RPF Sci: Basic Rocketry

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RPF Sci: Basic Rocketry

Post by Apophis » Fri Mar 27, 2020 3:17 am

So, after various conversations in the threads in Off-Topic, I have decided to start this series, RPF Sci, dedicated to expanding the knowledge of the forum.
This time we will be discussing basic rocketry. Different types of rockets, their advantages and disadvantages, and examples of each.

First, rocket types. There are three main designs:
Liquid-fueled open cycle.
Liquid-fueled closed cycle.
Solid fueled.

There are two main liquid fueled "cycles", open and closed.
First, let's discuss the main premise of how rockets work.
Fuel is pumped through the fuel lines from the LOx and RPF-1 tanks. For this pumping to start, first the pump needs to be started. How the pump works is that it ignites a small amount of fuel to spool up a turbine, which will then transit the liquid fuel from the tanks to the engine. The cycle explains how the exhaust from the pump is expelled.
Open Cycle
Example: RocketDyne F1
In an open cycle, the exhaust is expelled outside of the combustion chamber, and this exhaust is all waste, so the rocket loses some efficiency for the sake of simplicity.
Closed Cycle
Example: Kuznetsov NK-33
In the closed cycle, the exhaust from the turbine is expelled into the combustion chamber, which increases thrust and efficiency, however this design runs hot, and therefore more dangerous.

Cryogenic Liquid Fuels
The most commonly used liquid fuels are LOx, liquid oxygen, and RPF-1, a highly refined form of kerosene. This is preferred because, at the moment, it isn't very expensive to be produced, and contains a large amount of potential energy. These are called cryogenic fuels, which brings us to our next subject.
Hypergolic Liquid Fuels
A very common hypergolic mixture is fuming nitric acid and hydrazine. What makes hypergolic fuels unique is that when the nitric acid and hydrazine come into contact with eachother, they ignite. This is useful for the ignition of a cryogenic rocket fueled engine.

Solid Fuels
Solid fuel rockets are the most powerful and most efficient relative to their size. An example of power is this: One solid rocket booster provides 40% of the thrust to get the Space Shuttle to orbit, therefore, solid rocket boosters provide 80% of the thrust needed for the Space Shuttle to achieve orbit. However, there are disadvantages, mainly being that once a solid rocket booster is ignited, it runs on full power until it runs out of fuel. There is no way to control the power provided by solid rocket boosters, and therefore aren't very common.

This concludes Episode 1 of RPF Sci: Basic Rocketry.
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Re: RPF Sci: Basic Rocketry

Post by Annasiel » Tue Mar 31, 2020 5:55 am

I recommend against using hydrazine at home, though, for anyone reading this. It will kill you without proper PPE.
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