The principle of hot air balloon is very simple, there are only two difficulties in making it, one is the combustion device, and the other is the air bag.
The first point is that in the absence of a pressure vessel to provide gas fuel, only relying on firewood or charcoal to heat the air is inefficient and cannot fly very far due to fuel limitations. This is also the reason why the principle of hot air balloons was discovered very early in history, but the hydrogen balloon was the first to be put into use in actual combat. So Roland simply gave up the burning device and asked Anna to set it on fire.
The difficulty of the airbag lies in the airtightness, but for Roland, who has learned from the experience of his predecessors, this problem can be easily solved by using interlayer fabrics. The outermost layer of the airbag is a wear-resistant canvas, the middle is lined with a cow sausage film, and the inner layer is a light gauze, so that it can be sewn together to prevent air leakage, and at the same time, it is not afraid of birds' pecks.
Roland opened the bottom of the airbag and let Anna spray black fire with a temperature close to that of ordinary flames. The airbag slowly inflated, looking like a wrinkled winter melon. Considering that the hot air balloon needs to carry two people into the air, the diameter of the widest part of the airbag is five meters, and the intestinal membranes of twelve cows were used, and the sewing work took nearly a week. If it is not the lord who governs a place, he really might not be able to build such a big toy.
"Does it fly with the buoyancy provided by the hot air?" Anna asked. "I remember it was mentioned in the book that hot air always rises."
"Yes, hot air rises and cold air sinks are common natural phenomena. Using particle theory to explain, is that the movement of the hotter air balls intensifies, the ability to diffuse to the surrounding is strong, and the density will decrease after the volume expands. For the air around it that hasn't changed, it's lighter and therefore rises."
After Roland finished explaining the principle, he found that except for Anna's original expression, the other three were blank, which made him sigh secretly about the importance of talent.
When the airbag was fully inflated and floated upward, the traction rope was slowly straightened, and Roland was the first to flip into the gondola, and then took over Anna who was climbing.
"I'm still a little worried," Nightingale said anxiously, "Why don't you let me go up and have a try first."
"Trust me, nothing will happen," Roland smiled lightly, "and even if there is an accident, there will still be lightning."
"I will catch them, don't worry." Lightning patted her chest.
"And me!" Maisie patted her chest like lightning.
With a wave of shaking, the hot air balloon took the gondola off the ground and gradually climbed upwards. It didn't take long for the two to cross the top of the castle, and the whole picture of the town was presented to them one by one.
For Roland, such a sight is not unfamiliar, after all, he has seen skyscrapers, but in Anna's eyes, it is a completely new experience from the previous perspective. She leaned on the side of the basket and looked out, holding Roland's arm firmly with one hand, looking both excited and nervous.
This is the first time Roland has seen her with such an expression. Probably, someone whose feet have never been far from the ground will have a slight fear of heights when they fly into the sky for the first time.
After a while, the hemp rope used to tie the hot air balloon under the gondola was pulled to the limit, and the ascent stopped. The hemp rope is about 50 meters long, which is the height of fifteen or six storeys in later generations. Roland asked Anna to reduce the firepower, and the hot air balloon finally hovered in the air.
At the beginning, Lightning was still standing by the hanging basket. After seeing the stability of the basket, he felt relieved and played a chase game with Maisie around the hot air balloon.
Looking down from here, you can clearly see the roof of the castle, the town under construction everywhere, the Chishui River flowing from west to east, and the green farmland beside the river.
"How does it feel?"
It was not until Anna retracted her head that Roland asked with a smile.
"Thank you for your gift," she said excitedly. "I can fly so high."
"It can be higher," Roland sat down against the side wall of the rattan hanging basket, "If the hemp rope below is longer, it would be fine to fly ten times the distance, but the higher the air flow, the more complicated it is, and the safety Sex is difficult to guarantee. And this is only a rudimentary aircraft. When a piston machine is built in the future, ordinary people can fly faster than birds, higher than birds, and then back..." He looked up at the blue sky , "People can even fly out of this world and go to endless space."
"..." Anna held her breath, her eyes were shining, and something was about to come out.
"I can't promise to fly out of the world," Roland was amused by her appearance, "but creating a piston machine, so that ordinary people can fly like birds, should still be able to do it in their lifetime." In fact, with Anna there, There is no bottleneck in processing capacity, and the current shortcoming exists in material properties. Inferior pig iron can make do with steam engines, wrought iron can make guns, and steel revolving firearms smelted with black fire are not a big problem, but for internal combustion engines, I am afraid that high-quality cast iron, cast steel or aluminum is required. "It's all your credit for Border Town to be what it is now, Miss Anna."
After hearing this sentence, Anna was stunned. After a while, she sat down and said softly, "My mother died in a fire, but instead of being buried in the smoke and fire, I became a witch. For a long time, I I thought it was my awakening that caused this fire, and I hated myself as a witch. When I was locked in prison, I thought that this might lead to liberation, but you rescued me from prison and taught me How do I use my abilities... I didn't think that flames could be used for so many other than burning and pain." Anna paused, "I should be very satisfied to meet you, but now I find myself My thoughts have changed, and sometimes I feel suffocated and uncomfortable, hoping for more."
She climbed on Roland's shoulders, "Even so, do you still want to hire me?"
Her lake blue eyes sparkled, and her breath tickled on her face. Through the thin clothes, he could feel the other's soft body and thumping heartbeat. Even so, she did not avoid looking directly at her. When there was no Nightingale, she was always full of enthusiasm and initiative.
"There's..."
Before Roland could finish speaking, Anna had already sealed his lips.
After parting, he breathed lightly, "I want to hire you, all the time. Miss Anna."
"Um."
This time, he took the initiative to lower his head and get close to her.
…
"Hey, wait," Maisie chased the lightning for a while, then suddenly stopped in the air, looking at the empty hanging basket, "They're gone, Goo!"
"Ah?" Lightning glanced at him, "They just sat down."
"Doesn't that make it impossible to see the outside scenery?"
"The scenery can be seen at any time, but there are not many opportunities like this."
"Opportunity?" Maisie shook her wings and landed on Lightning's shoulder, "I don't understand Gu, do you want to go and see them?"
"That can't be done," Lightning hugged the dove. "This is a sacred ceremony that cannot be interrupted."
"Goo?"
"Anyway, you'll understand in the future. At times like this, it's fine as long as you don't see it. This is what my father's greatest explorer told me." Lightning threw Maisie, akimbo and said, "Run now, It's my turn to chase you!" (. If you like this work, you are welcome to come and vote, your support is my biggest motivation. Please come.)