I ask you to build tractors, but you build rockets?

On September 13, the official Weibo of the Aviation Development Commission released the launch notice of the Wentian and Mengtian experimental cabins on September 19 and 20.

The space agency is almost being led astray by Xinyuan. The pace is getting faster and faster, and it pays more attention to time efficiency. It also chooses to launch intensive launches of such important spacecraft.

Of course, the biggest reason is that there are many Xinyuan-2 rockets that can perform the mission, and it is very simple to extract two.

The Wentian and Mengtian experimental modules each weigh about 43 tons, and the Tiangong Space Station in the sky has continued to increase in operational quality due to high-frequency supply launches over the past year.

After the two experimental modules are launched, the Tiangong Space Station will surpass the Hila Space Station by a single digit advantage and once again become the world's second largest orbiting man-made object with a mass of 230 tons.

The Hila space station ranks third with a mass of 225 tons, while the axial module of the Advance ranks fourth with a mass of 220 tons.

It is a pity that the axial module of the Advance has a higher orbit, and it is not designed to dock with the space station. Otherwise, the combination would instantly surpass the ISS.

After the Aviation Development Commission released the trailer, Ma Yilong himself rarely appeared in the comments below, and then the Aviation Development Commission replied inviting Ma Yilong to come to Qiongzhou to watch the rocket launch.

Ma Yilong's reply was: "There is a chance."

In a seemingly simple and ordinary online interaction, both parties expressed their respective attitudes tacitly. As for Lao Ma himself?

When he sent the message, he had already decided to take a flight to Shanghai on the 17th and rush to China as soon as possible.

…

At the desert base, under the watchful eyes of Yang Wei and Yiqian base designers, a gray J-20 with different colors on the surface, as if the metal was oxidized, was pushed out of the hangar.

The trailer towed the verification aircraft, with the number 2201 painted on the side on the new surface, to the end of the runway. The cabin was opened for final inspection by the ground crew. The pilot in a gray spacesuit sat not far away, waiting for him to take the stage.

Yang Wei looked at the strong sunlight above his head and gave a thumbs up to the base researchers next to him:

"It's awesome that the heat-insulating invisible coating can be done so quickly."

"Not really. In fact, this has previous technical reserves. It just took some time to prepare."

The desert base has been carrying out the "Snow Falcon" project for more than half a year. Now it has finally completed the original design of the aircraft body and is ready to enter the trial production research stage.

An important technology of the Snow Bird Project is the thermal insulation/stealth coating that can withstand ultra-high temperatures.

Although in fact, the body temperature of an aircraft operating at 10 times the speed of sound can reach a maximum temperature of over 1,600 degrees Celsius when it violently rubs against the atmosphere, and the rest is around 700 to 800 degrees Celsius.

In theory, infrared remote sensing satellites can detect such high temperatures, but satellites also have blind spots, right? It is not easy to detect without obtaining the accurate flight path of the aircraft, so stealth is still the focus of consideration.

For example, the SR71 "Blackbird" reconnaissance aircraft has a maximum body temperature of more than 450 degrees when flying at speeds above Mach 3.2, and the average temperature exceeds 260 degrees, but the radar reflection area is less than 1 square meter. It is a typical stealth aircraft.

The goal set by the desert base for the snow swans is that the radar reflection area is less than 0.15 square meters.

The radar reflection area of ​​the J-20 is less than 0.05 square meters. The aerodynamic configuration and volume of the Snow Hu are there. 0.15 square meters is about the same. If it goes below 1 square meter, there are still not many radars that can detect it.

Even if it is noticed, with the flying speed of the snow swan, it can escape the pursuit of the missile by a little acceleration. With the current means, except for laser weapons, no missiles can pose an effective threat to the snow swan.

But the J-20 is different. After obtaining the XW-9, Yang Wei designed the J-20 interceptor model J-20B.

Compared with the J-20, the J-20B has a longer body, smaller wingspan, an empty weight of 22 tons, and a maximum take-off mass of more than 44 tons. It is a typical heavy-duty interceptor aircraft.

The J-20B sacrifices some maneuverability, but the two XW-9s it carries can bring an optimized maximum speed of 3.5 times the speed of sound and a maximum ceiling of 33,500 meters. Because of the fuel-saving characteristics of the XW-9 and the sacrifice of maneuverability in exchange for a smaller Due to the resistance of the airframe and the increase in internal fuel caused by the increase in the weight of the airframe, the cruise radius of the J-20B has increased to 3,000 kilometers, which is extremely exaggerated.

Such a J-20B requires major modifications to the fuselage skin, and it is still necessary to ensure that the damage to stealth is not too great, and the radar reflection area must still be limited to less than 0.05 square meters.

In more than eight months, through the cooperation of four research institutes, the skin problem of the J-20B was solved.

Unlike the SR71 that needed to reserve gaps more than fifty years ago to control the extended length of the skin at high temperatures, the J-20B uses expensive aerospace materials. There will never be any oil leakage, and the weight remains basically the same. The change is that the price has more than tripled.

The 611 Institute built a J-20B prototype verification aircraft, and then quietly flew to the desert base, where it was painted with special paint developed for the Snow Falcon.

Snowbirds need to re-apply the stealth/heat-insulating paint every time they fly. For the J-20B, it can be replaced after four or five flights. During this period, the ground crew will check some weak points and repair them before each flight.

This coating formula was secretly carried out at the beginning of the aerospace fighter program in the last century. During the development period of the "Shenlong", that is, around seven or eight years ago, major breakthroughs were achieved with heavy investment.

In Dou Ping's words, this kind of coating is currently the most advanced in the world, surpassing Aramco by a whole generation, so it is extremely confidential. The test flight of the J-20B must be carried out at a desert base.

The new paint has a dirty metallic color when applied to the skin. It is said that the price per kilogram is six figures, and the output is still very low. The J-20B uses production capacity that has been accumulated for four months.

Of course, this is also because Xuehu is still on paper, so the preparation is still in the laboratory.

When the official version of the J-20B enters service, it will definitely not use this kind of paint, but a downgraded version that reduces costs and simplifies the process.

More than half an hour later, the ground crew inspection was completed. The pilot in a spacesuit climbed into the cockpit and first checked whether the ejection device was jammed by anything.

Due to the high temperature, the J-20B no longer has a beautiful bubble cockpit. The front half is made of three pieces of thick flat glass, which looks a bit like Master Ba’s cockpit.

Moreover, the cockpit area looks a little like protruding on both sides. Because the J-20B is an unprecedentedly long cruise interceptor, it adopts a side-by-side two-seater layout to reduce the pilot's driving intensity and is more comfortable than a tandem two-seater.

"01 (Dongyao), are you ready?"

After a second or two, the test pilot pulled down the mechanical valve of the mask and fixed it, and then answered with the built-in microphone:

"01 is in good condition and ready for test flight!"

The J-20B's high-speed flight generates extremely high heat. In order to reduce weight, the cabin cooling equipment is limited in size. The air conditioner cannot be turned on all the time. Only the two pilots can turn it on for a while when they need to rest and change shifts.

Under normal conditions, the cabin temperature is as high as 39 degrees or more. If you don't wear a simple spacesuit, you will be fucked by the heat.

Yang Wei: "I order the high-altitude and high-speed flight test of No. 2201 to begin immediately!"

The J-20B's first flight had already been carried out on the 611. At that time, there was no stealth paint and it was all yellow. It was not conspicuous among the verification aircraft, but it only made a subsonic test flight.

The test pilot was instructed to push the throttle to take off. Because the XW-9 engine factor and the airframe aspect ratio were smaller, the taxiing distance was longer, and it took 400 meters to pull up.

Bad news: the tour is ending

Good news: I’ll start coding with all my strength tomorrow