50 minutes ago, Ray Proudfoot said:

I’m struggling to understand how this works when you’re not physically moving.

The Pod that you are sitting in, with the flight deck and computers , etc sits on a hydraulic assembly which cost millions of dollars. It moves many feet, up and down, and side to side, and any combination you could imagine. When you take off, the forward and upward movement of this pod, presses you into your seat, and you feel like you are accelerating. Same with turbulence and braking. Very realistic. 

 

 

Edited February 11, 20251 yr by Bobsk8

1 hour ago, Bobsk8 said:

The Pod that you are sitting in, with the flight deck and computers , etc sits on a hydraulic assembly

Got it. Essentially a full motion simulator. 👍

9 hours ago, Bobsk8 said:

When you take off, the forward and upward movement of this pod, presses you into your seat, and you feel like you are accelerating.

How they simulate forward and upward acceleration is to tilt the pod backwards. The pods can give momentary G forces above and below 1 G only for a about a second at time: the length of time it takes to move the hydraulics to the stops. If the acceleration is slow, it could happen over a few seconds but you wouldn't feel it. In fact, the sims "correct" to their neutral position so slowly that you don't perceive that it's happening.

Other than these brief 1-second bursts, they only have 1 G to play with. So you ask yourself: if I'm going to simulate forward acceleration and I only have 1 G, how am I going to do it? Well, in an aircraft that is accelerating down the runway, the net force vector in the aircraft points towards the rear--you feel pressed into your seat. The way to press you into your seat in the sim is to tilt it backwards, so that gravity is pulling you into the back of your chair. 

Similarly, when you apply the brakes on the runway, in real life, your body pulls on the shoulder straps, and the way to do that in the sim is to tilt the pod forwards towards the floor. The actual tilting only takes a few seconds; after that, the pod just holds its position pointing down. Then when you let up on the brakes, the pod levels off again.

The brief moments in the sim when you get slightly more or less than 1 G are used by the sim to underline the initiation of motions, but after the motion has been started, the only tool they have is tilting the gravity vector to simulate the sum of the forces on the aircraft. Accelerating down the runway: tilt the pod backwards. Braking on the runway: tilt the pod forwards. Turns would have the pod bobble around a bit as you enter the turn, depending on how smooth you are on the controls, but if the turn is coordinated, the pod is level, because the force vector is going down through the floor regardless of the bank angle. Side slip: tilt the pod right or left. Turbulence: bounce the pod around a little.

When I would watch the big sims from the outside, I could always tell when the pilots inside were taking off, braking, and practicing engine out scenarios. Other than that, because flight is coordinated most of the time, the pod is usually level (regardless of the attitude of the aircraft) except for little wiggles that indicate turbulence or less than perfectly smooth control applications.

 

 

Edited February 12, 20251 yr by prolixindec

I spent some time in the CAE factory in Montreal. The most interesting sim to watch in action was the military Helicopter when it was hovering.

I taught in Level-D sims, and I had plenty of time to watch them from the outside as I was waiting for my students to have their turn to go fly. 

One anecdote: the pods have access panels for getting inside to fix the electronics and the projection. Maintenance guys go in through those panels between sessions. When you're sitting in the sim getting ready to fly and a real human being stands up in front of the cockpit -- talk about things that kill the immersion...)