Details

A force balance implies that the sum of the forces is zero, thus drag equals lift:

,

,

where and are the forces in the and directions (N), is drag (N), is tension (N), is lift (N), is kite mass (kg) and , the gravitational constant.

The lift and drag coefficients are:

,

,

where is air density (), is wind velocity (m/s), and is the area of one side of the kite ().

In this Demonstration the coefficients of lift and drag and are assumed constant, which enables calculation of the tension in the string using the above equations.