In 2022, the Y-20 flew to Serbia to carry out a transport mission, and in a total of 3 days, the Y-20 flew 22 sorties, and related videos were also widely spread on the Internet.
[This is the scene when the C17 lands]
One of the details has attracted everyone's attention, that is, when the Yun 20 lands, the wings and tail will "shake violently", and everyone's hearts will tremble, for fear that they will "shake off".
Is it because the aircraft is "not strong", or is our technology too advanced?
[This is the moment when the Y-20 took off]
"Q bomb" of the Y-20 wing
When it comes to aviation aircraft materials, the first thing that comes to everyone's mind must be sturdy, after all, in the state of high-speed flight, the surface of the aircraft is subject to considerable air flow disturbance.
The oncoming air flow is like a cannonball, constantly causing damage to the aircraft, and if the material is not hard enough, it is easy to fly and disintegrate.
There are many ways to increase the strength of the material of the aircraft, such as starting directly from the raw material, using a large number of high-strength metals, or using new composite materials.
There is nothing wrong with improving the "anti-beating" ability of the aircraft, but in the process, we cannot ignore an important point, that is, the weight of the aircraft.
Generally speaking, the harder the substance, the higher the density, the greater its weight.
This weight will not only not help the performance of the aircraft, but will also become a burden.
【Large Aircraft Production Line】
Because the heavier the aircraft, the more engine thrust is required, and the fuel consumption naturally increases. And the higher the fuel consumption, the higher the cost.
If it is an ordinary passenger aircraft, it will affect the price of the ticket at most, fluctuating a few hundred yuan above and below the market average, but for military transport aircraft, its own weight is quite critical.
The high material-to-weight ratio of the transport aircraft means that its load capacity will be greatly reduced, even without load, which will affect its own range.
But having said all this, what does it have to do with the Y-20 wings and tail that we talked about today shaking off when landing normally?
【Y-20 transport aircraft】
The relationship between the 20 is big, in order to minimize the weight of its own materials without affecting its own performance, a large number of composite materials are used in the construction process.
Of course, we don't know what exactly this composite material is, based on advanced technology and material secrecy, but one thing is clear:
The hardness of the material itself is there, and compared to ordinary hard materials, the existing composite material of the Yun-20 is lighter, otherwise it would not have a maximum load of 66 tons.
But this composite material may be beyond everyone's imagination, making the wing have a certain "flexibility".
In addition, the maximum take-off weight of the Y-20 itself is also 220 tons, and it is normal for the wings to shake after such a behemoth falls from the sky.
The Y-20 is highly reliable
As long as it is not an accidental fall, the wings and tail of the Y-20 will not disintegrate in the shake for two reasons.
First, as I said before, a large number of composite materials used in the Yun 20 are hard, and the reliability is very high.
Second, before the aircraft is delivered, the relevant staff will carry out a large number of swing tests on the wings of the Y-20, which may be thousands or even thousands of times, simulating jitter in different states.
[Wing swing test during aircraft construction]
After a long period of test work, under the premise of ensuring stability and safety, the Y-20 can really get out of the production line.
It can be said that all the components of the Y-20 have been tested, and the staff have simulated a more extreme environment and meet the standards.
If you are not at ease, you can go and watch the landing video of the American C-17 transport aircraft, which follows the DC-10 similar composite materials, with a maximum take-off weight of 263 tons and a maximum load of 77 tons, which is about the same as the Yun-20 on the whole.
[The C-17 transport aircraft is very similar to the Y-20]
When this transport plane lands, the jitter amplitude is greater than that of the Y-20, and the United States has been in service for decades, and I have never heard of problems due to normal landing.
In addition, the Y-20 also has one thing that can ensure the reliability of the aircraft, that is, "fly-by-wire flight control".
To put it simply, this technology is to turn the pilot's operation into an electrical signal, and control the aircraft through various advanced avionics equipment.
The pride of the country - Yun 20
The traditional large aircraft piloting mode often tests the pilot's judgment ability, whether it is the timing of take-off or the angle of landing, the pilot needs to have a strong professional quality, so the pilot is not an ordinary person can serve.
【Fly-by-wire flight control cockpit】
However, it is not enough to rely on pilots with amazing professionalism, because no matter how strong human judgment is, it is difficult to compare with sophisticated intelligent electronic equipment, and large aircraft like the Y-20 know more about the overall situation of the aircraft than pilots and can make more reasonable judgments.
Once there is a mistake in the decision-making process during the flight control process, not to mention causing an air crash, it will at least reduce the service life of the aircraft.
Now the fly-by-wire flight control system solves this problem very well, it can not only provide more data information to the pilot, but also efficiently respond to the pilot's various operations, thereby greatly improving the aircraft's anti-risk ability.
In addition, the Y-20's supercritical wing is also a very eye-catching technology, this design technology can reduce the drag of the aircraft, thereby increasing the flight speed.
Generally speaking, a large-tonnage aircraft like the Y-20 has an amazing amount of drag when flying, but it can reach a speed of about Mach 0.8.
This is precisely because the leading edge of the supercritical wing is obtuse and rounded, and the speed of the air flow around the air is slowed down, so that the local flow velocity change tends to be stable.
However, it should be noted that this is not a novel technology, as Airbus used it in its own large aircraft back in the 70s of the last century.
China's current use in the Yun-20 can be regarded as a kind of catch-up with the world's excellent technology.
Of course, there are many excellent technologies for the whole body of the Yun-20, so don't look at the usual cute appearance of this transport aircraft, there is no difference between it and civil aircraft, but after careful study, there are bright spots everywhere.
Resources:
[1] Dang Tiehong, "The Development of NASA Supercritical Airfoils: Civil Aircraft Design and Research"
[2] Ministry of National Defense: "Kunpeng" will fly higher and farther"