The only disadvantages are that they are not economical and there is a production of undesirable torque.ġ. These are the advantages of a non-symmetrical aerofoil, that is the lift to drag ratio and stall characteristics are better and useful lift is produced at zero AOA. These have different chord lines and chamber lines. Non-symmetrical Aerofoil: Non-symmetrical aerofoil has different upper and lower surfaces such that the chord line is placed above with large curvature, and it is also known as a cambered aerofoil. In most of the light helicopters in their main rotor blades, these applications are fined. Symmetrical Aerofoil: This has identical upper and lower surfaces that produce no life at zero AOA such that the chord line and mean camber line are the same. The types of aerofoils that are used are as follows:
Mathematical representation is as follows: The lift coefficient is a relationship between the lift generated by a lifting body to fluid density, fluid velocity, and the associated reference area, this is a dimensionless coefficient. Pitching Moment: The moment or torque produced on the aerofoil bye the aerodynamic force is known as Pitching moment. The Angle Of Attack (AOA): The angle of attack is formed between a reference line on a body and the oncoming flow. When the aerofoil is moving through a fluid, the following are the terms used to describe the behavior:Īerodynamic Center: The centre where pitching moment is independent of lift coefficient and angle of attack.Ĭenter Of Pressure: The centre where the pitching moment is zero. Lower Surface: The lower surface is a higher static pressure surface which is also known as pressure surface. Upper Surface: The upper surface is associated with high velocity and low static pressure, which is also known as suction surface. The terms which are related to aerofoils are as follows:Ĭhord: Chord can be defined as the distance between the leading edge, at the front of the aerofoil that is the point, and has maximum curvature and the trailing edge, at the rear of the aerofoil, that is the point with a maximum curvature along the chord line.Ĭhord Line: Chord line is the straight line connecting the leading and trailing edges. An aerofoil can have many cross-sectional shapes. An Aerofoil is being designed with a shape that has the capability of producing lift with relatively high efficiency as it passes through the air. These are dependent on certain terms that need to be defined to understand the design.Īerofoil Terminology. The design of the aerofoil depends on the weight, speed, and purpose of the aircraft and mainly depends on the aerodynamic characteristics. A body that is of airfoil-shaped, moving through a fluid produces an aerodynamic force.
A similar idea is being used in the designing of hydrofoils which is used when water is used as the working fluid. Lift is the component such that the force is perpendicular to the direction of motion and drag is the component parallel to the direction of motion. Aerofoil is the cross-section design of the wing, blade, or sail. Aerofoil or also known as Airfoil is a structure with curved surfaces designed to give the most favourable ratio of lift to drag in flight, which is mainly used as the basic form of the fins, wings, and tailplanes of most aircraft.