When Yang Tingjian returned to Beijing, he handed over these materials to Liang Cai, and at the same time explained that the recipe and information must be kept strictly secret, and those who leak secrets will not be forgiven.

When Yang Tingjian returned to the "Dragon Gate Inn" in Beijing, he immediately wrote a letter to his cousin Yang Tingshu, who asked Yang Tingshu to go home to visit his family and hand over the salt-alkali resistant seeds to the red lady, and then immediately set off to take over the Nanjing Longjiang Bao Shipyard.

Yang Tingshu gave up the imperial examination, and originally helped Yang Tingjian manage the four-wheeled carriage workshop, Yang Tingshu really managed the four-wheeled carriage workshop in an orderly manner during this time, which shows that Yang Tingshu is capable in management, so Yang Tingjian decided to hand over Longjiang Bao Shipyard to Yang Tingshu to take care of.

The first thing Yang Tingshu had to do was to take over the Longjiang Treasure Shipyard, that is, to gather the craftsmen who had lost immediately, and at the same time repair the long-abandoned Treasure Shipyard, and to organize people to go to the Longjiang Treasure Shipyard's own woodland to log, these jobs will take at least half a year, at that time Yang Tingjian has completed the imperial examination, and he can personally go to the Treasure Shipyard to know how to build a galleon like the Trinity Holy One.

Regardless of whether he is admitted or not, it is impossible for Yang Tingjian to stay in Beijing to serve, the court struggle of the Ming Dynasty is too powerful, and the first shop Wen Tiren selected by Emperor Chongzhen is a villain who is keen to exclude dissidents, and has no achievements in governing the country.

"Heavy ears are safe outside, and Shen Sheng is dead inside."

After finishing his work in Beijing, Yang Tingjian stayed in the "Dragon Gate Inn", and then studied in the Zhegui Garden every day, and the gold and jade were often accompanied by waiting on the left and right.

Yang Tingjian has been running around all this time. Fortunately, the body that Yang Tingjian fused has real talent and learning, and after picking up the book and reviewing. There is no pressure at all.

Time flies, in a blink of an eye, it is the middle of February, and there is still half a month before the examination, Yang Tingjian has completed all the knowledge possessed by this body after two months of study, and the imperial examination is no longer difficult for Yang Tingjian.

But a secret document inside the brocade guard. But it made Yang Tingjian anxious, this secret document inside Jinyiwei was sent by the undercover agent arranged by Jinyiwei in Liaodong, and the approximate content is like this:

"On the eighth day of the first month of the fourth year of Chongzhen (1631). Houjin cast a red-coated cannon, and the cannon body was engraved with the words: Tianyu cheers the general. and the year of the casting, the names of the officials who supervised the making, and the names of the casters and blacksmiths. ”

Later Jinyuan had no firearms, and cannon casting began from then on. Later Jin used the captured craftsman Liu Han in Shenyang. Successfully copied the Western cannon. Named "Heavenly Blessing Helping General", they also created the "lost wax method", turning cast iron into cast steel, and carrying out complex annealing and quenching treatment on different parts of the artillery, so that the casting process was ahead of the Ming Dynasty.

Due to the taboo of the Manchurians, the Hongyi cannon was renamed the "red-clothed cannon". Huang Taiji set up a new battalion "heavy army" (Wuzhen Chaoha) in the Eight Banners Army, and later Tong Yangxing served as the chief military officer, and Cao Zhenyan served as the instructor. Artillery tactics began to be applied.

In Yang Tingjian's memory, he always thought that Houjin's firearms unit was brought by Kong Youde. Unexpectedly, Jiannu used the captured Han craftsmen to make it up themselves, which is a dangerous signal.

Yang Tingjian smelled a hint of danger from this secret document, once this Jiannu has a red-clothed cannon, then the strong city of the Ming Dynasty will not have much meaning to Jiannu, even if the red-clothed cannon cast by Jiannu is not very effective, but it is also a red-clothed cannon.

The Hongyi cannon does have its advantages in design, its barrel is long, the tube wall is very thick, and it is gradually thickened from the muzzle to the tail of the gun, which is in line with the principle of high to low bore pressure when gunpowder is burned; There are cylindrical lugs on both sides of the center of gravity of the gun body, and the gun can adjust the firing angle with this axis and change the firing range according to the amount of gunpowder; It is equipped with a crosshair and a light gate, and the trajectory is calculated according to the parabola, which is very accurate.

Most of the Hongyi cannons are about 3 meters long, with a caliber of 110-130 mm and a weight of more than 2 tons. The most prominent advantage of the Hongyi cannon is its range, which is an important part of the performance of heavy artillery, even today.

Yang Tingjian hurriedly locked himself in the room, and took out his mobile phone encyclopedia to check the relevant number of Jiannu's red-clothed cannons;

The earliest batch of Hongyi cannons used in the Battle of Daling River had an effective firing range of about 500 meters, and the maximum firing range was less than 1.5 kilometers. After the Manchu Qing Dynasty established the world, it continued to improve, so that the effective firing range reached 1,500 meters, and the maximum firing range reached 2 kilometers.

But its limitations are not small, such as being good at siege and clumsy in field warfare, let alone defending cities. The rate of reload firing is not high. Moreover, the cannon body is cumbersome and cannot quickly transfer positions, so in field battles, most of them can only bombard at fixed points before the start of the battle, and when the opponent's situation is reversed, they are often unable to maneuver and react.

The Hongyi cannon is a kind of recital, front-loading smoothbore artillery, and every time it is fired, it will deviate from the original firing position. According to the normal operating procedure, it is necessary to go through the steps of resetting, reloading, and setting the direction angle and elevation angle again. The most well-trained British Navy can only fire one shot in three minutes, and it is good that Jiannu can fire one shot every ten minutes.

It is not possible to increase the rate of fire of a front-loading gun, because after a single fire, it must be filled with water, extinguished the fire star, stretched into the chamber with a dry cloth to dry, then filled with gunpowder, combustibles, stuffed the shell, and then lit again, these actions are quite slow and cumbersome, not including the correction of the gun position.

This is a common problem with front-loading artillery, it is very good to be able to fire one shot in three minutes, but it is a pity that a running war horse can run a considerable distance in one minute, can it have time to fire a second shot? Therefore, the front-loading artillery is characterized by a slow rate of fire, but it is powerful, and there is no problem in bombarding the city wall, but it is a joke to deal with cavalry.

Jiannu cast these red-clothed cannons also to attack the Ming Dynasty's fortified city, they did not have a musket unit, because Jiannu still advocated the skillful archery and horse, they simply looked down on the Daming musketeers who could only shoot one shot and had to retreat, so they would not form a musket unit at all, which was determined by Jiannu's cognition.

Compared with Yang Tingjian's Shenwei cannon, Yang Tingjian's Shenwei cannon weighs only more than 900 catties, including the gun carriage, and the range is not comparable to Jiannu's red-clothed cannon.

The longest firing range of the Shenwei cannon is more than 3,000 meters, and the farthest effective firing range is two thousand meters, while the red-clothed cannon of Jiannu only has an effective firing range of a pitiful 500 meters, and the farthest firing range is only 1,500 meters, not to mention that the Shenwei cannon also has rifling.

Maneuverability and rate of fire are a few streets away from the red-coated cannon, and the Shenwei cannon is a French-cannon method that uses the sub-gun, and the theoretical rate of fire per minute can reach ten rounds, while the red-coated cannon of Jiannu is one shot every five to ten minutes, which gap is not something that the fishing and hunting people of Jiannu can catch up.

…… (To be continued......)

ps: The order of the previous chapters was wrong, and I have asked the editor in charge to revise it, and the brothers apologize to you.