Chapter 1011 New Request from President Chang
The rest of the people in the meeting room immediately criticized in their hearts the unethical behavior of speaking with heavy breaths and focusing on what was said after the heavy breaths.
In other words, the old guys sitting here are still in good health.
If you find someone with a weak heart, he or she would probably have been given a quick-acting heart-saving pill after listening to the first half.
However, considering that Liang Shaoxiu had advanced the project schedule by half a year, everyone was not really dissatisfied.
It starts with depression and ends with praise, but joy definitely still plays a dominant role.
Especially Guo Lin, the other chief designer.
As a successor product that absorbed many lessons learned during the development of the KJ-200, the development process of the KJ-2000's radar system was relatively straightforward.
Even ground testing began more than a year ago.
Even the rotatable radome encountered more technical difficulties than the radar itself.
But no matter how realistic the ground simulation is, it is impossible to completely restore the situation in the sky.
Otherwise, KJ-1 would not have been decommissioned so hastily.
It can be said that the entire KJ-2000 project is now mainly waiting for the platform.
Once the platform problems are solved, it will not be long before it is finalized.
However, Guo Lin is a pure electronic engineer after all. Even though he has collaborated with Chang Haonan several times before, his research objects were mainly equipment such as airborne pods, not the aircraft itself.
In contrast, Wang Xiaomi, who has been exposed to some aircraft design through the KJ-200, considers the issues more comprehensively.
"Comrade Shao Xiu, you just mentioned that the downwash generated by the wing increases, resulting in a decrease in the lift generated by the horizontal tail..."
"Although modifying the design of the radome can compensate for the total lift, the positions of the radome and the horizontal tail are different after all, and it is impossible to adjust the deflection angle. Will it affect the balance of the aircraft and the pitch controllability?"
Compared with the T-shaped radome of KJ-200, which only needs to consider the impact of crosswind and structural strength, the large disc expands the radar detection field of view but also brings a lot of aerodynamic troubles.
尤其是C909的体量相比波音707和伊尔76本来就小，而10.5米的雷达罩尺寸却比E3和A50U更大。
"Regarding the balance issue, the radome not only provides lift, but is also one of the main loads of the aircraft, which can affect both the lift center and the center of gravity of the aircraft. We have specifically tested the balance of the flight platform under different flight attitudes and confirmed that the current design will not have an adverse effect on the aircraft balance."
"As for pitch controllability... because the downwash causes the relative angle of attack of the horizontal tail to decrease, and the pitch moment provided by the horizontal tail is generally negatively correlated with the angle of attack, so unless it is at a very large negative angle of attack, the pitch controllability is almost the same as that of the C909 platform in a clean configuration, and it is even better at a positive angle of attack of more than 6 degrees..."
Liang Shaoxiu said as he showed a highly restored model of the KJ-2000 early warning aircraft:
"After calculation, after combining with 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 basically does not affect the flying quality."
Having said this, perhaps because he felt that it was not rigorous enough, he immediately added:
"At least it won't have a greater impact than the deterioration of heading stability..."
In addition to the fuselage itself, the core of the aircraft to ensure heading stability is the vertical tail, but after carrying an extra-large plate, the stability effect will inevitably be affected.
Even though Liang Shaoxiu specially lowered the height of the radome by 15 centimeters, raised the vertical tail, and added a pair of tail fins, he still could not completely restore the driving feel of the C909 itself.
However, this is a problem that all traditional early warning aircraft cannot avoid.
Fortunately, the aircraft's heading stability is inherently relatively redundant, and as a strategic support platform, the KJ-2000 will rarely have a flight attitude with extremely large inclination and sideslip angles, so it is not unacceptable.
"Then Mr. Liang, when can we start the flight test?"
After Liang Shaoxiu answered Wang Xiaomo's question, Guo Lin, who was sitting opposite him, could no longer suppress his urge to try -
Although he had served as the person in charge or chief designer of many projects before, they were basically small-scale projects.
Even the Air Force's Air-Ground 200 pod back then, in terms of the level of attention it received from superiors, was not on the same level as today's early warning aircraft.
It can be said that as long as the KJ-2000 can be finalized and delivered on time, Guo Lin will be able to firmly sit in the position of "successor to Academician Wang Xiaomo."
"Now that the overall design has been basically finalized, the next step is to conduct wind tunnel testing..."
Liang Shaoxiu replied:
"But we have a set of methods developed by... uh... Mr. Chang back then, so the wind tunnel won't take too long. If nothing goes wrong, we'll probably be done by the end of the year..."
Although Chang Haonan's current identity has become the leader of a friendly company next door, the experience and standards he left in the aviation industry system are still playing a role.
By locating the performance boundaries as quickly as possible and ensuring the reliability of the test results, the wind tunnel test plus flight test cycle can be roughly shortened to about half of the original time.
Hearing this answer, Guo Lin finally breathed a sigh of relief.
Fortunately, it was within his expectations.
But Liang Shaoxiu's next words made him feel anxious again:
"The biggest problem at the moment is the platform itself. The first C909 aircraft assembled by Shanghai Aircraft Corporation has just rolled off the production line and started its test flight. According to the original plan, they will deliver a mass-produced aircraft to us as a modification platform before the end of next year, so it is very likely that they 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 real pity if everyone's efforts to catch up with the progress were wasted because of waiting for the aircraft to be delivered.
After thinking it over 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 deliver us a Tu-214K assembled by Tupolev first, so that at least the prototype can fly?"
Figure 214K, where K stands for kntan.
That is the Tu-214 designed and manufactured in accordance with China Aviation Industry Standards.
Used to distinguish it from the Tu-204/214S produced earlier according to Russian standards.
There is almost no difference between the two models in terms of aerodynamics and structure, except that the former is equipped with a two-person cockpit and a new avionics system.
In order to improve production efficiency and worker training efficiency, Tupolev finally stopped the production line of the old model and started to deliver aircraft produced according to the Tu-214K standard to Aeroflot.
As a result, Aeroflot, which had already begun to adapt to Airbus and Boeing models, quickly said that it was really good, and even forced the Russian standards to move closer to the Chinese standards...
According to the original supply contract, before the delivery of the domestically produced version in China, several airlines planning to purchase the C909, such as United Airlines, will also receive a small number of Tu-214Ks in advance to conduct adaptive training for pilots and ground staff.
It should not be difficult to take one out and hand it over to Gaofei Group.
Sure enough, although the leader of the General Armament Department did not give a clear response immediately, he also said that he would apply to his superiors after returning.
Even if the company cannot deliver the goods in stock, it 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 has finally come to an end.
As for the radar part that Guo Lin is responsible for, there has actually been no need for any further progress since last month.
Just routine power-on test records.
It is sufficient to submit reports regularly, and there is generally no need to present them specifically at the seminar.
However, today, after Liang Shaoxiu's report ended, Wang Xiaomo did not immediately announce the end of the seminar.
"Xiao Guo, wait a moment."
As he spoke, he took out a file bag from his briefcase and handed it to Guo Lin, who had already started packing:
"A brother unit has submitted a new test request to us regarding the KJ-2000 airborne equipment. Please take a look."
The other party's description made the latter's eyes flash with surprise:
"A testing request from a brother unit?"
Generally speaking, when it comes to major core projects, we will try our best to avoid complications midway.
At present, the onboard equipment of KJ-2000 has almost completed ground testing. It is definitely not something that ordinary people can do to cram in new functions or technologies at this critical juncture.
With such doubts, Guo Lin took the file bag and opened it.
Inside was a document that wasn't very thick.
The first thing that caught my eye on the cover was a line of large characters:
"Feasibility test of network coding technology in airborne data link communication system"
"We want to get an airborne data link?"
Guo Lin had a look on his face that said "How come I didn't know about this?". Just as he was about to look up and ask Wang Xiao about the mold, he accidentally glanced at the unit that proposed it at the bottom of the cover.
China Express Aviation Power Group.
"call……"
All the confusion just now was swept away in an instant.
"That's not surprising..."
Guo Lin thought to himself.
He quickly flipped through the document, which briefly introduced the installation of an additional data transmission antenna on the KJ-2000 to achieve real-time information exchange between the early warning aircraft and the fighter jets in front.
Of course, at present it can only be done through direct transmission or ground relay transmission, so the effective range is limited.
However, this test is intended 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 the fighter planes...
New batches of J-10A and J-11B will also be equipped with the same antenna, while old batches or old 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.
"Yes."
Wang Xiaomo nodded:
"Although I also think that relying on ground stations to relay data... may have 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, so we don't have to worry."
"In addition, the current system only requires one-way transmission, that is, transmitting the information of the early warning aircraft to the fighter jets. It should not be difficult for your 14th Institute, but the complete form in the future will definitely require two-way transmission."
"Based on my understanding of Comrade Haonan, I suggest you make some preparations in advance, and it would be best if you can complete it in one step... At least you have to leave room for the two-way data link upgrade. Otherwise, I'm afraid that if we wait a few more months, his plan will be advanced again..."
