There are several choices in gaming motion platforms out there to choose from. Several different manufacturers have come up with novel ways to provide motion for sim games, and at various price points. One of the more popular offerings, and the one I choose is, the DOF Reality H3 Motion Simulator Platform. It’s affordable, powerful, configurable and flexible, and is very quiet in operation.
Motion simulators are still fairly new, niche tech. These things are not really “Out of the box – Plug-N-Play” as yet. Customizing, tweaking, troubleshooting and fixing are still needed to get the most out of these things and while the DOF Reality H3 is a quality rig, it is no exception.
The U-Joint
So, my rig had these annoying “ping” sounds while in operation. Roughly half of the movements in a typical session would create a fairly loud “ping” sound, like tight metal being forced to move and “breaking” from it’s stationary position. It didn’t stop the rig from moving, but it was always concerning. I had taken the rig apart a few times to try and find out what was the issue but never found anything. So, because there are so any metal-to-metal junctions on the rig, and because I am always in the seat playing and not sitting on the floor watching and searching for where the pings are coming from, I let it go for a while.
I remember reading in a few posts online that some people had u-joint problems and that they had replaced their u-joint with a new one. This got me thinking that maybe it’s my u-joint that’s causing the ping sounds. So, I took the rig apart one more time, this time concentrating on the u-joint itself. Here’s what I found.
I took the u-joint out and looked at it from the side and noticed that 2 of the u-joint caps, one on each plane, where not seated all the way down on the spider like the others. I could see a small gap between the oil seal and the landing on the spider that was not there on the other 2 caps.
So, I carefully removed one of the caps that wasn’t seating properly and sure enough, there was a flat washer stuck in the bottom of both caps! Bingo! Found my problem!
You see, the u-joint is held in place by 4 plates, 2 for the seat side and 2 for the base frame. These plates have large holes drilled into them and the caps of the u-joint fit into these holes. The whole assembly is then sandwiched together and held in place by 4 bolts that go through the frames. The spacing between the plates on each axis are set by the width of the frame the plates are bolted to. I think DOF Reality thought there was a need to reduce some spacing between these plates and simply added a flat washer in the u-joint on each axis to accomplish this. However, in my sample this was not the case.
The addition of the flat washers took up too much space and once I tightened the 4 bolts holding the u-joint plates to the frame, the u-joint couldn’t move freely, and this was causing my “pinging” problems. Once I removed these flat washers from the u-joint caps and put the rig back together, the pings are gone and the rig runs much better and smoother than ever before!
I suspect that this might have been the issue with others that have replaced their u-joint with a new one and fixed their problems. As well, I have seen pictures of others that have this washer installed in their u-joints and wonder if they are also having these issues. You might try removing these flat washers yourself and see if things are better for you.
Gearbox Upgrade
Just about everyone who has owned a DOF Reality Motion rig for a while is aware of the new SFU gearbox upgrades available from DOF Reality. New DOF Reality orders already come with these new gearboxes so if you are thinking of ordering a DOF Reality rig, don’t worry, you’ll get them. For us previous owners that received the original gearboxes, these new gearboxes are a must have! They are a bit quieter, much smoother, and offer a bit more range of motion than the original gearboxes. It’s a great upgrade!
I’m not sure what to do with the original gearboxes. Obviously, I’ll keep them for backup purposes, though I don’t think I would ever go back to them. Don’t get me wrong. The original gearboxes worked quite well enough so if you are looking to purchase a used DOF Reality rig that has the original gearboxes, go for it! It’s still a great motion rig, and you can always upgrade the gearboxes later!
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