Yang Wei can't really realize how powerful Xia Yu's flying skills are, but Yang Wei completely understands what the flying style is. Obviously, you can do flight maneuvers at a safer altitude, but Xia Yu's kid is just playing heartbeat with you.

The closest point where the somersault falls is less than ten meters above the ground, what is the concept? In Yang Wei's heart, this kind of altitude difference of more than ten meters is basically negligible in maneuvering flight, especially in vertical maneuvering, that is to say, Xia Yu did not collide this time can only be regarded as lucky, if he is unlucky, the result is naturally self-evident.

This is only the first time that Yang Wei has realized the side of Xia Yu's thorny head, and it is less than one percent of what Wu Jianming experienced at the beginning. In the next period of time, every time Xia Yu took off, Yang Wei would leave his work behind and stand in the tower waiting for Xia Yu to land safely.

Flying is not the same as anything else, even if you believe in one's level of flying skills, complex air conditions will always lead to accidents. Yang Wei, as the chief designer of Chengfei, has seen so many flight accidents over the years that even he can't count them, although he still maintains confidence in the J-20A in his heart, but Xia Yu's radical flight makes Yang Wei really can't put his mind at ease.

However, even though he was frightened by Xia Yu's flight, Yang Wei did not stop or persuade Xia Yu's flight, because when Xia Yu flew a few more times, he soon found that the J-20A had many things that could be improved. Especially for the flight parameters, in just half a month, in the flight manual of the J-20A, there are more than 20 improvements because of Xia Yu's improvement, which is not something that a random test pilot can do lightly.

Picking up the treasure, this is Yang Wei's most direct idea after realizing Xia Yu's ability, but Yang Wei would never have thought that when he took the already radical X20 plan drawings in his mind and asked Xia Yu to see what else needed to be improved, Xia Yu looked at it carefully for a while, shook his head, and actually said that this design was not radical enough, so it was not adopted......

"Hey, that's not radical enough?" Yang Wei pointed to the J-20 on the drawing and said: "I even put on the improved Emei model that was successfully developed by the 624 Institute a week ago, and the movable piece of the axisymmetric vector nozzle also uses the latest materials, because of the thrust and thrust-to-weight ratio of the new engine, I have even made some modifications to the aerodynamic shape, as well as avionics, flight control, radar, I have made changes in many places, okay?" ”

"Well, that's true." Xia Yu nodded in agreement and said, "But these are all changes based on the design improvement of the J-20B, but in my opinion, there are still many things that can be changed." ”

"So how do you change it?"

"For example, the axisymmetric vector nozzle can be changed to a flow field thrust vector nozzle." Xia Yu raised his eyebrows and said excitedly: "How good is the smooth thrust vector nozzle, even the mechanical moving parts of the nozzle are saved, the structure is simpler than the axisymmetric vector nozzle, not to mention, it can also reduce the weight, and even save a lot of maintenance things." ”

Flow field thrust vector nozzle? Yang Wei was stunned when he heard this, of course he knew what the flow field thrust vector nozzle was, this kind of new vector thrust technology that introduces lateral airflow in the nozzle diffusion section, changes and controls the area and direction of the main airflow to obtain thrust vector, is indeed much simpler in structure than several other thrust technologies, but the interference of the airflow is not as easy as imagined, which is also one of the main reasons for restricting the flow field thrust vector nozzle technology.

In Yang Wei's opinion, this proposal proposed by Xia Yu is too absurd, compared with the axisymmetric vector technology, the flow field thrust vector technology is still very immature, and the interference of the air flow can not be as stable as the calculation results to be applied to practice, undoubtedly driving a car with all the faults on the road. While the car can drive away, there's no way to know exactly when it's going to throw you on the road.

Shaking his head, Yang Wei said disapprovingly: "This is not good, although there is a trial model of the flow field thrust vector nozzle, but in the current ground test, the results are not stable, and it is very irresponsible to want to directly apply it to this aircraft, and if you replace the smooth thrust vector nozzle, not only the center of gravity of the X20 needs to be reset, but even the aerodynamic shape will have a relatively large modification, radical is radical enough, but it can't be separated from reality." ”

Hearing Yang Wei's words, Xia Yu smiled and said, "I know the difficulty of the flow field thrust vector technology, but this is not an unsolvable problem. I also learned some about the situation of the trial model, which is nothing more than that the airflow control technology cannot be stabilized, so more practical data is needed to improve. If we put it on the X20, we can gather a lot of useful information that will allow the X20 to finally use this nozzle technology directly. ”

After a pause, Xia Yu continued: "The core of our engine is still the turbofan 15, even when flying in the air, there is a problem with the flow field thrust vector nozzle, at most, it is just that the aircraft has no thrust vector, and it will not have much impact on the engine itself, right." ”

Speaking of this, Xia Yu didn't wait for Yang Wei to answer, and continued: "Moreover, the application of flow field thrust vector technology is only a matter of time, after all, the prospect of this technology is better than other vector technology, and now it can be used one step ahead of time, which can not only provide important practical information for the maturity of flow field thrust vector technology, but more importantly, the X20 equipped with a flow field thrust vector nozzle needs to be improved too much." For example, the engine will be shortened, the center of gravity will be changed, and the aerodynamic effect will produce a large deviation value, so the change of the shape of the aircraft is also predictable, so the flight control system also needs to be corrected, calculated and changed from the initial drawing, than to re-push it all and then change the design, right? Although this is almost equivalent to redesigning an aircraft, after all, it is based on the design improvement of the J-20A, and we can directly apply a lot of raw materials, which saves time and effort, and can not only make an almost new concept of the aircraft, but also meet the radical requirements put forward by the second chief. ”

Listening to Xia Yu's eloquent talk, Yang Wei also had to admit that Xia Yu's statement still had some truth, but just by relying on this, he wanted to persuade Yang Wei to apply a still very immature technology to X20, which was too simple. If the design and manufacture of an airplane can be completed by just talking about it, why do you need to do any calculations and tests? Without rigorous scientific and technological verification, even if a new aircraft can be made, it is just a spectacle, and it is thankful that it can take off and land safely.

Yang Wei, who disagreed with Xia Yu's opinion, quickly argued with Xia Yu, and the two of them expressed their opinions on the drawings on the table, and when they agreed with each other, this content was quickly remarked by Yang Wei, and then it will be modified into the design drawings of X20, when they disagreed, the two began to spit around, trying to persuade each other.

In the debate, Yang Wei gradually forgot about Xia Yu's identity as a test pilot, but regarded Xia Yu as a real researcher, for this more radical technical verification machine X20, Yang Wei and Xia Yu both invested their greatest enthusiasm, although they did not say it, but whether it was Yang Wei or Xia Yu, both of them made up their minds in their hearts, they must develop X20, and they must be able to watch X20 fly successfully.