• PURPOSE 
• HYPOTHESIS 
• EXPERIMENT DESIGN 
• MATERIALS 
• PROCEDURES 
• RESULTS 
• CONCLUSION 

 

• RESEARCH REPORT 
• BIBLIOGRAPHY 
• ACKNOWLEDGEMENTS 

• ABOUT THE AUTHOR 

Introduction
Humans need transportation in their daily lives. Transportation needs to be efficient and affordable. To make planes less costly we need to design a plane that can go the farthest distance possible and use the least amount of gas. We need to make airplanes aerodynamic, enabling the planes to move through the air with little air friction so the plane isn’t using as much gas to push it towards its destination.

Friction
Friction is when two surfaces rub against each other and create heat and slow the objects down. Friction wears on materials, making it difficult to accelerate. Friction also enables us able to walk, drive, or skate. Friction lets us move, but at the same time it slows us down as we do so. You can never stop friction completely, but can reduce unwanted friction in machines like car engines and factory machines by apply lubricants such as oil or grease. To make objects travel through air more easily one must make the object aerodynamic. 

There are three kinds of friction. The first one is rolling friction. This is produced when a rolling object goes over something and the friction slows the object, like a wheel on a car. The next one is sliding friction; it is when two things slide across each other, this friction can make the objects hot. The last one is air friction. This is when an object is slowed by air rubbing against the outer layer of the object, like an airplane, or the space shuttle through the atmosphere

Four Forces
There are four forces acting on any object being propelled through the air. They are lift, drag, gravity and thrust. 

Thrust 
Thrust is the force that propels an object through the air. The propellers on a plane provide the thrust for the craft, your arm is the thrust on a thrown baseball. 

Gravity
Gravity is the constant force that is affecting any object on earth. Gravity is constantly pulling an airplane toward the ground at 9.8 meters per second. Gravity holds everything to the ground, without gravity we would float away. To over come gravity an airplane needs lift.

Lift
 Lift comes from the wing shape of the plane called an airfoil. The airfoil has a rounded leading edge and a flat pointed trailing edge. The rounded upper surface makes the air flowing over the top of the wing travel faster than the air under the wing. The air under the wing moves slowly while the air on top is fast, making it unbalanced. The higher pressures under the wings push upward. Also the wing is pointed slightly up so is deflects air down. Putting the wing at a steeper angle will make the plane climb in altitude, pointing the wing down will cause the plane to drop. The speed that the wing is traveling through the air makes a difference, the greater the speed the more lift will occur. 

Drag
The last force is drag; drag is the force that pulls a plane backward when it is trying to move forward. The object’s shape affects the amount of drag that is produced. Objects that don’t create a lot of drag are called streamlined shapes or aerodynamically clean. There are three types of drag, they are friction drag, form drag and induced drag. Friction drag and form drag will affect any object, moving or not, but induced drag will only affect things that have lift, things that are flying. 

Friction drag is due to shear stress; friction has a strong effect on the boundary layer, which is a thin layer of fluid next to the surface of the object. The amount of friction drag depends on if the flowing layer of fluid is turbulent or laminar. If the fluid is laminar it’s flowing in orderly paths along the direction of the of the surface. If it’s turbulent the fluid’s paths and direction is flowing randomly. This only happens at high speeds. There is much more friction drag when the flow is turbulent than laminar. 

Form drag is drag due to pressure. The amount of form drag on an object depends on the shape of the object. If the object isn’t streamlined the drag force is mostly friction drag. When form drag occurs the thin layer of fluid separates from the object, the pressure on the rear surface decreases, which makes the pressure on the front larger. The result is a force pushes on the front of the object that is from form drag. Designers reduce this by streamlining the object.

HISTORY OF AERODYNAMICS
Leonardo Da’vinci was the first man to study flight scientifically. Da’vinci studied birds, he drew them and studied them and believed one-day people would fly with some sort of mechanical bird wings. In the late 1600’s sir Isaac Newton set a theory of air resistance, he said "It doesn’t matter whether an object is moving through a fluid, like air, or the fluid moves around it."  This theory helped other early day scientists like Samuel P Langley write the first paper on aerodynamics. In the mid 1800 was when people started to use aerodynamic principles to fly heavier-than-air aircraft. Oliver and Wilbur Wright designed, and flew the first successful propeller propelled aircraft in 1903. Earlier flights were with aircraft that were either lighter than air, balloons, or gliders. 

In 1891 George Cayley built a glider that carried a man across a small valley. As years passed people came out with better and better planes. No one really thought planes had much use; they were just used for mainly mail delivery. Then planes started being used for transportation. Although the planes couldn’t go that fast it was the fastest form of transportation at the time. Planes became vital in WW II. They weren’t originally meant for fighting but for patrolling, till soldiers realized they could throw grenades and bombs, and shoot guns from planes and they became air-fighting machines. Fighting planes were widely manufactured, and were used in every war since. 

Conclusion
Airplanes in the year 2003 are much more advanced from than planes from 50 years ago. Most of the planes are jet propelled, which is much faster than propeller planes. Our planes can reach super sonic speeds, break the sound barrier, and the fighter jets have many advanced missiles and guns and are one of the most effective and useful battle machine. The planes now are mostly used for transportation that can carry one hundred or more people at a time. They are a very safe form of transportation also. Your chances of getting in a car crash, than in a plane crash, is greater Air travel is the fastest way to travel, and for some is pretty fun. 
 
 

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