In the evening, in the guest house near the 112 factory, the visiting Grumman personnel were entertained, and Pelehaq and others were also quite happy.

The negotiations on the improvement of the J-8 2 were quite smooth, and compared to the delay of the Sabre project, the progress of this project was so smooth that it was hard for him to believe.

"Cheers to our cooperation!" When they came to China, they originally planned to drink the national liquor Moutai, but unfortunately they couldn't drink enough, so they drank very low foreign wine, which was similar to a drink.

Now, after three glasses of wine, Pelehaq is happy.

"For the sake of our cooperation, after a while, we invite you to visit our Grumman factory." Pelehaq said.

Hearing that he was going to Grumman's factory, Qin Feng was stunned for a moment, he had been there last time, and he had seen their Tomcat fighter, which was really shocking at the time, who would have thought that they would still invite?

The last time I went, it was for the Jian-7 CP project, and the comrades of the 601 Institute didn't go, which is true, but now, let's go and see it again?

"This time, you can go to our Dahe factory, where we have an X-29 technology demonstrator." Pelehaq said.

When he said this, Qin Feng suddenly lit up in front of him.

In the development sequence of military aircraft in the United States, those who enter service in the army are given a prefix such as F, but before entering service in the army, the prefix X is used.

As a military aircraft research and development unit, it must always maintain its own leading position, and it is necessary to carry out pre-research on the project, so that once the army needs it, it can come up with a bid at any time.

Now, this X-29 project, Qin Feng has also seen it in international magazines, and when he read it for the first time, Qin Fenggao felt full of black technology.

During World War II, warplanes were flat-winged, and after the end of World War II, when entering the jet age, the wings of fighters began to sweep back, which could reduce drag and adapt to the needs of jets.

And this X-29 is a forward-swept wing fighter! Its wings are tilted forward, and it looks like a Star Wars fighter in a sci-fi movie is ahead of its time.

In later generations, the Sukhoi Design Bureau once designed a forward-swept Su-47 fighter, this black fighter amazed the audience, making people feel the power of the Sukhoi Design Bureau, but few people thought that in fact, in the eighties, the Americans had begun to experiment with this wing.

The wing is forward, so in order to make better use of the space in front, it is simply a canard layout, with the canard wing in front and the main wing in the back, which happens to be a parallel structure.

The forward-swept wing has its unique advantages, that is, under the same lift, the drag is greatly reduced, because the pressure on the lower wing surface increases, the shock wave on the upper wing surface is weakened, and the wave resistance is small; In terms of spread, the center of pressure of the wing shifts towards the root of the wing, so the bending moment is small. If the bending moments are the same, the aspect ratio can be increased, which can further reduce the resistance.

However, for a long time, this kind of forward-swept wing was not used by aircraft designers because it also had a big problem, that is, aeroelastic divergence, if made of wooden planks, or aluminum alloys, it would quickly twist and crack with mechanical fatigue.

It is only now that the development of composite materials has a solution, for example, the wing structure adopts aeroelastic tailoring, and the wing wall panels are made of special composite materials, so that the elastic deformation is conducive to preventing divergence.

In addition to the X-29, the later Su-47, which was also designed this way.

The aerodynamic design of the whole fighter is quite unique, in addition to the forward swept wing and canard, the wing root of the forward swept wing is also equipped with a large side strip of the swept wing, although there is no horizontal tail, but at the end of the swept edge strip, two elevators are provided, the full-motion canard of close coupling brings great maneuverability, and the differential flaperon not only plays the role of the flap but also assumes the role of the aileron, even if it is the forward swept wing, it is also the airfoil design of the supercritical wing.

The whole plane looks quite unusual.

This is a forward-swept wing ultra-thin wing verification machine, of course, in addition to the verification of this forward-swept wing, it also has many other technologies, such as ultra-thin wing, static unstable design, digital fly-by-wire technology, VFC technology and so on.

Especially the last one, which has a kind of whimsical meaning, Vortex Flow Control (VFC) technology. At high angles of attack, the vertical tail of the fighter was blocked by the entire fuselage, and at this time the effect was very poor, and the yaw of the aircraft could not be controlled.

This technology is to install two nitrogen injection devices on the nose of the aircraft to spray high-speed nitrogen in the case of high angle of attack, so as to achieve the effect of enhancing the vortex, thereby increasing the maneuverability of high angle of attack, so as to provide more sufficient yaw torque for the aircraft in the case of high angle of attack.

Qin Feng has seen these introductions in the magazine, and the Americans are open in this regard, perhaps, it is also to release fog bombs, so that people think that the development of new aviation technology in the Americans is these, but in fact, people are already secretly engaged in stealth aircraft.

Compared with his current fighter, it is simply alien technology, Qin Feng heard that he could see this kind of aircraft, so naturally he couldn't suppress the excitement in his heart, the huge lifting body fighter of the MiG-29 has already been seen, and now this kind of fighter, I really hope to see it immediately.

"On our aircraft, we use the F404 engine, so you can see how we install it, we are very familiar with this engine, and it can be easily installed on the J-7 or on the J-8." Pelehaq said.

Inviting the Chinese to see their X-29 technical demonstrator, of course, has a purpose, which is to let the Chinese know that their technology is very advanced and can easily complete the modification of the fighter, and in the end, it is necessary to reequip the J-8.

"After all, for your J-8 fighter, our engine is the best and the only choice." Pelehaq said.

They have long had this intention, in fact, of course, it is not only the people in front of them who are invited, but the most important thing is Tu Lao them, although the Sabre plan is progressing slowly, it is still slowly advancing, if nothing else, next year, Tu Lao They should have a delegation, resident in Grumman, to cooperate with Grumman, after all, this is a tripartite cooperation project.

Pelehaq knows a lot about technology, but the coordination of the work of the parties involved in these collaborations is not his forte, and now, inviting them to see the X-29 is also a sign of friendship.

We want to improve the J-8, is there really only one option for the F404 engine? Of course not, after all, we also know that it is difficult to introduce.