Showroom DX - Compact Simulator

Many thanks to all for the kind words and encouragement.

@Atlas974 I think it is more a case of time and perseverance than actual skill. For many of us a 'build' extends way beyond just getting motion going. It is more an ongoing process of refinement and improvement, or maybe even obsession, in bringing your motion sim 'vision' to life. You learn a lot along the way and there are a number of members here that take that and then start a whole new motion sim project.

I had discussions a couple of weeks ago with Motion Dynamics about excessive play in one of the 60:1 gearboxes. They thought the issue was the motor to gearbox coupling, so I ordered 2 more prior to pulling the sim apart.

It turns out that the issue is keyway play on the shaft side slot of the keyway, with the key looking to be firm in the brass gear. I have advised Motion Dynamics accordingly and they will review this video and query the manufacturer.

My whole sim room is currently in a state of utter chaos during the updates I am doing.

The 60:1 gearbox with excessive keyway play has been shipped backed to Motion Dynamics today, for them to review.

I am temporarily refitting the 25:1 gearboxes, as Motion Dynamics is not yet certain on a timeline to review the 60:1. To their credit Shane from Motion Dynamics has said he is willing to pull the shaft out of another box if needs be.

I have ordered a new JRK to replace the one I damaged, plus a spare, and they should arrive either tomorrow or early next week.

The computer that runs my sim is also getting some attention. I am adding additional fans to the case and a touchscreen 5 fan controller. The temperature controller will be used to monitor the computer, and the simulator JRKs and Arduino. I am currently mocking up a PC 'dock', the main function of which is to tidy up cable and power management as well as enclose a number of audio amps and powerboards.

The new seat speaker mount is done other than feeding through the wires and adding the seat harness guides.

A before and after of cable management, with the new digital touchscreen fan controller fitted and additional 120mm programmable fan, with billet cover to match the simulator.

The computer specs are an i7-4770 Haswell Quad-Core 3.4GHz with 16GB Dual Channel RAM 1600MHz with Heatsink and Fins, overclocked Nvidia GTX970 Graphics Card, 250gb SSD, 2Tb 7500 HDD, Intel Liquid Cooling, 750W PSU, Microsoft Windows 8.1 PRO 64 Bit.

I will eventually do the outside in carbon fiber wrap, once the custom computer dock for the simulator has been built.

Thanks for he kind words @Fredrik J.

The sim is very rigid, despite being very light, with the suspended aluminum base plate, center support subwoofer post and cross motor brace greatly adding to the structural integrity of the design. The single tube for wheel and pedals has substantial bracing at the bends and does not flex, even with the Fantec pedals swinging off it. This was the early thrash testing using my father as a ride along 80kg crash test dummy and it does not flex, even though it is rough driving with a keyboard instead of controls: http://www.xsimulator.net/community/threads/dx-racer-compact-simulator.5866/page-8#post-67997

The seat detaches from the base with 4 post bolts and 2 nuts for the rods, and one person can easily pick up and carry the base. I can actually pick the whole sim up in one piece, but it is too awkward to carry that way.

With the 25:1 gearboxes my sim could lift its back end off the ground momentarily when it was switched on and the levers snapped from the rest to centered positions, which is one of the reasons I went to the 60:1, as they can hold the sim and a person sitting in it unpowered. It is in fact my office chair when not in use.

I have been having discussions with Motion Dynamics of late about the 60:1, as what I thought was movement in the shaft turns out to be compression of the brass gear.

Now Motion Dynamics and I have a bit of a different take on that. Shane from Motion Dynamic advises that the 60:1 gearbox is limited to 90nm at the shaft. First off that is the first time I have heard of that and I can not find any reference to such a limitation on the Motion Dynamics website.

While the manufacturer is of the view that the problem is caused by overdriving motors on reversals, I have my doubts. First, because of the JRK settings the motor is not just freewheeling in how it responds and what it can draw, and second because 90nm at the shaft is the equivalent of well over 200kgs. I know I carry extra padding and the Fantec gear is not light but on a balanced rig that seems unlikely. I am yet to do the math to verify but will when I have some free time. Irrespective of the cause the take away message should be to take care to limit fast reversals with these metal gear high torque gearboxes.

It makes @SeatTime's work with DIY ball screw actuators all the more interesting!

The issue with the 60:1 gearboxes compressing the brass gears prompted me to implement something I had planned to do someday, but not during this update, and that is to add heave.

I am using the tilt mechanism from the original DX Racer chair, as it allows me to have an adjustable setting for the user weight and chair. That way it takes very little to move for heave, as the adjustable sprung loaded pivot is taking the user and seat weight. And yes I have recycled the original Warthog base plate for the mount. The third engine is now mounted using 6mm aluminum angle, carefully slotted over the existing frame and locked down with the existing mount bolts that are also used to suspend the component tray.

Hopefully I will get some time tomorrow to make the universal joint adapter mount and finish the heave base clamp plates. I will then add another PSU and JRK and rewire the whole sim. A new 92mm fan will mount to the heave base plate with the JRKs moving under it.



The computer dock is slowly coming together. It will house the mini amps for the sound and haptic systems, along with powerboards and all wiring.