Chapter 175 Hot Air Balloon Tour

    The principle of hot air balloon is very simple, there are only two difficulties in making it, one is the burning device, and the other is the airbag.

    The first point is that without the pressure vessel providing gaseous fuel, firewood or charcoal alone can be used to heat the air, and the efficiency is low, and the fuel can't fly. How far. This is also the principle of hot air balloon that has been published very early in history, but it is the reason for the hydrogen balloon to be put into use in actual combat. So Roland simply gave up the burning device and let Anna heat the ignition.

    The difficulty of airbags is airtightness, but for Roland, who borrowed from previous experience, this problem is easy to solve - using laminated fabric. The outermost layer of the airbag is a wear-resistant canvas with a cow's intestine film in the middle and a light gauze on the inner layer, so that it can be sealed to prevent air leakage and not afraid of bird sniping.

    Roland opened the bottom of the airbag and let Anna spray a black fire with a temperature close to the normal flame. The airbag slowly swelled up and looked like a full It is a wrinkled winter melon. Considering that the hot air balloon needs to be lifted by two people, the outer diameter of the airbag is five meters in diameter, and the intestinal membrane of twelve cattle is used, and the sewing work is close to one week. If it is not the lord of the jurisdiction, it does not necessarily make such a big toy.

    "Does it fly with the buoyancy provided by the hot air?" Anna asked. "I remember in the book that hot air is always rising. "

    "Yes, hot air rises, cold air sinking is a common natural phenomenon. Using particle theory to explain, it is a hotter air ball. The movement is intensified, the ability to spread around is strong, and the density is reduced after the volume is expanded. For the air that does not change around, it is equivalent to lightening, so it will rise."

   ;;;nbsp;  After Roland finished the principle, in addition to Anna's expression of "the original", the other three are all stunned, so that he can not help but secretly lament the importance of talent.

    When the airbag is fully inflated and floated up, the traction rope is slowly straightened, and Roland takes the lead in the hanging basket, then picks up Anna in the climb. .

    "I still have some concerns," said the nightingale. "Would you like me to go ahead and try it?"

  ;    "Trust me, nothing will happen," Roland smiled easily. "And even if there is an accident, there is lightning."

     "I will catch them, rest assured." Lightning patted the chest.

     "And I am!" McGonagall learned how to shoot with lightning.

    With a sway, the hot air balloon took the gondola off the ground and gradually climbed up. Not long after, the two crossed the top of the castle, and the whole picture of the town was presented to them.

    For Roland, this scene is not unfamiliar. After all, he is also a person who has seen the skyscraper, but in Anna’s eyes, it is a kind of perspective. A completely different new experience. She squatted on the side of the basket and looked out, and one hand firmly grasped Roland's arm, which seemed exciting and tense.

    This is the first time Roland has seen her show her eyes, people who have never left their feet on the ground, and when they fly to the sky, they will produce a slight The fear of heights.

    In a short while, the hemp rope under the basket used to hold the hot air balloon was pulled to the limit and the rise stopped. The hemp rope is about 50 meters long, which is the height of the 15th and 6th floors of the later generation. Roland let Anna reduce the firepower, and the hot air balloon finally hovered in the air.

    Lightning was still in the basket at the beginning, and after seeing the basket was stable, he was relieved to play with the beer around the hot air balloon. game.

    Looking down from here, you can clearly see the roof of the castle, the town where construction is everywhere, the Chishui River flowing from west to east, and the river. Green farmland.

    "How do you feel?"

    Until Anna retracted her head, Roland asked with a smile.

    "Thank you for your present," she said excitedly. "I can fly so high."