First, all those that answered NO, are correct.
The force that elevates and keeps the airplane in the air is called "Lift"
The Lift (L) depends on the density of the air (the Greek letter Ro), the square of the Velocity (V²), the wing area, (S) and the wing characters like the shape of the profile and the angle of attack that are summed in the term "Lift Coefficient" or CL.
The Lift is measured in Pounds and when the Lift is greater that the airplane weight, the airplane will Liftoff or climb.
If we put all those into equation it will look:
L = CL ½Ro V² S
The air density is not the same all over the world and will be different with High pressure system, Low pressure system, the airport elevation above sea level or the flight altitude and it's a function of the air pressure and temperature (the colder, the denser).
The Velocity, is simply the speed of the airplane (the wing) relatively to the air around the airplane and is measured in Knots (Nautical mile/hour. 1 Knot = 1.15 mile/hour).
As you can see, the Velocity has great effect on the lift V² (and on head on accidents).
The wing profile: the greater the upper camber the greater acceleration of the air above the wing. when air (or fluid) is accelerated, the pressure drops (and the temperature increases).
When the pressure drops above the wing, the pressure difference between the lower and upper sides of the wing increases and an upward force is created - Lift.
That is the reason that on slow speed flying airplane the wing is very "thick", to create the maximum possible lift at slow speeds.
But this thick wing creates also a lot of Drag that is slowing down the airplane and costs more fuel ( we need more engine power to overcome this drag).
That's the reason that on the high speed airplanes the wing is more "thin" or less cambered.
Another problem is: when the airplane is flying near the "Speed of sound" speed (Mach).
The airplane may be flying at 80% of the speed of sound (or 0.8 Mach), but the air over the wing is accelerated to a speed greater than the speed of sound that creates a "Shock wave" (something like a wall) over the wing and drastical loss of lift (and all the airplane is shaking like vibrator).
You can see the fighters wings, very thin and very low camber.
The layer that the air velocity is increased from zero (on the surface) to the free stream velocity is called the Boundary layer, depends on the airspeed, this layer is normally turbulent and does not create any lift.
BTW, that's the reason that I increased the Shop Vac hose diameter, to have more "free stream" area.
So, next time if somebody will ask you "what keeps the airplane in the air", you answer: "The Captains salary", believe me, I know.
niki
The force that elevates and keeps the airplane in the air is called "Lift"
The Lift (L) depends on the density of the air (the Greek letter Ro), the square of the Velocity (V²), the wing area, (S) and the wing characters like the shape of the profile and the angle of attack that are summed in the term "Lift Coefficient" or CL.
The Lift is measured in Pounds and when the Lift is greater that the airplane weight, the airplane will Liftoff or climb.
If we put all those into equation it will look:
L = CL ½Ro V² S
The air density is not the same all over the world and will be different with High pressure system, Low pressure system, the airport elevation above sea level or the flight altitude and it's a function of the air pressure and temperature (the colder, the denser).
The Velocity, is simply the speed of the airplane (the wing) relatively to the air around the airplane and is measured in Knots (Nautical mile/hour. 1 Knot = 1.15 mile/hour).
As you can see, the Velocity has great effect on the lift V² (and on head on accidents).
The wing profile: the greater the upper camber the greater acceleration of the air above the wing. when air (or fluid) is accelerated, the pressure drops (and the temperature increases).
When the pressure drops above the wing, the pressure difference between the lower and upper sides of the wing increases and an upward force is created - Lift.
That is the reason that on slow speed flying airplane the wing is very "thick", to create the maximum possible lift at slow speeds.
But this thick wing creates also a lot of Drag that is slowing down the airplane and costs more fuel ( we need more engine power to overcome this drag).
That's the reason that on the high speed airplanes the wing is more "thin" or less cambered.
Another problem is: when the airplane is flying near the "Speed of sound" speed (Mach).
The airplane may be flying at 80% of the speed of sound (or 0.8 Mach), but the air over the wing is accelerated to a speed greater than the speed of sound that creates a "Shock wave" (something like a wall) over the wing and drastical loss of lift (and all the airplane is shaking like vibrator).
You can see the fighters wings, very thin and very low camber.
The layer that the air velocity is increased from zero (on the surface) to the free stream velocity is called the Boundary layer, depends on the airspeed, this layer is normally turbulent and does not create any lift.
BTW, that's the reason that I increased the Shop Vac hose diameter, to have more "free stream" area.
So, next time if somebody will ask you "what keeps the airplane in the air", you answer: "The Captains salary", believe me, I know.
niki
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