It seems that there is no hope for casting cannons in a short period of time, but Hong Tao is not giving up, he feels very unsafe with crossbow arrows alone, and the destructive power is too weak. If the bronze cannon is hopeless, then try the wooden cannon! Can wood still be used as a cannon? It is necessary that during the Anti-Japanese War, this kind of wooden cannon was still in use, which was generally stuffed with a bunch of stones as a shotgun, and the range and power were very bad. But now it's in the Great Song Dynasty, and it's not a devil with a loaded gun, and it's going to be used at sea, the range is not far away, Hong Tao can bear it, and the power is not great, Hong Tao has a way to transform, as long as it can be used!

How? Ever since he had whaleskin paper, Hong Tao has been writing down the things he remembers that might be useful for the present, including a howitzer he had seen in American museums in his previous life. It is a weapon during the American Civil War, firing a cannonball called a Hotchkiss grenade, that thing has a detailed introduction, it is very simple to make, Hong Tao has also done it on the Mouse Superman, jumping out more than 200 meters away, and it can explode, even explode in the water, it is very fun. At that time, Hong Tao used it to fry schools of tuna, and the sound of rattling could often be heard off the coast of Belize.

This kind of short-barreled howitzer and Hotchkiss grenade are the weapons and equipment that Hong Tao currently wants to make and feels feasible. Howitzers and cannons are a pair of opposite guns, the howitzer barrel is short, the muzzle velocity is small, and the trajectory of the fired ammunition is parabolic, while the cannon barrel is long, the muzzle velocity is large, and the launch trajectory is straighter. The cannon painted by Hong Tao is said to be a howitzer, but in fact, that thing is a mortar cannon, with a doubling ratio of only 5, short and thick, just like a cannon sawing off all the barrels in front, leaving only a small section of the tail behind, which looks funny. But don't underestimate this ugly thing, it has a lot of advantages. For example, the chamber pressure is low, the caliber is large, and it can be curved and fired, which is a sharp weapon for siege. Well, there are a lot of shortcomings, short range, small accuracy, weak penetrating ability, in fact, it is the prototype of the mortar.

Another advantage of using this cannon is that it can use relatively simple and crude flowering shells. Why were the ancient cannonballs solid? Why hasn't it changed for hundreds of years? The reason is very simple, casting and gunpowder technology is not up to par! If the shells want to hit accurately and far, it is necessary to lengthen the barrel, strengthen the sealing of the barrel, and increase the amount of propellant. However, the barrel was long, sealed, and there was more propellant, which brought another problem, the chamber pressure was too high. The shell had a thin skin, and it couldn't withstand the pressure of the chamber when it was fired, so it exploded directly in the barrel. If the shell has a thick skin, the charge will be less, and one explosion with two petals will not be as powerful as a solid shell.

Therefore, before the manufacturing process of shells was solved, flowering shells had been invented, but there were many restrictions on their use, especially in naval warfare, where cannons were generally used to fire solid armor-piercing shells to damage the structure of the opponent's hull. This situation did not change until the 19th century, which led to the transformation of wooden sail warships into steel-clad warships, because the wood could no longer withstand the blows of flowering shells.

In addition to the barrel, there is also a big problem with using the flowering projectile, which is the fuse, that is, if you let the flowering shell hit the target, it will explode? Before the invention of **, it could not be made**, and it would not be possible to make an impact ignition device. When a cannonball is fired, how to make it explode becomes the key, and there must be a reliable ignition device. At first, people used a medicine twist as an ignition device, but the burning speed of that thing was unstable, some of them exploded as soon as they were discharged, and some of them didn't explode for a long time, and they fell out to extinguish the fire.

Later, someone came up with a solution, which was to use a cork stick to make a zigzag passage in the middle, stuff it with gunpowder, and calculate the burning time. After many tests, the relationship between the flight distance of the shell and the speed of gunpowder burning was calculated, and different marks were marked on the cork, such as 100 meters, 200 meters, and 300 meters. When you need to use it, first visually measure the shooting distance, then cut the cork stick short according to the mark on it, and then stuff it into the fuse mouth of the flowering bullet. When a shell is fired, the high temperature in the barrel ignites the gunpowder in the cork, allowing the shell to explode with a delay, and if the timing is accurate, it can barely replace the trigger fuse.

But that's not enough, why? Because the temperature inside the barrel is very high when it is fired, if you don't do it, all the gunpowder in the cork will be ignited at once, and it will still explode in the barrel. So after summing up the lessons learned, it was discovered that if the cork was put at the muzzle, the chance of exploding the chamber would be smaller. But this was not enough to ensure the safety of the gunner, and later, during the American Civil War, a gadget called the Hotchkiss grenade appeared. It is also a round flowering shell, but it sits on a cork support, so that when the shell is stuffed into the barrel, you can refer to the position of the cork support to determine that the cork must be outward. Moreover, this cork tray can also prevent the propellant in the barrel from prematurely igniting the gunpowder in the cork, which is very reliable.

So can Hong Tao make these two things? Or can it be manufactured by relying on the current technical level of Jinhewan? Hong Tao thought he could try it. The bronze barrel is replaced with hardwood, and the outside is wrapped with copper hoops one by one. I'm not afraid of being bulky, anyway, it's put on a sailboat and don't need to be pulled around, and I make a gun carriage with a track below, which can also reduce recoil.

The cannonball is better done, so it is cast into a hollow sphere with ordinary pig iron, and then a pile of broken iron pieces are fixed in the sphere with soft wax, and the ** is installed in the middle. As for **...... If this thing can't be made again, then Hong Tao shouldn't mix it up, in fact, it doesn't matter if it can't be made, just go to a big city like Guangzhou to find a master craftsman in a fireworks workshop, catch him and let him build OK. It's just that the proportion of the formula is adjusted according to the standards of later generations, and then whale oil is added to press, dried and crushed into granules. Hong Tao did exactly that, he didn't want to test this thing from scratch, in case it blew up, wouldn't he be unlucky, why not use it if there were ready-made manpower? As for whether the people who were arrested and deceived are reliable or not, they must be reliable, because Hong Tao even deceived their families, and they all died if they dared to play tricks!

It's not enough to just cast cannonballs with pig iron, the pig iron thing is too brittle, even if the chamber pressure of the mortar cannon is low, it can't help it. According to the chamber pressure of the mortar, there are also 50 megapascals, one megapascal is almost about 10 kilograms of pressure per square centimeter, 50 megapascals is half a ton, a hollow pig iron ball, pressing half a ton of things, clicking in minutes.

"Hey, hey, hey...... It's Lao Tzu's turn to be professional! Hahahaha! At this time, it was Hong Tao's turn to make a move, and he also learned metal heat treatment, even if he mixed it again, he could remember the simplest pig iron toughening process. Because this topic is an annual exam, why? It was invented by Lu Da, a military expert in the Eighth Route Army. In the liberated areas back then, he used this method to make grenades and artillery shells, and his own family invented things, which of course had to be written into the textbooks, and the focus had to be the point.

Hong Tao's method is very, very simple, is to burn these pig iron balls red and put them in an iron box to seal them, and at the same time spray whale oil into them. This is called spheroidized heat treatment annealing, and after these hollow iron balls have cooled naturally, the pig iron will become black-hearted ductile cast iron. This kind of cast iron has strong toughness, and also has the characteristics of self-lubricating tools, which is convenient for processing, such as drilling holes, and the same thin and thick black-hearted toughness cast iron has several times higher compressive resistance than pig iron.

"My lord! Take me as an apprentice, I'm not going back, I'm always doing it here! Seeing that Hong Tao turned the pig iron ball that was thrown on the ground and broke like a trick into a black iron ball that was thrown to the ground and rolled all over the ground that was not broken, the blacksmith who had just been deceived and returned for less than two months directly accepted it.

"Get out of the way, it's not your turn to accept apprentices, I've been here for half a year, and I should be accepted first in order!" Although Qi Zu joined the board of directors, he never regarded himself as a manager, and he still worked with the blast furnace every day, smelting the iron ore mined with the copper ore, and making all kinds of iron and bronze tools for Jinhewan is his favorite. He has long been in contact with Hong Tao's knowledge of metal smelting, but he is always embarrassed to say it, and now when he sees that someone wants to rob the master, he is immediately anxious.

"You don't need to apprentice, I can't teach you this little skill, I only know some tricks, and it depends on you to do it. I'll write these things down and give them to each of you, and everybody has them. But you have to go to school to read and write, otherwise you won't be able to read what I wrote, right? Hong Tao does not have the hobby of being someone else's master, but he has an interest in imparting knowledge, and writing books and speaking has always been his dream.

With a usable shell, the rest of the matter is easy, there is a lot of cork, this thing is a Southeast Asian specialty. The work of carving lines in the cork sticks, calculating the amount of charge and burning time, Hong Tao handed over to Chen Mingen, and asked him to take the school children to do it. These children not only have to study, but also choose one or two learning directions according to their preferences, and they have to follow the master to learn handicrafts every day, whether it is farming, shipbuilding, ironmaking, or oil refining. As for how they do it and how they do it, Hong Tao does not participate, only puts forward a request for them, and the process is explored by themselves, not only to explore, but also to record the whole process, which may be a ready-made teaching material in the future.

The work of loading pieces of broken iron and gunpowder into the shells could not be done by the children, but there was no need for Hong Tao to go out in person, and he found Bo Zhu again, his daughter-in-law is the director of the Women's Federation, and her subordinates are in charge of dozens of women, so it is most suitable for them to do this work. As for how to do it, how to do it, Hong Tao still doesn't care, he only puts forward requirements and results, how to let them find their own way.