How does an airfoil use airflow to achieve lift?
An airfoil generates lift by exerting a downward force on the air as it flows past. According to Newton’s third law, the air must exert an equal and opposite (upward) force on the airfoil, which is lift. The airflow changes direction as it passes the airfoil and follows a path that is curved downward.
Why does the air flow faster over the top of an airfoil?
The shape of an airfoil causes air to flow faster on top than on bottom. The fast flowing air decreases the surrounding air pressure. Because the air pressure is greater below the airfoil than above, a resulting lift force is created.
How is the lift of an aerofoil controlled?
The Lift an aerofoil produces depends on a number of factors, some of which are beyond our control as quadcopter operators. Others, such as the rotational speed of the Rotors and hence the velocity of the air passing the aerofoil, can be adjusted and this is how we control the quadcopter as we fly it.
Which is the best description of an aerofoil?
An Aerofoil (or ‘airfoil’ for North Americans) describes the cross section of a wing, rotor, rudder, propeller or other lifting surfaces. They come in many shapes and sizes and are usually designed for a specific purpose or application.
How is the angle of attack of an aerofoil changed?
As a fixed Aerofoil design moves through the air at a constant velocity it would be beneficial to be able to vary the Lift produced. This is done by changing the Angle of Attack (AoA) of the aerofoil to the Relative Air Flow (RAF) and thus changing the amount and direction that the aerofoil moves the air out of its path.
Is the lift of an aeroplane always constant?
For an aeroplane of given weight, the lift for level flight must be constant (being equal to the weight). If L is constant, D must vary inversely as LID (or CL/CD). From the formula L = CL. jpV2S it can be seen that if L, p and S are constant (a reasonable assumption), then V is inversely proportional to VCL (or CLm).