https://www.aviationpros.com/engines-components/aircraft-airframe...

https://www.aviationpros.com/engines-components/aircraft-airframe-accessories/wheels-brakes/article/12256790/the-business-of-wheel-and-brake-mro

One of the oftenoverlooked, and certainly the least glamorous area of aircraft are the wheelsand brakes. Essential to the start and finish of each flight and of course allground movements, these expensive assets undergo tremendous force,environmental and temperature variances on each and every flight.

The regional andcommercial aircraft wheel and brake market is dominated by four OEMs, namely:Honeywell, UTC Aerospace, Meggitt, and Messier-Bugatti-Dowty. All productsfollow a similar construction, although boltless wheels are becoming morepopular now, as are carbon brakes.

Citation

Smith, S.M. (1986),"Aircraft Wheel Design and Proving", Aircraft Engineering andAerospace Technology, Vol. 58 No. 7, pp. 8-13. https://doi.org/10.1108/eb036311

Abstract

Aircraft manufacturers nowdemand wheels which are not only light but also have a long life capability. Atypical civil aircraft project such as the Boeing 757, requires a fullyapproved wheel with a demonstrated life of 50,000 roll miles which equates toapproximately 10,000 landings.

https://www.futuremarketinsights.com/reports/aircraft-wheels-market

https://aerospace.honeywell.com/en/learn/products/wheels-and-braking-systems

Honeywell's wheels and brakingsystems serves a broad portfolio of commercial and military aircraft, from thedemanding missions of the advanced F-35 Joint Strike Fighter, to theindustry-leading durability and energy absorption on the Airbus A380 – theworld’s largest airliner.

With customers ranging fromcommercial and defense aircraft operators, as well as airframe originalequipment manufacturers, Honeywell is focused on advancing aerospace technologyand worldwide service support through product innovation and a firm commitmentto customer satisfaction.

Our development teams continueto lead new industry standards in friction material performance and systemssolutions as we invest in next-generation technologies and advanced processes.

For more than 75 years,Honeywell has designed and manufactured aircraft wheels and brakes. Withmanufacturing and engineering centers in the U.S. and China, and repair andoverhaul (R&O) shops around the world, Honeywell is committed to advancingits technology and services worldwide to excel as the preferred supplier ofaerospace wheels and brakes to the industry.

Why Honeywell?

Aerospace wheels and brakingsystem design and manufacturing experience since the 1920s

Delivering excellence to theaviation industry through manufacturing, distribution, product support, repairand overhaul, and asset management services

Global R&O reach withfacilities in North America, Europe and Asia and licensees around the world

The superior support and globalservice reach of Honeywell’s R&O network ensures that every day, hundredsof airline customers provide safe, on-time and reliable transportation tothousands of passengers in diverse conditions

Advanced design capabilitiesincluding structural, thermal and dynamic analysis

Effective Tier 1 systemsintegration, engineering and program management for large, complex programs

Integrated solutionsencompassing brake control and landing gear systems

Collaborative design practicesand 3D model competencies for aircraft integration

Leading materials technologyresearch and development (R&D), non-destructive scanning and advancedlaboratories

Sustained quality improvementdriven by Six Sigma and Honeywell Operating System (HOS) foundations

Health monitoring andpreventive maintenance systems with data connectivity across the range ofaircraft equipment

https://www.parker.com/portal/site/PARKER/menuitem.c17ed99692643c6315731910237ad1ca/?vgnextoid=e5d76d8a0465e210VgnVCM10000048021dacRCRD&vgnextfmt=EN

https://aerosavvy.com/aircraft-wheels/

Airliner wheels aresubjected to the daily punishment of multiple takeoffs and landings. Tires areexposed to temperatures below -40°C during cruise. At touchdown, rubbertemperatures can momentarily exceed 200°C.

Wheels must handle themost extreme torture in aviation: a maximum weight, high-speed rejectedtakeoff: A fully loaded aircraft accelerates to takeoff speed, then stops onthe remaining runway. Tires withstand extreme heat and stress until theaircraft is safely stopped.

Few aircraft componentstake more daily abuse than the tire and wheel assembly.

Wheel Construction

Aircraft tires are toorigid to be forced onto a rim like automotive tires. Aircraft wheel hubs comein two parts. The inboard and outboard hubs are bolted together with the tirein the center, then pressurized with nitrogen.

Nitrogen Instead of Air

Graphic representation ofa Nitrogen molecule. Two nitrogen atoms connected by 3 lines.

A gas station air pump isfine for filling car tires, but large airliner tires must be filled with aninert, dry gas. Nitrogen is inexpensive and perfect for the job.

Nitrogen-filled tiresreduce the chance of fire or explosion (it’s an FAA regulation). Tire rubber isflammable and wheel brakes reach very high temperatures. A large tire with 200psi of atmospheric air would provide a lot of oxidizing power to feed a fire.Nitrogen does not support combustion, greatly reducing the risk of a tire fireor explosion.

Tire Pressure

Large airliners are heavy(right?). A Boeing 767 has a max takeoff weight of over 400,000 pounds. A fullyloaded 747-8 weighs nearly a million pounds. All that weight rides on a handfulof tires.

Automobile tires arepressurized to around 30-40 psi. If large aircraft tires were filled with 35psi, they would be flat under the weight.

Large aircraft tirepressures are ridiculously high. A Boeing 767-300 main wheel is inflated to 205psi. The high pressure supports the tire’s maximum rated load of 51,000 lbs.

https://www.hydro.aero/en/newsletter-details/what-you-should-know-aboutaircraft-wheels.html

Aircraft tires need towithstand an extremely wide range of temperatures that go from minus 60 degreesCelsius at an altitude of 10,000 meters to extremely high temperatures whenlanding in the world’s hottest regions. Add to that the fact that a long-rangeairplane such as the B747 will complete a total of more than 15,000 takeoffsand landings throughout its life, and it should come as no surprise that thetires on that aircraft will be changed over one hundred times.