Сборка шины и колеса

Обзор

Aircraft tire and wheel assemblies are among the most highly engineered components on any commercial aircraft, designed to withstand extreme loads, high speeds, and temperature ranges that have no parallel in ground vehicle applications. A main gear tire on a wide-body aircraft must support loads approaching 30 tonnes per tire during maximum landing weight operations, accelerate from rest to 290 km/h (180 mph) in a few seconds during takeoff, survive the thermal shock of landing friction, and then cool sufficiently for reuse within a typical airline turnaround of 30–60 minutes. These requirements demand materials and construction techniques far beyond those used in automotive or truck tires.

Aircraft tires are radial or bias-ply tubeless designs inflated with nitrogen rather than air. Nitrogen is used instead of air because it is inert — it does not support combustion or react with rubber compounds at elevated temperatures — and because its low moisture content prevents ice formation inside the tire at high-altitude temperatures and eliminates the pressure variation associated with humidity changes.

Принцип работы

Aircraft tires are constructed with multiple plies of high-tensile nylon, aramid, or steel cord fabric embedded in rubber, forming a belt structure capable of containing nitrogen at 200–250 psi (main gear) or 130–170 psi (nose gear) depending on aircraft type. The wheel itself is a forged two-piece assembly — typically aluminium alloy 2014-T6 or 7050-T74 — bolted together at a split-rim joint that allows tire mounting and removal. Some wide-body main gear wheels are magnesium alloy to reduce weight despite magnesium's higher flammability risk, which is managed by fire detection and suppression around wheel assemblies.

During takeoff, the tire accelerates from rest to rotation speeds producing centrifugal stresses that stretch the belt structure radially. At maximum speed, the contact patch flattens as the tire absorbs aircraft weight, generating friction heat in the tread compound. At liftoff, the spinning wheel must be contained within the wheel well; most aircraft do not actively brake the wheels after gear retraction, relying on aerodynamic drag within the wheel well to decelerate the spinning assembly. On some aircraft, a wheel-spin-down sensor confirms tire rotation has ceased before the wheel well doors close.

Основ��ые компоненты

• Tread: Outer rubber compound designed for high friction, abrasion resistance, and heat rejection. Aircraft tires are retreaded multiple times during their service life, with full tread sections replaced while the carcass and belt structure are reused.
• Belt Package: Multiple layers of high-tensile cord fabric providing structural integrity. Radial tires use cords running radially from bead to bead; bias-ply tires use cords at an angle to the centerline, providing a stiffer sidewall.
• Beads: High-strength steel wire bundles at the tire's inner edges that lock into matching grooves in the wheel halves, providing the pressure seal and transferring loads from the tire to the wheel.
• Wheel Halves: Forged alloy structural components with machined brake disc drive key slots (for rotor attachment), valve stem port, and bolt flange for half-joining. Must withstand brake heat conduction and transfer.
• Thermal Fuse Plugs: Pressure-relief plugs in the wheel rim that melt at a preset temperature to safely deflate the tire before pressure build from brake heat causes a blowout.
• Tire Pressure Monitoring (TPMS): Integrated pressure and temperature sensors transmitting data to cockpit tire pressure indication systems, available on modern aircraft to detect under-inflation before takeoff.

Применение на воздушных судах

• Boeing 737-800 — main gear: 50×20.0-22 tubeless bias-ply at approximately 195 psi; nose gear: 27×7.75-15 at approximately 175 psi; four main wheels total
• Airbus A320-200 — main gear: 46×17R20 radial at approximately 192 psi; nose gear: 30×8.8R15 at approximately 181 psi
• Boeing 777-300ER — main gear: 52×21.0-23 at 220 psi; twelve main wheels plus two nose wheels; highest individual wheel loads in commercial narrowbody service
• Boeing 787-9 — main gear: 52×21.0-23; nitrogen inflation standard; TPMS standard equipment

Преимущества и ограничения

Aircraft tires are extraordinarily durable relative to their operating conditions — a main gear tire typically achieves 200–400 landings before requiring retread, and the carcass may be retreaded six to eight times before condemnation. The use of nitrogen inflation provides consistent pressure over wide temperature ranges and eliminates corrosion risk from oxygen and moisture. Radial tire designs offer lower rolling resistance than bias-ply alternatives, contributing modestly to fuel efficiency during taxi operations.

The primary operational risk is under-inflation, which causes excessive flexing of the sidewall, generates internal heat, and can lead to rapid structural failure at speed. Under-inflation by 25 percent can reduce tire life by 50 percent; severe under-inflation risks a blowout during the takeoff roll. Pre-flight walk-around inspection includes visual tire condition and tread depth checks, supplemented by TPMS data on equipped aircraft. Foreign Object Damage (FOD) on runways and taxiways remains a persistent threat, with cuts or penetrations capable of causing pressure loss or structural failure. The use of very high inflation pressures means even small punctures can lead to rapid deflation.