN BELOW:

S NOINTERPRETED NEEDS

1Tyre life is measured against the number of landings that should be higher enough to match aircraft inspections.

2Reduced maintenance at operational and inspection level.

3Cut marks, bruises, blisters and minimal frictional effects should be encountered during the operational life

4Weather effects should have minimal or zero effect on tyre surfaces and rubber.

5Rubber of tyre should be of good quality to support described functions and usage.

6Tyre should not fail before completion of assign life in terms of number of landings.

7Cost should be affordable vis--vis utility.

8Should be able to support aircraft landing at rough surfaces, landing strips, ice and unpaved surfaces.

9Procedure and access for removal/installation should be easy and less time consuming.

10Tyre design and dimensions should allow it to get installed on existing wheel hub without requiring any modifications in hub assembly.

11Tyre design should allow instant cooling after brake application under high loading and momentum.

12Design, dimensions and weight loading capacity of tyre should be enough to support existing aircraft braking system without requiring any type of modification.

13Tyre should remain intact and in operational condition between temperature ranges from -25C to 60C.

14Charging of air pressure and its checking for inspection should have easy access.

15Tyre should be able to retain maximum pressure for a longer period of time without requiring frequent charging of pressure.

3.6ESTABLISH THE RELATIVE IMPORTANCE OF THE NEEDSGive Numerical importance to each customer need Feature is un-desirable I would not consider a product with this feature Feature is not important I would not mind having it Feature would be nice to have but it is not important Feature is highly desirable but I would consider a product without it Feature is critical I would not consider a product without this feature

S NORELATIVE IMPPORTANCEINTERPRETED NEEDS

15Tyre life is measured against the number of landings that should be higher enough to match aircraft inspections.

25Reduced maintenance at operational and inspection level.

35Cut marks, bruises, blisters and minimal frictional effects should be encountered during the operational life

44Weather effects should have minimal or zero effect on tyre surfaces and rubber.

54Rubber of tyre should be of good quality to support described functions and usage.

64Tyre should not fail before completion of assign life in terms of number of landings.

74Cost should be affordable vis--vis utility.

85Should be able to support aircraft landing at rough surfaces, landing strips, ice and unpaved surfaces.

93Procedure and access for removal/installation should be easy and less time consuming.

103Tyre design and dimensions should allow it to get installed on existing wheel hub without requiring any modifications in hub assembly.

114Tyre design should allow instant cooling after brake application under high loading and momentum.

124Design, dimensions and weight loading capacity of tyre should be enough to support existing aircraft braking system without requiring any type of modification.

133Tyre should remain intact and in operational condition between temperature ranges from -25C to 60C.

143Charging of air pressure and its checking for inspection should have easy access.

153Tyre should be able to retain maximum pressure for a longer period of time without requiring frequent charging of pressure.

3.6LIST OF METRICS AND NEEDS METRICS MATRIX Metrics should be dependent and not independent or variable Metrics should be practical Some needs cant be transferred into quantifiable metrics The metrics should include the popular criteria for comparison in the market place

4.INITIAL DESIGN METHODOLOGYIn order to approach the design and then manufacturing process, the team considered following areas vital to the manufacturing process of aircraft tyres.

1. Functional Requirements2. Material Selection3. Manufacturing and Assembly consideration4. Cost consideration

4.1FUNCTIONAL REQUIREMENTSThe main functional requirements for aircraft tyres are4.1.1 BalanceThe centrifugal forces exerted on the main wheel hub and axle during the rotation of the tyre depends mainly on center of mass and the orientation of their moment of inertia, referred to as balance, imbalance, or unbalance.

4.1.2 Camber thrustIt is the force generated perpendicular to the direction of travel of a rolling tyre due to its Camber angle.

4.1.3Centrifugal growthA high speed rotating tyre develops larger diameter due to the centrifugal forces moving the rubber tread away from the center, which may cause speedometer errors.

4.1.4 Circle of forcesThe circle of forces, traction circle, friction circle, or friction ellipse is a useful way to think about the dynamic interaction between a vehicle's tire and the road surface.

4.1.5 Contact patchThe contact patch is the area of the tread that is in contact with the surface.

4.1.6 Cornering forceCornering force or side force is the lateral force produced during turnings.

4.1.7 Dry tractionIt is the ability of tyre to deliver traction, or grip, under dry conditions.

4.1.8 Force variationThe tire tread and sidewall elements undergo deformation and recovery as they enter and exit the center line area of tyre foot print.

4.1.9 Load sensitivityIt is measured in terms of behavior of tyres under loading and off loading conditions.

4.1.10 Rolling resistanceRolling resistance is the resistance to rolling caused by deformation of the tyre in contact with the surface.

4.1.11 Self aligning torqueIt is the torque that a tire creates as it rolls along that tends to steer it, i.e. rotate it around its vertical axis.

4.1.12 Slip angleIt is the difference between a rolling wheel's actual direction of travel and the direction towards which it is pointing.

4.1.13 Stopping distancePerformance-oriented tyres have a tread pattern and rubber compounds designed to grip the road surface, and so usually have a slightly shorter stopping distance.

4.1.14 Work loadThe work load of a tire is the determination of under undue stress conditions that ,may lead to premature failures of the he tyre.

4.1.15 Tread wearThe tread wear is the wearing and tearing to which the tread of the tyre is subjected during its life span.

4.1.16 et tractionIt refers to the tyre grip under wet conditions on a surface.

4.2MATERIAL SELECTIONKeeping in view the functional requirements of the aircraft tyre as described above, team decided to choose synthetic rubber as one of main fundamental material for aircraft tyre manufacturing. A number of polymers are used to manufacture the aircraft type, brief description of each is given below.

4.2.1 Natural RubberNatural rubber has the chemical name poly-isoprene and consists of polymer chains all having an almost perfect structure. Natural rubber can attain a good regularity when stretched. Hence it crystallizes on stretching, resulting in a high gu, tensile strength. natural rubber is vulcanized with sulphur compounds that can cross link the chains because of presence of reactive double bonds making it stronger.

4.2.2 Poly-Butadiene RubberStereo specific catalysts can be used to polymerize butadiene to a high structure. Most of the poly-butadiene products are of the cis type but may have mix chain structure.

4.2.3 Styrene-Butadiene RubberThese are obtained by mixing two monomers butadiene and styrene. the chains contain random sequence of monomer chains, which gives them rubber like behavior but does not allow to crystallize upon stretching.

4.2.4 ButylThis polymer contains mostly iso-butylene units with just a percentage of iso-prene units. Hence, unlike butadiene and natural rubber products, this polymer contains only a few percentages of double bonds.

4.2.5 Ethylene Propylene RubberThis elastomer is a butadiene with one chlorine atom replacing one hydrogen atom.

4.2.6 NitrileThis is a co-polymer of two monomers, butadiene and acrylonitrile, Like SBR it has an irregular chain structure.

4.2.7 HydrinIt is a copolymer of epichlorohydrin and ethylene oxide that is primarily amorphous with small amounts of crystallite.

4.2.8 RoyalthermIt is a relatively nw compound and is silicone modified EPDM. It is a good value for mechanical properties.

4.2.9 ParelParel elastomer is a sulphur-capable copolymer of propylene oxide and allyl glycidyl ether. This polymer elastomer is finding use in applications where good dynamic properties and flexibility at extremely low temperatures are important.

4.3DESIRED CHARACTERISTICS IN AIRCRAFT TYRE RUBBERSFollowing are few material characteristics that need to be taken into consideration while selecting a material for aircraft tyres.

4.3.1 Tensile StrengthSince the polymer is never extended to more than a fraction of its ultimate elongation and tensile strength because of the presence of reinforcements, there is a considerable amount of controversy regarding the value of the properties. However, the tensile strength is a good estimate of quality of the rubber. It is measured in pounds per square inch. A high value of tensile strength is preferred.

4.3.2 Percentage ElongationThe percentage elongation of the rubbers is the ratio of the change in length to the original length. The percentage elongation is a good indicatot of the quality of rubber and is measured in interval scales ranging from zero to 800.

4.3.3 ModulusThe modulus of rubber is measured usually as the stress in the compound when stretched to three to four times of its original length, the stress is calculated on the basis of the specimens original ;length, a higher value of modulus is preferred.

4.3.4 Heat GenerationThe heat generated in the tyre is the most important factor resulting in its premature failure during the service life. The properties of most polymers changes with heat. A low rate of heat generation would allow greater life for operation.

4.3.5 High TemperaturesHigh temperatures reduce the properties of the polymers and cause the cords to separate.

4.3.6 Fluid ResistanceThe resistances of elastomer to liquids lie in the volume changes that occur with time and temperature, the change in physical properties as the rubber absorbs the liquid, the low temperature flexibility.

4.3.7 AbrasionAbrasion is initiated by the local stress concentrations at the contact between the track asperities and rubber. The abrasion causes the formation of ridges perpendicular to the direction of abrasion. These ridges are saw tooth shaped with the teeth pointing against the direction of abrasion.

4.3.8 TractionTraction is the adhesion of the tyre to the surface. The tract of the tyre depends on three variables, tread design, tyre construction and tread compound.

4.3.9 AdhesionThe capability of the adhesive system is important in determining the mass of tread, the angular speed that this mass can be rotated and the displacement that the tread mass can tolerate when it passes through the surface contact point.

4.3.10 ProcessibilitySince the tyre has to be built on the drum and then cured in the mold, r rheological properties of rubber such as green strength, building tack, and creep resistance are very important properties.

Considering above factors, Butyl was selected as the most appropriate material form manufacturing of the aircraft tyres.

4.4DESIGN AND MODELINGFor the designing and modeling of the aircraft tyres, The Pacejka "Magic Formula" tire models was employed. Pacejka has developed a series of tire design models over the last 20 years. They were named the 'magic formula' because there is no particular physical basis for the structure of the equations chosen, but they fit a wide variety of tire constructions and operating conditions. Each tire is characterized by 10-20 coefficients for each important force that it can produce at the contact patch, typically lateral and longitudinal force, and self-aligning torque, as a best fit between experimental data and the model. These coefficients are then used to generate equations showing how much force is generated for a given vertical load on the tire, camber angle and slip angle.

The Pacejka tire models are widely used in professional vehicle dynamics simulations, and racing car games, as they are reasonably accurate, easy to program, and solve quickly. A problem with Pacejka's model is that when implemented into computer code, it doesn't work for low speeds (from around the pit-entry speed), because a velocity term in the denominator makes the formula diverge. An alternative to Pacejka tire models are brush tire models, which can be analytically derived, although empirical curve fitting is still required for good correlation., and tend to be less accurate than the MF models.

The general form of the magic formula is

where b, c, d and e represent fitting constants and R is a force or moment resulting from a slip parameter k.

4.5Manufacturing Considerations and Major PartsFew of the major considerations that are to be emphasized during the manufacturing of the aircraft tyre are discussed as under.4.5.1 TreadThe tread is the part of the tire that comes in contact with the road surface. The portion that is in contact with the road at a given instant in time is the contact patch. The tread is a thick rubber, or rubber/composite compound formulated to provide an appropriate level of traction that does not wear away too quickly. While designing thetread, void ratios would be kept small to provide more rubber in contact with the road for higher traction, but may be compounded with softer rubber that provides better traction.

4.5.2 BeadThe bead is that part of the tire that contacts the rim on the wheel. The bead is typically reinforced with steel wire and compounded of high strength, low flexibility rubber. The bead seats tightly against the two rims on the wheel to ensure that a tire holds air without leakage. The bead fit is tight to ensure the tire does not shift circumferentially as the wheel rotates. The width of the wheel hub in relationship to the tire is an important factor in decideing the shape of tyre bead.

4.5.3 SidewallThe sidewall is that part of the tire that bridges between the tread and bead. The sidewall is largely rubber but reinforced with fabric or steel cords that provide for strength and flexibility. Sidewalls are molded with manufacturer-specific detail, government mandated warning labels, and other consumer information, and sometimes decorative ornamentation, like whitewalls. Thus the team decided to take guidelines from regulations issued by US Department of Transportation.

4.5.4 ShoulderThe shoulder is that part of the tire at the edge of the tread as it makes transition to the sidewall. The team decided to take guidelines from regulations issued by US Department of Transportation.

4.5.5 PlyPlies are layers of relatively inextensible cords embedded in the rubber to hold its shape by preventing the rubber from stretching in response to the internal pressure. The orientations of the plies plays a large role in the performance of the tire and is one of the main ways that tires are categorized.

4.6ESTIMATED COSTS4.6.1Design CostIn design phase, majority of costs were associated with accessing US Department of Transportation Regulations, internet; A Modeling Software, Rubber Specifications, World Rubber Manufacturer Catalog, Human Resource Pay.

EntityRough Order of Magnitude CostUS Department of Transportation Regulations2500 USDInternet25 USDModeling Software5000 USDRubber Specifications500 USDWorld Rubber Manufacturer Catalog500 USDHuman Resource Pay25 USD Avg/Hour

4.6.2 Manufacturing CostThe manufacturing cost would involve the following costs.

EntityRough Order of Magnitude CostRaw Material100 USD/tyreSpinning and Weaving Process50 USD/tyreCompounding Process75 USD/tyreBead Wiring and Forming25 USD/tyreCarcass Forming25 USD/tyreBuffing15 USD/tyreVulcanizing100 USD/tyreFinishing85 USD/tyreInspection Cost35 USD/tyreHuman Resource50 USD/tyreMachine35 USD/tyreTools15 USD/tyreCost of Quality50 USD if rework required

These costs are estimated to be on average of 610-660 USD per aircraft tire where the company was already buying an aircraft tire from foreign vendor at a price of 2000 USD.

4.6.3 Total Project CostThe total project cost is the sum of both design and manufacturing costs and is estimated to be around 50000 USD on a rough order of magnitude.

5.DFM AND DFA PRINCIPLESFollowing DFM principles were applied during this project.1. The Team decided to use Butyl Rubber for the reasons that it was full filling the requirements for functional parameters and was easily available with rubber manufacturer and retailers and distributors in required grade having desired physical and chemical properties.2. Part features and tolerances were such that these do not require any special processes.3. No special tooling was emphasized except for NDI equipment.4. General tooling was recommended to undertake manufacturing process.5. Most of the dimensions are with general tolerances except the tight tolerance at the Bead.6. Most of the operations involved are low labor cost except the NDI that required high skill and special equipment.7. The process was progressive one as the final part was a single entity.8. Step-by-step and one directional manufacturing technique is applied here.

6.GENERAL PROCESS MAP

Original Design Review

Review Client RequirementClient Requirement

Handed Over to CustomerTesting and EvaluationSimulation and ModelingConceptual DesignDesign ReviewQuality InspectionManufacturingDesign ApprovalDetailed Design6.1MANUFACTURING PROCESS MAP

Cord TwistingWeavingHigh Tensile MachineCalendaringCuttingBandingDipping MachineBanbury MixingBatch Off MachiningHeat RollingTread ExtrudingBead FormingCarcassingVulcanizingFinishingTread SkiveringInspectionRelease

6.2MANUFACTURING PROCESS SCHEMATIC DIAGRAM

7.ACCEPTANCE CRITERIAFollowing acceptance criteria was reversed engineered from the design of the aircraft tyre of company RICHELIN (name changed for confidentiality) for our design.Tyre Size6.00-6Ply Rating6Speed Rating 120 mphLoading1750 lbsPressure42 psiThread DesignRBSkid Depth0.18 inchTyre Weight7.8 lbsMax Unbalance6.0 Oz-inOutside Diameter16.90-17.50 inchSection Width5.90-6.30 inchShoulder Dia15.30 inchShoulder Dia5.8 inchLoaded Radius6.9 InchAspect Ration0.91

8.INSPECTION CRITERIAFollowing is the inspection criteria for the tyre that have been manufactured after processing through above manufacturing steps. The conditions given below are not acceptable.

1.Cuts

2. Swirl Wraps

3.Thread Separation

4.Groove Cracking

5.Rib Undercutting

6.Rubber Heating

7.Cut or Snug

8.Ozone or Weather Cracking

9.Kinked Bead

10.Inner Tyre Damage

9.REJECTION CRITERIA Tires with cuts penetrating into the inner liner and with cuts reaching to more than 40% of the actual number of plies. For Radial tires, cuts reaching 40% of the belt plies.

Tire with cuts and weathering reaching the carcass plies on the sidewall and the bead area.

Tires with spot wearing exposing the carcass or belts.

Tires with signs of cord-melting from overheating at the bead base.

Tires with broken, bent or exposed bead wire.

Tires with wrinkles on the inner liner surface.

Dually mounted tires where one has burst in operation (Both should be scrapped).

Tires with casing separation.

10.TESTING AND VALIDATIONFollowing test would be conducted to check for the good tyre.1.Geometric Test.This test allows for a complete analysis of the tire sidewall and tire tread width areas. These measurements ensure that the tire will not have any defects that were not able to be detected by the uniformity and dynamicbalance tests. These defects could include bulges or depressions in the tiresidewall, as well as in the tire tread that could compromise the integrity ofthe tire and the ride quality of the vehicle.

2.Compression Test.This test helps to determine if the tyre manufactured has the capacity to sustain the loads and aircraft momentum for what it has been designed.

3.Elastomer Check.Elastomer of the tyre rubber after manufacturing is verified to be within the required and specified limits as per the design requirwements.

4.Radiographic Testing.This test helps to detect the subsurface cracks in the rubber of the tyre that can not be detected by normal visual methods.

5.Dynamic Balancing.This test measures tires according to static, couple, and upper and lower plane imbalance. If not properly checked, these forces can cause an aircraft to bounce, have tire wobble, and not steer properly.

6.Uniformity Test.This test measures force variation, run out, and sidewall appearance. Without properly checking these forces, the integrity of tire and quality is dramatically affected. These forces can cause a vehicle to bounce, vibrate, and not steer properly.

7.Wear Rate.Real time simulation of the tyre would be carried out to measure its wearing during brake application under dry and wet conditions. These would provide a good estimate for the life to be assigned to the tyre.

11.CONCLUSIONWith the financial challenges arising from the deregulation of the air-travel industry, the airlines are faced with the challenge of reducing operating costs to remain competitive. As a result, the airlines have demanded that the aircraft manufacturers produce new designs with high reliability and low maintenance requirements. In basic design, costs associated with the aircraft tyre may be reduced by aiming at simplicity, compactness, and minimum weight and maintenance requirements. Simplified design and improved manufacturing techniques, are being used to reduce the part-count.

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