Why Are These 2 Fabrics So Cattle? Special Fabric Like The Shenzhou Spaceship Parachute

In the grand parade to commemorate the 70th anniversary victory in the war of resistance against Japan, helicopters flew the two flags flying across Tiananmen at a speed of 180 kilometers an hour, and were inspected by the leaders of the party and the state.

The national flag is 9 meters long and 6 meters wide, and the flag is 7.5 meters long and 6 meters wide.

This is the first time China has hoisted such a huge flag to fly at such a high speed.

It is not simple to let flags and military flags flutter in high speed, but this is a major problem in the preparations for parade.

180 kilometers an hour, skimming through the air without damage.

What are these two red flags?

Why?

China used the parachute technology of the Shenzhou spacecraft to return to land and made huge national flag and military flag.

In September 3rd, in commemoration of the 70th anniversary victory in the war of resistance against Japan, the two flags were hoisted by helicopters flying over Tiananmen at a speed of 180 kilometers per hour, and were inspected by the leaders of the party and the state.

The national flag is 9 meters long and 6 meters wide, and the flag is 7.5 meters long and 6 meters wide.

This is the first time China has hoisted such a huge flag to fly at such a high speed.

It is not simple to let flags and military flags flutter in high speed, but this is a major problem in the preparations for parade.

The red flag is stronger than the super typhoon.

About one hundred days from the parade, the Beijing Institute of space technology of the China Academy of space technology received a request for assistance.

At that time, the huge red flag high-speed flight damaged, poor performance problems, has plagued the parade preparation unit for several months.

As the development unit of China's only Spacecraft Recovery and landing technology, Beijing space Electromechanical Research Institute immediately organized parachute experts to develop red flag.

Jiang Changhong, director of parade red flag project at Beijing space Electromechanical Research Institute, said that the red flag hung on the plane's cable will be subjected to tremendous airflow, and the wind will be stronger than the super typhoon.

"The red flag used for everyday use will be torn to cloth at this speed."

However, the parade protection unit put forward the red flag not only can not swing at will, but also in the stretch state, and after high-speed flight, the wire is not damaged.

Red flag and parachute in the air state is similar and not exactly the same, for parachute experts, this is also a new topic.

Experts say that from the traditional aerodynamic point of view, the load of red flag without any "burden" in the air is far less than the parachute of the Shenzhou spacecraft returning to the cabin weighing about 3 tons.

However, it is precisely because of this light state that the red flag is uncontrolled and uncontrolled at high speed, which leads to serious damage to the red flag in a short period of flight.

Teng Hai Shan, who has more than 20 years of experience in parachute design and has been a deputy chief engineer of the recycling lander, carefully studied the damaged red flag before.

They found that the red flag in flight is exactly the same as the force in the park, and all the forces are concentrated in the tail. Therefore, it is necessary to make a special design for the red flag tail.

Jiang Changhong said, every time the red flag's swing shape is completely different, and the force corresponding to each shape is different from the wind on the flag surface. We must calculate clearly the force of each wind on the red flag at any time. This is the problem of fluid mechanics.

After the red flag is subjected to the force of the wind, it is necessary to calculate immediately how the red flag will swing. This is the problem of solid mechanics.

The original fluid mechanics problems and the separate solid mechanics problems have already been very complicated. It is more difficult to solve these two problems and solve them.

The expert set up a simulation model of huge red flag's dynamic characteristics in high-speed flow field, and carried out a lot of simulation calculations.

Every time the flag flags for one second, it will have to be calculated on a high-performance workstation for a day.

After the calculation, experts prescribe the prescription: the first thing to do is to limit the sharp swing of the red flag, secondly to replace the new suitable materials, and finally to improve the quality of sewing and curling.

Special fabric like the Shenzhou spaceship parachute

The red flag used special cloth like the Shenzhou spaceship parachute.

Jiang Changhong said: "the parachute made of this material can carry a manned spacecraft re-entry capsule weighing up to 3 tons, and the parachute can be folded and placed in a large trunk.

If you use this cloth to make a garment, it is lighter than an egg.

This material has been widely applied to daily necessities, such as the popular ultra light breathable outdoor skin windbreaker, easy to carry and durable shopping bags.

The red flag fabric is specially made by specialized manufacturers.

After each arrival, the developer hung up the cloth and irradiated the cloth with more than 50 strong light lamps.

The density, the uniformity of dyeing and the effect of color under illumination are carefully examined to ensure that every inch of cloth used for red flag processing meets the requirements.

However, if the red flag made of this material is too pparent, the flying display will not be effective.

Therefore, the Beijing Institute of space mechanics and electronics invited special materials research and development manufacturers to spread a special coating on the cloth, even if the red flag's pmittance is just right, ensuring the brightness of the long distance viewing on the ground, and enabling the red flag to have good rain proof ability, so as to cope with the bad weather such as moderate rain and strong wind.

During a flight drill, a heavy rain came unseen, and the red flag stood the test in the rain for nearly an hour.

Sewing and stitching site (China Institute of space technology)

"Acupuncture skill"

The technical content of the huge red flag is not only reflected in the design, but also in the production.

The red flag is large, and the cloth is not so wide, so the space parachute sewing technology is used to splice seven pieces of cloth together.

This technology is essentially the same as sewing clothes at ordinary times, but the sewing used in space parachute has strict requirements for sewing machine selection, sewing form, sewing width, stitch length, suture tightness, sewing material and so on. It must meet the requirements of space standards.

If we make garments according to the space standards, the cost will be higher, but the quality of the products will be absolutely first-class, and it will not be opened for decades.

According to introducing, as the only unit engaged in the research of Spacecraft Recovery and landing technology in China, Beijing space Electromechanical Research Institute has seized many key technologies in the field of Spacecraft Recovery and landing, and has successfully completed the spacecraft.

The development of more than 30 types of recovery systems, such as cabin and return satellite, has made China the third country in the world to independently master the technology of spacecraft return. The success rate of recovery is at the advanced level in the world. For example, the collection of Shenzhou series spacecraft has been completed with perfect results, ensuring the safe and healthy return of ten astronauts. The Chang'e five test vehicle has successfully landed, ensuring that China's lunar exploration phase three reentry and return flight test has been completed successfully.

The Beijing space Electromechanical Research Institute has also developed giant red palace lanterns in the grand celebration of National Day 50th anniversary and 60th anniversary parade.