
Ch03-H6927.tex 30/6/2007 12: 19 Page 57
Static Equilibrium and Trim 57
noticeably large fins and in some cases the aircraft have two fins attached to the outer
edges of the upper fuselage.
3.6 CALCULATION OF AIRCRAFT TRIM CONDITION
As described in Section 3.1, the condition for an aircraft to remain in steady trimmed
flight requires that the forces and moments acting on the aircraft sum to zero and that
it is stable. Thus, in order to calculate the trim condition of an aircraft it is convenient
to assume straight or symmetric flight and to apply the principles described earlier
in Chapter 3. For a given aircraft mass, cg position, altitude and airspeed