Forming a group: Phillippe and I have been friends this year, and I could tell he put a lot of work into his projects, as do I, which is why I thought we would work well together. I do not have much background on rockets, so working with Phillippe would help educate me on rockets quicker and easier. I have a strong feeling Phillippe and I will work very well together because we both have the drive for a good grade. Model Rocket Motors: There are two general types of model rocket motors, end burner motors and core burner motors. In the next section, end burner and core burner model rocket motors will be explained to my best ability. End Burner Motor: First off, an end burner engine is an engine that is known in amateur rocketry. A end burner rocket engine is an engine that has a cylindrical stick of fuel, with no gaps between the casing wall, which in this case is a round piece of cardboard, that can withstand lots of pressure. These engines have a bit of room between the fuel and the igniter, just enough so the motor can accept the igniter (in our case, an E-Match). The purpose of an igniter (or E-Match) is so that the rocket engine can be swiftly ignited from a safe distance. With our type of rocket engine, there is much more surface area for fuel to burn than an end burner, creating more pressure and ideally more thrust. These engines are used widely, and worth making if they are properly made. Some people want a small initial thrust and a long burn time after, and some want all the fuel to pretty much blow out of the bottom end. Core Burner Motor: The second motor that will be described is a core burning motor. These have a bored out hole, or also known as a core, running through the exact center of the fuel of the motor. These motors are much more dangerous than end burning motors. They are much more likely of exploding before launch due to the surface area and fuel ratio. When the E-Match is lit, the burn travels quickly all throughout the motor, giving it an intense inertia (initial thrust). There are multiple ways of coring a rocket motor. Our method was after the rocket and its fuel had been compacted using a modified press, a holder and a drill press were used to core our motors at the exact size we chose. Below and above this paragraph, are both the end burner (top) and the core burner) from before being lit and after the fuel runs dry. The Two Types Of Rocket Fuels: There are two types of fuels, and these mixtures can very. The two types of fuels are, potassium nitrate/sugar or black powder.
Potassium Nitrate/Sugar: The first rocket fuel is potassium nitrate/sugar mix. This propellant consists of 3 groups; the fuel, the oxidizer and the additive(s). In this case, the fuel is sugar. You can use all types of sugar(s) but the most used sugar is sucrose. And as an oxidizer, what is used is KNO3, which is potassium nitrate. With rocket candy the average ratio for the fuel is 65% KNO3, and 35% sugar mix. Sometimes people add 1% iron oxide, which makes the thrust rate amazingly higher. These engines can been melted down to a paste, or can be pressed with 1,000's of pounds. The reason for it needing to be packed with thousands pounds of pressure, is you cannot have any air pockets in the motor. If you do, your thrust will go down and your engine will not work that great. Black Powder: The second rocket fuel is a black powder rocket motor mixture. Black powder is usually used in model rocket motors. What these motors consist of is charcoal, sulfur and potassium nitrate. Everyone has there own ratio opinion, including us, but the most used one is 75:15:10. When people are making these engines, the amount of each component can be adjusted, which will change how the black powder burns. Most of the time these black powder rocket motors are only produced in small sizes, due to these being extremely explosive, ESPECIALLY when cored.
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AuthorGabriel M. Archives
December 2015
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