Nuts and Volts - April 2014

your cabin should be designed to fit your needs. Mounting to a Pedestal

For this particular simulator, I chose a pedestal mounting system (Figure 6). This is nothing more than a scrap automotive universal joint (as you might find on a drive shaft) from a junkyard. Usually, these cost little or nothing.

I hired a local welder for a few dollars to cut and weld this shaft to a large metal plate. Looking again at Figure 2, note that the pedestal is not centered under the cabin. It should be mounted so that it is far enough back on the cabin that some weight will always be on the front pitch cylinder. By keeping the cylinder under constant load, you will always have control of your platform’s position.

The same is true for your side roll axis. As seen in Figure 7, the pedestal mounts slightly behind and aft of the rider and simulator’s center of gravity to keep both the pitch and roll cylinders under constant load. You will also notice in the photo that I had two chains and springs attached to keep an additional load on each cylinder at all angles.

You may or may not find this necessary, but since I wanted a wild ride, I added the springs so that the tilt of the cabin would be as rapid and wide as possible on the return stroke of each cylinder. The Electronics

Thanks to Weeder Tech — whose ads I found in Nuts & Volts years ago — electronic connection of the original simulator to the computer was extremely simple. Let’s briefly talk about what the electronics do.

The Virtual Flyer is a complete closed-loop system, which is to say that the computer running the simulation monitors the exact position of the simulator platform and adjusts that position to match events on the screen approximately 20 times each second.

In order to accomplish this, your computer simply needs an input/output module capable of opening and closing the four air valves that move the simulator. It also needs to read the position of the platform via two feedback potentiometers.

Figure 6 shows the two feedback potentiometers on the base of the simulator. Attached to each potentiometer is a heavy armature and a length of chain that attaches to the base of the cabin.