Performance of aircraft addresses quantitative measurement of the flying vehicle’s capabilities, seeks its operation optimization, and pushes its flight limits. In this chapter, we continue the steady flight analysis with focus on operational performance. The steady climbing operation becomes the starting point, where the rate and angle are identified as main performance measures. Through statics, the measures are based on excess power that is further elaborated respectively based on two different representative engine types: jet and the propeller, and the optimal flying speeds are calculated respectively for each individual performance measure. The climbing naturally leads to the ceiling performance that covers the altitude envelope. After learning how high is the flight, we discussed how far and how long the flight can be (range and endurance).

In this chapter, we discuss performance measurements and analysis when the aircraft is engaged in maneuvering operations, which involve acceleration in motion. In addition, some other performance aspects related to accelerated flight are addressed to conclude our discussions in this performance part. Aircraft accelerated performance covers the accelerated motion in flight operation. A centripetal acceleration is required to sustain level or vertical turn, as such the aerodynamic lift needs to take extra responsibility not only to balance weight but also to provide additional force. The load factor is introduced. The V-n plot provides much-needed performance measures, and it is incorporated with other considerations: aerodynamic limits, structural limits, and so on. It provides a comprehensive picture of flight envelope. The acceleration also leads to the combined accelerated climbing discussion, from energy perspective, to enable the aircraft engage in speed change as well as altitude change, that one can jump from one energy height to the other.

Finally, the acceleration is well used to estimate takeoff and landing performance.

The closing chapter addresses the computational simulation of flight dynamics systems to verify and validate flight control design. The concept is to implement the designed flight controller into the closer-to-reality flight system and run extensive flight simulations in closer-to-reality emulated environment, so as to further assess the flight control system’s behavior. It is a critical stage in aircraft systems engineering process. Flight systems development follows a typical systems engineering process where the V-shape chart covers the top-down design steps followed by the bottom-up verification and validation steps. The simplified five-step procedure illustrates the key stages through the autopilot development. Flight systems simulation becomes highly integrated throughout the development. Full nonlinear flight dynamics allows the linear system based control design to be tested in a full nonlinear simulation environment with limited environmental variation, and flight simulator provides the opportunity of testing the design function in full system, including interactions and under a more comprehensive environmental influence.

In this chapter, we will cover some representative feedback flight control channels and autopilot functions. The focus is placed on the application of classical control theories to flight control field, and the physics insight of control effects from flight dynamics perspective. We focus on applying classical feedback control techniques to the flight dynamics to regulate aircraft motion to achieve some desired dynamic behavior. Four (4) representative classical control techniques are covered, that is, the PID control, the root-locus design, the lead, and lag compensators. Various single-input single-out channels (SISO systems) are selected to illustrate the usage of these methods. They may seem similar in the concept, by treating the object as the transfer function. However, the emphasis is placed upon the physics of these channels. It reminds us, again and again, we need to be flexible and adaptive in using these approaches, the flight dynamics is the key.

What is aircraft flight in Earth’s atmosphere about? What are the subjects of scientific study? What are first principles to understand and analyze flight? These are some of the questions that first-time learners are often asking. In the first and introductory chapter, we attempt to address these fundamental questions in a systematic, gradual approach to lead readers into this exciting domain with proper preparation. This chapter serves as an introduction to the subjects of atmospheric flight. By using a simple paper plane example, the concepts of dynamic behavior and relevant performance are illustrated. As a foundation for the study, the standard atmospheric model is introduced, followed by airspeed and its calibration. These models are developed by some first principle governing equations. Further, typical aircraft configurations and anatomy are described, with general terminology used in aviation.

The concept of linear quadratic control comes from the principle of optimization, that is to find a feasible control solution to achieve the best-possible (optimal) performance in terms of a certain objective function. When applied to flight control problems, the generic control objective function is expected to reflect desirable flight dynamic performance. Because of its well-structured design and generic objective function, the linear quadratic flight control becomes one of the most popular modern flight control methods, having the status almost equivalent to the PID control to the classical flight control. Linear quadratic flight control is to find an optimal solution to address the flight dynamics problem, not just for its regulation (going back to its equivalent state) or tracking (following a reference command) problem, but also in the sense of minimizing a performance index (an infinite time integral) J. The performance index takes a general quadratic scalar function format that covers both the “energy” of the flight states and the scale of control inputs, adjustable by parameter matrices Q, R of some properties.

Dynamic modes of aircraft demonstrate transient behavior of various flight states, at certain initial conditions, under the influence of disturbances, or under control surface inputs. Compared with static stability and control, a topic covered in the last chapter, dynamic modes and responses to input provide further insight of the flight characteristics. Aircraft dynamic modes and dynamic responses are core to understand dynamic flight behavior, they are associated with the stability and control concepts we have learned in the last chapter, but provide a detailed insight how the flight states converge to their equilibrium operating point. Therefore, we have the full and complete definition of stability by the location of roots of flight dynamics characteristic equation in LHP. In addition, the representative longitudinal modes and lateral modes reveal dynamic flight performance and corresponding flight states. The impact of control surface deflection is also addressed. Flight modes and dynamic responses are based on the foundation of linear systems and feedback control theory, the focus is placed on its special features representing aircraft dynamics.

Aircraft performance addresses quantitative measurement of the flying vehicle’s capabilities, seeks its operation optimization as well as sets its boundary. In the first chapter of the performance part, a steady level flight is sustained by the power plant to generate propulsion to balance applied aerodynamic forces. We focus on the force-related performance measurements when aircraft is engaged in steady flight operation, no acceleration is involved, therefore the statics of flight serves as the governing principle for technical analysis. Aerodynamic forces of lift and drag are first introduced, followed by propulsion thrust and power required to sustain the steady level flight, depending on the engine type and property. Thrust and power available indicate the propulsion capacity. Of course, the performance focuses on the optimal flying speed to achieve best-possible performance from thrust/power perspective.

Kinematics is the “branch of classical mechanics which describes the motion of particles, bodies, and systems of bodies without consideration of the masses of those objects nor the forces that may have caused the motion,” according to the popular Wikipedia. As such, in this chapter, we will address the geometric movement with respect to the subject of aircraft. We adopt the mathematical tools of vectors and matrices to provide the systematic analysis of flight motion, coining the name of vectorial flight kinematics. Three main reference frames are built, one as the inertial reference frame, one in the body-attached format for rigid-body motion analysis, and one to follow flight path (trajectory) for performance analysis. The velocity vector covers the 3DOF translational motion, while the angular rate vector covers the other 3DOF movement showing orientation change. It provides the foundation for the full 6DOF aircraft motion. In addition, through rotation matrix defined by aircraft Euler angles, other states associated with the motion analysis, such as position displacement, orientation can be derived accordingly.