With the first time, it's much faster to do it again.

  And it's still a trial production, only to make it bigger. The cobblers then took apart the balloons that had been glued together, soaked them medicated to tighten the hide, and then added a new, equally soaked hide, which of course took much faster than the original production time.

  The tendons, willow frames, and small iron stoves were all improved according to Zhou Nan's prompts.

  Zhou Nan still lives in the craftsman's yard every day, and still watches the craftsmen's improvements to the hot air balloon every time, except for a few suggestions, he does not comment again, and more let the craftsmen solve it themselves.

  When the craftsmen saw that the horses respected them so much, and that they knew that the horses were waiting to use the balloon, they worked day and night. With the improvement again and again, the balloon gradually increased, and the stones that replaced the weight of people in the willow frame were added little by little, and finally on the morning of the third day, the hot air balloon that could carry two people was made.

  Zhou Nan came to watch again in the morning, only to see that the craftsmen first skillfully hoisted the balloon with six ropes fixed on the upper part of the balloon, roughly stretched, and there was a blacksmith standing in the willow frame below, and there were two stones next to the blacksmith, weighing more than 100 catties.

  The blacksmith took charcoal from a basket beside him, lit it in a small iron stove, and burned it vigorously, and the mouth of the small iron stove reached into the opening of the balloon. As the charcoal in the small iron stove became more and more vigorous, more and more, the huge cowhide balloon gradually stretched out and stretched, and the stretched balloon was two zhang square, and the huge balloon was already high above the roof, about to cover the whole yard. At this time, the balloon no longer had to be hoisted by the six ropes, but could already be suspended in mid-air.

  Zhou Nan watched nervously, only to see that when the charcoal in the basket was almost half used, the hot air balloon finally pulled and contracted, and slowly lifted the willow frame from the ground along with the blacksmith and stones in the willow frame.

  A thick rope was tied under the willow frame, and the other end of the rope was tied to a millstone stone, and in the exclamation of the craftsmen, the millstone was also slowly hoisted, and with the fluttering of the balloon, it swayed slightly.

  This time, Zhou Nan did not stop, but asked people to start the timer, and asked people to drag the willow frame, and the willow frame finally stopped rising. Under the silent gaze of everyone, the blacksmith in the willow frame according to Zhou Nan's command, according to the lifting changes of the balloon, to slowly add charcoal, so that the balloon always maintained this height.

  Eventually, when the charcoal in the basket ran out, the balloon began to fall, and the balloon lifted the weight of at least three people for nearly half an hour. If it's just the weight of two people, it's estimated that the time will be a little longer.

  Zhou Nan, who was excited, immediately asked these craftsmen to put away the balloons and willow frames, and then prepare an extremely long rope, bring enough charcoal, put these on the carriage, and called Zuo Xiaosi's team of Eagle Guards, and called Han Gui and Ma Daqiu, the heads of the pro-army, and asked the two to take their subordinates and go out of the city together with the craftsmen and balloons and other things on these carriages.

  Although there are no electric wires in the city, if the hot air balloon is lifted into the air, it is not easy for people on the ground to follow, and it is too shocking in the city. That's why Zhou Nan decided to take people outside the city to really test fly a hot air balloon.

  More than a dozen miles northwest of Gu'an City, Zhou Nan asked the craftsmen to begin assembling and inflating the balloon, preparing it for liftoff. Zhou Nan asked people to tie the long rope to the willow frame to prevent the hot air balloon from drifting away.

  After everything was ready, Zhou Nan himself got on the willow frame and instructed the craftsman to start timing after the balloon was lifted into the air, and record the length of the rope to see how high it could rise. He also told Zhou Fu that when he waved his hand down, Zhou Fu would shoot an arrow into the air to see if he could shoot it to the height of the balloon. Seeing this, Zhou Fu hurriedly stopped, "Da Lang, it's not a trick to rise to a high place, let me do it for you!" ”

  Zhou Nan smiled and said, "It's going to be fine." You're just guarding the rope underneath, don't let me fly away. Hahaha! Saying that, he instructed the blacksmith to increase the fire, and after a while, Zhou Nan only felt that his feet were floating, and the balloon had begun to slowly leave the ground, taking him and the blacksmith up.

  1 zhang, 2 zhang, 3 zhang, 5 zhang......

  The balloon was getting taller and taller, and looking down from the willow frame, the craftsmen and guards below were getting smaller and smaller. The blacksmith, under the command of Zhou Nan, also stopped the fire and looked around curiously below.

  Only then did Zhou Nan realize that he had forgotten a big thing - wear thicker! At this time, it was a cold winter, and it was high in the sky, which was significantly colder than on the ground. Luckily, there was no wind, and there was a rope pulling underneath, and the balloon was only slightly displaced from where it had just been raised.

  It wasn't until Zhou Nan felt that the height of the balloon was enough to lift into the air, so he stood on the edge of the willow frame and waved his hand downward. Although Zhou Nan also understood that through the initial velocity, the maximum height of the arrow that ignored the resistance could be calculated, but he didn't know the initial velocity of the first bow and arrow, and second, the physical formula that was very unfamiliar to him really had no fate. So Zhou Nan had no choice but to use the test algorithm again, and let the people below test shoot again and again.

  I saw Zhou Fu take out his bow and arrow and shoot an arrow in the air not far from Zhou Nan, and this arrow flew over the height where Zhou Nan was located with a swish, and continued to drill upward.

  Zhou Nan ordered the blacksmith to light the fire again, and the balloon began to slowly rise again. Zhou Nan estimated that this time he exceeded the range of the bow and arrow, so he waved his hand downward, this time, when Zhou Fu's arrow god came up, the speed was obviously much slower, and Zhou Nan could almost see what the arrow looked like when it flew.

  Zhou Nan let the balloon fly a little higher again, and waved his hand downward. This time, Zhou Fu's arrows couldn't catch up, so Zhou Nan waved down with both hands. In the meaning of the appointment just now, both hands wave at the same time, which means to record the height of the current balloon.

  After waving his hand, Zhou Nan, who couldn't stand the cold, didn't wait for the charcoal to burn, so he began to tell the blacksmith to turn off the stove and wait for the balloon to drop little by little.

  Without fire and heat, the balloon quickly descended downward. The ground was getting closer and closer, until there was a shock under his feet, the willow frame finally fell to the ground, and the balloon had not completely cooled down, Zhou Nan asked with a smile, "Who wants to go up and have a look?" ”

  Zuo Xiaosi couldn't wait for a long time, and when he saw Zhou Nan asking, he was the first to jump into the willow frame. Zhou Nan asked the blacksmith to load a basket of charcoal, and then ordered the blacksmith to relight the fire and lift it into the air, and at the same time ordered someone to bring a leather robe for Zuo Xiaosi and the blacksmith to wear on their bodies.

  No matter how Zuo Xiaosi lifted into the air, Zhou Nan asked the craftsman who had just recorded the height, when the bow and arrow could not hit the balloon, the height of the balloon should rise to a height of twenty zhang. The bow that Zhou Fu usually uses is already a hard bow, even if there are bows in the enemy army that have a longer range than Zhou Fu's bow and arrows, it is almost impossible to penetrate the balloon.

  In addition, the arrow shot from below can only penetrate the lower part of the balloon, and even if a few holes are shot through the lower part of the balloon, it only enlarges the opening of the lower part of the balloon, and does not affect the flight of the hot air balloon.

  On this day, Zhou Nan sent people back to the city to fetch charcoal several times, and asked the Eagle Guards to take turns to go up, until the Eagle Guards were proficient in controlling the rise and descent of the hot air balloon, and then they returned to the city. Like Song Chungui, please collect x Song Chungui.