14.4: Centre of Gravity
Click the folder button 'Design Computation' and click into input field 'CG X
[m]' to enter the desired value. All values are valid; the dimensional unit for
entered data is 'meter' [m]. The centre of gravity is related to the airplane's
zero-point in X-direction. Since the zero point of the airplane can be shifted,
one must watch out here little. For the beginning it is useful to put the
airplane's zero-point to the leading edge of the foremost wing, in order to
exclude misunderstandings.
Near the input field are Up/Down-buttons located. They can be used to change
the centre of gravity with mouse clicks.
A click on the right mouse button pops up a menu to set the increment between 0.00001m
and 1m.
Below the input fields the button 'Start Computation' is located. If you click
this button, the Vortex-Lattice computation will start. An iteration
computation with several passes (approximate computation) starts. The program
changes stepwise the angle of attack to approximate the desired centre of
gravity. If the program exceeds 90° angle of attack, the computation will abort
with an error message.