Winging a 3DOF (pitch, roll, yaw) build.

Hey everyone. Been watching a slew of diy builds and came up with an idea to build a 3dof consisting of pitch, roll, and "true" yaw as I mainly flight sim in VR. My biggest demon was coming up with a way to not have to build a traction loss attachment and rather have the upper frame simply yaw out over center of gravity. Most of the materials just arrived over the weekend and today, and just cut the base frame and partial seat frame steel up today after work. I'm hoping the link for the pics work, this is only my second post here so I'm still learning the websites curve. Anyhow, the plan is simple. Bottom frame with a turn style type bearing welded to 1/4" plating, then a CV axle from a late 70s VW (that I already welded one end fast so it doesn't pivot) welded to the turnstyle. Another 12x12 plate will be welded to to working end of the CV axle, and the seat frame as well as the pedal/monitor/controls frames will all tie into. This will be powered on 3 24V jazzy motors, each on its own IBT2 and power supply through an Arduino R3. Fingers crossed the link works. I will post every step as I go. Any questions about the parts in the pic, ask away and I'll try to explain in detail as more pictures follow. https://photos.app.goo.gl/biozFXf9psUgG1yf6

Will do, I'm looking to do the bottom frame and bearings by Wednesday evening. Apologies if I jumped the gun, but just wanted to get this build thread going so as I complete, I can just snap and upload. Once that extremely hard part to explain (bearings/bushings/plates) is shown in photos, the plan will start to speak for itself. Looking forward to your input as well. Again, I'm ridiculously new here but I see your name all over the place. Don't hold back on me, I take criticism very well. Salute!

Pressed bushing (1-1/4" diameter) into the 2 block bearings. Cut the yaw arm out of the 1/4" steel plate with cutting wheel. Welded them all up this afternoon along with the CV axle and it swings nice and smooth. Finishing up my pitch and roll rods as well. Brought the seat (X Rocker Nemesis and seat plate up to the garage a few minutes ago. Still have some last checks of measurements and will weld that up on top of the CV axle. Probably won't work on it anymore this weekend, my mixed gas bottle is running very low. Will exchange that on Monday after work and hopefully have a seat frame to show off as well.

https://photos.app.goo.gl/f3JRy7RCCRK5iLxs6

Here's the latest progress. Took some close ups of my center of gravity yaw lever system to clarify how this is going together. Now, the bottom frame cross sections are not welded in, neither is the bottom plate to the cross sections. It's all just propped up on there. Here's some questions to pick your brains. My pitch and roll rods are 30" in length (rod ends not attached). Having said, would mounting them halfway up the seat back be a suitable point? If not, I could always raise the motors by building platforms for them, but I'd rather not if not necessary. Also, I've noticed a majority of shoulder mounted rod setups have around roughly 5 degrees of angle. My next step is permanently welding the base cross sections in and I'd like to get some input to get me in the ballpark so I can get these motors mounted, pinned to the seat back, and start the pedal/monitor frame. If y'all have any questions for me, fire away.

https://photos.app.goo.gl/64rvvAiP1kqo1bQC9

I've given that some thot. I pressed bushings into my rod ends to allow extra throw for the rods. I figured that way if I had to have the rod ends at the shortest position, it would still allow the full 22° of bearing travel. One thing I haven't looked into yet is setting the yaw motor travel distance. To be honest, I don't intend to have it swing more than a few degrees. Just a lil more than enough to feel the rotation. So if simtools pro (already purchased, never used) allows to set travel limits, things should work out well.

I think I understand your concern with motor geometry. Are you speaking of the rods/ends locking out? If so, all I have done so far was make 2 marks on each seat back rail, tilted through full range of of motion, and held in place while manually swinging yaw lever. I was pretty surprised how little "sway" there was as I eyeballed the marks on the seat back rails. If youean something other than that, please let me know. Thanks again!

Loud and clear. I think I will be ok there. My process is going to involve pinning the seat frame at the farthest point of travel in pitch and roll, then manually yaw to see just how far the bearings allow the rod ends to rotate through and/or around the bearing bolts before rod length becomes affected. I'll be doing this at both full fwd and left, the full aft and right.

I should have listened to your first post and provided a sketch. Yes, there will be a mid frame attached to the yaw plate dedicated solely to the 2 rear motors so they swing with the seat frame. I got so tunnel visioned about asking advice for rod angles/motor height I completely lost sight of that. I'm at work now, and I understand 100% what you would like to see. I'll draw up the yaw plate/motor mount design on next break and post it.

Here's a quick photo edit of the motor frame that's going to be welded to the mid plate. The blue circles rep the motors. Being the mid plate is only 6-1/4" above floor level, the motor frame will be slightly angled upwards to allow full pitch up clearance and not slam the motors into the ground. They are already cut at 36" in length, which will be plenty long to achieve pitch and roll rod angles, it's just the angle degree itself that is confusing to me. Aside from the 5° I commonly see here, another recommendation I see here often is to just make sure the motor lever and control rod form a 90° at center. I guess I can start by combining them both, having 5° on the rods as well as a 90° at the connection. Thoughts?

Hit an unexpected snag today. The bearings I bought ended up being self leveling type. After welding seat frame to the CV joint, the entire upper frame and shaft canted to the right about 4 degrees. These were not supposed to be self levelers. So I checked the order, got the part number, and bounced it across Google and found that everyone that sells this bearing describes it as self leveling EXCEPT the retailer I bought it from. Too late now, it's all welded up. So I just finished fab'ing out a brace system for the shaft to spin inside of. Once I cut my base pieces I'll have it all together shortly. Was hoping to work on the motor mounts today, but that'll be tomorrow. Ah well, life happens. Right now it is all jigged up and centered/leveled within 0.1 degree using a digital protractor. More pictures to follow tomorrow as the motors get mounted.

Here's today's work. Braced the axle, added some supports, and attached the motor mount frame. Going to add 3 cross braces to it, but nonetheless it is already extremely solid. The upper frame gets the full 22.5 degrees of travel in all directions. Mount plate is not permanent yet, gotta put on rod mounts and get angles first. Left plenty of length on the mount frame so I can slide plate back if need be. I tilted the seat back and stood on the motor mount frame and bounced a few times. Not a single squeak. Very happy about that. I didn't measure the yaw travel yet, but I can already tell it swings a lot more than I plan to set it at. Finished fab'ing for today, but I'ma grab something to eat and maybe I'll start figuring out where/how I'm going to mount that yaw motor.

Been a few days, got the motors and rods hard mounted. Took measurements and ran simcalc. According to the help section, everything is ok as it sits, however, I would like more pitch available as I do 99.9% flight sims. Playing around with simcalc, I can cut my rods down to shorten the Z axis and angle my motors to really increase the roll efficiency while also greatly improving the pitch travel. Are there any drawbacks to cutting the rods and going from a shoulder mount to a "mid-back" mount? The numbers seem to look good, but I'd really like to hear your feedback. Pics included. Thanks

Running motion visualizer along side simcalc and having issues. After applying the same values, the results are drastically different. Yes, i know the respective programs have their X Y and Zs labeled differently, but motion visualizer will not change pitch value results after shortening the pushrod Y axis and recalculating. When changing Z axis in simcalc, the pitch changes what i believe to be accordingly. Is MV still buggy? Should I just trust and stick with simcalc?

Wired up the 3 potentiometers and IBT2s last night. Spent about 2 hours this afternoon on simcalc. Afraid to go any further due to being unsure of the simcalc/motion visualizer differences. Hoping someone can school me on my last post here about it being ok to cut rods down and mount them half way up the back instead of shoulder mounted without losing a ton of leverage. In the meantime, Ill start measuring/cutting/assembling the pedal/monitor frame.