What is CL CD?
The lift/drag ratio is used to express the relation between lift and drag and is determined by dividing the lift coefficient by the drag coefficient, CL/CD. A ratio of L/D indicates airfoil efficiency. The maximum lift/drag ratio occurs at one specific CL (Lift Coefficient) and AOA (Angle of Attack (AOA)).
How do you get a CD from CL?
The induced drag coefficient Cdi is equal to the square of the lift coefficient Cl divided by the quantity: pi (3.14159) times the aspect ratio AR times an efficiency factor e. The aspect ratio is the square of the span s divided by the wing area A.
How to calculate the lift coefficient for the A320?
What I’m doing is the following: during cruise, the lift is equal to the weight of the aircraft ( m g) so that I used the cruise table taken from the FCOM to get the speed, the wing area is known ( 122.6 m 2) and I calculated using a tool online the air density at FL290 (29,000 ft). The result is that the lift coefficient is 0.03029.
How is the drag of an aircraft calculated?
In these studies, a simple quadratic relation often assumed to compute the drag of an aircraft based on the required lift. This so-called drag polar describes an approximation of the drag coefficient based on the total lift coefficient.
What is the drag polar of an aircraft?
The mean absolute difference among 20 common aircraft for zero-lift drag coefficient and lift-induced drag factor are 0.005 and 0.003 respectively. At the end of this paper, the drag polar models in different flight phases for these common commercial aircraft types are shared.
Which is an example of a drag converter?
The wing can be seen as a drag to lift converter, of which the already high efficiency can be increased further. This is an on-going effort: some examples of current research are boundary layer suction, morphing wings, plasma control, and blended wing-body aircraft shapes.