I know that full-motion simulators, typically used to train pilots on commercial aircraft, have limits to how much they can tilt. They can't go upside down, for example. What happens if the pilot goes outside those limits, by doing a loop for instance? Does the simulation continue with the loop and the just the physical tilt effect gets ignored, or does the whole simulation shutdown and reset?
The motion systems in simulators do NOT mimic the airplane's attitude. Whether the airplane is right-way-up, upside-down or inside-out has no effect on the motion system.
The motion system is used to move local gravity around to mimic the accelerations felt while flying. eg. To mimic the braking during landing, the cab tilts forward, moving local gravity forward relative to the cab, making it feel like you're hanging in the straps due to the braking. Note that when you are braking during landing, the cockpit is level, and yet you are still propelled forward.
No they cannot do loops. During a loop, the pilot feels an increase in effective gravity (n). A motion system can only increase Z-forces by going up, but has to stop this when the travel stops are reached. It then goes imperceptibly back to neutral position, while the manoeuvre continues without the motion system being able to contribute to it.
So the motion system will tilt and heave during the initiation manoeuvre for the loop, will then heave some more until actuator stroke runs out, and them slowly return to neutral.
Motion systems are great for commercial airliners, which cannot do loops. For fully aerobatic aircraft such as military jets, G-suits and G-seats are used that simulate secondary g-force effects:
- A G-seat lowers the seat pan slightly and loosens shoulder straps when pulling g.
- A G-suit pumps up air chambers around the trouser legs, so that the pilot feels the blood flow restriction that reduces blood being drained from the brain, thereby delaying unconsciousness.
G-suits are used in the actual jets, pilots wear them inside the simulator as well.
At Flight Safety in a Class D simulator, the aircraft I have flown there will do aerobatic maneuvers, such as spins, loops and barrel rolls, but they will not provide realistic motion feedback. However the simulator visual display and instruments will emulate the aircraft, as the dynamic requirements exceed the design limits of the motion simulation.