Independent Study Project

Independent Study Project: Motorcycles

By: Rafea Parkar Submitted To: Mr. Ramwa Date: 22/May/2007

Acknowledgments I would like to thank my colleagues for the helpful ideas that they provided me with (special thanks to Numaira who gave me links to many different topics). I would like to thank my Mom and Dad who gave me motivation when I had given up on this project. I would like to thank myself for the many hours of work that I put into the research of this very broad and in depth topic. But most of all I would like to thank my older sister, Abeer Parkar, who helped me the most in finishing this topic. She helped me with proofreading all my work, finding me knowledgeable books from central library, and sharing all the knowledge she has from her previous grade 11 physics class. Introduction My independent Study Project will focus on motorcycles. This essay includes a history of motorcycles, which will explain how the idea of the motorcycle came to be. The essay includes a quick description of the current operation of motorcycles. There is also a description of the motorcycles major parts and there overall purpose in making a motorcycle function. This essay also includes a very through and deep amount of scientific principles involved in motorcycles. Further more there is a section on how motorcycles have impacted the society and also a bibliography listing every single site where I got all my information from. Historical Development of the Machine Motorcycle history begins in the second half of the 1800s. Motorcycles are descended from the "safety bicycle," a bicycle with front and rear wheels of the same size and a pedal crank mechanism to drive the rear wheel. Despite some early landmarks in its development, motorcycles lack a rigid pedigree that can be traced back to a single idea or machine. Instead, the idea seems to have occurred to numerous engineers and inventors around Europe more-or-less simultaneously. The inspiration for the earliest dirt bike, and arguably the first motorcycle, was designed and built by the German inventors Gottlieb Daimler and Wilhelm Maybach in Bad Cannstatt (since 1905 a city district of Stuttgart) in 1885. The first petroleumpowered vehicle, it was essentially a motorized bicycle, although the inventors called their invention the Reitwagen ("riding car"). They had not set out to create a vehicle form but to build a simple carriage for the engine. However, if one counts two wheels with steam propulsion as being a motorcycle, then the first one may have been American. One such machine was demonstrated at fairs and circuses in the eastern United States in 1867, built by Sylvester Howard Roper of Roxbury, Massachusetts. There exists an example of a Roper machine dating from 1869, but there is no patent existing and nothing proves it was a working model. It was powered by a charcoal-fired two-cylinder engine, whose connecting rods directly drive a crank on the rear wheel. The Roper machine predates the invention of the safety bicycle by many years, so its chassis is based on the "boneshaker" bike. In 1868, the French engineer Louis-Guillaume Perreaux patented a similar steam-powered vehicle, which was probably invented independent of Roper's. In this case, although a patent exists that is dated 1868, nothing indicates the invention had been operable before 1871. Nevertheless, these steam-powered vehicles were invented prior to the first petroleum-powered motorcycle.

Description of the Current Status, Operation, & Consequence The Motorcycle’s current status is that it is still in function and use within the modern world. It operates as a Transportational vehicle all over the world. The consequence of motorcyles being used as transportational vehicle is thouroughly explained in “The Usefulness/Impact on Society” section of this essay. List of Materials and Justification for their Use A Motorcycle basically consists of a Frame, Handle bar, Two Wheels/Ties, Engine, Pedal, Suspension System, Saddle, Brake and Shifter. 1) Frame – Is the main body, that all the components are basically attached to 2) Tire – Attached to the frame, the function of the two tires is to spin and move the motorcycle either move forward or backwards (reverse) 3) Engine – is the source of power/work that provides the the enegry to spin the wheels. 4) Handle Bar – this allows the rider to control the direction of the motorcycle 5) Brake – The brakes are located on the Handle bar, this allows the to slow down the motorcycle 6) Pedal – the pedal is located near the area where your feet rest, pressing down on the pedal makes the engine to exert more power 7) Shifter – also located on the handlebar, it changes the gear of the motorcycle, making it having a faster constant speed or lower. 8) Suspension system – this allows the frame to stay stabble by absorbing all the wobbling and shaking that is formed by the friction of the tires on the ground. 9) Sadle – this is where you sit. The Scientific Principles Invovled I have included 3 physics principles related to the motorcycles: Torque, Doppler Effect, and Heat engines. And I have also included a very indept and intresting principles from the sceince of of the motion of motorcycles known as Motorcycle Dynamics. Motorcycle Dynamics is a very new science type and thus I have included a very large portion of information about it in my essay. Torque: Torque: General Information E = (τ)(θ) E is the energy, τ is torque & θ is the angle moved, in radians. Torque has dimensions of force times distance and the SI units of torque are stated as "newton metres”. Even though the order of "newton" and "metres" are mathematically interchangeable, the BIPM (Bureau International des Poids et Mesures) specifies that the order should be N·m not m·N. The joule, which is the SI unit for energy or work, is also defined as 1 N·m, but this unit is not used for torque. Since energy can be thought of as the result of "force dot distance", energy is always a scalar whereas torque is "force cross distance" and so is a (pseudo) vector-valued quantity. Of course, the dimensional

equivalence of these units is not simply a coincidence; a torque of 1 N·m applied through a full revolution will require an energy of exactly 2π joules. Torque: Application to Motorcycles Torque is part of the basic specification of an engine: the power output of an engine is expressed as its torque multiplied by its rotational speed. Internal-combustion engines produce useful torque only over a limited range of rotational speeds (typically from around 1,000–6,000 rpm for a motorcycle). The varying torque output over that range can be measured with a dynamometer, and shown as a torque curve. The peak of that torque curve usually occurs somewhat below the overall power peak. The torque peak cannot, by definition, appear at higher rpm than the power peak.Understanding the relationship between torque, power and engine speed is vital in automotive engineering, concerned as it is with transmitting power from the engine through the drive train to the wheels. Typically power is a function of torque and engine speed. The gearing of the drive train must be chosen appropriately to make the most of the motor's torque characteristics. Torque is also the easiest way to explain mechanical advantage in just about every simple machine including motorcycles. Doppler Effect: Doppler Effect: General Information f' = ( v / v ± vs ) ( f ) f’ is the observed frequency, f is the emmitted frequency, v is the speed of waves in the medium (in air at T degrees Celsius) & vs is the velocity of the source (the thing emitting the sound). The Doppler affect is a change in transmitted frequency which is perceived to have occurred by a receiver as a result of the existence of relative motion between the transmitter and the receiver. The magnitude of the Doppler shift is directly proportional to the rate of relative velocity between the transmitter and receiver. The Doppler affect is evident to man as the change in the pitch of sound of a fast moving vehicle as it passes us affect. If we consider the use of relative units of measure for both distance and time, rather than pre-defined absolute units (which have no natural relationship to the observation of current interest), then the Doppler affect may still be physically perceivable, but the mathematical value assigned to the frequency and wave length will remain identical for all receivers and independent of the amount of motion. And if the mathematical value of the frequency and wave length are constant, then so too must be the mathematical value of the relative velocity. Doppler Effect: Application to Motorcycles The horn on a passing motorcycles will start out higher than its stationary pitch, slide down as it passes, and continue lower than its stationary pitch as it recedes from the observer. Astronomer John Dobson explained the effect thus:"The reason the siren slides is because it doesn't hit you." In other words, if the horn approached the observer directly, the pitch would remain constant (as vs, r is only the radial component) until the vehicle hit him, and then immediately jump to a new lower pitch. Because the vehicle passes by the

observer, the radial velocity does not remain constant, but instead varies as a function of the angle between his line of sight and the horn's velocity. Heat Engine: Heat Engine: General Information

TH

QH

QC

TC

W TH is the heat energy, TC is the cold sink, QH heat at relativly high tempreture, QC removed heat at a relativly low tempreture & W is work formed from some of the energy from the heat input. A heat engine is a physical or theoretical device that converts thermal energy to mechanical output. The mechanical output is called work, and the thermal energy input is called heat. Heat engines typically run on a specific thermodynamic cycle. Heat engines are often named after the thermodynamic cycle they are modeled by. They often pick up alternate names, such as gasoline/petrol, turbine, or steam engines. Heat engines can generate heat inside the engine itself or it can absorb heat from an external source. Heat engines can be open to the atmospheric air or sealed and closed off to the outside (Open or closed cycle). In engineering and thermodynamics, a heat engine performs the conversion of heat energy to mechanical work by exploiting the temperature gradient between a hot "source" and a cold "sink". Heat is transferred from the source, through the "working body" of the engine, to the sink, and in this process some of the heat is converted into work by exploiting the properties of a working substance (usually a gas or liquid). Heat Engine: Application to Motorcycles All motorcycles have engines inside them that make the wheels on the motorcycle spin and thus allowing the motorcycle to have motion. The engines of motorcycles are all made of heat engines. The heat engines of motorcycles in general use gasoline to ignite and form the heat enegry for the heat engine to function.

Motorcycle Dynamics:

Motorcycle Dynamics: General Information Motorcycle dynamics is the science of the motion of motorcycles. It is concerned with the motions of bikes, their parts, and the forces acting on them. Specific subjects include balancing, steering & braking. Motorcycle Dynamics: Balancing A bike remains upright when it is steered so that the ground reaction forces exactly balance all the other forces it experiences such as gravitational, inertial or centrifugal if in a turn, and aerodynamic if in a crosswind. Steering may be supplied by a rider or, under certain circumstances, by the bike itself. This self-stability is generated by a combination of several effects that depend on the geometry, mass distribution, and forward speed of the bike. Tires, suspension, steering damping, and frame flex can also influence it, especially in motorcycles. Motorcycle Dynamics: Balancing – Forward Speed The faster a bike is moving forward, the smaller the steering inputs need to be in order to move the wheels back under the center of mass in a timely fashion. Motorcycle Dynamics: Balancing – Center of Mass Location The farther forward (closer to front wheel) the center of mass of the combined bike and rider, the less the front wheel has to move laterally in order to maintain balance. Conversely, the further back (closer to the rear wheel) the center of mass is located, the more front wheel lateral movement or bike forward motion will be required to regain balance. This can be noticeable on long-wheelbase recumbents and choppers. A bike is also an example of an inverted pendulum. Thus, just as a broomstick is easier to balance than a pencil, tall bikes (with a high center of mass) can be easier to balance than short ones because their lean rate will be slower. Motorcycle Dynamics: Balancing – Trail A factor that influences how easy or hard a bike will be to ride is trail, the distance by which the front wheel ground contact point trails behind the point where a line through the steering axis intersects the ground. In traditional bike designs, with a steering axis tilted back from the vertical, trail causes the front wheel to steer into the direction of a lean, independent of forward speed. This can be seen by pushing a stationary bike to one side. The front wheel will usually also steer to that side. In a lean, gravity provides this force. Motorcycle Dynamics: Steering – Gyroscopic Effects The role of the gyroscopic effect in most bike designs is to help steer the front wheel into the direction of a lean. This phenomenon is called precession and the rate at which an object precesses is inversely proportional to its rate of spin. The slower a front wheel spins, the faster it will precess when the bike leans, and visa-versa. The rear wheel is prevented from precessing as the front wheel does by friction of the tires on the ground, and so continues to lean as though it were not spinning at all. Hence gyroscopic forces do not provide any resistance to tipping.

At low forward speeds, the precession of the front wheel is too quick, contributing to an uncontrolled bike’s tendency to oversteer, start to lean the other way and eventually oscillate and fall over. At high forward speeds, the precession is usually too slow, contributing to an uncontrolled bike’s tendency to understeer and eventually fall over without ever having reached the upright position. This instability is very slow, on the order of seconds, and is trivial to counteract for most riders. Thus a fast bike may feel stable even though it is actually not self-stable and would fall over if it were uncontrolled. These roles of gyroscopic effect and precession are often given as the prime reasons that bicycles and motorcycles are inherently stable. While they have an effect at significant speeds, the role of caster angle, and the rider's steering action, actually provide the bulk of a bike's inherent stability at lower, nominal speeds. This is easily proven. As a first example, a bicycle rider at even the slowest speed of 1 or 2 MPH can easily keep the bike stable. The contribution of gyroscopic and precession effects are absolutely negligible at such a speed (only the rider's steering and body movements influence stability at such speeds). A bike with a free steering mechanism can be given a push at a relatively slow speed, and due to caster effect, will move smoothly with stability. If there is no rider then there are no significant gyroscopic effects whatsoever. Motorcycle Dynamics: Braking Most of the braking power of standard upright bikes comes from the front wheel. If the brakes themselves are strong enough, the rear wheel is easy to skid, while the front wheel often has enough stopping power to flip the rider and bike over the front wheel. This is called a stoppie or an ‘endo’. However, long or low bikes, such as cruiser motorcycles can also skid the front tire, causing a loss of the ability to balance. Motorcycle Dynamics: Application to Motorcycles The overall science of the motion of motorcycles – Motorcycle Dynamics – helps motorcycle manufacturers to develop safer motorcycles. It also helps manufacturers to make much more efficient motorcycles, making it easier for the rider to balance, steer, and apply the brakes on his vehicle.