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Lift is always accompanied by a drag force, which is the component of the surface force parallel to the flow direction. Lift is mostly associated with the wings of fixed-wing aircraft , although it is more widely generated by many other streamlined bodies such as propellers , kites , helicopter rotors , racing car wings , maritime sails , wind ...
Backspin produces an upwards force that prolongs the flight of a moving ball. [4] Likewise side-spin causes swerve to either side as seen during some baseball pitches, e.g. slider. [5] The overall behaviour is similar to that around an aerofoil (see lift force), but with a circulation generated by mechanical rotation rather than shape of the ...
The lift coefficient C L is defined by [2] [3] = =, where is the lift force, is the relevant surface area and is the fluid dynamic pressure, in turn linked to the fluid density, and to the flow speed.
For example, a pitching moment comes from a force applied at a distance forward or aft of the cg, causing the aircraft to pitch up or down. A fixed-wing aircraft increases or decreases the lift generated by the wings when it pitches nose up or down by increasing or decreasing the angle of attack (AOA). The roll angle is also known as bank angle ...
= where is the aircraft lift coefficient. The lift and drag forces can be applied at a single point, the center of pressure. However, the location of the center of pressure moves significantly with a change in angle of attack and is thus impractical for aerodynamic analysis.
Lift and drag are modeled as the products of a coefficient times dynamic pressure acting on a reference area: [6] = = where: C L is roughly linear with α , the angle of attack between the vehicle axis and the direction of flight (up to a limiting value), and is 0 at α = 0 for an axisymmetric body;
This diagram shows lift as perpendicular to the longitudinal body axis. In most technical usage, lift is perpendicular to the oncoming flow. That is, perpendicular to the longitudinal stability axis. At low angles of attack, the lift is generated primarily by the wings, fins and the nose region of the body.
In flight a powered aircraft can be considered as being acted on by four forces: lift, weight, thrust, and drag. [1] Thrust is the force generated by the engine (whether that engine be a jet engine, a propeller, or -- in exotic cases such as the X-15-- a rocket) and acts in a forward direction for the purpose of overcoming drag. [2]