Hello,
I managed to make a first version of my sim work;
however, I'm afraid I was forgetting the correct adimensionalization (I looked up
Roskam's 'Airplane Flight Dynamics and Automatic Controls).
Can you please tell me if I understood correctly? In VSP .stab output:
- derivatives wrt angles multiply angles in rad (differences wrt trim values, e.g. Cl_alpha*(alpha-alpha_trim), Cl_delta_rudder * (delta_rudder-delta_rudder_trim) and so on);
- derivatives wrt p, q, r multiply pb/(2U_trim), qc/(2U_trim), rb/(2U_trim), respectively, in rad;
- derivatives wrt u multiply U/U_trim, derivatives wrt Mach multiply Mach/Mach_trim, (non dimensional),
where the trim conditions are U_trim, alpha_trim and so on.
So, for instance, Cx = Cx0 + Cx/alpha*(alpha-alpha_trim) + Cx/beta(beta-beta_trim) +
+ Cx/p*(pb/(2U_trim)) +
Cx/q*(qc/(2U_trim)) +
Cx/r*(rb/(2U_trim)) +
+ Cx/u*(U/U_trim) + Cx/M*(Mach/Mach_trim) +
+ Cx/delta_aileron(delta_aileron-delta_aileron_trim) +
Cx/delta_elevator(delta_elevator-delta_elevator_trim) +
Cx/delta_rudder(delta_rudder-delta_rudder_trim)
Thank you in advance,
Luca