What are their sizes, how they are made and why do they need to be worn out or partially burned during landing?
At first glance, aircraft tires seem quite small compared to the total size of an aircraft. However, in reality, aircraft tires are much bigger compared to conventional car tires. For example, the tires of a Boeing 737 are up to 27 / 7.75-R15 in inches, meaning they have a diameter of 685.8 mm, a width of 196.85 mm and a rim of 381 mm.
Tire structure of Michelin.
About the chemical composition is similar. Complete aircraft tires are made up of four basic materials: rubber, nylon, some special wires and steel. Rubber here is usually natural rubber, because they have better specifications, such as the ability to disperse heat. However, the structure is formed by a process called vulcanization, with many overlapping layers such as nylon, Kevlar . Technical standards of hardness, durability, abrasion . also more stringent than standard tires, including super sports cars or racing tires.
The gas injected into the tire will be inert like nitrogen, to minimize the increase or decrease of tire pressure due to temperature. Because if it contains a lot of air, steam combined with high temperature and pressure upon landing will make it automatically explode when the limit is reached. And another thing is the inert gas also helps to resist corrosion on the inside of the rim.
PSI is Poundper Square Inch - meaning the pressure in Pound is applied to every Square Inch. And according to reports, aircraft tires are pumped to about 200 psi, 6 times the psi of average car tires. In fact, according to an experiment recorded by National Geographic, the tires of a Boeing 737 aircraft can withstand over 900 psi of pressure before exploding.
This design is to prevent Hydroplaning or Aquaplaning situations, which occur when tires move on slippery roads when it rains. These vertical grooves also help create better grip between the runway surface and aircraft tires, helping to stabilize the direction and assist braking. If the blocks were used in the form commonly found on automobile tires, they would simply burst under pressure at landing.
And all aircraft tires do not need some diagonal groove or other shape to activate or assist in changing direction when traveling like on other means of transport.
Firstly, the tire pressure is very high. Second, each tire has an average load capacity of up to 38 tons and each aircraft will have from 14, 22 or 32 tires depending on size and type so the load will be shared for many tires. Third, the tire is made of durable materials, with a special pattern system. These three things help them to bear good load and operate persistently.
As soon as the plane lands, at the first moment, the tires will slip instead of rolling. The aircraft will drag them along the runway until the tire's rotation speed coincides with the aircraft's speed. This is why aircraft tires often emit smoke every time they land and this also wears off a part of its rubber on the runway. To be able to do this, the state-of-the-art anti-lock brakes designed specifically for the aircraft will squeeze and release the brakes hundreds of times every second, in order to reduce the landing distance to the lowest level.
Most common tire wear comes from landing. The rubber on the tire will partially ignite until the tire rotates at a suitable rotational speed on the ground of the aircraft. This causes great smoke and wears off part of its rubber, leaving it on the runway. Airports often use high pressure water or chemicals to remove this rubber.
An average aircraft tire can make about 450-500 landings before needing to rebuild grooves. A tire can be reworked 7 times over their lifetime. Changing tires can take from 40 minutes to two hours.
In practice, however, each tire manufacturer has specific wear criteria to determine when an aircraft needs tire replacement. Sometimes abnormal problems appear on the tire body such as cracking, breaking, special wear . and they can be replaced immediately.
Even when not in use, the aircraft needs to change tires periodically. Moreover, outside temperatures also affect tire life, for example, aircraft often have to fly over the sea, or have to land at airports with high temperatures near the desert, with runways often available. sandy.
Depending on the type of aircraft, manufacturer and other criteria, aircraft tires are priced from a few dozen USD, several hundred USD to several thousand USD each.
So, if you want to know the specific price of a tire in a specific position on the fuselage, you need to get the serial number on the tire and ask the airline's purchasing department. Prices will also change if you or the airlines have a long-term contract with the tire company.
Yes of course. The storage space for airplane tires looks like the picture above. And not just tires, an airline will store many parts of the aircraft and they are strictly managed by a separate department. They are responsible for purchasing, lending, repairing, exchanging components . for their own company or even another company if required to cooperate.