In this post reader will come to know about the basic working principle of Aeroplane, there are many different types of aeroplane, but the most common and general design of aeroplane will be taken into consideration for comprehension.

Parameters :

An Aeroplane while in working condition is acted upon by four forces which are reasonable for motion of aeroplane :

                              (1) Weight of Aeroplane.
                             (2) Lift force
                             (3) Thrust Force 
                             (4) Drag force

fig 1
  •  Weight : Weight of the airplane acts in the downward direction, towards the gravity. 
  •  Lift : Lift force acts on the aircraft to lift it, Lift is the effect when higher pressure of air applies an upward force (lift) on aircraft wings as shown in figure. 
  •  Thrust : Air Thrust force is produced by propellers/Jet engine/rocket (depends on type of plane). This force lets the aeroplane to move in the forward direction. The most important thing is that This thrust should overcome the atmospheric pressure acting on aeroplane.
  •  Drag : This force acts opposite to the forward motion of aircraft. It can be said as the retarding force applied by air on airplane.
Directions of the above forces is shown in fig 1.
     
         
            Let us consider the aeroplane is at rest at the ground level, when plane starts, Thrust is created by the propellers/ jet engine etc. This thrust lets the aeroplane move in the its forward direction. This is because when propellers start propelling thrust, air pressure at direction of thrust force becomes low and at opposite side it becomes high so plane of moved forward from higher to lower air pressure as shown in fig below.





     Going forward, plane reaches a specific minimum velocity at which an upward lift is produced on wings of aircraft which neutralises weight of the plane and at ground level aircraft reaches at equilibrium. Reason behind it is that when aircraft achieves a specific velocity, the speed of air passing from upper side of aerofoil of wings increases as shown in fig below.

and hence from higher pressure  to lower pressure lift force is produced. To increase pressure on aerofoil the angle of attack of aerofoil /wings and area of the aerofoil can be changed at different conditions as shown in fig  below :

At the crucial height where atmospheric pressure becomes very less, aircraft cant go higher, at that maximum height the weight is totally neutralised by lift, lift is exactly equal to weight of plane. While landing of the plane the horizontal speed of aeroplane in air needs to become less and this condition is achieved by increasing drag force by adjusting aerofoil area as shown in fig above. Increase in drag force decreases velocity and lift of aeroplane.The Aeroplane then comes down. And lands on base. At the crucial efficiency of propellers is Max and at ground level it's minimum.




Published By -

Shreyas S Chaudhari