Airplane Flight Dynamics: Open and Closed Loop

Course Outline

Day One

• The general airplane equations of motion: reduction to steady state and to perturbed state motions; emphasis: derivation, assumptions, and applications
• Review of basic aerodynamic concepts: airfoils—lift, drag and pitching moment, lift-curve slope, aerodynamic center; Mach effects; fuselage, and nacelles—destabilizing effect in pitch and in yaw; wings, canards, and tails—lift, drag, and pitching moments; lift-curve slope; aerodynamic center; downwash; control power; Mach effects
• Longitudinal aerodynamic forces and moments: stability and control derivatives for the steady state and for the perturbed state, example applications and interpretations

Day Two

• Lateral-directional aerodynamic forces and moments: stability and control derivatives for the steady state and for the perturbed state, example applications and interpretations
• Thrust forces and moments: steady state and perturbed state
• The concept of static stability: definition, implications and applications
• Applications of the steady state airplane equations of motion: longitudinal moment equilibrium, the airplane trim diagram (conventional, canard, and flying wing), airplane neutral point, elevator-speed gradients, the nose-wheel lift-off problem; neutral and maneuver point (stick fixed)
• Applications of the steady state airplane equations of motion: lateral-directional moment equilibrium,
  minimum control speed with engine-out

Day Three

• Effects of the flight control system: reversible and irreversible flight controls; control surface hinge moments, stick and pedal forces, force trim; stick-force gradients with speed and with load factor; neutral and maneuver point stick free; effect of tabs—trim-tab, geared-tab, servo-tab, spring-tab; effect of down-spring and
  bob-weight; flight control system design considerations—reversible and irreversible, actuator sizing, and hydraulic system design considerations; applications of the perturbed state equations of motion—complete and approximate longitudinal transfer functions; short period, phugoid, third mode, connections with static longitudinal stability, sensitivity analyses, equivalent stability derivatives; complete and approximate lateral-directional transfer functions—roll mode, spiral mode, Dutch roll mode and lateral phugoid, connections with static lateral-directional stability, sensitivity analyses, equivalent stability derivatives

Day Four

• Review of handling qualities criteria; MIL-F-8785C and FARs, Cooper-Harper ratings, relation to system redundancy, the airworthiness code
• Introduction to Bode plots: method of asymptotic approximations, interpretations of Bode plots, airplane Bode plots, applications of inverse Bode method; introduction to linear feedback systems, the root-locus method and the Bode method to synthesize control systems
• Introduction to human pilot transfer functions; analysis of airplane-plus-pilot-in-the-loop controllability; synthesis of stability augmentation systems—yaw dampers, pitch dampers; effect of flight condition, sensor orientation and servo dynamics

Day Five

• Synthesis of stability augmentation systems—yaw dampers, pitch dampers, α-feedback, β-feedback; effect of flight condition, sensor orientation, and servo dynamics; basic autopilot modes; longitudinal modes—attitude hold, control-wheel steering, altitude hold, speed control and Mach trim; lateral-directional modes—
  bank-angle hold, heading hold, localizer and glide-slope control, automatic landing; coupling problems—roll-pitch and roll-yaw coupling, pitch rate coupling into the lateral-directional modes, nonlinear response behavior; effects of aeroelasticity—aileron reversal, wing divergence, control power reduction; effect of aeroelasticity on airplane stability derivatives; example applications