Difference between revisions of "User:无心十二载/Sandbox"

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== 火箭升空的基本知识 ==
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=== Heatshield ===
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{{See also|Heat shield}}
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You also have to care of excessive heat or else dire consequences may result. Usually, heat is generated during reentry when you hit the dense atmosphere at insane orbital speeds of multiple times the speed of sound. The air being pushed out of the way is superheated and transfers some of its heat to the payload. Very small and sturdy satellites can be risked to survive reentry a bit warmed up if they follow a shallow enough reentry trajectory, but heavier payloads (usually manned pods) will require a dedicated part such as a heat shield.
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A heat shield is composed of ablative material, that gradually melts away during reentry, absorbing a lot of heat in the process. It should be placed right below the payload that is to return to Kerbin and has to have a sufficient diameter to cover the payload fully. It also is directional, so you have to ensure to hit the atmosphere with the heat shield facing forward. If your payload tumbles just slightly during reentry, a non-protected area could face the heated atmosphere and suffer explosion from overheating.
  
让一个物体从 [[Kerbin]] 星球飞上太空并呆在那里(也即进入稳定轨道)所要克服的困难只有两项:重力和[[Atmosphere#Drag|阻力]]。
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The heat shield is fairly heavy. With experience, you can reduce its weight by reducing the thickness (right-click the part and reduce the amount of ablator), shaving off some more valuable kilograms. It also has an integrated decoupler, meant to be triggered after leaving the dense atmosphere, to reduce the weight the parachute has to slow down.
  
牛顿万有引力定律告诉我们,引力与物体间的距离呈平方反比,因此随着你远离 Kerbin 的中心,你所受的重力会迅速衰减。但仅仅飞的高是不够的,为了入轨你还需要积累足够的水平速度。合适的水平速度能够使你在仅受重力作用的情况下保持轨道高度不变,而这被称之为轨道速度。对于 Kerbin 来说,你大概需要 4000 m/s 的 [[Delta-V]]。
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<hr><hr>
  
空气阻力相较于地表高度近似于指数衰减,于[[atmosphere|大气]]上界减少至零(Kerbin 的大气上界为 69,078 米)。相较而言,飞行器的重量要比阻力重要得多,不过一个好的外形设计依旧能大大增加你火箭的运载效率。在高速条件下,空气表现得就像液体一样,火箭必须把前方的空气排开从而让自己挤进去。这也是为什么现实生活中的火箭与飞机总是''流线型''的,这种外型使得它们更容易将前方的空气分开并赶到舰体旁边。如果你设计出一块砖头状的东西,那么不要怀疑它的飞行轨迹也会跟砖头一个样。
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=== 热盾 ===
 
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{{See also|Heat shield|热盾}}
所以设计火箭的规则也就三条:让它尽量的轻,让它尽量的光滑,再给它足量的推力。相当简单不是吗?
 
 
 
先设计你的负载,然后再另外设计你的运载火箭是非常好的习惯,这一方面会让你以后能使用标准化的运载火箭来运载各种相近的载荷,另一方面也在培养你预估所需运载火箭的能力。
 

Latest revision as of 14:02, 14 October 2024

Heatshield

→ See also: Heat shield

You also have to care of excessive heat or else dire consequences may result. Usually, heat is generated during reentry when you hit the dense atmosphere at insane orbital speeds of multiple times the speed of sound. The air being pushed out of the way is superheated and transfers some of its heat to the payload. Very small and sturdy satellites can be risked to survive reentry a bit warmed up if they follow a shallow enough reentry trajectory, but heavier payloads (usually manned pods) will require a dedicated part such as a heat shield. A heat shield is composed of ablative material, that gradually melts away during reentry, absorbing a lot of heat in the process. It should be placed right below the payload that is to return to Kerbin and has to have a sufficient diameter to cover the payload fully. It also is directional, so you have to ensure to hit the atmosphere with the heat shield facing forward. If your payload tumbles just slightly during reentry, a non-protected area could face the heated atmosphere and suffer explosion from overheating.

The heat shield is fairly heavy. With experience, you can reduce its weight by reducing the thickness (right-click the part and reduce the amount of ablator), shaving off some more valuable kilograms. It also has an integrated decoupler, meant to be triggered after leaving the dense atmosphere, to reduce the weight the parachute has to slow down.



热盾

→ See also: 热盾