■■■에어포일(Airfoil) 구조로 인해 발생되는 양력 vs. 수직 추력

[석수]

양력 : 날개에서 에어포일로 인해 발생되는 힘


추력 : 프로펠라가 돌면서 만들어지는 위로 뜨는 힘

에어포일 airfoil = 비행기 날개를 수직으로 자른 단면의 모양

■ 에어포일의 다양한 형태

Aerofoil

Airfoil also spelled as aerofoil, is a shaped surface, such as an airplane wing, tail, or propeller blade that produces lift and drag when moved through the air.


Airfoils

Airfoil is a cross-section of a wing or blade; thus, it is a two-dimensional shape. A typical airfoil and its main terminology are shown in Fig. 3.1. When an airfoil is located in a fluid flow, as shown in the figure, its first point that hits the wind is called the leading edge (assuming that wind blows from left to right). Similarly, the last point of the airfoil on which the wind leaves the airfoil is called the trailing edge. The straight line that connects these two points is called the chord. The dashed line shown on the figure is called the camber line which is a line such that the thickness of the airfoil is equal on its both sides. Note that the thickness is measured perpendicular to the camber line.




In a symmetric airfoil, the camber line and chord are identical. Such a case is shown in Fig. 3.1b. Thus we can conclude that if an airfoil is not symmetric, its chord and camber line are not the same. Other than that, other things are the same in both cases.

The chord of an airfoil is important because, as we will see in the future, it is used to nondimensionalize the airfoil's lengths. By nondimensionalizing, all similar airfoils show similar behavior. This fact is used in determining the aerodynamic properties of airfoils and airfoil families.





추력(推力, thrust)

추력(推力, thrust)은 뉴턴의 제2운동법칙과 3운동법칙으로 설명되는 반작용의 힘이다. 

계(界;system)에서 물체(질량;mass)를 움직이거나 가속할 때 그 반대 방향으로 같은 힘이 작용하는데, 물체에 반대로 작용하는 힘을 추력이라 한다.

프로펠러 항공기가 날아다닐 수 있는 것은 프로펠러가 비행 경로 반대 방향으로 물질(공기)를 밀어내는데 이때 공기는 비행 방향으로 추력을 발생시키고 이 힘으로 비행체가 날아가는 것이다.


foil 

noun (METAL SHEET)


[ U ]

a very thin sheet of metal, especially used to wrap food in to keep it fresh:

tin foil

UK aluminium foil


foil 

verb [T] (PREVENT)

to prevent someone or something from being successful:

An attempted coup against the country’s military ruler was foiled yesterday.



foil 

noun (BLADE)

[ C ]

a thin, light weapon with a long blade used in the sport of fencing



foil

verb [ T ]

to prevent someone or something from being successful:

The prisoners' attempt to escape was foiled at the last minute when police received a tip-off.



foil 

noun (COMPARISON)

[ C ]

something or someone that makes another's good or bad qualities more noticeable:

foil for The older, cynical character in the play is the perfect foil for the innocent William.




FOIL

noun [ U ]
 
mathematics

abbreviation for first, outer, inner, last

the rule for multiplying two binomials (= statements that have two numbers or symbols each)