Table of Contents
Lift, velocity and Drag
For a plane to rise into the air, some force must be created that is greater or equal to the gravitational force. It is this force that is called the lift. When air flows over the aerofoil of a plane then lift is created. The shape of an aerofoil makes air to flow faster on the top than at the bottom. Pressure is thus lower at the top due to increased speed but greater at the bottom causing the lift. When the Bernoulli’s equation in non-compressible flows is balanced when there is an increase in velocity, pressure decreases. Therefore the speed of air is higher at the top of the wing lowering the pressure and lift is created due to increased pressure below the wings.
From the equation
Is the lift coefficient, is the air density, is the velocity of air, and is the area of the area of the wing.
Drag comes in from Newton’s third law of motion where; for every action, there is always an equal and opposite reaction. As a plane flies, it exerts a forward action force; this action receives an equal and opposite reaction from the wind, air. This reaction is referred to as the drag. When the velocity increases drag also increases.
Is the coefficient of drag, and A the cross-section area of the plane on which the reaction, drag, is exerted. When the drag coefficients are low, the efficiency or rather the velocity of the plane increases.
There are two forms of drag; the parasite and induced drag. Parasite drag is the air resistance that a plane experiences due to the air in which it is moving along. It is increasing with the square of the velocity. It is observed when the velocity is decreased where the angle of attack also increases and so the thrust must be initiated to increase the lift and minimise drag. Lift and drag are observed when the aircraft elevator moves upwards; the planes control yoke pushed backward to maintain the continuity principle, the air above the aerofoil increases speed as per Newton’s equation which increases lift.
- Davis, T. W., & Spedding, G. R. (2015). Lift and Drag Measurements of a Gull-Wing Configuration Aircraft. In 53rd AIAA Aerospace Sciences Meeting (pp. 2015-0027).
- Shyy, W., Aono, H., Kang, C. K., & Liu, H. (2013). An introduction to flapping wing aerodynamics (Vol. 37). Cambridge University Press.