CO 2 Dragster Notes. It’s all about… AERODYNAMICS!!. 4 Basic principles to Aerodynamics:. A. Lift. B. Thrust. C. Weight. D. Drag. In an airplane, when: Drag = Thrust & Weight = Lift the plane will fly STRAIGHT & LEVEL.
It’s all about… AERODYNAMICS!!
In a race car (Indy or F1 style) the car is designed like an upside-down airplane wing which creates downforce rather than lift. This keeps the car on the ground and prevents lift-off.
Again, the shape of the chasis is similar to an upside down airfoil (airplane wing). The air moving under the car moves faster than that above it, creating downforce or negative lift on the car. Airfoils or wings are also used in the front and rear of the car in an effort to generate more downforce. Downforce is necessary in maintaining high speeds through the corners and forces the car to the track. An Indy ground effect race car can reach speeds in excess of 230 mph using downforce. In addition the shape of the underbody (an inverted wing) creates an area of low pressure between the bottom of the car and the racing surface. This sucks the car to road which results in higher cornering speeds.
Because of the amount of downforce a race car creates, (in theory) if a race car is traveling at high enough speeds (+200kph) it could travel along a wall or even upside down on a road without falling!
The amount of drag that your hand creates depends on a few factors, such as the size of your hand, the speed of the car and the density of the air. If you were to slow down, you would notice that the drag on your hand would decrease.
·When you are driving along at a constant speed, the power produced in the engine is converted to force at the tires. If the drag and force (engine) are equal then you maintain your speed.
Drag > force = slowdown
Drag < Force = speed up!
Acceleration - Newton's Second Law states that the acceleration (a) of an object is directly proportional to the force (F) applied, and inversely proportional to the object's mass (m). That is, the more force you apply to an object, the greater the rate of acceleration; and the more mass the object has, the lower the rate of acceleration.
·As mass increases (and engines stays the same size) you will not accelerate as quickly
·With your CO2 dragsters, everyone has the same size engine (CO2 cartridge) but the smaller the vehicle (lighter weight) the faster it will travel (in theory)!
· Material - Tires with higher sulfur content tend to have a lower rolling friction (this is one strategy that most hybrid car vendors use to improve fuel efficiency)
·Wheel/Tire Dimensions - rolling friction is related to the flex of sidewalls and the contact area of the tire. For example, at the same pressure wider bicycle tires have less flex in sidewalls and thus lower rolling resistance (although higher air resistance)
·Extent of inflation - Lower pressure in tires results in more flexing of sidewalls and higher rolling friction.