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Alexis DiGregorio Lab Report One
Introduction
The purpose of this project is to design a rocket that will be able to successfully launch as well as return to the ground safely and without breaking. We will use outside knowledge as well as what we learned in class to design unique rockets. We must build these efficiently and use the materials provided.
We will first make a scratch design of the rocket and make all of our measurements to make sure everything fits as it needs to. We will then start construction, starting with the body tube and motor mount and ending with the recovery system and the wings (and the decorations). Throughout the building process we will test individual parts, for example we will test the motor mount, and the stability of the rocket as well as test the parachute. Once the rocket is completely done we will test how if flys and then we will launch it.
Our progress so far has been very good, we have finished all parts of the rocket by the due date. We have completed the motor mount, body tube, nose cone, and our recovery system and we just finished gluing our fins on to the rocket. We have also measured our center of pressure and center of gravity. Next we will be painting our rocket and putting the final touches on it.
Background
I have limited past experience in constructing rockets. I have also never used a 3D printer but I have worked around them and seen how they work. I do have experience in construction, in my previous science classes I have constructed many things, mostly cars. And I have used saws, scalpels and different types of glue. I have also had experience in physics because I am currently taking the class.
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Methods
Our body tube is made of 4-5 scantrons rolled into a tube. Our motor tube is made of the tube provided. We secured it with our motor mount which was rolled up scantrons glued to the inside of our body tube. Our nose cone is was made with the 3D printer. We then made our recovery system, our parachute was made of a thick plastic bag, we then connected it to our nose cone with string and connected the nose cone to the rocket with a large rubber band. Our fins are made of balsa wood in the shape of a rhombus.
Motor mount-
The purpose of the motor mount is the hold the motor in the rocket without it being in
direct contact with the body tube. Our motor mount is one scantron cut in half wrapped multiples times around the motor tube in two places. We then glued this to the inside of our body tube. We
decided to design our motor mount this way because we thought it would be the most stable as
well as being simple to construct and not requiring too many materials.
Image 3- Diagram of motor mount connected to motor tube with dimensions
Body tube-
The purpose of the body tube is to hold all the components of the rocket together, it holds the
motor mount, which holds the motor, as well as the recovery system. Our body tube is constructed of multiple scantrons wrapped around one another. We used elmers glue to hold
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past rockets the smaller ones did the best. Our body tube is 16.3cm tall and 3.5cm in diameter, with a 10.99 cm circumference.
Image 4- Body tube of rocket with labeled dimensions
Nose cone-
The purpose of the nose cone is to allow air to flow smoothly around the rocket. Our nose cone is made of plastic material and was constructed with the 3D printer. We designed it using an online design program. We decided to have the tip pointed instead of rounded because we thought it
the nose cone too long or too large because we did not want the rocket to be top heavy. The nose cone when attached to the rocket is 6.3 cm long but when out of the body tube it is 7.8cm long. It
is 3.3cm in diameter, with 10.4cm circumference.
Image 5- Nose cone with dimensions in and out of the body tube
Recovery System
The purpose of the recovery system is to allow for your rocket to return safely and undamaged
to the ground. For our recovery system we decided to use a parachute instead of streamers because, although a parachute is less reliable, when it does come out of the rocket it works better
than the streamers (we also tested it multiple times to make sure it would come out of the
rocket). We then attached our parachute (made of a plastic bag) to our nose cone with green waxy string which acted as the shroud lines , and we attached out nose cone to our rocket with
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the rocket we folded it into a scantron multiple times and then glued it to the inside of the body tube.
Image 6- Recovery System, parachute, shroud lines, and shock cord
COG:COP-
The center of gravity is the pivot point and the balance point of the rocket. The center of
Pressure is the center of the surface area of the rocket. The center of pressure must be below the center of mass. Our center of gravity is towards the middle of the rocket and our Center of
Image 7- Center of Gravity (COG) and Center of Pressure (COP)
Fins-
The fins allow for more aerodynamic stability and help the rocket fly straight up. Our fins are
made of balsa wood and are secured to the rocket with wood glue. We found the area needed for our fins with the equation SAf=SAbt (Pbt)/Pr (where P is the center of pressure and SA is the
surface area). Then we divided our fins into a square and two identical triangles on the sides to
make it easier to design our fins with the right surface area. We designed four identical fins and then cut then out using a saw. We then glued them on one at a time over a period of four days.
We decided to use four fins instead on three because we thought it would make the rocket more
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Image 8- four fins glued with wood glue onto body tube of the rocket
Engine selection- (selected for us)
