Day FOUR

Webpages visited:

http://home.comcast.net/~clipper-108/lift.htm

I visited this site to better understand the cause of lift..

The argument of Bernoulli’s principle which says that if air speeds up the pressure decreases is the main argument for an airplane’s lift. The high pressure below the plane is trying to move towards the low pressure which causes lift. However, this argument only holds true if the principle of “equal transit times” is true. Many experiments have shown though that air on the top of a curved wing usually travels faster than the air underneath the wing, which muddles the theory that air must travel faster over the top of the wing to reach the same point at the same moment the air underneath the wing reaches there (equal transit times)

http://danielmiessler.com/blog/why-planes-fly-what-they-taught-you-in-school-was-wrong

I have more belief in the second theory that uses newton’s laws to describe lift. I could better visual this method because its like putting your hand outside the car. If you hold it parallel to the wind, you are able to control your hand with relative ease. However if you increase the angle of attack ( described in previous post), more wind is diverged downward and your hand moves upward because the massive amount of lift force. Using Newton’s third law of reactive forces, this theory makes more sense to me than Bernoulli’s principle. However the difference in air pressure theory still intrigues me and it might be that both these theories cause lift.

http://www.decodedscience.com/airplane-wings-how-lift-is-created/6595

Lift created by different parts of the wing:

The force of lift completely depends on the interaction of air molecules with airplane wings. Consider a single plate of the wing exposed horizontally an even airflow in the air

  1. The plate is exposed to the airflow.
  2. Air molecules slide past the plate.
  3. A very few molecules interact with the plate, and that interaction too is at a slanted angle providing low static pressure.

Airplane wings are never built in-line with the fuselage of the aircraft. These wings are always installed at a slight angle. This angle of the wing is termed as the angle of inclination When this inclination is applied to the plate:

  • Air molecules strike against a greater portion of the plate.
  • Much of the plate is exposed to perpendicular strikes of the air molecules.
  • The air mass exerts a reactive force that creates the lift of the aircraft

Explanation of wing:

the wing should be considered as a object that scoops the air, diverting the air from the horizontal to the angle of attack. Also the lift of a wing is proportional to the amount of air diverted downward, which is also proportional to the wings area.

Mechanics of an airplane that help during take off and landing:

Just to restate the airplane’s wings create the lift necessary to flow. The slats and flaps help to create lift by enlarging the surface area of the wing, which allows more air to be diverged downward. This increase in lift is important for both take off and landing. Spoilers are also an important component to the wings of an airplane. These are small plates that are on the back of each wing and are used to disrupt the flow of air, decreasing lift ( used during landing).

Summary of learning:

From today’s research I feel i am almost at 100% for understanding the basic principles of lift and the components of an airplane that allow it to take off, stay in the air, and land. However, i am still confused what theory actually causes lift. I feel that there is an on going debate to this topic so i should just pick one and roll with it

Misconceptions/surprises:

Not many surprises today

I am just confused on the actual cause of lift and i will try to figure out which theory i stand by soon

Videos/photos:

here is a video that describes in depth the forces on an airplane in flight

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2 thoughts on “Day FOUR

  1. Hi Pranal, great blog but I have a quick question here do you think the fact that less air molecules on top of the wing contributes to the lift as well. I have heard that the lack of molecules above the wing can create a sort of vacuum effect. What do you think?

  2. Great blog. My research matches up with yours well. The discrepancies between the two principles seem to fascinate the both of us. Since I didn’t focus on take off or landing, I was able to learn about that from your blog. You explained everything very well.

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