CO2 Dragster Design (Compressed Air, too!)

Research and Development Objectives Research in CO2 auto design involves the study of a few sciences related to the motion of your dragster. Aerodynamics- the study of how solid objects displace fluid air and other gases; Physics- the study of matter in motion; Tribology- the study of friction;

Terms to Know- Aerodynamics Fluid Mass Aerodynamics Drag Lift Rear Suction Down Force Frontal Area

Research- Aerodynamics Air- Is a type of fluid such as water that can be directed or displaced; Has mass and is measured in terms of pressure; Applies direct and frictional forces to objects in motion;

Research- Aerodynamics You should be aware of four aerodynamic principles- Drag Lift/Down Force Drag Coefficient Frontal Area

Research- Aerodynamics Drag is a combination of two forces that will work against the acceleration of your CO2 car. Frontal Pressure occurs when tiny molecules of air hit the front of your car and is forced away to make room for other molecules to hit it. Rear Suction occurs when an empty pocket of air is created in the back of your car resulting in a vacuum cleaner effect that tries to pull your car backward.

Research- Aerodynamics Lift is similar to rear suction in that a thin empty pocket occurs as air passes over a flat surface causing the car to lift. Down Force is due to high pressure in curved surfaces that causes the car to be pushed down. (Up next, notice how the windshield takes the shape of a spoiler.)

Research- Aerodynamics Drag Coefficient is a way of expressing how slippery a car is. Here is a tip to increase your speed and lower your drag coefficient- (the more ways you can eliminate drag, turbulence, rear suction, lift and down force, the faster your car will go)

Research- Aerodynamics Frontal Area is the total of all surfaces in the front of your vehicle which cause drag. Area = Length x Width

Review With one hand, which can be thrown further, a football . . . or a soccer ball?

Tips for Aerodynamics Avoid flat upright surfaces in the front of your car to reduce turbulence. Avoid flat upright surfaces in the back of your car to reduce rear suction. Shield as much air at the bottom of your car to maintain traction. Keep the surface area exposed to oncoming air to a minimum.

Force = Mass x Acceleration Research- Physics Force = Mass x Acceleration Heavier objects require more effort to move at the same speed; It is easier to push a CO2 car out of the ditch than to push an actual car out of the ditch.

Research Physics Heavy Mountain Bike Durable For Rough Terrain Requires more Energy Light Racing Bike Fast For Long Distance Requires less Energy

Tips for Physics Avoid unnecessary extensions and ornaments that add weight to your car. The lighter you design your car, the more power will be used out of your CO2 cartridge. Make sure that your drill holes are straight and accurate to reduce extra forces acting on your car.

Research- Tribology Tribology is the study of friction between solid surfaces. Friction is a force that resists movement. Friction is found between moving parts and surfaces. Without friction, objects would never come to rest. Where will you find friction forces acting on your car?

Research- Triboloby Does the paint job affect your car: Why or why not?

Tips for Tribology Painting your car will reduce aerodynamic friction. Axel design is important to reducing friction. Lubrication of the axels can reduce friction. Less ground contact wheels have with the ground, the less friction will be present.

Review Tips- Aerodynamics Avoid flat upright surfaces in the front of your car to reduce turbulence. Avoid flat upright surfaces in the back of your car to reduce rear suction. Shield as much air at the bottom of your car to maintain traction. Keep the surface area exposed to oncoming air to a minimum.

Review Tips- Physics Avoid unnecessary extensions and ornaments that add weight to your car. The lighter you design your car, the more power will be used out of your CO2 cartridge. Make sure that your drill holes are straight and accurate to reduce extra forces acting on your car.

Review Tips- Tribology Painting your car will reduce aerodynamic friction. Axel design is important to reducing friction. Lubrication of the axels can reduce friction. Less ground contact wheels have with the ground, the less friction will be present.