In the past, when China was engaged in turbofan six, it made some mistakes, subjectively thought that this kind of aircraft was very simple, ignored the objective laws of engine research and development, and wanted to put various engines together, but the result was that it was not matched for many years.

Now, the experts in the aero engine department have finally understood, so if you want to have a new starting point, the best way is to map and copy a mature core machine, as long as there is a core machine, plus an outer duct, it can become a variety of engines, small bypass ratio, that is, fighter engine, large bypass ratio, is a passenger aircraft engine, increase turbine, output power, that is the gas turbine, the most needed is the core engine.

If it is completely self-developed, it requires strong technical strength, as well as financial support, research and development at the first level, so that it can master all the laws of the engine, but the price is definitely not what the current country can bear, after all, the domestic investment is less than a fraction of the foreign capital, in this case, the development of an engine, you can only take a shortcut.

For the domestic surveying and mapping imitation, that is absolutely familiar with the road, the country has also imitated a lot of weapons and equipment, now, as long as the target is found.

This object is CFM56, as long as the core aircraft is copied and copied, coupled with a suitable duct, a good fighter engine can be made to solve the big problem of lack of engines in the current military aircraft research and development.

Hearing Song Lao's narration, Qin Feng also understood Song Lao's worries.

"Generally speaking, the research and development of the engine must be earlier than the development of the fuselage, after all, the technical difficulty of the engine is the greatest, and the Americans have begun the pre-research of the core engine of the third-generation aircraft five or six years in advance before developing the fighter." Qin Feng said to Song Lao: "So, if we set the engine on this newly developed Taihang now, I'm afraid we won't be able to catch up with our progress." ”

Old Man Song's headache is here.

"For our third-generation aircraft, if there is still a turbojet, the performance will undoubtedly be reduced, especially the most important range, which will be shortened due to the increase in fuel consumption, but if we wait for this engine, we are afraid of delaying the progress."

It can be seen from the surveying and mapping imitation of the MiG-21MF that the Air Force was an urgently needed project, but now, it has become unwanted, and now the J-10 is a key project of the Air Force, but the Air Force does not put all its hopes on the J-10, because the Air Force knows the weakness of the domestic industrial base, and knows that the technical difficulty of this aircraft is very great, and it may not be able to be successfully developed.

If the demarcation line is to see if the plane can be built, as long as it can be built and enter the test flight stage, then this aircraft will be almost no problem, if it has been stuck on the drawings, it will be the same as the previous Jian-9 project, I am afraid it will end without a problem.

If you want to build it as soon as possible, you must have a qualified engine, and it is obvious that Taihang engine cannot undertake this mission.

"Therefore, we can only follow the indicators of the Turbojet-15 at this stage." Qin Feng put forward an opinion to Song Lao: "Use this engine for test flights first, wait until the turbofan-10 project is finalized, and then replace it with this advanced engine." ”

Song Lao smiled bitterly at Qin Feng: "Yes, this is also our plan now, but even this plan is full of variables, and it is not easy to change the engine." ”

This is not a car, as long as there is a place in the engine room to change the engine, it is necessary to install it, and the engine of the fighter is very laborious.

The simplest example, the Americans' F-16 fighters, which originally used F100 engines, were replaced with J79 for export, which is not just a matter of thrust reduction, because of the mismatch, but also a copper hoop on the outside of the J79, which adds more than a ton of weight.

The diameter of the two engines must be the same to be replaced, this is only one of the points, the other most important point is the air intake flow, if the air intake flow of the two engines is different, then you need to have a different air intake, modify the air intake, you have to re-blow the wind tunnel, which is tantamount to directly developing a new fighter!

Qin Feng also frowned, yes, without an engine, there is no way to talk about advanced fighters, and this engine is not responsible for the main engine factory, in short, this is a big problem, a big problem that plagues the Jian-10 project.

The two engines have their own merits, first look at the turbojet 15, which is the supporting engine of the MiG-23, the characteristics of the advanced engine, such as high performance, long life, easy maintenance and it is unavailable, the advantage of this engine is that it is mature and reliable, and it can be used when you pick it up, although the model surveyed and mapped out is definitely inferior to the prototype, but you can still know what it can be done in general. This is a great benefit to J-10.

However, domestic engine experts, as well as some experts in the military who have high expectations for this fighter, all believe that a new turbofan engine should be designed for the J-10, and only the advanced turbofan engine can give the J-10 various performance requirements when designed, otherwise, due to the problem of overweight and fuel consumption, it will make the J-10 have a big gap with the third-generation aircraft in terms of maneuverability and range, and air time.

That's a big contradiction.

In this contradiction, Taihang engine has begun to enter the field of vision of decision-makers.

During this time, Beidaihe held a departmental meeting of the aviation industry, and after voting, experts agreed that the Taihang engine represents the direction of the future, and in order to promote the research and development of domestic engines, it is necessary to choose the Taihang engine on the J-10.

However, since the founding of the People's Republic of China, there has not been any self-developed engine in China, and the engine of the third-generation aircraft is even more difficult, completely beyond the domestic industrial level, so the superiors have no confidence in the self-developed engine; Therefore, the Commission of Science, Technology and Industry for National Defense rejected the results of the vote and specified the turbojet 15 engine.

In this way, what kind of engine the J-10 uses is still a mess, and it will ultimately have to be determined by Song Lao.

Song Lao is very conflicted about this, even if there is already a sequence, using the turbojet-15 as the engine for the test flight, and using Taihang as the engine for officially equipping the troops, even so, he has no bottom in his heart.

"Old Song, I think that the state still has to take the opinion of this matter, and for us, it is a key to get the full-scale prototype out first."