This version of the model includes the equations of motion (EOM), the force and moment
calculation from the aerodynamic tables, the environment model, and the "Controls
Selector" block which maps aileron, elevator, and rudder demands to deflections of the six
control surfaces.
Batch Trimming
Trimming consists of calculating aileron, elevator, and rudder deflections that zero out
the forces and moments on the airframe, or equivalently, keep the body velocities
ub,vb,wb and angular rates p,q,r steady. Because thrust is not used during descent, one
degree-of-freedom is lost and the trim condition must be relaxed to let ub to vary. The
Trimming and Linearization of the HL-20 Airframe