Flight Simulator

In today’s world of personal computers, everybody with a joystick has flown some kind of a flight simulator. They are so sophisticated that their flight dy­namics and cockpit layout approach the commercial product. However, the visual display confines the experience to a two-dimensional projection of the view out the window.

Workstation simulators are the elder cousins of the gaming simulator. With more computer power they model with greater fidelity the dynamics of the airborne vehicles, the surrounding terrain, and the cockpit layout. Large CRT screens with stick, rudder, and throttle give the pilot a realistic environment, albeit confined to two-dimensional displays and visual sensory feedback only.

The ultimate flying experience, short of air time, is in the six-DoF cockpit simu­lator mounted on a motion platform with full-scale cockpit and three-dimensional visual cueing. These are the simulators for commercial and military air crew train­ing. They have detailed six-DoF flight dynamics, accurate displays, and tactile feedback.

For military applications, where “blue” engages “red,” at least two simulators are needed. In close-in-combat (CIC) training, the two sides must “see” each other to practice evasive maneuvers and missile firing tactics. Dome – or tent-like screens envelop the cockpits and give the pilot a three-dimensional, large field-of – view perspective. One of the issues, which I will address, is the integration of the missiles into the simulation experience. Fidelity of the missile simulation must be balanced with execution speed.

I will define some general terms of flight simulators before treating the individual topics. As reference, I recommend the book by Rolfe and Staples.1 If you want to spend a delightful week in Cambridge, Massachusetts, attend the Massachusetts Institute of Technology summer course on fundamentals of flight simulation.2

Definition: A flight simulation is the dynamic representation of the behavior of

a vehicle in a manner that allows the human operator to interact with the simulation.

The dynamics are modeled mathematically by Newton’s and Euler’s laws, whereas the immersion of the operator occurs by sensory stimulants. A flight simulation can mimic any manned vehicle, from single propeller-driven pleasure craft to hypersonic aircraft and spacecraft.

Definition: A model is a representation, physical or analytical, of the structure

or dynamics of a system or process.

A physical model could be a subscale model airplane or a joystick masquerading as the flight controls. We distinguish between tangible and recorded models. Tangi­ble models are the cockpit, controls, instruments, and simulator domes. Recorded models are airport scenes, terrain models, wind and gust profiles, and sound effects.

Analytical models are based on physical laws expressed in mathematical terms. Some examples are Newton’s and Euler’s laws, INS error model, aerodynamic forces, actuators, propulsion units, and seekers.

The facility that comprises the flight simulator consists of five major compo­nents (see Fig. 11.1): aircraft model, the mathematical model of aircraft dynamics; vision system, the scene feedback to the pilot’s eyes; motion system, the vestibu­lar feedback to the pilot’s ears and tactile senses; acoustic system, the acoustic feedback to the pilots’ ears; and instruments, cockpit dials and displays. The pilot, receiving visual, acoustic, and vestibular feedback, controls the aircraft with the help of the cockpit instruments. A major part of the facility is devoted to the faith­ful replication of those stimuli. Deleting the motion system and simplifying the vision system can attain significant cost savings. You can find these shortcuts in some military trainers like the F15 simulator with its emphasis on medium-range intercepts and, of course, in any of the workstation simulators.

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