
Ch12-H6927.tex 20/6/2007 16: 38 Page 332
332 Flight Dynamics Principles
It is assumed that the wing to which equation (12.20) relates is of constant thick-
ness with span and that it has a rectangular planform, which is most unlikely for a
real practical wing. Alternative and rather more complex expressions can be derived
which are specifically dependent on wing geometry to a much greater extent. How-
ever, there is no guarantee that the estimated drag coefficient will be more accurate
since it remains necessary to make significant assumptions about the aerodynamic
operating conditions of the wing.
It is also difficult to obtain a simple and meaningful