Automotive Engineering: CO2 Dragster Design Benjamin Syms Middle School Technology Education Lesson Objectives • Apply processes and resources to solve technological problems • Design and build a transportation to solve a problem • Students will relate automotive engineering principles (such as aerodynamics) to CO2 dragster design Design 0bjectives • The main objective of your production should be producing the fastest, best performing design keeping in mind the looks of the dragster. • It should simply be as good looking, neat, clean, and fast as possible. • Aerodynamics Factors that • Total Weight of the Dragster may affect the speed of the dragster • Friction What is Aerodynamics? • The word comes from two Greek words: • aerios, concerning the air, and • dynamis, meaning powerful. • Aerodynamics is the effect of airflow and the forces involved when an object moves. • It is an important consideration in designing a vehicle is aerodynamics. Drag equals Resistance • Drag is the uneven or turbulent air movement that slows the vehicle down. • A poorly designed vehicle uses more fuel. • A body with an overall rounded or square shape will cause air to break away from the streamline into swirls of air. • Vehicles have less resistance if they are rounded in the front and tapered off to a point in the rear (teardrop shape). Aerodynamic Considerations • The main considerations in aerodynamics are: • Reducing drag, to increase top speed and fuel efficiency • Increasing down force, so that the car has more grip. • A car with a more aerodynamic shape goes faster and is more fuel efficient. Reducing Drag • The main factor to work on is the shape of the vehicle. • The shape must minimize flow detachment and reduce frontal pressure. Minimize the build up of frontal pressure. This is done by reducing the frontal area of the car. This means minimizing the grill and making the sure that the windscreen is as flat as possible so that it causes the least possible resistance to motion. Poor Effect Somewhat Improved Most Efficient Downforce As air flows over the car it experiences areas of relative high and low pressure. Downforce is an aerodynamic force that tends to press the cars tightly against the ground, allowing the tires to grip the track with more force. Weight Considerations • The effect the dragster weight on its speed is a simple concept. • Simply put: The heavier your design, the slower the dragster will be on the track. Friction and the Dragster Friction reduces the speed of your designed dragster. The following steps will help you reduce friction in your design. Check and make sure that: • There is no paint or dirt inside the axle holes. • The bearings installed correctly. • The wheels spin freely. • The washers are on the axel. • The wheels are straight on the axel. • The tires tight against the wheel hub. Reducing Friction 1. Use Aerodynamics to assist car operation. 2. Use Graphite on axles to reduce friction. Any Questions?
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