Post 9 - PIT - Class Summary

Class Summary

I really enjoyed this class. I especially liked the freedom of the projects and the test and re test aspect of them. The thing I liked most about the class was seeing the results of when your project goes well and works. There was nothing I disliked about the class. My favorite project was the co2 car. This is because I like cars and enjoyed learning about the aerodynamics. I also liked winning the race at the end of the project. The under siege project was good fun too, it was interesting tweaking the loft and firing arm length.

If I had to change something about this class it would be to make the packets with the projects smaller so we had more time to work.

I really enjoyed this class and have recommended it to a few friends. 

Post 8 - PIT - Under Siege

Under Siege 

The project was a partner project. In this project we had a choice of builds. We had to choose between three options, a catapult, a trebuchet, or a ballista. We chose to build a catapult. There was no limit to the size. We couldn't use any motor to power the catapult. The goal of the project was to fire a marshmallow as far and as accurately as possible.

The technological concepts in this project were different lofts, rubber band amounts, and catapult arm length. The different lofts were created by angling the whole catapult to create different flight paths for the marshmallow.  We changed the amount of rubber bands to change how far the marshmallow would go. The last concept was the arm length. We made this longer and longer until we found the right length for the best distance.

My learning goals for this project were to learn how to find the best loft and arm length for optimal accuracy and distance, and to be able to make a catapult that had the ability to re fire.

This is our finished project. It was made mainly of wood. We made the base and the supporting arms first, then added the firing arm. After some experimentation we added the base to add height and loft, to increase distance. We added the bottle cap on the firing arm to hold the marshmallow before firing. The rubber bands were stretched over a  dowel rod to create elastic potential energy.

The feedback for our catapult was mainly good. It shot a maximum 26 feet, and on the accuracy test we made it in first try. We were very happy with the catapult's performance and the build quality.

If I were to redesign the project there are a couple of things I would change. I would increase the height of the supporting arms to allow a better range of firing arm motion. I would also enclose the sides of the base for a  more appealing overall look.

The main technological resources of the project were the rubber bands, firing arm, and dowel rod.
The rubber bands provided the power to move the firing arm and to launch the marshmallow. The firing arm was how the marshmallow was launched, it moved upwards and hit the dowel rod which flung the marshmallow.

The biggest problem of the project was the rubber bands. If stretched too much they snapped, which was extremely frustrating towards the start of the project. Also, after a few launches the rubber bands became stretched out and lost their power.

We over came this problem with two solutions. Firstly we made the top dowel rod thinner to reduce the total are of rubber band stretching on the wood. Secondly we changed where the nail on the firing arm was to remove unnecessary stretching,

Post 7 - PIT - CO2 Car

CO2 Car

This was my first project in the second technology class, Problems in Technology.

This project was a partner project. We had to design and build a car powered by a co2 cartridge. We could any materials we wanted except another power source. The car had to be at least 5 ounces to qualify. We couldn't modify the co2 cartridge whatsoever.

The technological concepts of this project were aerodynamics and down force. These will effect how fast the car will go. We needed the car to be as aerodynamic as possible. This made it have less resistance against the air and therefore made the car faster. Down force is how much the air traveling the car is pushing it into the ground. Too little and the car wont get the best traction, too much and it'll slow down the car.

My learning goals of this project were to be able to test and retest over and over to find the best aerodynamics for our car, learn how to keep the car light yet durable, and how to get the wheels in the best spot.

 The car is made from one piece of wood. We cut the general shape out then proceeded to sand down the edges and body to further reduce air resistance. The wheels were put on a metal axle through a hole drilled at the front and back end. we cut the axles to the perfect length to get the wheels at the right spot on the car. We then drilled a hole in the back for the co2 cartridge to fit.

All the feedback about the car was great. It won the racing bracket by a long shot. It's best time was 2.11 seconds. It was designed very well, it had little air resistance due to the extensive aerodynamic changes.

If I were to redesign the car there isn't much I would change. I would try and keep the top surface completely flat because it had gotten a little uneven due to the large amount of sanding. Other than that I don't feel there is anything I could improve.

The main technological resources of this project were the axles, wheels, and co2 cartridge. The wheels and axles allowed the car to move freely. The co2 cartridge was the propulsion for the car. Without it the car wouldn't be able to move on it's own.

The biggest problem in this project was sturdiness. Our goal was to create a lightweight yet strong car. Our first car broke as we had the front end too thin.

We overcame this problem by making the front end thicker. This added weight which we didn't want but we made the middle to back end thinner to reduce the extra added weight. This kept the car light and fast, yet durable. The car no longer broke when hitting something head on.