Drill-Powered Vehicle Competition
In my component design class, my team was tasked with designing and constructing a three-wheeled vehicle to be powered by a Ryobi 18V Drill. The vehicle had to be under 50 lbs, and our budget was $200. My team chose to compete in the hill climb category, the goal of which was to haul as much weight as possible up a hill course.
On this team, each member was assigned a role, and I was chosen to be the project manager. This meant I was in charge of making sure my team members knew what tasks needed to be done, ensuring we stayed under-weight and under-budget, and making sure all project related assignments were completed satisfactorily and on time. In order to make these objectives happen, I built a spreadsheet tracking project milestones, a spreadsheet for tracking the budget, and a task to-do list that I kept updated, allowing the team and I to always know what needed doing. In addition to these management tasks I also worked on the physical project with the team. This included helping design the frame, manufacture the drill plate and its sub-components, cutting and preparing frame members for welding, extending the drill’s trigger mechanism, and running rpm/torque and tractive force analysis.
Our first step was to design our frame and price out an initial budget, making sure both our frame weight and steel costs gave us sufficient flexibility for our weight limit and budget, respectively. We designed the frame in SOLIDWORKS and used FEA to estimate our frame to have a minimum factor of safety of one with 600 lb loading. We knew the frame would most likely be able to support more weight than 600 lbs if our welds were sufficiently strong.
Our next consideration was our drive train, which started at our drill. Because we chose to compete in the hill climb, we knew a high gear ratio would maximize the torque we could produce at our driven wheel and increase the amount of weight we could haul. Because of this, we decided to create a two-stage transmission. To accomplish this, we needed a plate to secure our drill and sprockets.
We designed the drill plate to secure the drill and planned to run a keyed drive shaft from the drill through a first set of pillow blocks with press fitted ball bearings to insure stability. We would connect a 12-tooth freewheel sprocket to our drive shaft with a threaded, keyed adapter. We also planned to mount a bike cassette onto the drill plate and connect its largest sprocket with our freewheel sprocket to form the first stage of our transmission. Next we would chain the smallest sprocket on the cassette to a large sprocket attached to our rear wheel, to complete the second stage of the transmission. From drill to final sprocket, our vehicle had an 8:1 gear ratio. We also implemented a mechanism to tension each of the chains ensuring adequate force transmission while driving.
When manufacturing the parts for the drill plate, we used a mill and an inside micrometer to bore out a hole within a 0.009” press fit tolerance range we calculated. We also used a lathe to turn down our drive shaft to the correct diameter to fit our bearings, and to turn a hex end to fit our drill chuck. When creating the frame, we cut our members down with a band saw and then coped the circular tubing to create a better fit for welding.
To allow us to steer, we pulled the fork off an old bike, manufactured a new head tube, and welded the modified fork onto our frame. To make actuating the drill while driving the vehicle easier, we extended the wires connecting the battery, trigger, and drill, allowing us to pull the trigger out of the drill housing and mount it on our handlebars.
After assembling all components, our bike came out to weigh 41 lbs, well under the 50 lb limit. During the competition we managed to haul a load of 947 lbs up the 15% grade hill, far exceeding our expectations. This made our vehicle the strongest pound-for-pound contender in the two sections competing that semester. We also came in under-budget, with final costs equaling $197. Overall, we claimed second place for the heaviest load carried, being out-hauled only by a team that exceeded both the weight and budget requirements.
This project taught me lots about both vehicle design and successful project management. I improved my machining, time management, project management, design, and analysis skills, and had fun doing it.
The complete vehicle on race day
Fluid Phenomenon Research
The final task of my fluid mechanics course was to research a fluid mechanics phenomenon and apply it to a design problem. My partner and I chose to research the physics behind frisbees. Through our research we found their flight relies on two main principles: Bernoulli’s principle for lift and gyroscopic inertia for stability. With this understanding, we were able to identify and isolate equations to predict flight path, and set up an iterative solver in order to calculate trajectories. Using this solver, we could find the optimal angle of attack for any given initial throw velocity and also find the optimal launch velocity and angle of attack for hitting a target a certain distance away. We applied these abilities to our design problem, which was finding the optimal launch conditions for hitting a frisbee golf target from 40 meters away. Check out our paper below for more details on our methods and findings!
Diagram of forces on a frisbee--weight, lift, and drag--and velocity with initial flight direction
Pot Odds Pro iOS App
Recently, I became interested in learning some strategy for the game of poker, and learned about the concept of "pot odds." Pot odds are the ratio of how much you stand to gain versus how much you must risk in a given situation. When converted to a percentage, pot odds represent the minimum frequency you must win the hand in order for the play to be profitable in the long run. Pot odds are an extremely useful decision-making tool, so I wanted to quiz myself to get better at calculating them in games. However, I couldn't find any apps on the App Store that allowed users to practice their pot odds calculations. So, I made one myself.
Pot Odds Pro allows users to learn about pot odds, practice calculations, and customize their training experience through advanced settings. On the main page, users have three exciting game modes to choose from. In Freeplay, users are quizzed with randomized problems, giving them a chance to calculate opponent bet size and the corresponding pot odds they would receive. Time Limit and Problem Limit modes allow users to test their speed in a controlled environment. On the information page, denoted by the academic cap, users can read about what pot odds are, how to use them to make decisions, and how to improve at calculating them. On the settings page, users are given a multitude of options to customize their experience, from modifying initial pot size to their hypothetical opponent's bet sizes and frequencies.
I single-handedly created the entire app, from code to app icon to App Store copy. The app is structured in the MVVM or Model-view-viewmodel form, allowing for dynamic control of what the user sees, and easy manipulation of the data behind it.
Try the app for yourself! Check out the App Store page link below or look up "Pot Odds Pro" in the App Store on any iPhone running iOS 17.2 or later. Also, take a look at the app's FAQ and Privacy Policy below!
Pot Odds Pro App Store page