However, Chenggong Aviation is impatient, and Tengfei Group has no choice, the development cycle of aero engines is there, and it is not that Tengfei Group can get up quickly if it wants to.

What's more, the difficulty of the medium-thrust aero engine is a straight increase compared with the difficulty of the previous model, not to mention anything else, the HX-4-1 core engine has developed to the third generation, and the temperature before the turbine is only 1280 degrees Celsius.

And this temperature does not even meet the minimum target of a 6 megawatt core machine.

It is important to know that the performance indicators of the 6 MW core machine formulated by Tengfei Group, that is, the engineering model HX-6-11 medium-sized core machine, are:

Air flow 11 kg\\s

The compressor pressure ratio is 84

The total temperature of the gas at the outlet of the combustion chamber is 1600~1650 Kelvin

Turbine stage 1

The design cycle power is 6 MW

Kelvin is the internationally accepted unit of calculation of pre-turbine temperature, and when converted to Celsius, 1600 Kelvin is about 1326 degrees Celsius.

In other words, the entry-level standard of the HX-6-11 medium-sized core machine is higher than that of the top-of-the-line version of the HX-4-1 core machine.

Every time an aero engine increases by one degree Celsius, it requires a lot of money and experience in materials, processes, engineering, design, and manufacturing.

Because of this, the development of HX-6-11 medium-sized core aircraft has been launched, and it has also been included in the 863 key development projects and the "Eighth Five-Year Plan" projects for key support.

But Rao is so, it will take at least five years to come up with an engineering prototype, and if there are twists and turns during the period, seven or eight years are ordinary, or even more than ten years are not surprising.

There is no way, just the turbine blades to improve the heat resistance of this pass is not easy to cross, it requires a variety of means to be used comprehensively to achieve, involving several categories, dozens of disciplines, very test the comprehensive strength of the research and development unit.

Just because Tengfei Group has serious experience in this area, and can only jointly tackle key problems with other scientific research institutes, key universities and other supporting factories, the problem is that many technologies are blank in China, and they can only start from scratch to slowly explore.

For example, in order to increase the heat resistance temperature of nickel-based alloy turbine blades, it is necessary to coat a ceramic coating on the surface, because the heat resistance of ceramics is very high, which can effectively protect the turbine blades from being burned out by high temperatures.

However, this ceramic coating is not a ceramic tile at home, which can be formed by burning it in the fire, but it needs to withstand high temperatures at the same time, it must have a certain toughness and strength, because the coating must not only withstand high temperatures, but also withstand the strong centrifugal force when the turbine rotates at high speed.

However, ceramics are a material that is known to be fragile, so how to overcome its fragility, so that it does not fall off when the blade rotates at high speed, does not break, and is easy to process, can simply drive experts and engineers in the field crazy.

And this is just a small microcosm of the convenience of various technical breakthroughs of HX-6-11 medium-sized core machine, the application of integral wheel disc, compressor integrated bearing, integral blisk and metal matrix composite materials......

Almost every one of them is maddening.

So I just want Tengfei Group to be fast, but I can't be fast.

Fortunately, the so-called light fighter project is only a theoretical demonstration stage, and even if the Pakistani side makes up its mind, the engineering design will take several years to complete, so it is still too late for Chenggong Aviation to have time.

However, the Pakistani military delegation did not know about these things, and of course, even if they were to ask the Pakistani military to post on the Tengfei group.

Because they want high-performance mid-level trainers and light fighters, not separate aero engines.

What's more, in terms of the power of light fighters, the successful aviation has not been skimmed, and the Pakistani military delegation does not have to use the pole.

As for the power of the intermediate training aircraft, China may not have access to American-made engines for some reason, but Pakistan has a very solid relationship with the United States because of the Soviet invasion of Afghanistan.

Therefore, in the intensive itinerary of the Pakistani military delegation, there was no visit to the Ascendas Group at all.

Originally, this matter was over according to the established itinerary, but Major General Zarif, who witnessed the shocking scene of Yun 15, as the military attache of the Pakistani Embassy in China, was precisely the intermediary between the Pakistani military delegation and the country, and Major General Zarif and Lieutenant General Rahman, who led the delegation, were classmates of the military academy, and were later sent to the United States for further study together, and after returning home, they also fought side by side in New Delhi.

Properly together through the window, together with the gun, vaguely together what a pure iron buddy.

So when Zarif met Rahman, he began to praise the Yun 15, and then took the photos and talked about the shocking scene at that time, and finally fell to the topic, hoping that Rahman could go to the production plant of the Yun 15 to see, and it was better to order some back.

Once or twice, Rahman can still hold on, after all, the itinerary has been set in the country, not to mention that the entire Pakistani military delegation of more than 40 people, belonging to different departments and different factions, although Rahman is the head of the delegation, but the real dominance is not strong, because of this, Zarif The first few persuasions were prevaricated by Rahman.

I thought that this would be the end, and then I went back to China directly after the itinerary.

As a result, Rahman far underestimated Zarif's perseverance, if it didn't work once or twice, then three or four times, and if he didn't agree, he would simply take it as a chanting and torture Rahman until he nodded.

That's it, Zarif also took advantage of his familiarity with China, and used China's local products, which are in high demand in Pakistan, to win over the delegation.

As the so-called cannibalistic mouth is short, taking people short, although it is some local products, it is also a face, not to mention that Zarif's request is not too much, that is, after visiting Chenggong Airlines, I will stop by to see Tengfei Group.

And the reason is also very formal, to examine the production of replacement power for intermediate training aircraft.

As for the investigation of aviation power, no one cares about these details, anyway, it is the Tengfei Group, and it is not the same everywhere?

In this way, relying on old connections, old classmates, old local products, and his transcendent status as a military attache in China, Zarif insisted on inserting an unplanned part of the military delegation's scheduled itinerary.

So there was a scene of the Pakistani military delegation visiting Ascendas Group.

However, because the Pakistani military delegation is not monolithic, some people give Zarif face, so naturally some people do not buy it, for example, Professor Ali Khan and two of his assistants from the Department of Aeronautics and Astronautics of Karachi University of Technology scoffed at Zarif's approach.

Feeling that this is another intra-military transaction, not only opposes the change of itinerary, but also openly accuses Zarif of using power for personal gain, but his arms can't twist his thighs, and Professor Ali Khan is still not enough to see how honest he is, but he still doesn't see enough in front of the military, so even if he opposes it, it's like a fart, and no one pays attention to it at all.

This made Professor Ali Khan both helpless and annoyed, and in a fit of rage, Professor Ali Khan, who had not come with him, also came to the Ascendas Group, if not for anything else, just to see with his own eyes how the bubble that Zarif boasted of bursting.