C919 opens a new route again. How can a tiny aviation tire carry a plane weighing hundreds of tons?

□ Don't respect the principle of becoming a green pine

Recently, China Eastern Airlines' first C919 passenger plane with the aircraft number B-919A flew from Shanghai Hongqiao Airport to Guangzhou Baiyun Airport, marking the official opening of the fourth commercial scheduled route for the domestic large aircraft. The commercial operation of the domestic large aircraft C919 is inseparable from aviation tires that can work normally under high speed and high impact conditions. A medium-sized passenger plane weighs 100 tons after loading, a large passenger plane weighs more than 200 tons after loading, and a super passenger plane weighs about 400 tons after loading. How can a small aviation tire withstand such a heavy weight?

Aviation tires belong to Class A among aircraft parts and are important parts of aircraft. When the aircraft takes off and lands, aviation tires play an important role in taxiing, bearing weight and reducing impact. The take-off and landing time of the aircraft is short, and aviation tires must function in an instant. Therefore, aviation tires are top products in the tire manufacturing industry, and with the rapid replacement of aircraft, the requirements for them are also more stringent.

At present, my country's aviation tires face problems such as strict technical requirements, high material indicators, and complex structural design. The number of aircraft takeoffs and landings will cause certain wear on the tires, resulting in the replacement or renewal cycle of aviation tires during use. Therefore, materials are the basis for the development of aviation tires. In order to make aviation tires adapt to the needs of aircraft development, the research and development and application of aviation tire materials are the current focus.

The skeleton materials of aircraft tires have great potential. Common skeleton materials include nylon cord, aramid cord, polyketone cord, carcass cord, belt cord, etc. Unfortunately, no material can meet all requirements so far. In order to make full use of the advantages of different materials, researchers have designed composite cords. Composite cords are mainly divided into two types: plied composite cords and core-skin composite cords. In this way, the use of improved composite cords can better meet the needs of aircraft tires.

The C919 aircraft, which will soon take its maiden flight, was photographed at the apron of Shanghai Hongqiao Airport in May 2023 (Source: Xinhuanet)

Recently, the bionic synthetic rubber aviation tire developed by the Changchun Institute of Applied Chemistry of the Chinese Academy of Sciences has made a major breakthrough, indicating that my country has transformed natural rubber from an agricultural product into an industrial product, overcoming the stringent requirements of natural rubber quality on geographical location, no longer relying on imports, and dynamically adjusting production according to market demand, solving the technical bottleneck of the entire chain of aviation tires from raw materials to design and manufacturing to evaluation and verification. The bionic synthetic rubber aviation tire has achieved two original technical breakthroughs from "0" to "1" in bionic synthetic rubber and digital tire industrial software, providing a new solution to solve the strategic security of natural rubber in my country.

Only by designing the structure of aircraft tires can aircraft tires be continuously improved and developed. Reasonable structural design can improve the performance and service life of aircraft tires. Aircraft tires are mainly composed of five parts: carcass, tread, sidewall, bead and belt layer. The concentration of stress causes the temperature of the bead to rise and the deformation to increase. In the design of aircraft tires, the optimized design of the outer contour, tread, carcass, etc. is very important. Through structural design, the various components of aircraft tires can be coordinated to produce superior performance. Improving the tread structure can alleviate the radial compression stress of aircraft tires, thereby improving durability and wear resistance. Designing the sidewall to be straight can effectively improve the longitudinal rigidity, thereby eliminating the compression deformation of the bead and improving durability.

Therefore, the research and development of advanced materials and the continuous optimization of tire structure are the reasons why aircraft tires can withstand hundreds of tons of weight. The continuous progress of rubber materials, skeleton materials, production technology and equipment has provided the "soil" for the development of my country's independent aviation tires. Research and development of new materials, optimization of structure and development of new technologies are the development direction of independent and localized aviation tires.

(The author Mo Zunli is a professor and doctoral supervisor at Northwest Normal University, and Cheng Qingsong is a graduate student at Northwest Normal University)