Have you ever wonder how mankind is able to fly through the air? How a massive Boeing 747 is able to lift off the ground and float over 30,000 feet in the air? Perhaps, you may have wondered why wings come in many different wing shapes and sizes. This research project will explain the fundamental forces involved in flight to examine the differences in various wing designs for airplanes.
Flight is the process that allows an aircraft to be able to fly through the air. The idea of flight first came about in China over 2000 years ago. The Chinese flew kites and began to dream about humans being able to sail through the air. Afterwards, humans for centuries began to attempt to fly by mimicking the way birds flew. However, this feeble attempt obviously failed because humans lacked the strength birds have. Leonardo do Vinci was the first one to make real studies of flight. He drew hundreds of designs to illustrate his theory of flight, such as his Ornithopter. It was not until the the first successful flight in 1903 at Kitty Hawk by Orville and Wilbur Wright when the dream of mankind became reality. Even though the fight successful flight lasted a mere 12 seconds, mankind was now able to fly.
In reference to our AP Physics B class, the study of aerodynamics falls well under the Fluid Mechanics topic. The air is a very light fluid, which makes it harder for flight. The force of buoyancy of air would be very minuscule as compared to the force of buoyancy of water, due to the density difference of the two substances. Also, Bernoulli's Principles are introduced in this topic and provides a simple explanation for lift. Since the air on top of a curved wing takes longer to travel than the air on the bottom of the wing, it must travel faster. In essence, there is less pressure ,which leads to the uplift of the wings. This principle can be manipulated to control aerodynamic actions. Of course, there are other forces, like drag and thrust, that must be accounted for.
The topic of aerodynamics of airplanes may be of interest to the general public because airplanes have become a casual mode of transportation today. Prior to the Wright brothers, the ordinary passenger airplanes would have been only a dream to the public. In fact, most would have scoffed at the fact that people would be able to travel through the air. In effect, people might be interested to know the physics behind the revolutionary phenomena of aerodynamics. Furthermore, some individuals may be intrigued to learn the basics of flight in order to contribute to future developments of aircrafts and extend the research into outer space.
Current level of application includes passenger aircraft (domestic and international), high speed jets that exceed the speed of sound, and other aircrafts such as gliders and other small airplanes. The faster a plane moves, the higher the Mach number is, which is found by dividing the speed of the plane in the fluid by the speed of sound in the same fluid. The problem with this is that the faster the plane travels a new form of drag is introduced called wave drag. This form of drag is created because of the energy lost due to the compression of air as the plane travels closer to the speed of sound. With planes that reach and go beyond the speed of sound, a shock wave is formed and on the ground a sonic boom is heard. The more wave drag something reduces lift of an airplane and is a limiting factor for aircrafts on Earth. Also, the energy a plane consumes and needs to carry is another limiting factor.
The future of this topic involves creating faster, more fuel efficient, and more agile airplanes. In addition to these fundamental needs, there has been extended research in space planes and suborbital flight. The future of aviation is headed towards place mankind not into air, but into space and towards extending our boundaries.

Basic Aerodynamic Forces



Thrust is an aerodynamic force that must be created by an airplane in order to overcome the drag and the weight of an airplane. It's the force that makes an aircraft move through the air. Airplanes create thrust by the spinning blades of a propeller, a rotating turbine pushing air from the back of a jet engine, or by ejecting hot gases from a rocket engine. Thrust is generated by accelerating a mass of gas. The engine does work on the gas and accelerates the gas to the rear of the engine. The magnitude of the thrust depends on the amount of gas that is accelerated and on the difference of the gas through the engine. Thrust is not always necessary as shown by gliders. However they work differently in that they have a very high lift-to-drag ratio. The lift that is created is usually many times the the drag that is created. So since their lift-to-drag ratio is around 60, most commercial airplanes have a L/D of about 17, they are able to fly through the air without a propulsion system.
external image Drag_Curve_2.jpg
external image moz-screenshot.jpg


Drag is an aerodynamic force that opposes an aircraft's motion through the air. It is caused by the interaction and contact of a solid body with a fluid. In this interaction, the velocities of the aircraft and the surrounding area are different; thus causing drag.
external image 7613c56c8438ae8fa328dcbd4f4f4e7c.png
C is the drag coefficient
u is the velocity of the mass relative the to the fluid
p is the density of the fluid
A is the area perpendicular to the direction of motion
F is the force of drag

Skin Friction is the interaction between the molecules of the air and the solid surface of the aircraft. The magnitude of the skin friction depends on properties of both solid and gas.
Form Drag is a source of drag depends on the object's shape. As air flows around a body, changes in velocity and pressure occur, thus creating a force.
Induced Drag is caused by the generation of lift. This drag occurs because the air flow near the wing tips is distorted as a result of the pressure difference between the top to the bottom of the wing.

Drag is similar to friction in that it is the force that inhibits the movement of objects. However is it is different in that it is dependent on the speed of the object moving through the fluid. Furthermore, the drag coefficient of objects is dependent on skin friction and form drag. It varies as a function of speed, flow direction, object shape, fluid density and fluid viscosity.

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Weight is the magnitude of the gravitational force that acts upon an object. Gravity is always directed towards the center of the Earth and is approximately uniform throughout. In effect, the acceleration of gravity is constant in calculations and weight is directly proportional to the mass of an object. Therefore, the formula given for the force of gravity, or weight, is F=ma=mg;(m=mass of object, g= acceleration due to gravity). In a plane, there are many components that account for mass and ergo the weight. However, such masses can be seen as collected in a point called the center of gravity, which can be found by the formula: (summation of mass×distance/summation of mass). The center of gravity is important in the balance of an aircraft and can affect how it is maneuvered. A major factor that affects flight is the change of mass due to consumption of fuel. As fuel is used up, the mass decreases and as a result, the center of gravity changes. The pilot must take this fact into account in order to maintain the balance of the aircraft.

The force of lift is an essential force in aerodynamics to overcome the force of weight. Lift is always perpendicular to the relative wind and the direction of flight. The magnitude of lift is determined by several factors, such as velocity, shape, and size of the aircraft. Similar to weight and center of gravity, the force of lift can be determined at one point called the center of pressure. Furthermore, following Bernoulli's Principle, the compression of air at two ends will cause such a force.
The equation limg238.gif
gives the lift force, in which CL is the lift coefficient, a the angle of attack in radians, and A the area of the wing.
The force of lift on each wing can be calculated to overcome the weight.
On the AP fluid section, Force= Pressure×Area and P+þgy+½þv²=const. If þgy cancels out, F=PA=A(½þv²)
Once you add the angular components and take into account the lift constant, the equation for force of lift is derived.

The amount of lift depends on these things:
  1. the wing's airfoil shape
  2. size (area) and shape of the wing
  3. angle of attack
  4. density of the air
  5. speed of flight

When these four forces work harmoniously, flight can be controlled as demonstrated by this video:

Importance of Wing shape
The shape of a wing greatly influences the performance of an airplane. The speed of an airplane, its maneuverability, its handling qualities, all are very dependent on the shape of the wings. There are, for our purposes here, 3 basic wing types that are used on modern airplanes: straight, sweep and delta.
The straight wing is found mostly on small, low-speed airplanes. General Aviation airplanes often have straight wings. Sailplanes also use a straight wing design. These wings give the most efficient lift at low speeds, but are not very good for high speed flight approaching the speed of sound.
a picture that shows the different styles of straight wing configurations
a picture that shows the different styles of straight wing configurations
The swept wing (forward swept or sweptback) is the wing design of choice for most modern high speed airplanes. The swept wing design creates less drag, but is somewhat more unstable for flight at low speeds. A high sweep wing delays the formation of shock waves on the airplane as it nears the speed of sound. How much sweep a wing design is given depends upon the purpose for which the airplane is designed to be used. A commercial jetliner has a moderate sweep. This results in less drag, while maintaining stability at lower speeds. High speed airplanes (like modern jet fighters) have a greater sweep. These airplanes do not generate much lift very during low speed flight. Airplanes with sweep need to take off and land at high speeds.
a picture that shows the different styles of swept wing configurations
a picture that shows the different styles of swept wing configurations
From above, a delta wing looks like a large triangle. It has a high sweep with a straight, trailing edge. Because of this high sweep, airplanes with this wing are designed to reach supersonic speeds. The landing speed of these delta-winged aircraft is also fairly fast. This wing shape is found on the supersonic transport Concorde and the Space Shuttles.
a picture that shows the different styles of delta wing configurations
a picture that shows the different styles of delta wing configurations


Sonia Bansal - What exactly did the Wright Brothers do to create a plane that flew?
They created wings on a plane and ran very very fast.
Angad Sidhu - What are the physics behind the landing mechanisms?
That is a whole new topic in itself, but generally the brakes on the landing gear and the flaps on the wings help the plane slow down.
Robert Lopez - Does altitude affect drag in any way?
Yes, induced drag is stronger at higher altitudes.
Nauma Haider - What is the purpose of the elevators located on the wings?
Elevators are actually located on the tail and control the pitch of the aircraft. Ailerons are on the wings and they control the banking and turning of an airplane.
Brandon Siegenfeld- Why would high sweep wings delay the formation of shock waves?
This is because less drag is induced.
Kevin Norris - Why didn't the Ornithopter work?
Well because simply humans aren't strong enough and are too heavy to flap wings and be able to fly. In addition ornithopters aren't practical for flight
naveen shetty - lol what are the dangers of landing during a thunderstorm, and why
Because of the transfer of electricity
Ari Horowitz - If a majority of the passengers on a plane were located towards the back, would that effect flight?
With larger aircrafts not really, but on smaller aircrafts it would cause difficulty because the plane would not be balanced
Sam Edwards - How do these principles apply to helicopters?
The same principles apply such as pressure differences and such. But the force of lift is the dominating force so the helicopter must be directed to compensate for that
Sohini Sheth- When you notice an airplane taking off or landing, there are flaps on the wings. What's the effect of either keeping the flat down or keeping it up during flight?
Flaps are used to control the plane. It can be used to increase drag by extending the flaps out for landing. It is used to help slow down the plane by creating more drag. During take off it increases the area on the top of the wing as compared to the area on the bottom of the wing thus creating less pressure on top and assists in the creation of lift
Greg Sturm - This doesn't have much to do with physics, but I found your history of flight interesting. I don't think China should get credit for simply dreaming about flying like a kite or a bird. I mean I could dream about teleporting across the world in a second but you can't attribute that to me if it is ever invented. And what exactly do you mean by "mimicking the way birds flew?" Just flapping their arms up and down?
Yes exactly that, well the Chinese were the first to use kites. They used kites not only during festivals and such, but also used it during battles by attaching warriors to it, equiped with bows and arrows to attack their enemies or spy on them
Douglas Chin - How is the Boeing X-48B blended wing prototype better than standard plane models used today?
One way they are better is that this prototype is 30% more fuel efficient than an airplane of similar size that carries the same payload.