__Lift/Drag Ratio__Unfortunately, the flying speed of the airplane is not the most accurate mathematical value with which to measure the amount of lift and drag being produced. To do this mathematically, we must examine the relationship between lift and drag by use of the

In the picture at left, we see a graph with

Of course, as a private pilot you will not required to calculate drag coefficients either mathematically or using any other means, but it is a good learning experience to start becoming familiar with such graphs as you will need to recognize them on a knowledge text.

**lift to drag ratio**.In the picture at left, we see a graph with

**drag coefficient**on the vertical axis and**angle of attack**on the horizontal axis. The airplane is also shown in terms of flying speed and the matching angle of attack for certain speed.Of course, as a private pilot you will not required to calculate drag coefficients either mathematically or using any other means, but it is a good learning experience to start becoming familiar with such graphs as you will need to recognize them on a knowledge text.

Here at right, the same airplane is shown as slowing from a fast flying speed to a slow flying speed. The

The coefficient of lift, and thus total lift, will always increase as angle of attack is also increased. However, we notice in the graph that once the airplane has reached or exceed the

**coefficient of lift**is shown on the vertical axis and the**angle of attack**on the horizontal axis.The coefficient of lift, and thus total lift, will always increase as angle of attack is also increased. However, we notice in the graph that once the airplane has reached or exceed the

**critical angle of attack**, the amount of total life being produced diminishes rapidly.Taking both the coefficient of lift and the coefficient of drag into account, this brings us to the picture at left showing the ratio between these two on the vertical axis, and angle of attack shown on the horizontal axis.

This is now representing the the proper

The increase in lift will continue to the point of the

This is now representing the the proper

**lift to drag ratio**that was presented at the top of this page. By the graph we can observe a large increase in total lift as the lift to drag ratio increases while the angle of attack also increases.The increase in lift will continue to the point of the

**most efficient angle of attack**, where the highest amount of lift is gained for the lowest amount of drag is generated. Once the angle of attack has gone past this point, the amount of lift being produced will only decrease.