Jiayi felt that he was almost full of medicine recently, his mouth was the smell of medicine, and the smell of Chinese medicine was also permeated with the smell of Chinese medicine, and his parents thought that he had some serious illness and kept taking medicine. In fact, he recently learned the art of distinguishing medicine with the old medicine man, and tried herbal medicine every day.

This is really not a simple technique, Jiayi does not always try poisonous herbs, some non-toxic herbs also try, remember the body's reaction. It is really miserable to try some poisonous herbs at intervals, and the difference between before and after the toxicity is not placed. The worst time was to eat poisonous oxtongue root, this medicinal onset was slow, he thought it was not enough to eat, ate a little more, and then pulled his stomach for a day.

He felt that his teacher had been a little strange lately, as if he was in a hurry to hand over all the knowledge he had mastered, as if he was in a hurry. He also asked Yao Lao, but Yao Lao sighed and didn't say anything.

Recently, while learning medicine discrimination with Yao Lao and being a guinea pig, he is trying to make a crossbow.

The production of a crossbow is simple and simple, that is, a bow is embedded in the crossbow body, and the crossbow machine can be added, but it is actually quite complicated to say that it is complicated, because the accuracy and power of the bow are not simple to do well.

Jiayi's confidence in planning to make a crossbow lies in his father Gary, Gary has learned to make bows and arrows, and the bows and arrows at home are made by Gary, and the power is okay, although Jiayi is not strong enough to pull it full, but the arrow can be shot into the body of a wild boar. This is not an easy matter, wild boars are not only thick-skinned, but also always wrapped in thick mud shells, and it is not easy to use bows and arrows to produce enough damage.

He was going to make a crossbow with an eccentric wheel, and it would not be easy to add an eccentric wheel to the crossbow, but he wanted to try.

First of all, he went to his father and begged him to make himself a crossbow, a bow made of purple shirt wood that had been stored for more than three years. This wood was cut down by Gary after he went to the mountains and put it at home to dry in the shade, so that he could make his own longbow later. The wood used to make the bow should not be exposed to the sun and needs to be dried in the shade, otherwise it will affect the elasticity of the bow and it is easy to crack.

In fact, Jia Yi remembers that the best treatment method for wood should be to soak it in water for a year, and then dry it naturally, so that the performance of the wood is the best, but it will take longer.

Since there is ready-made wood at home, it is used directly, and it is uncertain how this crossbow will be made, there is no need to pursue perfection in materials, and besides, it is too late in time. You can't just want to make a bow now, and you won't make it until more than ten years later.

Gary didn't just make a crossbow for Jiayi, a crossbow didn't use so many materials, and since the wood had been broken, Gary made two bows by the way. Speaking of which, in fact, Kaichi's crossbow is incidental.

After making the crossbow, the crossbow arm is next, dragging the rack of the bow above. This is also something that Gary helped do. Well, in fact, it was Gary who actually did it, and Kaichi just provided the idea. The crossbow machine was made to order in the town, bronze, because bronze is easy to shape, and the finished product is relatively hard, of course, these are what the blacksmith who made the crossbow machine told Jiayi.

It's nice to have a dad who knows how to carpenter.

The most important thing left is the eccentric chakra. It is not easy to make a suitable eccentric wheel, he originally wanted to use cow bones to grind one out, but after grinding a simple eccentric wheel, it is not suitable. Because he had not actually come into contact with modern compound bows in his previous life, he did not know enough about the principle of the eccentric wheel.

He didn't give up. Although he is not very clear about the specific specifications of the eccentric wheel, he did learn about the eccentric wheel on the Internet, because he is very interested in bows and arrows, after all, is it a boy. He knows that the principle of the eccentric wheel is actually the principle of leverage, the use of a large and a small two combined concentric wheels to achieve the purpose of labor-saving, when pulling the bowstring, the bow arm bends, and at the same time the large wheel releases the length of the bowstring, the small wheel is tightened, the diameter of the large and small wheels is different, and the larger the proportion, the more labor-saving. And the eccentric wheel is an upgrade on this basis.

Although Jia Yi doesn't understand the specific working principle of the eccentric wheel very well, but fortunately, he has a perverted memory after crossing over, and many things from his previous life are remembered at the bottom of his mind, as long as there is a need, he can slowly read out the memories of that time through searching.

The first time was that he was too contemptuous of the eccentric chakra, which led to the inappropriateness of the made, but now, he turned back the memory of the eccentric chakra in his mind and carefully studied and understood. At the same time, in order to better understand the principle of eccentric wheels, he also turned out the knowledge of pulleys and levers in physics in his mind to learn, as well as trigonometric functions and linear equations in mathematics.

He didn't pay attention to it at the beginning, but now when he wants to use this knowledge, he realizes that his knowledge has long been returned to the teacher, and the knowledge he knows best now such as Java and html has become useless, after all, he doesn't even have a primitive punching computer, let alone an electronic computer. These are not as good as physical chemistry in secondary school.

Fortunately, he still has the memory of this study in the depths of his mind, and now he can turn it out and learn it again very quickly. Moreover, the knowledge that has been re-learned seems to be more firmly remembered and understood more deeply. It seems that when I have time, I have to turn this knowledge out and learn it again.

In fact, Jia Yihe can copy the eccentric wheel in his head, copying the appearance of the eccentric chakra he has seen. It's just that he doesn't know the specific specifications of the eccentric wheel, and he can't see the specific size of the eccentric wheel from the picture. It's like a hamburger that is willing to beat chicken, it is so big on the advertisement, and it is so big when you get it, the gap can be even bigger than you imagined. Second, after an in-depth understanding of its principle, you can design and customize the specifications you need.

While learning related knowledge, he performed simple calculations on the sand table. Then, he made a simple bow out of flexible branches, then made a model out of wood and mounted it on the bow to experiment.

From concentric wheels, to eccentric wheels, and then to eccentric wheels of different specifications, in practice, he gradually understood the principle of eccentric wheels. The labor-saving of the concentric wheel is linear, and the eccentric wheel is rectangular, because when the bow is drawn, in fact, the diameter of the large wheel outside is always larger, so that the proportion of the large and small wheels has been expanding. Therefore, at the beginning, the force is gradually increased, and the force will remain unchanged after reaching a point, and the force used will become smaller if you continue to pull.

Once he figured it out, he began to make the eccentric wheel on his crossbow. Theoretically, the larger the large wheel, the larger the ratio to the diameter of the small wheel, the more labor-saving. However, if the ratio is too large, the effort will be saved, but the power of the bow and arrow will be affected, and the speed of the pruning will be reduced. Therefore, it is necessary to choose a good ratio, and it is not as labor-saving as possible.

He made the eccentric wheel he needed out of wood, tested it on a simple bow he experimented with, and wrapped the model in clay to make the clay model. This time, he didn't plan to use bones to grind out the eccentric wheel, because the eccentric wheel is a pulley stacked on top of each other, one large and one small, so it can't be made successfully with bones.

He was going to a blacksmith to pour a pair of eccentric wheels out of bronze.