CO2 Dragster DesignCO2 Dragster Design(Compressed Air, too!)(Compressed Air, too!)

Research and DevelopmentResearch and DevelopmentObjectivesObjectives

Research in CO2 auto design involves the study Research in CO2 auto design involves the study of a few sciences related to the motion of your of a few sciences related to the motion of your dragster.dragster.

• AerodynamicsAerodynamics- the study of how solid objects displace fluid - the study of how solid objects displace fluid air and other gases;air and other gases;

• PhysicsPhysics- the study of matter in motion;- the study of matter in motion;

• TribologyTribology- the study of friction;- the study of friction;

Terms to Know- AerodynamicsTerms to Know- Aerodynamics

FluidFluid MassMass AerodynamicsAerodynamics DragDrag LiftLift Rear SuctionRear Suction Down ForceDown Force Frontal AreaFrontal Area

Research- AerodynamicsResearch- Aerodynamics

Air-Air-– Is a type of fluid such as water that can be Is a type of fluid such as water that can be

directed or displaced;directed or displaced;– Has mass and is measured in terms of pressure;Has mass and is measured in terms of pressure;– Applies direct and frictional forces to objects in Applies direct and frictional forces to objects in

motion;motion;

Research- AerodynamicsResearch- Aerodynamics

You should be aware of four aerodynamic You should be aware of four aerodynamic principles-principles-– DragDrag– Lift/Down ForceLift/Down Force– Drag CoefficientDrag Coefficient– Frontal AreaFrontal Area

Research- AerodynamicsResearch- Aerodynamics

DragDrag is a combination of two forces that will is a combination of two forces that will work against the acceleration of your CO2 work against the acceleration of your CO2 car.car.– Frontal PressureFrontal Pressure occurs when tiny molecules of air hit the occurs when tiny molecules of air hit the

front of your car and is forced away to make room for front of your car and is forced away to make room for other molecules to hit it.other molecules to hit it.

– Rear SuctionRear Suction occurs when an empty pocket of air is occurs when an empty pocket of air is created in the back of your car resulting in a vacuum created in the back of your car resulting in a vacuum cleaner effect that tries to pull your car backward.cleaner effect that tries to pull your car backward.

Research- AerodynamicsResearch- Aerodynamics

LiftLift is similar to rear suction in that a thin is similar to rear suction in that a thin empty pocket occurs as air passes over a flat empty pocket occurs as air passes over a flat surface causing the car to lift.surface causing the car to lift.

Down ForceDown Force is due to high pressure in curved is due to high pressure in curved surfaces that causes the car to be pushed surfaces that causes the car to be pushed down. (Up next, notice how the windshield down. (Up next, notice how the windshield takes the shape of a spoiler.)takes the shape of a spoiler.)

Research- AerodynamicsResearch- Aerodynamics

Drag CoefficientDrag Coefficient is a way of expressing how is a way of expressing how slippery a car is. slippery a car is.

Here is a tip to increase your speed and lower Here is a tip to increase your speed and lower your drag coefficient- your drag coefficient- (the more ways you can eliminate drag, turbulence, (the more ways you can eliminate drag, turbulence,

rear suction, lift and down force, the faster your rear suction, lift and down force, the faster your car will go)car will go)

Research- AerodynamicsResearch- Aerodynamics

Frontal AreaFrontal Area is the total of all surfaces in the front of your vehicle is the total of all surfaces in the front of your vehicle which cause drag.which cause drag.

Area = Length x WidthArea = Length x Width

ReviewReview

With one hand, which can be With one hand, which can be thrown further, a football . . .thrown further, a football . . .

or a soccer ball?or a soccer ball?

Tips for AerodynamicsTips for Aerodynamics

Avoid flat upright surfaces in the front of Avoid flat upright surfaces in the front of your car to reduce turbulence.your car to reduce turbulence.

Avoid flat upright surfaces in the back of Avoid flat upright surfaces in the back of your car to reduce rear suction.your car to reduce rear suction.

Shield as much air at the bottom of your car Shield as much air at the bottom of your car to maintain traction.to maintain traction.

Keep the surface area exposed to Keep the surface area exposed to oncoming air to a minimum.oncoming air to a minimum.

Research- PhysicsResearch- Physics

Force = Mass x AccelerationForce = Mass x Acceleration

Heavier objects require more effort to move at the Heavier objects require more effort to move at the same speed;same speed;

It is easier to push a CO2 car out of the ditch than to It is easier to push a CO2 car out of the ditch than to push an actual car out of the ditch.push an actual car out of the ditch.

Research PhysicsResearch PhysicsHeavy Mountain BikeHeavy Mountain Bike•DurableDurable•For Rough TerrainFor Rough Terrain•Requires more EnergyRequires more Energy

Light Racing BikeLight Racing Bike•FastFast•For Long DistanceFor Long Distance•Requires less EnergyRequires less Energy

Tips for PhysicsTips for Physics

Avoid unnecessary extensions and ornaments that add Avoid unnecessary extensions and ornaments that add weight to your car.weight to your car.

The lighter you design your car, the more power will be The lighter you design your car, the more power will be used out of your CO2 cartridge.used out of your CO2 cartridge.

Make sure that your drill holes are straight and accurate to Make sure that your drill holes are straight and accurate to reduce extra forces acting on your car.reduce extra forces acting on your car.

Research- TribologyResearch- TribologyTribologyTribology is the study of friction between solid surfaces. is the study of friction between solid surfaces.

Friction is a force that resists movement.Friction is a force that resists movement. Friction is found between moving parts and surfaces.Friction is found between moving parts and surfaces. Without friction, objects would never come to rest.Without friction, objects would never come to rest.

Where will you find friction forces acting on Where will you find friction forces acting on your car?your car?

Research- TribolobyResearch- Triboloby

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

Tips for TribologyTips for Tribology

Painting your car will reduce aerodynamic Painting your car will reduce aerodynamic friction.friction.

Axel design is important to reducing friction.Axel design is important to reducing friction. Lubrication of the axels can reduce friction.Lubrication of the axels can reduce friction. Less ground contact wheels have with the Less ground contact wheels have with the

ground, the less friction will be present.ground, the less friction will be present.

Review Tips- AerodynamicsReview Tips- Aerodynamics

Avoid flat upright surfaces in the front of Avoid flat upright surfaces in the front of your car to reduce turbulence.your car to reduce turbulence.

Avoid flat upright surfaces in the back of Avoid flat upright surfaces in the back of your car to reduce rear suction.your car to reduce rear suction.

Shield as much air at the bottom of your car Shield as much air at the bottom of your car to maintain traction.to maintain traction.

Keep the surface area exposed to Keep the surface area exposed to oncoming air to a minimum.oncoming air to a minimum.

Review Tips- PhysicsReview Tips- Physics

Avoid unnecessary extensions and ornaments that add Avoid unnecessary extensions and ornaments that add weight to your car.weight to your car.

The lighter you design your car, the more power will be The lighter you design your car, the more power will be used out of your CO2 cartridge.used out of your CO2 cartridge.

Make sure that your drill holes are straight and accurate to Make sure that your drill holes are straight and accurate to reduce extra forces acting on your car.reduce extra forces acting on your car.

Review Tips- TribologyReview Tips- Tribology

Painting your car will reduce aerodynamic Painting your car will reduce aerodynamic friction.friction.

Axel design is important to reducing friction.Axel design is important to reducing friction. Lubrication of the axels can reduce friction.Lubrication of the axels can reduce friction. Less ground contact wheels have with the Less ground contact wheels have with the

ground, the less friction will be present.ground, the less friction will be present.