"Are you so sure?" Zhao Yuqing frowned slightly, then muttered himself: "I don't know how you got so much information. What kind of makeup spy is more unbelievable than novels."

Yang Tianfeng smiled unanimously, lowered his head and continued to look at the documents in front of him.

Zhao Yuqing seemed to be thinking, and suddenly spoke after a while: "It's reasonable to promise your life, thank you for your own good!"

Hum? Yang Tianfeng suddenly raised his head and looked at Zhao Yuqing. His expression gradually changed from being surprised. He understood that this girl finally knew what her sister was hiding.

"General Yang, if you can save my sister and she is willing, then I won't care about your affairs!" Zhao Yuqing finally revealed her true appearance, and her eyes rolled out her expression showed that she was still the little girl who had not experienced much.

"Yes, she can only be willing." Yang Tianfeng smiled slightly and said, "What kind of life-saving grace? I don't have this idea. Just like before, your sister is free, staying or leaving, and no one interferes."

"My sister--" Zhao Yuqing sighed softly and said, "If her illness is cured, I think she wants to stay, although she didn't say that. However, we can't let our family know about this matter for the first time."

"Then I'll help you cover it up!" Yang Tianfeng smiled and poured a cup of tea for his sister-in-law and handed it over, "How did you know that it was your sister who told you?"

Zhao Yuqing took the teacup and did not drink it immediately. She smiled sly and said, "I heard a few words outside what you two said in the room. My sister, without cheating, she said everything when I was fooled." After a pause, Zhao Yuqing suddenly felt a little sad, "My sister may feel that she can't get rid of the disease, so there is no need to bother hiding it from me."

"The disease can be cured, I am 70% or 80% sure." Yang Tianfeng first comforted him and said, "Don't worry, go and accompany your sister. Or go to rest. You look a little tired, and these days must be very hard."

"I'll wait a little longer, maybe the medicine can be made in advance!" Zhao Yuqing said, "General Yang, you're busy with your life. I'll sit here and don't bother you, right?"

Yang Tianfeng nodded gently and continued to look through the documents.

Rocket launchers have the characteristics of simple structure, strong firepower, high firing speed, fast response and good surprise. Compared with other artillery, rocket launchers can quickly pour a large amount of explosives into the target. Although their accuracy is low and the loading time is longer, they are cheap and easy to produce.

In Yang Tianfeng's view, low prices and easy production are the key points he is concerned about. Compared with body-barred cannons of the same caliber, rocket launchers have extremely high cost performance (the cost is equivalent to 1/3 to 1/20 of the same caliber artillery). As for accuracy, Yang Tianfeng believes that this is not the point. How can there be a good thing that is cheaper and easier to build than body-barred cannons, and can achieve the accuracy of body-barred cannons?

Germany has taken detours in weapons research and development and equipment. Its technology is too fine and its pursuit of perfection is defeated by the massive weapons made by the Russians. For example, rocket launchers, due to their advantages in the field of rocket engines, the Germans pay more attention to the precision strikes of heavy rockets at long distances.

Obviously, such requirements make it difficult for the production speed and quantity of weapons to meet the requirement of winning in war. It would be a little too late to change the course until the middle and late stages of the war, Germany's war resources were scarce.

Of course, Yang Tianfeng would not follow Germany's mistakes. Based on the production and manufacturing level of the arsenal, he borrowed more weapons from the Soviet Union.

Solid fuels are considered to be the cutting-edge technology in others and require thousands of formulas and experiments. However, for Yang Tianfeng, such technological achievements that do not rely too much on hardware facilities are something he can easily obtain.

Because solid fuel is used, the pump transmission system required for liquid fuel is eliminated. The main structure of rocket engines is the ignition device, combustion chamber, nozzle, which is much simpler than conventional engines of automobiles and motorcycles.

Although the structure is extremely simple, there are still difficulties. Because when the propellant is burning, the combustion chamber has to withstand high temperature and high pressure, and the nozzle is also ablated, and it needs to be made of high-strength alloy steel, or equipped with thermal insulation lining and spray-painted ablation materials.

Did I not express it clearly? Yang Tianfeng did not immediately start solving the difficulties raised by the arsenal, but instead touched his chin and thought.

As for rocket launchers, they are not the kind of high-tech rockets used to launch satellites. The flight time is very short, and the special steel currently produced should meet the requirements, right?

After thinking for a while, Yang Tianfeng understood a little. The arsenal must be doing static experiments, not live-fire tests. In this case, the technicians may ignore the flight time of the rocket and only see that under high temperature and high pressure, the combustion chamber is burned out and the nozzle is also ablated.

Although this does not need to be solved immediately, Yang Tianfeng still picked up his pen and wanted to write down the spray material containing graphite and give the arsenal technicians no need for too strict requirements.

"Oh, this word is written-"

Yang Tianfeng looked up in shock and found that Zhao Yuqing had not left, but was still sitting there, slanting his mouth and savoring his words.

"You said, I'll write." Zhao Yuqing took on the job for herself without hesitation, "Who made you hurt? I wrote it with my left hand... Tsk tsk, it won't make people laugh at me!"

"Your sister's side--" Yang Tianfeng gestured with his hands, "Who is taking care of?"

"Zhai Xiu'er, Tofu Xishi." Zhao Yuqing bowed slightly, said in her mouth, and had already taken all the paper and pen in her hand, sitting in a straight position, shaking her pen, "Tell me, I'm ready."

Yang Tianfeng smiled helplessly, sorted out his thoughts, and slowly started talking.

"I can say hurry up, I can keep up."

Oh, this girl - Yang Tianfeng rolled her eyes slightly.

…………….

The sun rose to mid-air, and the sun shone through the window paper on Zhao Yurou's face. She slowly opened her eyes, woke up for a while, turned her face sideways, and found that her sister was lying beside her, sleeping soundly, with a smile on her face.

She gradually remembered what happened tonight. Zhai Xiuer was taking care of her. She remembered that she had a fever and felt uncomfortable. It seemed that when it was almost dawn, a doctor came to give her an injection.

The door was pushed open with a creaking sound, and Zhao Yurou narrowed her eyes and looked at it secretly.

Yang Tianfeng walked in gently, observed Zhao Yurou's condition, and reached out to test the temperature of her forehead. When he wanted to turn around and leave, he found that Zhao Yurou had opened her eyes wide, frowned slightly, and was staring at him.

"Haha, you sister." Yang Tianfeng smiled and pointed at Zhao Yuqing and whispered: "It's very interesting. Well, I gave you an injection. One course of treatment is six days and it should be cured. By the way, I have asked someone to take care of you. She doesn't have to be so tired. I have a lot of things to deal with. But I won't leave these days, so I'll just contact and provide guidance here by phone."

Zhao Yurou looked at Zhao Yuqing with her lips, nodded gently, and said, "You can go and have so many things to deal with, it's not possible without you. Don't always care about me, it's a big man, it makes people laugh at. That, have you really made a special medicine?"

Yang Tianfeng nodded and said, "As long as it is not a rare antimony agent patient, the effect can be guaranteed. Of course, this will take time to verify. As for you, it is a bit difficult to say."

"A dead horse is treated as a living horse." Zhao Yurou was very informative. She smiled and said, "Is it not difficult to see the patient die or try it boldly."

Yang Tianfeng shook Zhao Yurou's little hand and said, "It's best if you can see it openly. I asked the doctor to check more and test more. You eat more foods containing vitamin B and vitamin C. If there is anemia, you have to inject fresh blood. Haha, you said it's quite coincidental. Our blood types are the same."

Zhao Yurou wanted to speak, but she felt her throat choked, so she had to force her to smile and hide the dampness in her eyes.

"Good rest. Those two girls are almost here. You sister, you sleep like a pig, a little unreliable." Yang Tianfeng smiled and pinched the tenderloin hard, turned around and walked out.

Zhao Yurou lay on the bed, blinking her eyes slowly, feeling mixed in her heart, and she couldn't calm down for a moment, and she heard a muffled groan coming from beside her.

Zhao Yuqing's mouth was so pouting that she could tie the oil bottle, and she was sulking with her eyes open.

"Yuqing, you are awake, why are you pouting? Why are you unhappy?" Zhao Yurou asked with her face sideways.

"Hmph! He actually said that he was a little pig." Zhao Yuqing got up and said angrily.

"Haha." Zhao Yurou smiled and said, "Why take it seriously for a joke?"

Zhao Yuqing rolled her eyes and said, "Sister, if I hadn't seen him save you, I wouldn't have agreed to you two. I'd have to bring you back to Kunming and let my parents teach you a lesson."

Zhao Yurou sighed and said, "You are still too young and don't understand many things. Although I have nominal relationships with him, Yang Tianfeng is useless. I am free to come and go. Men are all very proud, and I want to stay. Naturally, I have to maintain nominal relationships and not let people talk about him behind their backs."

Zhao Yuqing blinked her eyes and thought for a while, and said, "Sister, I think he cares about you very much. You, that, don't seem to hate him. Otherwise, why do he touch your head and pinch your hands, and you won't be angry. I want me to say, since he has agreed to the victory of the Anti-Japanese War, you can just mess around like this, right?"

"I, I don't know either." Zhao Yurou smiled bitterly and said, "Or, when my illness is cured, we will go to Kunming. Sometimes it is really annoying to think of these things."

Zhao Yuqing didn't understand very well, but nodded according to her sister's wishes. After pausing for a while, she exclaimed sincerely, "Yang Tianfeng is really amazing, and seems to know everything. He doesn't even think about the difficulties that others can't solve even if they want to break their heads. Well, sometimes they can think about it. But I can find a solution. You said he was traveling and studying abroad, spying and stealing, but I don't believe it. Even if someone took the information to him and asked him to memorize it, he couldn't remember so clearly, so many, right?"

Zhao Yurou frowned slightly and said thoughtfully: "I have such doubts, but I can't think of anything else."

"This guy must have something to hide from him." Zhao Yuqing narrowed her eyes, tilted her head, and snorted, "I have to make the truth come to light."

Zhao Yurou looked at the girl's appearance and chuckled softly. Her knowledge, experience, and psychological maturity were not as good as Yang Tianfeng. She still wanted to be a big detective?
Chapter completed!