how aeroplane fly

7/26/2019 How Aeroplane Fly

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How airplanes fly


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Basic principles of flight

The basic principles of why and how airplanes fly

apply to allairplanes, from the Wright Brothers' first

machine to a modern Stealth Bomber, and it's actually

not difficult to understand how airplanes get, and stay,

airborne.

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Aerodynamic forces !ssentially there are four aerodynamic forces that act

on an airplane in flight" these are lift, drag, thrustand

gravity#or weight$.

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Thrust

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Thrust

(orward force during the flight. Several ways to produce this force)*ets, propellers or

roc+ets #pushing the air bac+ward$.

The same effect for a propeller moving a large mass of

air bac+ward at a relatively slow speed, or by a *etmoving a small mass of air bac+ward at a relatively

high speed.

(or *et aircraft, the means of thrust is the gas turbine

engine.


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DRAG



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DRAG

esistance force due to the motion of the aircraft

through the air.

(or an airplane to maintain steady flight, there must be

sufficient lift to balance the weight of the airplane, andthere must be sufficient thrust to overcome drag.


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WEIGHT

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Weight

The weight of an airplane is the force, which actsvertically downward toward the center of the earth andis the result of gravity on the airplane.

The weight of an airplane acts through the center of

gravity #1.2.$. This is the point through which the resultant of the

weights of all the various parts of the airplane passes,in every attitude that the airplane can assume.


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I!T



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ift The wings of an airplane are designed so that

when moved through the air hori5ontally, the

force e6erted on them produce a reaction, it

is this reaction that lifts the weight of theairplane.

7ift on an aircraft acts through the center of

pressure #1.8$.


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How wings generate lift 9 cross section of a typical airplane wing will show the top

surface to be more curved than the bottom surface. This

shaped profile is called an 'airfoil' #or 'aerofoil'$.

:uring flight air naturally flows over and beneath the wing.



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How wings generate lift 9ny given 'parcel' of air gets split in two as it hits the leading edge of the wing, and both halves of that

parcel actually meet up again at the same moment as they come off the trailing edge of the wing.

So because the air moving over the top of the wing has more distance to cover #because of thecurvature it is forced to follow$ in the same amount of time as the air passing below the wing, it has to

move faster.

(aster moving air is less dense than slower moving air, so this speed difference results in a lower air

pressureon top of the wing, and a higher air pressure below the wing. The result of this pressure

gradient is that the wing, and hence the plane, is pushed upwards by the higher pressure.

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How wings generate lift ;ne of the argued theories of lift generation is that some of the air that passes

beneath the wing is deflected downwards.

This causes an opposite upward force in accordance with Newton's 3rd Law of

Action & Reactionthat acts upon the underside of the wing, effectively pushing it

upwards.

It's widely agreed that this upward force also occurs because the air that comes

over the top surface of the wing moves downwards as it flows off the trailing edge,hence forcing the upwards reaction.

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How wings generate lift



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!6ercise



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how aeroplane fly

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