Siheyuan: I eat melons while doing scientific research

Chapter 1094 Telex
"Well, there is this problem. Even if power-assist devices are added, it cannot change the fact that the pilot is essentially competing with the aircraft." When it comes to this, the people who feel it most deeply should be the comrades who are engaged in high-mobility tactical aircraft.

To put it simply, the most typical one is the fighter jet.

"As the size and speed of our fighter jets increase, not to mention the early pure wire-pulling systems, even the hydraulic servo systems have similar problems. The entire force transmission path still exists." Speaking of this, the comrades who work on fighter jets have something to say.

"Well, even bombers are like this. Although they are not the fastest and their maneuverability is not the strongest, it is very difficult to operate them purely by pulling wires. The hydraulic system not only needs to consider the mechanical connection, but also the establishment of hydraulics, which requires an additional subsystem."

"There is more than one set. The reliability of hydraulics is not as good as that of pure mechanical systems. If you want high reliability, you need two sets, and they must be independent of each other." There were comrades present who were responsible for operating the system and were very clear about these situations.

In fact, some aircraft that sound very advanced were not that advanced at the beginning. For example, the early "Hangar Queen" F-15 was hydraulically powered and used two independent hydraulic control systems.

After discussing for a while, everyone remembered that Chief Engineer Gao only talked about the disadvantages but did not mention how to solve them.

"Chief Engineer Gao, do you want to solve this problem electrically?" Everyone was no fool, especially the comrades at the Cifei Factory who were quite familiar with Gao Zhendong, so they just asked directly.

Gao Zhendong nodded. "Yes, that's what I think. I was thinking, can we develop a system that uses electrical signals to transmit control signals? The benefits of this may be more than what I just mentioned. I initially named this technology fly-by-wire."

——Fly-by-wire control, this is what Gao Zhendong wants to do. In a few decades, any military aircraft of a slightly higher grade will definitely adopt this technology. Of course, it is not only used in the military, but also in civilian use. Although this thing is expensive, it can actually bring great benefits to the designers, manufacturers and operators. It is a typical win-win technology.

Among actual products, there are many new technologies that seem to be full of sincerity in the manufacturers' publicity, but in fact they have no practical benefits to users. The only reason why manufacturers adopt them in large numbers is that they look good and save money, but they are not very cost-effective and may even be a step backwards.

But fly-by-wire is not.

This thing is not as simple as it sounds, just transmitting up, down, left, and right information to the wings of the aircraft. It can bring many benefits.

"Fly-by-wire control? Comrade Zhendong, can you tell me in detail?" The chief engineer of the Defense Work Committee became interested all of a sudden. This thing sounds good and must be a good thing.

Gao Zhendong nodded: "The most basic idea is to convert the pilot's control instructions into electrical signals, and then transmit them to the actuating mechanisms of each controlled control surface through wires, decoupling the movement of the wing surface from the pilot's operation in terms of mechanical connection."

"But what are the benefits of this? Mr. Gao, this technology sounds expensive and technically difficult, but there is no essential difference between electrical and mechanical transmission. If the electrical signal is fast, the wire control cannot be compared with it in terms of timeliness due to elastic deformation, thermal expansion and contraction, friction coefficient, etc., then the rigid connection of the hydraulic system does not have this problem, and the feedback speed is basically the same as that of the electrical signal."

A comrade who was engaged in hydraulic control raised a question about this, and other comrades nodded in agreement. If it was only to solve the time delay problem, then this expensive-sounding technology would not have much of an advantage.

Gao Zhendong stood up and began to draw an airplane on the blackboard in the conference room.

"You are right. But even if we put aside all other advantages and only consider the agility, hydraulics also have inherent defects compared to electric transmission. That is, mechanical + hydraulic transmission actually has transmission delay, but this delay is solved at a high cost."

As long as elastic deformation exists, the mechanics will inevitably cause delays and other connection problems, and the longer the transmission path, the more serious the problem will be, and more complex designs must be used to solve this problem.

For example, hydraulic systems are almost all rigidly connected, which brings huge weight and is very costly.

Gao Zhendong mentioned another unsolvable defect: "In essence, at high speeds and large maneuvers, the problem of mechanical or hydraulic sluggishness has not actually been solved. The direct resistance of the control surface to the operator during maneuvers is inherent, and this is not even related to the delay itself."

It's like driving a car. Although it will turn obediently as soon as you turn the steering wheel, the lightness of the rack and pinion assisted turning and the body posture and response of the hydraulic assisted turning are difficult to compare with those of the electric assisted turning.

"But although some transport aircraft use hydraulic power assistance, they are still mainly based on wire pulling, right? Wouldn't this take both weight and delay into consideration?" Some comrades felt that this did not seem to be the case.

Gao Zhendong smiled and said, "Because they are transport aircraft, they don't need to be so agile. And even if it is a transport aircraft, the other advantages of fly-by-wire control are enough to allow it to replace mechanical and hydraulic control."

"Hmm..." The comrade who raised the question fell into deep thought. It seemed that this was the case. Transport planes didn't seem to have any requirements for agility or delay.

"Let's ignore the problem just mentioned. Among the benefits brought by fly-by-wire control, it is the most insignificant one. After all, it is replaceable to a certain extent. Let's look at other benefits." Gao Zhendong said with a smile. Comrades, let's put this matter aside for the time being. Chief Engineer Gao makes sense. As long as the other benefits are great enough, even if the indicators are delayed, it is worth replacing.

Everyone watched Gao Zhendong writing on the blackboard.

"The first is weight. As we all know, cables are much lighter than steel cables and connecting rods. Although we may need to lay a lot of cables, overall, this set of things is still lighter than hydraulic ones. If hydraulics want to ensure reliability, the cost is very high. Multiple sets of independent hydraulic control connections are very expensive."

At this point, Gao Zhendong also made a joke: "Besides, we all know that electricity is weightless." From a macro perspective, there is nothing wrong with this statement.

Everyone laughed and nodded. The weight advantage alone was enough to attract people. As for the wire control method, it seemed that it could only be used on small aircraft today when the speed and weight of aircraft were getting bigger and bigger.

"The second is structural convenience. As we all know, wires can be bent, and so can electricity. Compared with rigid connections and wire connections that have strict requirements on the installation location and structure, which other systems must compromise on, the advantages of fly-by-wire control in this regard are unparalleled. It can be inserted into any gap!"

Not to mention rigid connections, even the cable, which is nominally a soft steel cable but actually still has requirements for the layout of the transmission path, cannot be compared with fly-by-wire control.

This is easy to explain. Once Gao Zhendong explains it, everyone will understand.

For those who work on aircraft structures, the rigid connection path is something that can be described with an idiom: "like a fishbone stuck in the throat."

"Yes, the fewer things like this that have strict requirements on space and paths, the better."

"In this way, the number, location and size of the openings on the structural parts can be easily adjusted, which is very beneficial to the design of the aircraft body."

"Well, it can reduce material requirements and processing difficulty. From a manufacturing perspective, it can also save costs, and there is no need to make other compromises for this system."

"It's not just about manufacturing, it's also about maintenance! If it's designed properly, it's much easier to replace wires than to replace rigid connectors."

"..."

Seeing that the comrades were getting more and more excited and bringing the topic to a whole new level, the chief engineer of the Defense Work Committee smiled and knocked on the table: "Comrades, let's not rush to discuss it. Let's listen to Comrade Zhendong finish his words."

Everyone stopped discussing and felt a little embarrassed. Hey, once we saw something good, we forgot everything else.

Gao Zhendong didn't care. If it was attractive, it just showed that this technology had huge advantages.

"Third, the control of fly-by-wire is more refined. In layman's terms, the control resolution is higher, which plays a very important role in enhancing the maneuverability of the aircraft. At the same time, it is easier to integrate with airborne sensors, airborne computers, and control systems. The control signals sent by the computer can be implemented on the actuator in a more direct way. The combination of the two can greatly improve the maneuverability of the aircraft. More refined, more direct, fast response, and easy integration, these four points together, in fact, are the core reason why I want to engage in fly-by-wire control - it can improve the maneuverability of fighter jets."

Gao Zhendong spoke happily, but his comrades seemed a little confused.

"Chief Engineer Gao, the maneuverability of an aircraft is determined by the characteristics of the aircraft itself, right? No matter how precise the control, how fast the response, or how many input parameters of various sensors there are, there is no way to fundamentally improve the maneuverability of the aircraft." Comrades who are engaged in aircraft overall design or aerodynamics were puzzled by this and directly raised their objections.

Gao Zhendong laughed. "Well, I can't elaborate on this here for the moment. Anyway, everyone should remember that with fly-by-wire control, we can use a new concept and technology to greatly improve the maneuverability of the aircraft. Moreover, this technology not only improves the maneuverability of the aircraft, but also brings other benefits, such as reducing the design weight, reducing the required thrust and so on."

With a "buzz" sound, all the comrades at the scene became agitated.

What kind of magical technology can bring such a powerful effect?

Improving maneuverability, reducing weight, and lowering demand, each of these is the dream of comrades engaged in aircraft design. How could Mr. Gao use one technology to meet these three demands?
(End of this chapter)