Chapter 1222 Turbofan 20, fighting for the initiative!


    One week later, Yanliang Airport.


    It is early autumn, and the autumn wind blowing from the North China Plain to the land of Guanzhong is whistling, and there is inevitably a slight chill in the air.


    However, for outdoor operations with meteorological requirements, autumn is often an excellent time window to catch up.


    In his previous life, Chang Haonan was born in a wind tunnel. He basically traveled between Base 29 and Huairou Science City, and rarely experienced the hardships of outfield work.


    In this life, I can make up for everything.


    Standing in a newly completed multi-functional hangar, Chang Haonan raised his head slightly and looked at a twin-engine jet transport aircraft parked not far in front of him.


    The plane had not yet completely lost power, and there were still more than a dozen ground staff standing around. It was obvious that it had just landed not long ago.


    This Y-9 prototype numbered 90002 is almost identical to the previous one in terms of body structure and avionics equipment. It can be regarded as a realization to a certain extent of what Liang Shaoxiu proposed when he drew the cake: "the first flight is the first flight." The heroic words of "complete body".


    The only difference is that the two turbofan engines under the wings of the No. 02 prototype are so large that they are even a little uncoordinated -


    It is the twin-engine turbofan 20.


    Since the load threshold of a medium-sized transport aircraft often depends on the strength of the cargo hold, compared with the early state of the PS90A when equipped with the first flight, the maximum load capacity on paper of this "full blood version" of the Y9 has not changed and remains at 23 ton.


    However, the maximum take-off weight has increased by more than 10%, from the original 81 tons to 90 tons.


    This means more fuel can be carried at full load.


    Combined with a new engine that reduces fuel consumption by more than 30% compared to PS90A, Yun-9 has an amazing range that should not belong to this size at all—


    Even though the larger-diameter engine brings greater resistance, the range of the 25-tonne fully loaded aircraft still jumps from a pitiful 2,500km to nearly 4,000km, almost tying the European A400M transport aircraft that is also under development.


    You must know that the maximum take-off weight of the latter is more than 1.5 times that of the Yun-9.


    Although this is just a sweet comparison under specific conditions (the optimal working range of the turboprop engine is relatively narrow, so when the operating conditions deteriorate, the original fuel consumption advantage will be quickly wiped out, or even turn into a disadvantage), but at least On the publicity level, it still has enough impact.


    Moreover, eliminating two engines will also significantly reduce direct maintenance man-hours per flight hour, which is extremely valuable for smaller or less experienced transport aviation.


    In fact, when the No. 02 prototype left the factory one and a half months ago, the second air test version turbofan 20 numbered 20102 was already installed under the right wing.


    However, the Y-9''s position in China''s aviation industry spectrum is not just about replacing the old Y-8 and seizing the international market.


    More importantly, the turbofan 20 is still used for the real hard work behind, that is, the civilian version of AE1500 to conduct part of the technical verification.


    Therefore, if anyone with a sharp eye observes carefully, they will find that although the size and specifications of the engine pods on the left and right sides of the No. 02 prototype are the same, there are very slight differences in the position and number of openings on the side...


    "Previous groups of test pilots generally reported that the new engine not only has greater thrust, but also has a much faster throttle response than the original PS90A. It is very comfortable to use and requires almost no additional adaptation time."


    Liang Shaoxiu, the chief designer of Yun-9, stood next to Chang Haonan and introduced the current test flight situation to the latter while walking in circles:


    "The only fly in the ointment is that when flying in harsh weather conditions...or strictly speaking, in high humidity environments such as rainy days or clouds, you can obviously feel that the noise and vibration amplitude of the new engine is greater than normal, and Fuel consumption will also deteriorate accordingly.”


    "Although from the data point of view, these do not exceed the fluctuation range specified in the manual, if they are equipped in batches to the troops, it may affect the operational confidence of ordinary pilots, and the huge fluctuations in fuel efficiency will also affect the flexibility of transportation task arrangements. sex."


    Considering the issue of universality, the training syllabus does not require most pilots to have a particularly strong sense of self-challenge.


    Therefore, compared with the group of test pilots who dance on the tip of the knife every day, the adaptation period required by combat units after replacing new equipment is significantly longer.


    And it is also more affected by the characteristics of the equipment itself.


    For example, during the large-scale replacement of third-generation aircraft in recent years, the principle of the aviation force is to try to ensure that J-10s are replaced with J-7s, J-11s are replaced with J-8s, and the replaced J-8s are replaced with J-6s.


    Although flying a transport aircraft is not as exciting as a fighter jet, because the tasks that need to be performed are more diverse, large-scale replacement is by no means an easy task.


    "I know this situation..."


    Chang Haonan did not show any surprise, and just nodded calmly:


    "The intercooler of the 01 batch turbofan 20 prototype is integrated on the stator blades, so after the air with excessive humidity passes through, large-sized water droplets will condense and hit the mover blades further back."


    "Although I use iron-based materials to ensure sufficient stiffness and surge margin, on the one hand it will still affect the service life, and on the other hand it will also increase the weight of the engine...Military transport aircraft may not care much about these, but if you want to in the future For civilian use, this problem must be overcome..."


    Military aircraft will have professional staff officers to conduct mission planning before each takeoff, but the routes of civil aircraft are almost fixed.


    If the engine''s fuel consumption fluctuates too much, then on a day of high humidity, low temperature, and headwind flight, if the extra fuel reserved in accordance with aviation industry practice cannot support the destination, you will be in big trouble.


    While they were talking, the two of them had already walked around to the left side of the plane.


    Several technicians whose uniform styles are obviously different from those of the Aviation Industry Group are standing on an inspection frame, preparing to perform maintenance on this new batch of engines numbered 20201, which has just completed its first flight. Chang Haonan motioned to Liang Shaoxiu to take two steps closer, then raised his hand and pointed to the high-pressure compressor part behind the fan:


    "Although the basic structure of the batch 02 engines has not been modified, a set of condensation control modules has been added in front of the inlets of the three sets of intercoolers. If nothing unexpected happens, it should be able to significantly improve the situation you just described. ”


    If Mr. Richard Partridge from Rolls-Royce was also present, he would have been very surprised after hearing this conversation.


    Because what Chang Haonan just downplayed was the core problem that he had previously thought was "difficult to solve in aero engines"...


    "So, during today''s test flight, three cloud-piercing flights were specially arranged to verify this new... uh... control module?"


    Liang Shaoxiu squinted his eyes and took a closer look, but due to the long distance and poor angle, he could not directly see the changes in the internal structure of the engine.


    With the continuous development of aviation technology, the degree of specialization in aircraft design and aerospace design has also increased.


    Most people cannot switch seamlessly between these two routes like Chang Haonan.


    "Academician Chang."


    At this moment, a voice, accompanied by hurried footsteps, sounded from behind the two of them.


    It is Zhang Zhenhua, the deputy chief designer who is fully responsible for the turbofan 20 on-site test flight.


    He also held a piece of paper material in his hand that he hadn''t even had time to bind:


    "The analysis results of this test flight are out, and the performance of the new batch of products... can be said to be completely unexpected."


    Liang Shaoxiu, who was a little doubtful just now, couldn''t help but open his eyes wide:


    "Performance...what specifically does it refer to?"


    Zhang Zhenhua replied without raising his head:


    "Compared with the right engine that has not been upgraded, the impact force suffered by the No. 3 rotor of the left engine during cloud penetration is reduced by about 75%, thus reducing the additional vibration amplitude by about 90%. In addition, the cloud layer The impact on fuel economy is also significantly different..."


    As he spoke, he turned to the next page:


    "When running at maximum thrust, the fuel consumption of the left engine in clouds is only 107.6% of that in dry air, while the right engine reaches 115.9%. Of course, the difference in this case is not too big... The key is to use When running at cruise thrust, the fuel consumption of the left engine in clouds is still only 118.1% of that in dry conditions, while the right engine can reach 141.5%..."


    “…”


    Liang Shaoxiu walked around behind Zhang Zhenhua with a face full of shock and confirmed the contents of the paper with his own eyes:


    "But I see on the drawings...the two engines only have a very slight difference in the structure of the compressor part?"


    "That''s right."


    Chang Haonan took two steps forward, took the report from Zhang Zhenhua, and explained while flipping through it:


    "The so-called condensation control module is actually not complicated at the mechanical level. It is just an additional set of condensers combined with three three-way valves. The real core lies in the control program. It needs to ensure that the temperature of the humid air entering the intercooler is lower than The corresponding dew point temperature under this condition..."


    "This control process is of course relatively complex, but compared to directly modifying the cycle parameters of the intercooler, it is still several orders of magnitude simpler."


    After hearing this, Liang Shaoxiu opened his mouth several times in succession, but in the end no words came out.


    Okay, since he is the one who designs airplanes, as long as he knows that the power is good enough, that''s all.


    After a few minutes of silence, Chang Haonan probably finished browsing the entire report, then raised his head and looked at Liang Shaoxiu:


    "Mr. Liang."


    The latter''s thoughts were interrupted by this sudden voice:


    "exist!"


    "I remember that according to the plan, the Y-9 will participate in the Singapore Airshow to be held in February next year?"


    Liang Shaoxiu nodded:


    "Yes, we are already preparing relevant materials and preparing to submit them to the air show organizer."


    "That''s just right."


    There was obvious excitement in Chang Haonan''s tone:


    "Please coordinate with the Aviation Technology Import and Export Group and try to allow the No. 02 prototype to be exhibited."


    "In addition, we will also send a full-size model of the Turbofan 20 to the airport at that time. Remember to leave a conspicuous booth next to the aircraft!"


    (End of chapter)