As a fourth-generation aircraft positioned as a multi-role fighter, you design the air intake to the top of the wing, this design is definitely very rare, and even Yang Hui at this time said that he couldn't understand it. Pen, fun, and www.biquge.info

To say that before the plan was made public within the company, Yang Hui did get some news from Chief Lu Division, and said that the light four plan was technically generally the technical inheritance and optimization of the J-12 fighter that was not mass-produced and put into service that year, and Yang Hui did not have too many ideas about this at that time, at least the last chief Lu engineer in his later years when he designed the light four plan, he also took the route of large-scale optimization on the basis of the J-12 fighter.

What Yang Hui never expected was that if the plan that Chief Lu came up with this time was really said to be inherited on the basis of the J-12, it seemed to be a little bit, such as the design scheme of the lower wing adopted by the Light Fourth Institute.

And because in the design of the J-12 in the early years, the nose air intake design similar to the J-7 was adopted, so the problem at this time came, the air intake of the light four must be redesigned, based on this consideration, and then there was the plan that everyone sees now.

At this time, Yang Hui was also in a puzzle, but as far as the plan given by the current Hongdu Lu Chief Division, no matter from which point of view, it seems that the aerodynamics of the aircraft are very different from the typical fourth-generation aircraft.

Taking advantage of the fact that everyone had not raised any questions at this time, Yang Hui whispered to communicate with Chief Master Lu in advance, and the response he got was: "Don't be busy answering this question first, I will immediately introduce the unique design of this light four plan, and there must be many people who are puzzled by this now, so let's listen to it together." ”

After speaking, Chief Engineer Lu directly signaled the assistant who was playing the video data to pause first, and then stood up again and personally explained the design ideas of the pneumatic scheme this time.

At this time, everyone's eyes have gathered, and everyone knows that they are about to enter the main topic, no one wants to miss the wonderful explanation of the grandmaster-level chief designer like Mr. Lu, and this plan is definitely the culmination of Mr. Lu's lifetime aircraft design experience.

However, Chief Engineer Lu did not directly say why the design of arranging the air intakes on the wings must be adopted this time, but first worked with everyone to clean up the development path of the fighter air intake, and if you want to talk about the development road, you must start from scratch.

"Since the aircraft entered the jet power era, the design of the air intake has always run through the overall design of all aircraft, which is also an important indicator that all aircraft designers must make trade-offs in all aspects, and every progress in the design of the air intake will also cause great changes in the aerodynamics of the aircraft."

At this time, with the explanation of Chief Lu Division, the big screen also began to change with the content explained by Chief Lu Division, from the very beginning of the nose fixed non-adjustable air intake and both sides fixed non-adjustable, the typical design of this era is MiG-17, MiG-19, F-86 and other early first batch of fighters They are all nose fixed non-adjustable air intake, and the strong five of the Republic belongs to the two sides of the fixed non-adjustable.

There is nothing to say about the subsonic air intake with a fixed and unadjustable design in the early days, and then Chief Lu directly skimmed it, and in the glorious era of adjustable air intakes, that is, the MiG-21, Mirage 3, and F-15 models represent the three-dimensional adjustable nose, three-dimensional adjustable on both sides, and two-dimensional adjustable on both sides.

At this time, it was finally said that there were some serious topics, and Chief Lu took the opportunity to introduce the first question in the meeting: "Everyone is the chief designer of aircraft design, and they must naturally know why the Soviet fighter has been using the nose air intake scheme before the MiG-23 and does not let go, because the nose air intake can make the aircraft still ensure sufficient air intake needs when doing a large maneuver, so the Soviet Union, which pays more attention to the maneuverability of the fighter, has retained this design for a long time." ”

At this point, it may seem like it's still off the mark, but it's already vaguely touching the most important core of this time: the relationship between the layout of the air intake and the maneuverability of the aircraft.

Obviously, the Soviet Union chose to take air in the nose because it insisted on the supremacy of mobility, and the NATO countries chose to give up part of the maneuverability because they wanted to free up the huge space in the nose, so as to install what they considered to be more critical radar electronics.

So there is a phenomenon in the sixties, the American point-tipped fighter is always inferior to the Soviet nose intake fighter in maneuverability, this is because the early side air intake is not very good in maneuverability, and this is more because of the early American fighter wing using the design of the upper wing.

But there are some exceptions, such as the American F-4 Phantom fighter and the French Mirage 3 fighter, a closer look will show that these two fighters have a lot in common, they both use a lower wing design, and the air intakes on both sides are arranged to pass above the wing, and the air intakes are slightly extended to the front of the wing.

That's right, this is the NATO countries in the early two sides of the air intake design of the aircraft after in-depth observation of the new aerodynamic design, in order to have better maneuverability of the fighter, first of all, we must know that the use of the lower wing design is the best fighter wing design scheme, it is inherently better than the medium wing and upper wing design.

With the design of the lower wing, it is inevitable that the air intakes on both sides will be arranged above the wing, but if the air intakes are placed directly above the wing, a new problem will be found: due to the blocking and separation of the air flow by the leading edge of the wing, the aircraft only needs to have a slightly larger elevation angle to cause insufficient air intake.

So there was no choice but to move the air intake forward to the front of the wing to avoid the blocking of the airflow by the lower wing at high elevation angles, at the cost of extending the air intake a little further and there would be some extra weight.

Then, based on this theory, there is the layout of the air intakes of the F-4 and Mirage 3 fighters, anyway, as long as the wings do not block the airflow near the air port, then the aircraft's maneuverability at large elevation angles is much better.

As for saying that the air intake above the wing will lead to a decrease in maneuverability, this will indeed happen, such as A-4 attack aircraft, K8 trainer aircraft, etc., because the position of the air intake of these aircraft is almost the same position as the leading edge of the main wing, and the main wing blocks the air flow when the aircraft is maneuvering, and the insufficient air intake of the air intake naturally leads to a decrease in engine efficiency.

Therefore, if anyone says that the maneuverability of the aircraft placed above the wing on the intake tract is very bad, it is definitely a partial generalization. But then again, there are naturally many reasons why people generalize, otherwise how can there really be waves without wind?

So, where does the wind that makes this wave come from? This brings us to another great discovery in the history of fighter aerodynamics. (To be continued.) )