Super Weapon Swap System

Thinking of history, Qin Guan had a sigh. In history, the jian-8 and Rb 199 passed by.

At that time, because of the low level of technology and the lack of advanced aircraft, the Han country was forced to develop a J-8 interceptor with two engines on the basis of the J-7. However, the technical level was still very low and had no great advantage.

In the 1980s, when the West opened its door and went to the west, we knew how backward our own side was. Therefore, at this time, Han began to move closer to the west, hoping to develop our own aircraft by introducing western technology.

They also took a fancy to rb199. The West promoted the use of rb199 to replace the J-7 engine, and 6601 also planned to use rb199 to replace the J-8 engine.

However, at this time, the J-7 project suddenly leaked out. As soon as the West heard that the Han country was developing this kind of fighter bomber, it immediately became cautious.

It can also be seen from this point that the West will not sincerely hope that Han will be strong. Even if Han has advanced fighters, it will not let Han have bombers. After all, the attack ability of bombers may pose a threat to the West.

The west thought that the Han country bought rb199 to be used by the J-8, which was embarrassing. At that time, the J-8 was a confidential project. The West didn't know that 6601 was all suffering. Finally, the West closed the door, and the J-8 had no hope of changing the engine.

Now, great changes have taken place. After the introduction of male cat fighters, the J-8 project is no longer confidential and has become a foreign arms sales project. In this case, it is normal to replace the J-8 with a world-class engine and then push it to the international market.

After the 6601 was responsible for its own profits and losses, it also learned from the pain. It not only changed the telex operation for the J-8 2, but also completed the matching of the new engine.

Now, Qin Guan stands at the rear fuselage of the J-8, and you can see that there have been obvious changes.

The previous J-8 used the tail cover of the ejector.

Equipped with a powerful jet engine, mankind has entered the era of supersonic flight. Due to the net pressure of the aircraft flying at supersonic speed, the exhaust pressure of the engine increases, resulting in the drop pressure ratio of the nozzle (the ratio of the pressure of the engine exhaust flow at the nozzle section to the ambient pressure) also increases, reaching 15-20 or even higher.

At this time, the exhaust flow at the nozzle outlet works under the condition of extreme under expansion, so that the thrust loss is as high as tens of percent! In order to "recover" this part of thrust, engine designers added an outer sleeve or ejector cover at the outlet of the main nozzle, which is equivalent to adding a tube skirt outside the pleated skirt, which is the ejector nozzle.

The ejector nozzle adds a new ejector outlet section behind the original main nozzle contraction end, that is, the throttle section. In this way, the main air flow introduces one or more new flows before leaving the engine or aircraft, resulting in an increase in the total exhaust flow. Moreover, the nozzle with this structure allows the air flow to continue to expand, further increasing the exhaust speed and increasing the thrust of the engine.

However, this is all theoretical, and even there is no specific formula to describe it in theory. Most of them come from aircraft experiments.

The tail cover of the J-8 is not only very heavy, but also can not play the role of the tail cover of the ejector. It will only lose thrust in vain.

This design was once popular in the 1940s and 1950s, but in fact, except for very individual states, the performance state of the ejector tail cover can not be calculated at all, and can only be inferred reluctantly by relying on the test results.

The previous J-8 was actually designed to cross the river by touching a stone, almost from the J-7. Naturally, there were many defects.

Now, after the rb199 engine is replaced, the cumbersome ejector tail cover is removed, because the three generations of engines carry their own tail nozzle, which is more advanced and belongs to retraction and expansion nozzle.

The retraction and expansion nozzle can be regarded as a "double pleated skirt" with two small ends connected together. It makes the nozzle channel narrow first and then expand, allowing the air flow to further accelerate into supersonic flow after reaching the sound speed at the throat. Because the nozzle can be adjusted at the end section (throat) of the contraction section and the outlet section (exhaust port) of the expansion section, it has both good subsonic and transonic performance and excellent supersonic performance.

The J-8 finally removed the tail cover of the ejector, which made Qin Guan feel a burst of joy. Of course, he knew that this thing must be removed, but later generations will come to the 1990s.

After all, the expected benefits of this design are actually the result of the mixed effect of designers' past experience and subjective speculation, lacking rigorous scientific and engineering basis. Xiong Guo later did a lot of transformation and comparative flight test work on the old model, including the test of the ejector tail cover, which proved that it was useless.

Therefore, in the 1990s, with the easing of relations with Xiong Guo, Xiong Guo's experts were used in the form of technical assistance to modify the tail design of the J-8 series.

In this way, the tail has been greatly changed. In addition to the tail nozzle, it is the criticized tail tip.

It can be said that with this transformation, the rear fuselage of the J-8 has changed greatly. As for the front, it has not changed much.

The nose is still the same. The three piece windshield in the cockpit has a high back. The pilot doesn't have any backward vision. It's still an authentic second-generation aircraft.

"Mr. Qin, how do we change this plane?" Mr. Gu asked Qin Guan.

Qin Guan nodded: "the later modifications are not bad. If the engine and inlet can match well, the performance should be greatly improved."

As soon as these words came out, President Gu nodded again and again: "yes, it is a reborn performance improvement. Our aircraft will be able to defeat the J-11 and obtain the order of the air force."

Hearing what President Gu said, Qin Guan could not help frowning.

For 6601 Institute, as the big brother in the development of Han military aircraft, it certainly can't tolerate the embarrassment that they don't have fist products. Now they work so hard to improve their fighters, there is only one idea, that is, to equip their fighters for the air force.

But is it possible?

The fighter equipped by the air force must be able to produce independently. The landing gear problem is not big, and the engine problem is big! If the engine of this aircraft needs to be imported, it will be stuck by the western world at any time.

"What? Mr. Qin, do you still think my plane can't meet the needs of the air force?" Mr. Gu asked when he saw Qin Guan's appearance.