At the celebration of the 100th anniversary of the founding of the Communist Party of China held on July 1, five helicopters in the aerial display echelon flew over Tiananmen Square each flying one party flag and four slogans.

Why did the party flag unfold smoothly under the helicopter at the centenary celebration of the Communist Party of China? Special fabrics, "wind pocket" design, "Seven steps to the flag"

China News Service Beijing, July 1 (Ma Shuaisha and Zhang Yajing) Aerial display at the 100th anniversary celebration of the founding of the Communist Party of China held on July 1 The five helicopters in the echelon flew over Tiananmen Square, each flying a party flag and four slogans.

The giant party flag is 9 meters long and 6 meters wide, and the giant slogan is 14 meters long and 2.5 meters wide. It was unscathed and unfolded flatly at a flying speed of 160-180 kilometers per hour at high altitude. In fact, under the aerodynamic impact of such high-speed flight, the tail of an ordinary giant flag will vibrate violently, causing partial damage to the edge of the flag, and then causing the entire flag to be torn.

htmlOn the morning of July 1st, a meeting to celebrate the 100th anniversary of the founding of the Communist Party of China was held grandly in Beijing’s Tiananmen Square. The picture shows the flight celebration performance before the start of the conference. China News Service reporter Sheng Jiapeng Photographed by

In order to develop a huge party flag with high strength and high quality, researchers from the 508th Institute of the Fifth Academy of China Aerospace Science and Technology Corporation applied spacecraft aerodynamic deceleration technology and parachute development experience through aerodynamic-fluid-solid coupling simulation analysis. Analysis, flexible product structure design, test simulation and other means are combined, while drawing on the experience in the development of the "9.3" military parade giant red flag and the National Day 70th anniversary giant red flag, so that the technology of keeping the giant party flag flying at high speeds intact will be more refined.

Selected fabrics and refined craftsmanship

Under the premise of ensuring strength, the lighter the flag material is, the less destructive force it will cause when loaded onto the flag surface. After comparing various types of materials, the 508 Research Institute's development team finally selected a high-strength brocade silk material used for spacecraft parachute canopies as the flag surface material to adapt to the erosion of high-speed airflow.

This material has high strength and light weight. Even if a small area is damaged, there will be no serious detachment and the shaking sound is small. The linear density of its brocade filaments can reach 20 denier or less, and its thickness is only one-third of the diameter of ordinary hair, but its strength can reach twice the strength of ordinary civilian brocade filaments, which is Shenzhou spaceship The parachute canopy material is 17% stronger and 15% lighter.

However, considering that the light transmittance of this material is too strong, 508 Institute worked together with material manufacturers to solve the problem and used a special coating process on the original fabric. This not only improved the appearance, the flag pattern was clearly visible from the ground, but also made the party flag have a lot of characteristics. Good rainproof ability, even if the raindrops fall on the flag surface, they will slide off quickly.

html On the morning of July 1, a meeting to celebrate the 100th anniversary of the founding of the Communist Party of China was held grandly in Tiananmen Square, Beijing. The picture shows the flight celebration performance before the start of the conference. Photographed by China News Service reporter Mao Jianjun

"Wind pocket" design to improve stiffness

In view of the use environment, the stiffness of this light and soft brocade silk material is not enough to meet the requirements of a huge party flag. When encountering high-speed airflow impact in the air, it is not only easy to If it is damaged or torn, the tail of the flag will be greatly deformed, which will greatly affect the display effect of flying. To this end, the 508 Research Institute's development team optimized the flag structure design and improved the overall stiffness of the flag by adding a "wind pocket" structure to the tail of the flag. The cross-section of the

"wind pocket" is a trapezoid, located on both sides of the tail of the flag. The size of the trapezoid is designed according to the size of the flag. When the flag is flying at high altitude, the "wind pocket" is fully inflated to increase the aerodynamic stability of the flag. The existence of the wind pocket can greatly improve the force-resisting ability of the tail of the flag and greatly reduce the pressure of wind on the tail of the flag. It not only ensures that the flag unfolds perfectly and flatly, but also protects the flag from damage.

"Seven steps to build a flag", strict control

After receiving the task of developing and processing party flags and slogans, the 508 Research Institute's development team analyzed, summarized and summarized various flags used in major celebration flying events, forming a unique " The "seven steps to make a flag" technical processing technology is "picking, cutting, dotting, sewing, checking, recording and completing". Each flag material is carefully selected. Those with stains, damage, or broken threads will not be used. Fabrics with obvious color differences will be replaced decisively.

Because it is a huge party flag and slogan, the splicing and sewing of fabrics are required during the processing.Each piece of fabric must be left naturally for more than 12 hours before cutting to release material stress and avoid shrinkage due to stress after cutting, resulting in dimensional deviations.

Each cut flag surface is marked with sewing positioning points to ensure that the flag pattern is perfectly presented after splicing. Each splicing position uses the sewing process of a spacecraft parachute to ensure that the number of stitches within the fixed sewing size meets the range requirements.

After each party flag and slogan is produced, it is inspected and accepted according to the development standards of aerospace parachutes, including raw materials, apparent quality, sewing quality, installation position, and product size. It also has independent and complete quality process records that can be traced layer by layer. From the selection of materials to the finished product, every step of the process is strictly controlled to ensure nothing goes wrong.

This task of developing and processing party flags and slogans follows the red palace lanterns and military parades to commemorate the 70th anniversary of the victory of the Anti-Japanese War, giant red flags, huge red flags for the 70th anniversary military parade of the founding of New China, and large-scale After the inflatable lantern project, it once again took on the task of developing a huge red flag. (End)

Source: China News Network