Chapter 691: The longer the range, the more things to consider
"Hahaha, I've never heard of this 'unit range cost' before."

"You know what, after using this indicator, the cost increase really looks much better."

Everybody was laughing happily, and the boss thought for a long time and then started laughing.

"Comrades, don't worry about the cost at all! I just estimated that the overall cost increase will not exceed 20%."

"So low?" Everyone was shocked.

"This new drug is actually not expensive. It is only a few dollars more expensive than the old drug for the same volume. Also, have you noticed a special feature of this new drug?"

"What characteristics?"

"This new propellant is a cast type..."

As soon as this sentence was uttered, everyone reacted instantly.

The casting mold is easy to deal with. As long as the shape of the projectile is designed well, the casting process is studied well, and the mold is prepared, the subsequent production process will not be complicated.

Especially when they plan to use a single-propellant dual-thrust configuration, the grain is cast as a whole, and there is no need to consider issues such as the interface of the dual propellants, nor is there any need for secondary casting.

Gao Zhendong said that the complexity of processing star-shaped or other complex propellants increases costs, which is a general conclusion, but specific analysis is required for specific situations, as different equipment is different.

For example, ballistic missiles may even require humans to carefully craft them.

As for things like 107 fire, there is no need for that. It’s fine as long as it’s roughly right. Just cast it and be done with it.

"The comrades who are developing the new propellant are really thoughtful. It has good performance, low price, and is easy to produce. Hahahaha."

"We've done it, we'll use it all! We can't let down the hard work of the comrades who worked on the propellant."

"According to the most conservative estimate, the range is increased by more than 35%. Just thinking about it is exciting!"

Comrades who are engaged in rockets of other calibers do not know that the 107 rocket has already started launching satellites without making any external changes.

Comrades from the 130th and 180th divisions have now met up in the capital, and under the leadership of the Defense Working Committee and the Land Equipment Bureau, they are heading straight for the Third Rolling Mill, Branch .

The comrade from Changfeng Factory who is in charge of 180 has taken the previous records of Fenglei Factory and studied them first.

I watched it and was full of praise!
"So that's it..."

"Found it, found it. The problem with the last experiment was found..."

"It seems we can't use this bullet type anymore. We need to make major changes!"

It seems incredible, as if everyone is like Granny Liu entering the Grand View Garden.

But the truth is so exaggerated that every word of Gao Zhendong is new knowledge to them. You should know that on the original timeline, the 71mm rocket launcher was not completed until 180, and its range was still 10 kilometers. It can be seen how weak the relevant technology was at that time.

Gao Zhendong received them again. This time, there were comrades from Changfeng Factory, who were "transfer students", so Gao Zhendong's opening remarks were a little different.

"Hello, comrades from Changfeng Factory. You just arrived. Regarding the last discussion between me and the comrades from Fenglei Factory, is there anything I can add?"

The comrades from Changfeng Factory said, "No, no, Chief Engineer Gao's last speech was very easy to understand, and the comrades from Fenglei Factory also kept very detailed records. We have basically digested it."

What Gao Zhendong said was not actually a complete theory, and it was mainly some superficial knowledge, so there was no very complicated content. For the comrades at Changfeng Factory, it was quite easy to understand.

Gao Zhendong nodded: "Well, let's continue with what we talked about last time. Last time we discussed the defects of turbo-engine rockets, which is that at high diameters, the flight of the projectile is prone to instability, and this defect is innate and difficult to avoid by improving the design and increasing the processing accuracy..."

Moreover, for rockets, blindly improving the processing accuracy may not look good in terms of cost and production capacity.

"Then should we abandon rotational stabilization and use tail stabilization instead?" asked a comrade from Changfeng Factory.

Their concern is that the tail fin needs a large space to stabilize and the directional tube cannot be used. The original 180mm rocket launcher used a directional cage between the directional tube and the Katyusha rail, which was probably taken into consideration in this regard.

Gao Zhendong neither confirmed nor denied: "No, rotational stability is still needed, and tail fin stability must also be installed, with folding wings for stability. Of course, this rotational stability does not require the use of a turborocket engine to start the spin. For lighter warheads, you can consider using the tail fin to tilt at a certain angle to start the spin, and even add a fixed winglet on the head to enhance the stabilization effect. The combination of rotation and wing surface can play a stabilizing role together."

There are two types of winglets on the tip of a rocket, one fixed and one movable. The former plays a stabilizing role and also provides a stabilizing torque at the warhead end, which is beneficial to the stable flight of the rocket. The latter is a controllable rocket, but this thing is still a bit far away.

Gao Zhendong did not dare to recommend inertial navigation correction for rockets at this time, because it was too expensive. Although the Chijian-61 individual anti-tank missile was equipped with a gyroscope, there was only one gyroscope, and the accuracy requirement was not high. Moreover, it was not used for inertial navigation, but for missile attitude control and acquisition, so it was not expensive. A full set of inertial navigation was very expensive at this time. Therefore, we could only work hard on the missile body, try to use simple physical means to achieve stability, and try to reduce the cumulative error during flight.

"Folding wings?" The comrades from Fenglei Factory were a little puzzled.

There is no other reason. The coordination between the directional tube and the rocket is very close, and the folding wing is difficult to arrange.

Due to the structure of the rocket, the folding wings cannot be cut into the tail of the missile body, as that would affect the installation of the rocket engine.

Gao Zhendong thought about it and drew a picture on the blackboard.

“You may consider this approach.”

The three curved tail fins are consistent with the curvature of the outer periphery of the projectile. They are normally folded and hugged tightly against the projectile body, and unfold after launch.

When the comrades from Fenglei Factory saw it, they said, "Wow, this thing is good. It looks simple and quite clever."

Gao Zhendong reminded them: "This is the simplest folding method with the least impact on the projectile, but it is not the best folding method. If the range is longer, it is easy to drop the bullet."

It has defects, but it is not unusable. It must be used within a certain range. After all, this method is simple, has little impact on the missile structure, has a large tail area, and has a good stabilizing effect.

The second half of this sentence made the comrades at Changfeng Factory feel disappointed.

Ever since they knew that the 130 could hit the target up to 40 kilometers, they had higher expectations for the range of the 180. After a preliminary calculation, they felt that a hard range of 50 to 60 was no problem, but whether it could be accurate was another matter.

When I heard that this method might cause the bullet to drop if I shot far away, how could I not be anxious?
"Chief Engineer Gao, why is this?"

Gao Zhendong smiled and said, "This has nothing to do with the structure of the missile, spin, stability, etc. It involves aerodynamic issues. A circular rotating object will produce the Magnus effect when flying in the air, which will generate a lateral force on the missile that is perpendicular to the direction of rotation."

Gao Zhendong knew that they were completely clueless about this matter, both in theory and in practice. Instead of waiting until they discovered the problem and took a detour before solving it, it would be better to nip this problem in the bud.

The Magnus effect has been discovered many years ago, so you can just talk about it without making up its origin.

By the way, this Magnus is not the Magnus in WH40K who tied important information to a nuclear bomb and sent it to his father, which directly blew up the shithole under his father's ass. Loyalty!!!!!!!!!
The comrades from Changfeng Factory looked at the drawings and explanations drawn by Gao Zhendong. At first they thought they had learned it, but later they found that it was not correct.

"But the projectile body is basically uniform, and the lateral force it receives is also uniform overall. In other words, the projectile body is offset as a whole. As long as this issue is fully considered, it may have a certain impact on the accuracy, but it will not cause the bullet to fall, right?"

Well, as expected of a researcher, you absorb information quickly and have some ideas for solving problems, but things are not that simple.

"Well, you're right. But the problem with the curved folding wing is the arc. When it's unfolded and rotated, it looks a bit like a cylinder from an aerodynamic point of view..."

The comrades at Changfeng Factory looked at the circle that Gao Zhendong added to the picture and suddenly realized: "I understand. In this small section of the tail wing, the approximate circle is much larger than the missile body. The Magnus effect is unbalanced with the missile body. This imbalance will eventually deflect the missile body, causing it to drop or cause large-scale misalignment."

Gao Zhendong nodded: "Yes, that's the problem. So for a 25km missile, you can consider using this structure. After all, it is really simple and convenient. For larger ones, it is not recommended. Even a 40km one is not recommended."

"What do you use for those 40 or above?"

Gao Zhendong drew a picture.

"Although the straight folding wings have a slightly greater impact on the shape of the missile body, considering that this is the throat of the rocket engine, the overall impact is actually not that great. Overall, this is better than the curved folding wings."

Comrades from the Land Equipment Bureau felt that Gao Zhendong’s explanation was too detailed and it would be better to just use the straight folding wings, not to mention the curved folding wings.

Changfeng Factory and Fenglei Factory don't think so. They want to understand every possibility and its advantages and disadvantages. Different solutions may not be used here, but may be used there.

Just like a turbo engine, it is not suitable for long-range missiles, but it is perfect for use in a range of 10 kilometers.

There is no garbage technology, only garbage design.

There is no equal between good technology and good results. The Japanese have a lot to say about this. Many people have not figured out how they used a bunch of advanced active phased array technologies to come up with a detection range of 37 kilometers.

"If the tail wing is stable enough, can we give up rotational stability? After all, the Magnus effect brought about by rotational stability may cause the missile to deviate and increase the error even without using curved folding wings."

Gao Zhendong shook his head: "No, because rockets need to be cheap, and tiny rotation is one of the best ways to improve the accuracy of rockets while keeping them cheap."

(End of this chapter)