Chapter 1011 New requirements from Mr. Chang


    ??For this kind of immoral behavior of speaking loudly and focusing on the words after the big breath, the rest of the people in the conference room immediately violently criticized in their hearts.


    That is to say, the elders sitting here are relatively strong.


    ??If you are looking for someone with a bad heart, after listening to the first half just now, you will probably need Suxiao Jiuxin Pills.


    ?However, considering that Liang Shaoxiu advanced the project schedule by half a year at a time, everyone is not really dissatisfied.


    Suppression first and then expansion, joy is definitely still the main thing.


    Especially Guo Lin, who is another chief designer.


    As a replacement product that has absorbed many experiences and lessons learned during the development of the Air Police 200, the development process of the radar system of the Air Police 2000 can be considered straightforward.


    Ground testing began even more than a year ago.


    ? Even the rotatable radome encountered more technical difficulties than the radar itself.


    However, no matter how realistic the ground simulation is, it is impossible to completely restore the situation in the sky.


    Otherwise, Air Police No. 1 would not have been hastily dismounted.


    It can be said that the entire Air Police 2000 project is mainly waiting for the platform.


    The platform problem is solved and the finalization is not far away.


    ?However, Guo Lin is a pure electronic engineer after all. Even if he has collaborated with Chang Haonan several times before, his research objects are mainly equipment such as airborne pods, not the aircraft itself.


    In contrast, Wang Xiaomo, who has been exposed to some aircraft designs through Air Police 200, needs to consider issues more comprehensively.


    “Comrade Shaoxiu, you just mentioned that the downwash airflow generated by the wings increases, resulting in a decrease in the lift generated by the horizontal tail..."


    “Although modifying the design of the radome can make up for the total lift, the position of the radome and tail is different after all, and it is impossible to adjust the deflection angle. Will it affect the trim and pitch control of the aircraft?”


    Compared to the T-shaped radome of the Air Police 200, which almost only needs to consider the impact of crosswinds and structural strength, the large disk not only expands the radar detection angle of view, but also brings a lot of aerodynamic troubles.


    In particular, the C909 is smaller in size than the Boeing 707 and IL-76, but the 10.5-meter radome is larger than the E3 and A50U.


    "As for the trimming issue, while the radome provides lift, it is also one of the main loads of the aircraft. It can affect the lift center and center of gravity of the aircraft at the same time. We have specifically tested the balance of the flight platform under different flight attitudes to confirm the current The design will not adversely affect aircraft trim.”


    "As for the pitch controllability... because the impact of the downwash airflow causes the relative angle of attack of the horizontal tail to decrease, and the pitching moment provided by the horizontal tail is generally negatively related to the angle of attack, so unless it is in a very negative angle of attack attitude , otherwise the pitch controllability is almost similar to that of the C909 platform with a clean configuration, but it is even better at a positive angle of attack above 6°..."


    Liang Shaoxiu said and released a highly restored model of the Air Police 2000 early warning aircraft:


    “After calculation, after combining the radome, the net stability margin of the entire aircraft is still 10.7%. Although it is slightly lower than the data of the clean configuration, it will basically not affect the flight quality.”


    At this point, maybe he felt that it was not too rigorous, so he added another sentence:


    “At least it will not have a greater impact than the deterioration of heading stability...”


    ?In addition to the body itself, the core of the aircraft''s directional stability is the vertical tail. However, after carrying an oversized plate, the stability effect will definitely be affected.


    Even though Liang Shaoxiu specifically lowered the height of the radome by 15 centimeters, raised the vertical tail, and added a pair of tail fins, he still could not fully restore the driving feel of the C909 itself.


    However, this is an unavoidable problem for all traditional configuration early warning aircraft.


    Fortunately, the aircraft''s directional stability has a large redundancy, and as a strategic support platform, the Air Police 2000 will rarely have a flight attitude with extremely large inclination angles and sideslip angles, so it is not unacceptable.


    “Mr. Liang, when can the flight test start?”


    After Liang Shaoxiu finished answering Wang Xiaomo''s question, Guo Lin, who was sitting opposite, could no longer restrain his eagerness to give it a try.


    Although he has served as the person in charge or chief designer of many projects before, these were mostly small projects.


    Even the air-drying 200 pod back then was not at the same level as today''s early warning aircraft in terms of the level of attention it received from its superiors.


    It can be said that as long as the Air Police 2000 can be delivered on time, Guo Lin can firmly occupy the position of "successor of Academician Wang Xiaomo".


    “Now that the overall design plan has been basically determined, the next step is to do wind tunnel testing…”


    Liang Shaoxiu replied:


    “But we have a set of methods developed by... uh... Mr. Chang, so the time for blowing the wind tunnel will not be particularly long. If nothing else happens, it will probably be completed before the end of the year..."


    ??Although Chang Haonan''s identity has now become the leader of a friend next door, his experience and standards in the aviation industry system still play a role.


    By locating the performance boundary as soon as possible, the wind tunnel test plus flight test cycle can be roughly shortened to about half of the original time while ensuring the reliability of the test results.


    Hearing this answer, Guo Lin finally breathed a sigh of relief.


    Fortunately, it was within his expectations.


    But Liang Shaoxiu’s next words made his heart hang in the air again:


    "The biggest problem at the moment is the platform itself. The first C909 aircraft that Hufei Group is responsible for final assembly has just rolled off the assembly line and started test flights. According to the initial plan, they will deliver a mass-produced aircraft to us as a modified aircraft before the end of next year. platform, so it is very likely that it will not be able to keep up with our accelerated progress..."


    ?This time, not only Guo Lin, but also Wang Xiaomo frowned slightly.


    It would be a pity indeed if everyone’s efforts to meet the schedule are wasted because of waiting for the delivery of the aircraft.


    After thinking again and again, he turned to look at the leader of the General Armament Department next to him:


    “Can you consider coordinating with the relevant units to first deliver us a Tu-214K that will be assembled by Tupolev, so that at least the prototype can fly?”


    Figure 214K, where K stands for Китай. It is also the Figure 214 designed and manufactured in accordance with China Aviation Industry Standards.


    Used to distinguish it from the earlier Figure 204/214S produced with the Russian standard.


    ?There is almost no difference between the two models at the aerodynamic and structural levels, except that the former has been equipped with a two-person cockpit and a new avionics system.


    So in order to improve production efficiency and worker training efficiency, Tupolev finally stopped the production line of the old model. Instead, Tiangangdi began to deliver aircraft produced according to the Tu-214K standard to Aeroflot.


    ? As a result, Aeroflot, which had already adapted to Airbus and Boeing models, quickly expressed that it was really good, and even had a tendency to force the Russian standard to move closer to the Chinese standard...


    According to the original supply contract, before the domestic version is delivered to China, several airlines such as United Airlines that plan to purchase C909 will also receive a small amount of Tu-214K first to adapt to pilots and ground staff. train.


    It shouldn’t be difficult to take one out and give it to the Haofei Group.


    ?Sure enough, although the leader of the General Armament Department did not immediately give a clear response, he also said that he would make an application to his superiors after returning.


    Even if we cannot deliver ready goods, we can at least ensure that one of the next batch of aircraft delivered within the year will be used as a transformation platform...


    …


    The discussion on aircraft design finally comes to an end here.


    As for the radar part that Guo Lin is responsible for, there is actually no need to make any progress since last month.


    ??There are only routine startup test records.


    Reports can be submitted regularly, and there is generally no need to report them specifically at a seminar.


    ?But today, after Liang Shaoxiu’s report, Wang Xiaomo did not immediately announce the end of the seminar.


    “Xiao Guo, please wait a moment.”


    He said as he took out a file bag from his briefcase and handed it to Guo Lin, who had already started packing his things:


    “A brother unit has submitted a new test request to us for the Air Police 2000 airborne equipment. Take a look.”


    ?The other party’s description made the latter’s eyes flash with a hint of surprise:


    “Testing request from brother unit?”


    Generally speaking, when it comes to major core projects, we will try to avoid unnecessary complications in the middle.


    At present, the airborne equipment of the Air Police 2000 has almost completed ground testing. It is definitely not something ordinary people can do to incorporate new functions or technologies at this juncture.


    With such doubts, Guo Lin took the file bag and opened it.


    Inside is a document that is not too thick.


    The first thing that catches the eye on the cover is a line of large characters—


    “Feasibility Test of Application of Network Coding Technology in Airborne Data Link Communication System”


    “Want to develop an airborne data link?”


    ? Guo Lin had an expression on his face like "Why didn''t I know about this?". Just when he was about to raise his head to ask Wang Xiaomo about the specific situation, he accidentally glanced at the sponsoring organization at the bottom of the cover -


    China Aerospace Power Group.


    …


    All the confusion just now was gone in an instant.


    “That’s not surprising…”


    ?Guo Lin thought in his heart.


    ? He ??quickly opened the document, which briefly introduced the installation of an additional data transmission antenna on the Air Police 2000 to realize real-time information interaction between the early warning aircraft and the forward fighter.


    Of course, currently it can only be done through direct transmission or ground relay transmission, so the effective range is limited.


    ?However, this test is to prepare for the future launch of high-throughput communication relay satellites, so satellite transceiver antennas will be reserved at the hardware level.


    As for fighter jets…


    ? New batches of J-10A and J-11B will also be equipped with the same antenna, while older batches or older models can temporarily solve the problem through a pod.


    “So... our 14th institute needs to integrate the search information of the early warning aircraft radar into this airborne data link communication system?”


    ?Guo Lin raised his head and asked tentatively.


    “That’s right.”


    ?Wang Xiaomo nodded:


    "Although I also think that relying on ground stations for data relay... there may be too many intermediate links, but Comrade Haonan said that he has a way to solve the problems of high transmission delay and low transmission rate caused by multiple relay nodes. Let''s Don''t worry."


    “In addition, the current system only requires one-way, that is, transmitting the information from the early warning aircraft to the fighter jets for reception. It should not be difficult for your 14th institute, but the complete form in the future will definitely require two-way.”


    "Based on what I know about Comrade Haonan, I suggest you make a plan in advance. It''s best to get it right in one step... at least leave space for upgrading the two-way data link. Otherwise, I''m afraid that if you wait a few more months, his plan will be over. It’s ahead of schedule again…”


    (End of this chapter)