The nose intake can't be said to be backward. If the air intake efficiency is discussed alone, the nose air intake is the best. Modern fighters will be eliminated just because they need to install radar on the nose. China really came from behind. However, no matter how advanced the inlet is, it can't improve the combat power of the aircraft to a higher level, but only slightly reduce the weight and increase the stealth.
Simply put, this is the passive booster. Many cars now have turbochargers, which pressurize the air through turbofans. The relative technical content is very popular today, but the space on the fighter is too small to be realized by the fan system. Because the jet engine itself works like this, it is impossible to realize DSI on a fighter without any internal power.
First, lose weight. Second, the clamshell inlet requires wind tunnels and supercomputers, which are available in China, and both are rare. Thirdly, the clamshell inlet can block the infrared characteristics, which are necessary for stealth aircraft. Therefore, the front infrared characteristics of Su -57 are obvious, and it cannot be regarded as a real stealth aircraft.
This was not invented by Americans, but was put forward by China in 1980s. At that time, due to financial constraints, the materials could not be made, and they were exchanged with Americans during their honeymoon. Although it is only a bulge, it must have accurate aerodynamic data to get it out. A little bit will affect the intake efficiency. Different aircraft have different intake structures. Copying is useless, and the result must be obtained through frequent aerodynamic experiments.
F 16 also has a big fishbone stuck in the throat, which is comparable to the early model of J-10A. Before that, the four sticks above the J-10A intake pipe made domestic military fans laugh as if there were four fishbones stuck in their throats. Later J- 10B models all adopted clamshell intake pipes. Without those four sticks, we can laugh at the fishbone in F 16' s throat now!
Besides, don't think that wind tunnel blowing has no technical content. First, the construction of the wind tunnel will test this technology. Secondly, there must be some theoretical research to determine the shape of the parts to be blown, and then through continuous experiments to improve and promote theoretical research. Those who blew Japan and Holland into the sky just couldn't get into the wind tunnel. Not many countries have the ability to build wind tunnels. Those who have the ability to pay and those who have the ability to build are two different things. And there is no need to build a wind tunnel, and everything is fine. Therefore, it has nothing to do with small countries. After all, the cost is too high, and it is an infinite cycle to build it without large-scale use.
It is really rare in the world to be called an aviation power. Either develop one or two planes or become an aviation power. A strong aviation industry country needs powerful and comprehensive industrial supporting capabilities, full-spectrum research and development capabilities, full-spectrum experimental capabilities and other factors. For example, the wind tunnel discussed in the comment area is one of the symbols of a strong aviation industry, especially the supersonic and hypersonic wind tunnels, which are absolutely high-tech.
First of all, you need a complete large-scale wind tunnel group, which is not expensive, just120 billion, oh, it's dollars. By the way, it's not bad to build some gadgets like supporting power stations. Then, you need a supercomputer, which is not expensive. Tianhe-2 is said to be almost 3 billion yuan, and the use fee is calculated separately. What, you've never played? Then spend hundreds of billions to explore slowly! Finally, you need a basic but relatively perfect aerodynamic model for fighter design and manufacture. If not, it is estimated that it is cheaper to sell it to your door. Do you want to ask people10 billion dollars for sale?
China and the United States should start to study the inlet technology at the same time, and there is no generation difference, such as duck wing. In fact, China just has limited funds, but with funds in recent years, it will definitely like to follow suit. In the last century, we put forward many engine schemes with first-class indexes, and all of them were dismantled. Can you spray experts in the field of materials science? This won't do either. Materials science needs long-term accumulation. It's like laying a foundation. The difference is that it will continue to develop. Technology can overtake in corners, and materials are too difficult. Very dependent on accumulation. Our materials started too late and developed really fast.
For example, technology is like strength. Hard exercise can improve you faster, but the material is height. Even if you eat ginseng every day, you can't grow too tall. This is a scientific law. I can't help it The material development of our decade is absolutely very fast. So don't spray the engine, which is really not a problem for engine research and development experts.
The intake range of DSl is not as wide as CARET, so it is not easy to take into account the non-adjustable subsonic supersonic intake of DSI, either supersonic or subsonic. The F-22 with CARET can only be abandoned. Although it pays a weight price, it has a wider intake range and takes into account the subsonic supersonic intake requirements, so the subsonic supersonic performance of the F-22 is outstanding. It is useless to simply drill holes and pump air, because the angle of the surface of the object is there, the angle of the shock wave is almost limited, and the air behind the shock wave cannot flow to the front of the shock wave, so the supercritical overflow problem of the inlet will still exist. DSI can only do a certain design point well. For supersonic environment, too high or too low speed will lead to the decrease of inlet efficiency.
One is original, the other is not mentioned, and there is no comparison. Any DSI inlet is more advanced than other inlets, but it also has its shortcomings, that is, the speed adaptation surface is narrow. Unless the deformable convex design is adopted to solve the influence of the sudden change of boundary layer airflow on the engine with the increase or decrease of speed, it is uncertain whether the J-20 uses deformable convex or not, and it may also face the problem of metal materials. The problem of DSI is not that the advantage is concentrated within twice the speed of sound, but that the efficiency is maximized only within a certain speed range, which is set at the beginning of design. The reason why there is an advantage within 2 times the speed of sound is because the first two fighters using dsi are single engines, and the highest speed is within Mach 2. After the emergence of the J-20, this statement is self-defeating, because the J-20 can never give up the top speed above Mach 2. It is reported that the J-20 is an adjustable dsi, but there is no official statement.
Cutting-edge technology depends on a large number of scientific and technological talents and economic input, and the sound overall industrial system is only a feature or helplessness of our country. Because even if we have money, I don't use the industrial technology of other countries. Europe, America and India do not have these concerns, but it also has its drawbacks.