Post 10: Summary

     The Problems in Technology class was beneficial to my growing in the technology field but kept the elements of fun and challenge to problem solving. During this class, I learned about the tools even more. Before this class, I hardly used the power tools and I mostly concerned myself with the designing part of the challenges. Now, I feel more comfortable in the lab and I am able to work more confidentially with the drills and saws. Another thing that the class taught me was about planning. Many of the projects has multiple aspects to it, thus I had to be all inclusive with the thought process. Getting into the project without a well laid out plan often meant what we made was going to fail. Seeing the difference an extra day in the computer lab could do was influential to my problem solving methods. Another main focus of the trimester seemed to be aerodynamic principles. We used the concepts of lift and drag in the CO2 powered vehicles to ensure we were able to make the car fast. We used aerodynamic principles a little in the ballista project since we wanted the marshmallow to fly as far as possible. Now, we are finishing with a glider project where we revisited the concepts of lift and drag. I have become very familiar with these concepts and are able to apply them to more everyday situations. Beyond these technological concepts, I learned about physical components such as torque. These things I already knew about from a physics class, but I was able to apply the concept to a real life situation to help solve problems.

Airfoils used to explore drag and lift

    The projects in the class have been a blast to conquer. The first project of the CO2 powered vehicles was fun since we got to make two cars. We were able to correct our mistakes with the first car in designing the second car. The end product was a second car that functioned very well. The siege the castle project created a heightened sense of independence since we were given many choices in how we wanted to go about solving the problem. We had the opportunity to pick the type of machine we wanted to create which we then had to seek out information about. This project gave me real experience with problem solving since the hand holding of old projects wasn't an aspect. The last project that I am working on is a glider project. The challenge is to build an aircraft that will stay afloat for a long period of time. This final project has been a lot of fun since it also wasn't well planned out. We were able to get all the initial research we needed for designing the craft and from there is has been testing of many different designs. The freedom of the project has been great for my further exploration with problem solving skills.

Projects done this class

     With my interest in engineering, I will used all of the skills I have learned in this class. I know that I will have many labs where I am required to use the tools I have become familiar with. Problem solving skills will also play a huge role in my classes. This one technique that I am working toward perfecting will help with all aspects of my education in the future no matter what. Working in a team has also helped my openness. I am used to cooperating with other and listening to all design ideas. Working in groups is inevitable and people skills are necessary. Being able to research and design on my own will aid in my study of various machines. Since I am interested in mechanical engineering, the concepts that I have learned about in each project will be very relevant. I know that going into college, I will already have many of the skills that I will need to be successful by working through this class. 

Post 8: Seige the Castle

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     In this project, we made a launching device to shoot a marshmallow accurately but also far. This represented two challenges of the problem. We researched physical concepts such as torque to design the machine. The ballista has two arms which is connected by a string attached to the end of the arms. When you pull the string back, the arms rotate back as well. When you let the string go, the arms return to the starting position which brings the string back to its original position and ushers the marshmallow forward with it. To complete the challenge, we made a frame to with these arm elements to shoot the marshmallow forward. We started by making a mini model to help us understand some of the design concepts we will need to use.

Mini model of desired machine

Technological Concepts

    For this project, there wasn't many concepts to research. One concept we spent time thinking about was torque. Torque is a driving force of rotation. Increased torque will result in greater power of the swinging arms of the ballista. With the increased power, the projectile will go farther. No other major concepts were explored. We had to use different way to make the ballista more sturdy. We used supporting beams to hold up the frame. Another thing we added for a sturdy base was pieces of wood on the side holding two other pieces of wood together. We would add a flat piece of wood on two by fours which would make the pieces stay together. This was added support to help prevent the ballista from falling apart.

Learning Goals

     The goal for this project was to independently use our resources to figure out how to make the best machine to launch the marshmallow. We were given all the tools we could need but there was no directs research for the project. Based on what you wanted to create, you had to figure out what would be the design to maximize firing distance. We took time to research different aspects of the ballista and had to apply these concepts to our design. Time management with planning was key. Without a good plan, there would be too much redesign to get a good ballista. Time management came into play with thinking about research and actually creating the ballista.  The other thing we learned about during this project was design and redesign. After initial construction of the ballista, there were things we had to figure out to make it work better.

Description

    In this project, we made a ballista. A ballista is similar to a bow and arrow launching device. The basic idea of the ballista is a base holding two legs with a frame for arms, that deal with launching, and a launching runway through the center. The arms stick out from the center of a rectangular frame and are attached by a string that goes straight across from the end of one arm to the end of the other. The string is pulled back which pulls the arms back as well. The torque for that arms comes from the end of the arms near the center of the frame being twisted in string. The arm is snapped forward when the string is released, which takes the string from the end of the 'launch runway' back to the resting position and the projectile is ushered forward. This was our initial design. We added more the frame to make it more sturdy and also added some 2 by 4's to the base in the front to give it an angle. The angle helped us with shooting far distances.

Ballista in resting position

Ballista when loaded

Positive Feedback

     The ballista we made ended up being very good. After a lot redesign, the ballista could shoot up to 28 feet. The accuracy was above average as compared to the rest of the class. We were able to get the marshmallow into the bin twice of our three tests on the final day. We also met most of our set goals in the beginning. We wanted to focus on accuracy. The ballista could successfully shoot the distance we wanted with little testing and marked positions of pulling the string back. We also used all of our time tweaking the machine to make it the best we could. We used our time efficiently to give us enough days to get everything just right and still have the paperwork done. This was also an accomplishment for us since we thought we were not going to be able to make all the changes we need to get it to work right.

Redesign Paragraph

    If given another chance, we would try to make the ballista more clean cut. In the end, after all the redesign, the ballista was not aesthetically pleasing. To make the machine better, it would have been beneficial to spend more time planning. We did enough research to know how it works, but we were hoping that the initial design based on the mini model would be able to shoot as far as we needed it to. Once we got going,  we found that it wasn't working as planned. If I could redo it, I would have stopped at this point and looked more into the problem. It would have been easier to address all issues at once instead of stumbling upon new problems each day. The ballista could have been more powerful, sturdy, and aesthetically pleasing if were were able to do less correcting of problems.

Technological Resources

   Throughout the process, we used many different things. In the beginning, we did research on the computer. We found many different designs for ballistas online. We combined different ideas to create one we felt would work well. We then had as much wood as we needed to create our ballista. We had limited selections when it came to adhesives. The screws we were using we not always long enough and we didn't have the greatest nails available. This was an issue when it came to cutting the wood pieces and assembling the ballista. We would have to be careful the way we planned to put it together to make sure we would be able to make it sturdy. We had limited time, as well. This was not that much of an issue for us since we got started quickly and left plenty of time to fix any problems.

Biggest Challenge

     One of the biggest challenges was getting enough power to ballista. We kept having issues with how far the ballista could shoot. To begin with, the ballista could only shoot about 10 feet. We needed it to shoot at least 25 feet. We kept taking the machine apart and twisting the arms in the ballista more to add more power. The wood was not strong enough to withstand the force of the string, though. We added more string to the wood to increase the tension which would decrease the amount of times we needed to twist the string. This fix helped the power substantially. We ended up also getting thicker wood that would allow us to twist the string more. These small changes aided the power enough to a point which our farthest shooting distance was 28 feet. It took us many days to make the adjustments since it was difficult to take apart the ballista, but in the end it worked well.

What I Learned From the Project

    From this project, I learned about the redesign process. Before, I hadn't done much redesign because I didn't have much time make changes to projects. This time, we had plenty of time and plenty of problems for fixing. With redesign, you have to be careful because you don't want to create more problems. The other aspect is with redesigning is the appearance part. Just adding a bunch of things to the project took away the feeling of the project being one piece. In the end, it all seemed like a bunch of pieces randomly put together. In some ways, we were careful about the looks with taking it apart to add a piece or to replace a broken two by four, but many of the times we just added things to the frame to improve performance. Redesign takes time for thought. You need to address specific problems and make a list of possible solutions before you can start changing your machine. In the beginning, we just tried different things to see what would work. By the end, we figured out we should do more research into the problem before changing the project because it amounts to less work in the end. Redesigning  was essential to this project, so I became very familiar with the ups and downs of the process.

Post 7: Aerodynamics Challenge

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     In this project, we used aerodynamic concepts to build a car. The goal was to make the car be as fast as it could. We were given a block of wood to carve a design out of and the car has to weigh at least 5 ounces and be at least 10 inches long. Wheels were provided. We designed the car by thinking of the purpose of the design of real cars and trying to apply these to design features of our cars. The way we approached the building part was to design a car, cut the general shape out of the wood, and do lots of sanding of the wood until the body was exactly the way we wanted.

Technological Concepts

    Two main focuses of the project were lift and drag. Drag is the air resistance opposing motion of a moving object. Lift if the force acting to bring a object off the ground. To maximize the speed of the car, lift and drag should be minimized. The car will have least resistance to forward motion is both of these things are kept to a minimum. There were other concepts that we researched, such as air foils, but these were less necessary when it came to the building and designing thus we did not use this information much.

Learning Goals

     Learning goals centered around aerodynamics. We wanted to explore how different shapes of cars could affect their aerodynamics. We would also like to know how simple changes can be made o positively affect the cars speed. Another concept we would like to explore is the weight distribution of the car and how much that affects the speed of the car.  Another goal was to become comfortable with using the machines in the lab again since its been a year since I've been in the lab. These things fit right into the project and we ended up learning much of the material with planning and designing the vehicles.

Description

    We ended up making two cars. Our first car was pointed at the front with a rectangular back. There was a gradual curve to the car to transition from thin to wide. It ended up not being symmetrical. This car has most of the weight concentrated in the back of the car. We cut a basic triangle out of the block to start with and sandedit to be smooth. The second car has larger curves both on the top and the sides. The back was blocky and the front came to a point. The car was better planned out so the curves were more smooth and the car was symmetrical. This car was more uniform with weight distribution since the whole car was thin. This car we cut all the curves and then just sanded a little bit to make it smooth.

First Car

Second car

Positive Feedback

     Our second car ended up being very aesthetically pleasing and well designed. It performaned better than average as compared with the class. Both of the cars went fairly fast (completed the track in less than 2.05 seconds). One car advanced into the semifinal round while the other one lost due to falling off the track. They both ran well when tested before the final race. Both of the cars had smooth edges. We worked efficiently in this project and were able to build two designs that we can up with. This helped us with building the second car since we knew the process of whatto do.

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    If given another chance, we would plan the cuts in the first car better. It would have looked better and been more similar to our original idea if we drew out the plan on the car before cutting. Another design factor that I would have incorporated is a flatter car. A flat top would allow the air to flow right over the car and it could help minimize lift. I would have also liked to explore having tilted axles so only a couple of the wheels touched the ground. This could have minimized friction the car needed to overcome to start moving and could have made the car's time decrease.

Technological Resources

   Throughout the process, we used many different things. In the beginning, we did research about aerodynamics on the computer. We then had a wedge of wood to shape into the car. The limited amount of wood constrained the size of the car, but it ended up not really being a problem since we wanted the car to be small and light. When shaping the wood, we had all the power tools we would have needed to cut out designs and perfect it. We ended up using the scroll saw a lot since we needed to cut curved edges. We used the electric sander to make sure all of the edges were smooth. We had a access to all the tools we needed in cutting and smoothing the wood. The wheels were provided for us. This meant we did not have options to pick wheels that would help make the car go fast.

Biggest Challenge

     One of the biggest challenges was sanding the bodies of the car to perfect. The first car ended up being rough and unsymmetrical. The idea was to create a basic shape for the car and sand the car down to what it should be after. The car was cut roughly symmetric, but when we made the edges smooth, it ended up unsymmetrical. Thus, the car was not perfect. We took more off to try to fix it but the car ended up getting shorter so we stopped changing it. We took this into account when making the second car and were able to perfect the second car with careful planning. This second car was hard to sand because of the many curves. When we sanded a part, it became more flat and changed the design. This means some of the places we left rough instead of smoothing the surface which negatively affected the aerodynamics. This challenge taught us that planning is very important in design and building of projects.

What I Learned From the Project

    From this project, I learned how various aspects could affect the speed of a car. I saw different designs and saw which ones worked best. Curved designs seemed to be popular and worked well as well as thin cars. Aerodynamics ended up seeming less important than the weight of the car. The car designs were fairly similar and they all worked well. Our first more chunky car went slower than our lighter more sleek car. The weight distribution was the big difference between to the two cars. In making two cars, we learned design and redesign fairly well. Changing things with a problem was essential in making a good second car. I also learned how to more skillfully use the tools and which saws could be used for different cuts. We tried to use the band saw for many of the carving but we learned that the scroll saw was better for the complex cuts.