Bernoulli's principle?

Question

If Bernoulli's principle is what creates lift and makes flight possible, how is sustained inverted flight possible?

Answer 1

bernoulis theorem"-
if air moves fast parallel to surface of any object then the pressure above the surface is less than the pressure below the surface
working of aeroplane"-
aeroplane consists of a large prpeller at its front
so it flows back the air.the pressure at above the wings(P2)is less then the pressure below(p1)the wings.p2-p1 gives the resultant upward thrust
the ofthe wings are made as larger as to obtain an upward thrust.hence aeroplane flies

Answer 2

Airplane lift is the result of two things: (1) the shape of the wing, which has to do with the Bernoulli principle, and (2) the angle at which the wing meets the wind, known as the "angle of attack." The most efficient wings make use of both factors.
The Bernoulli principle for now you're going to have to take on faith. Angle of attack is easier. You see angle of attack in action whenever you stick your palm out the window while driving down the highway. Angle your palm upward and the wind forces your hand higher. Angle your palm down and the wind forces your hand lower.

Same with planes. When you're zipping down the runway during takeoff, the Bernoulli principle generates a certain amount of lift. But to get that last crucial boost you pull up the plane's nose. This increases the angle of attack on the wings, popping the welds on the engine and sending you into a flaming cartwheel of ... Whoops, wrong index card. Actually, increased angle of attack provides the lift needed to get you flying.

Generating lift is easier at cruising speed, so stunt pilots can flip the thing over and rely on high angle of attack alone to keep them in the air (i.e., they keep the nose up and the tail down). This isn't a very efficient way to fly, since increasing your angle of attack also increases your aerodynamic drag. Too much drag = stall = plane drops like rock. For that reason stunt planes need low-drag wings, heavy-duty construction (so they won't disintegrate in midair)

Answer 3

Same basic principal. Many wings are actually symmetrical. A slight positive angle of attack will provide the altered airflow to generate lift. This works right side up as well as upside down. Even with a common asymmetrical wing, a little added AoA when inverted will generate lift though not as efficiently.

Answer 4

What produces lift is a combination of Bernoulli's
principal - causing a low pressure area above the upper surface of the
wing - and Newton's Third Law - a reaction to the air particles being
pushed down by the bottom of the wing cause the wing to move up. We
generally consider these two laws to contribute to lift.

The amount that each of these contributes to lift is a function of the
cross section of the airfoil and angle of attach - the angle between the
wing (actually the chord line of the wing) and the relative wing (the wind
that is made by the forward motion of the airfoil). Some airfoils have a
greater curvature (camber) on the upper surface of the wing making the
Bernoulli effect greater at lower angles of attack.

Getting to your question... an airfoil that is made to fly with a greater
curvature on the top can fly - though not as efficiently - inverted as
long as the angle of attack is established in the upward (opposite of
gravity) direction. Some airfoils are made symmetrical to allow them to
fly equally well right-side-up and up-side-down. Airliners are unlike
candidates for symmetrical airfoils, but nimble aerobatic aircraft often
feature these.

The short answer... angle of attack controls lift.

Answer 5

aerobatic aircraft that are intended to be flown upside down have a more symmetrical airfoil than say a passenger plane would have. symmetrical meaning the upper and lower surfaces have nearly the same curvature. this way the plane creates the same amount of lift regardless if it is right side up, or upside down.