aQuestions


 * Types of Engine**
 * How Brakes Work**
 * How Tyres Work**
 * Stopping a Moving Vehicle**
 * Racing Car Physics**

=**1. Types of Engine**= //View the web page on [|Basic Engine Parts]// //valves// //piston// //piston rings// //connecting rod// //crank shaft// //sump// //Explain the principle of an Internal Combustion Engine?// //How is this principle used in the core of a car engine?// //W////hat is the four-stroke combustion cycle?// //What are the names given to the 4 strokes?// //What happens during the Intake stroke?// //What effect does Compression have?// //What is the job of the Spark Plug?// //What happens when the gasoline is exploded?// //View the web pages on [|How Two Stroke Engines work] [|Two- Stroke Basics][|The Two-Stroke Cycle] // //Name some devices that might have 2 stroke motors.// //What are some of the advantages of 2 stroke motors?// //What are some disadvantages of 2 stroke motors?// //What names are given to the two strokes?// //Explain the differences between a two stroke and a four stroke engine in terms of Fuel Consumption, Manufacturing Costs, and Environmental Impact.//
 * __Basic Engine Parts__**
 * Write a brief note about the functions of the following basic engine parts:**
 * //s//**//park plug//
 * __The Internal Combustion Engine.__**
 * //View the web page on the [|Internal Combustion Engine] //**
 * Answer the following Questions:**
 * __How Two Stroke Engines Work__**
 * Answer the following Questions**
 * __Comparisons of Four-Stroke and Two-Stroke Motors__**

//What are the 4 reasons we do not use two stroke engines in our cars and trucks ?//

//What does the Term 1500 cc mean?//


 * __Summarise the steps or strokes in a complete cycle of the following engines__ //://**

//Two stroke://

//Four Stroke://

=**2. How Brakes Work**= d e f
 * //Read the following article about How Disc Brakes Work//**
 * []**
 * []**
 * //Write the correct labels for this diagram//**
 * a**
 * b**
 * c**
 * //What is the function of the caliper?//**
 * //Where do the brake pads squeeze?//**
 * //What slows the disc down?//**
 * //Why are brakes vented?//**
 * //What slows the disc down?//**
 * //Why are brakes vented?//**
 * //Why are brakes vented?//**


 * //Read the following article about how Drum Brakes Work//**
 * []**


 * //Write the labels for this diagram.//**
 * a**
 * b**
 * c**
 * d**
 * e**
 * f**
 * g**

=**3. How Tyres Work**=


 * __Label this diagram__**
 * a**
 * b**
 * c**
 * d**
 * e**
 * f**
 * g**
 * h**


 * //Why is it important to have your tyres at the correct pressure?//**


 * //Label the diagram below indicating tyre inflation.//**



=**4. Stopping a Moving Vehicle**= The process of stopping a moving motor vehicle can be broken into three phases: recognition, reaction and braking. During each of these phases, the motor vehicle will travel a certain distance. The sum of these individual distances is known as the //stopping distance.// It is the stopping distance that determines whether the vehicle will be able to stop safely or not.

In order to stop safely, first the driver needs to recognise that there is a reason to stop. This might happen if the driver sees any of the following: a traffic light changing to red, a stop sign, a pedestrian stepping onto the road or an oncoming car swerving into the wrong lane. The time that it takes a driver to recognise the need to stop will depend on a number of factors. These include: the driver’s level of alertness or distraction, fatigue, visibility, blood alcohol concentration, and driving experience. Recognition time is difficult to measure by itself, so it is often combined with reaction time (which is the time between when a driver recognises a hazard and when the driver reacts to the hazard by braking or swerving) and given as a **//recognition/reaction time//.** A moving vehicle will travel a certain distance during the recognition/reaction time. This distance is known as the **//reaction distance//** (‘recognition’ is dropped for convenience). **Reaction distance is directly proportional to the speed of the vehicle**; that is, the faster the vehicle is going, the longer the reaction distance. If a hazard is closer than the reaction distance, it cannot be avoided. Fortunately, there are few hazards that appear suddenly at such short distances. In Australia, one example is the case of a kangaroo hopping out onto a highway. Braking occurs between the instant when the brakes are applied and the moment when the vehicle comes to a complete stop. The distance the vehicle travels in this time—the **braking distance**—depends on the initial speed, the condition of the road (including surface water or ice), the condition and tread-pattern of the tyres, the amount of pressure applied to the brakes by the driver and the use of brake assistance technology like an anti-locking brake system (ABS)
 * Recognition and reaction**
 * Braking**

//What is meant by reaction distance?// //From the laws of physics we know that Velocity = distance / time. Re-arrange this equation to show how you could work out time if you know velocity and distance T =// //What is the reaction distance of a car travelling at 11.1 m/s?// //Work out the reaction time?// //What factors affect braking distance?// //Draw a scatter graph of braking distance versus speed for a car under wet conditions.// //What is the shape of this graph?// //Use this graph to interpolate the braking distance for a car driving at 70 km/h?// //Examine the data and write a sentence to **compare** braking distance in DRY weather with WET weather.// //What is meant by stopping distance? How is it calculated?// //If the driver had a faster Reaction time, explain how this would affect Stopping distance?// //What are some of the factors that affect reaction time?//
 * Performance Test Calculations**
 * = **Speed** ||= **Reaction Distance (m)** ||||= **Braking distance (m)** ||||= **Stopping Distance (m)** ||
 * = **(km/h)** ||= **m/s)** ||=  ||= **DRY** ||= **WET** ||= **DRY** ||= **WET** ||
 * = 40 ||= 11.1 ||= 22.2 ||= 6.6 ||= 9.2 ||= 29 ||= 31 ||
 * = 60 ||= 16.7 ||= 33.3 ||= 15.6 ||= 21.5 ||= 49 ||= 55 ||
 * = 80 ||= 22.2 ||= 44.4 ||= 28.7 ||= 39.0 ||= 73 ||= 83 ||
 * = 100 ||= 27.8 ||= 55.6 ||= 45.5 ||= 61.5 ||= 11 ||= 117 ||
 * = 120 ||= 33.3 ||= 66.7 ||= 66.2 ||= 89.3 ||= 133 ||= 156 ||
 * Answer the following Questions**

Clearly not all cars have the same Braking distance. Braking distances for cars are measured using the standard 100 – 0 test. As the name suggests this involves measuring the distance it takes for the car to come to rest if the brakes are applied when the car is travelling at 100 km/h

//Rank the cars from Best to Worst according to their Performance in the 100 – 0 test//
 * **Car** || **Braking Distance (m)** ||
 * BMW M3 || 30.6 ||
 * Mazda MX5 || 31.7 ||
 * Porsche 911 Carrere || 36.7 ||
 * Mercedes Benz C32 AMG || 36.4 ||
 * Ford FalconXR8 || 35.3 ||
 * Holden Monaro CV8 || 37.1 ||

//Make a list of all the factors that affect Stopping Distance//

=**5. Racing Car Physics**=

The principles which allow aircraft to fly are also applicable in car racing. The only difference being the wing or airfoil shape is mounted upside down producing down force instead of lift.

The Bernoulli Effect means that: if a fluid (gas or liquid) flows around an object at different speeds, the slower moving fluid will exert more pressure than the faster moving fluid on the object. The object will then be forced toward the faster moving fluid. The wing of an airplane is shaped so that the air moving over the top of the wing moves faster than the air beneath it. Since the air pressure under the wing is greater than that above the wing, lift is produced.

The shape of the Indy car exhibits the same principle. The shape of the chassis is similar to an upside down aerofoil. The air moving under the car moves faster than that above it, creating down force or negative lift on the car. Aerofoils or wings are also used in the front and rear of the car in an effort to generate more down force. Down force is necessary in maintaining high speeds through the corners and forces the car to the track.

Light planes can take off at slower speeds than a ground effects race car can generate on the track. An Indy ground effect race car can reach speeds in excess of 230 mph using down force. In addition the shape of the under body (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 cTeams that plan on staying competitive use track testing and wind tunnels to develop the most efficient aerodynamic design. The focus of their efforts is on the aerodynamic forces of negative lift or down force and drag. The relationship between drag and down force is especially important. Aerodynamic improvements in wings are directed at generating down force on the race car with a minimum of drag. Down force is necessary for maintaining speed through the corners. Unwanted drag which accompanies down force will slow the car.

The efficient design of a chassis is based on a down force/drag compromise. In addition the specific race circuit will place a different demand on the aerodynamic setup of the car. A road course with low speed corners, requires a car setup with a high down force package. A high down force package is necessary to maintain speeds in the corners and to reduce wear on the brakes. This setup includes large front and rear wings. The front wings have additional flaps which are adjustable. The rear wing is made up of three sections that maximize down force.

The speedway setup looks much different. The front and rear wings are almost flat and are used as stabilizers. The major down force is found in the shape of the body and under body. Drag reduction is more critical on the speedway than on other circuits. Since the drag force is proportional to the square of the speed, minimizing drag is a primary concern in the speedway setup. Lap speeds can average over 228 mph and top speeds can exceed 240 mph on a speedway circuit. Effective use of down force is especially pronounced in high-speed corners. A race car travelling at 200 mph. can generate down force that is approximately twice its own weight

.Generating the necessary down force is concentrated in three specific areas of the car. The ongoing challenge for team engineers is to fine tune the airflow around these areas.
 * Front wing assembly
 * Chassis
 * Rear wing assembly

Chassis designers and builders are constantly at work evaluating the race car as a total aerodynamic system. Rule modifications and safety regulations designed to reduce cornering speeds keep engineers seeking alternative aerodynamic advantages. Currently there are only three chassis designs used in competition for the 1994 season.Indy Car Chassis Constructors Not only are there only three chassis designs in current competition, but there are only four engines available to the teams. In addition, these engines are leased from the factories and are not rebuilt by the teams. They are replaced with new engines, by CART regulations. This enables car manufacturers to continue their developmental programs in racing and maintains a competitive balance in the series. The engines have been downsized in order to produce a more efficient aerodynamic car design. Still capable of producing between 750-800hp, the engine size is important in reducing the size of the car. Ian Bisco, vice-president and general manager of Cosworth Inc. in the United States explains, "To give you an idea of the what a difference the compactness makes to the car, one of our designers claims that at 230 mph the difference between the old car (1992) and the new car, is like giving the engine another 20hp." Engineers and Constructors design new cars with the overall aerodynamic efficiency of the car as the starting point.
 * Design and Test**
 * Lola
 * Penske
 * Reynard
 * Engines**
 * Ford Cosworth XB V8
 * Ilmor Indy V8
 * Honda Indy V8
 * Menard V6

Indy car construction is governed by CART rules and evolving regulations designed to afford the driver the best protection possible. Whether the chassis is mass-produced or custom built, research and development takes months to get an efficient design on the track. Lola Cars Ltd. of Cambridgeshire, England is the major supplier of Indy car chassis (32 out of 50 chassis used in 1994). Since Lola supplies chassis to the majority of teams, design flaws are seen quickly and feedback is constant. Teams that design and build their own chassis such as Penske, do not get the same amount of feedback. Feedback and performance data provide builders a starting point for their next effort. Chassis designers rely on CAD (computer-aided design) tools and software to design the "monocoque", or tub. CAD insures accuracy and allows quick part modification. Currently over 50% of the parts on an indy car are designed on a CAD system. A large scale drawing board is still used however, allowing designers the full view of the chassis.
 * Designing a new Chassis**

The design team will go through several steps: 1. 40%-scale plans: The major components of car are then placed into this scheme, the engine, the gearbox, the side pods and the fuel tank in an overall package. The idea is to get the weight distribution worked out for model fabrication. 2. 40%-scale model (suitable for wind tunnel testing):During this testing components such as the chassis shape, underwing, side pods and radiator, are reconfigured and reshaped to optimize the the aero shape of the car. 3. Detailed drawings:

Based on the wind tunnel testing these drawings will be the final working plans for the chassis.

Wind tunnel testing is used extensively when designing a new car. The model is placed in the test section of the wind tunnel where airflow measurements are recorded. The rolling road wind tunnel uses a quarter scale model and a moving belt beneath the model to simulate the relative motion between the vehicle and the road. Wind tunnel simulation is of particular interest for racing teams where:
 * Ground clearance is minimal.
 * Down force/drag statistics can be measured.
 * The small differences in aerodynamic characteristics can mean winning or losing.

The Rahal/Hogan racing team uses the Aeronautical and Astronautical Research Laboratory in Columbus Ohio. This 7 X 10-ft. subsonic wind tunnel simulates high-speed ground aerodynamics on a 40%-size Indy car model. The model rides on a moving ground plane or rolling road while a model support system controls the vehicle ride height. In this type of wind tunnel simulation, the ground surface should move at a velocity equal and opposite to that of the vehicle. Measurements are recorded on aerodynamic forces for the entire vehicle, with particular attention on wheel rotation and underbody flow characteristics. This type of testing allows the designers to physically test out ground effects, including wing configurations and underbody surface pressures. Wind tunnel testing allows constructors to test new designs in response to modifications in regulations.

At the conclusion of the 1992 Indy car racing season, the CART technical committee modified existing regulations to afford the drivers more protection (particularly in response to forward impacts). The 1993 car must be 5 inches longer to better protect the drivers legs and knees. More material (carbon fiber) was to be used in the chassis construction, and the internal size of the chassis was larger than the 1992 car. In addition, regulations were modified to reduce cornering speeds on the speedway circuits. The aerodynamics of the car were decreased by restricting the size of the underwing (venturi) to 8 inches in height and by reducing the size of the speedway rear wing to its present dimensions (32 inches in height x 43 inches wide). A new, smaller Chevrolet engine was also available. These regulation changes, coupled with the development of a new, smaller engine, meant that chassis design would be new for 1993. This gave engineers the opportunity to redesign the underwing of the car to comply with the new regulations. Team designers utilized wind tunnel testing to determine the best aerodynamic setup for the new design. Nigel Bennett, Penske team designer said, "We test in the wind tunnel over 100 days per year, and have a full time aerodynamic team. No change of shape on an external part of the car is made without it being tested in the wind tunnel." According to Bennett, "The results from the rolling road wind tunnel tests, (undertaken at South Hampton University in England) are extremely accurate in predicting down force and drag figures the actual car produces on the track."

**//What principle is applied to racing vehicles to help keep them on the ground?//** **//Why is it important that racing vehicles are aerodynamic?//**


 * //What is down force? How does it influence the racing vehicle?//**


 * //What is drag? What factors in vehicle design affect drag?//**


 * //How does vehicle design change when the car is racing on a street/road circuit or speedway?//**


 * //What are the three main areas design engineers are working on to reduce drag?//**


 * //What are the main steps involved in the design of a new car?//**