Showroom Smitty's Rotary Servo 6DOF build (Complete!)

Feature-creep alert!
So I already had a plan for the flight controls, which was to use the hall-effect gimbal i already made...

Until I found this in a DCS forum thread!:


It's from vpforcecontrols.com, their website isnt even up yet but this force feedback platform looks really great. They sell a DIY kit as well, which is what i am going to see if i can integrate into the frame (that box just wont work for me):

My pilot bud tells me rudder feedback is more important than the stick itself, so a 3rd motor will be used there. My initial calcs show this could give 5kg pressure on the stick and 20kg (!) on a rudder pedal with the right gear reduction.

Got many bracket pieces and the main lift rods painted!

We ran the brackets in a tumbler for a while, but getting the last piece out was a chore. I think it was stuck in the bottom for a while, took a good 10 minutes of digging thru the pellets to find it.

Not pictured, but we got many of the clamp collars welded onto the steering & monitor brackets.

nah, we only get about 3 hours per week to work on it. you guys will be the first to know!
Upper frame is next!

Got the main connection blocks started. The alum bars are the lift arms and the steel blocks will become the upper mounting points on the moving frame. Also the baby gearboxes for the FFB joystick came in. This pic shows the layout of how the joystick will be set up:

That control loading system looks interesting. I'd like to know more about it. Have you tried it out before buying? How much torque do these motors have? Are those motors recommended by VP force? Do they have much cogging Sorry for all those questions

That mechanical system you have there (with the rod connecting to the roll axis) could introduce a little "axis contamination", but I am not sure how much, or if it is even noticeable. Might not be an issue. The longer that rod, the less contamination you will have.

I'd be very interested in hearing how this system performs.

Cheers, Dirty

Yep, i calculated the arc swing to be about 6mm toward the right at its endpoints of the 35deg travel, but im probably going to adjust it to about 20 deg full deflection. should barely be noticeable. i also thought in the future if i wanted to make a yoke style or spitfire style i could lock the rotation on that axis and make a little bellcrank thing for roll without moving the servos.. but thats a much future upgrade and i like sticks better than yokes.

I did not try the joystick, the guy is based in Lithuania, but he posted a anticogging demo video:

The joystick motors are 1.6Nm peak, 1.24Nm sustained. The base VPForce unit uses 5:1 ratio on the belts and a shorter stick, i'm going with 10:1 on the longer stick to get about 8lbf/4kgf

I'll know soon enough, just got the fedex tracking #!

VPForce doesn't have much of a website yet but there is an active discord server at https://discord.gg/n5hBaPkAKv

Thanks for posting.

I just looked into this guys YT Channel and it looks like he knows what he's talking about. Also, from the setting options in his software alone it appears that this might be the control loading solution I was looking for.

I guess the bottleneck will be the implementation of FFB cues in the sims, but that's a different story. I hope there's a way to interface the controller myself instead of having to rely on the sim to provide cues for me.

Keep us posted on how things are going with this system.

Cheers,... Dirty

I dont play DCS but they say that has proper FFB support, and i think xplane does as well. I'm all in on MSFS and i'll be using the XPForce software to translate simconnect vars to FFB: https://www.fsmissioneditor.com/product/xpforce/

I got around to testing the joystick setup, in a single axis. It’s so amazing!! But, the gearboxes I got first were pretty cheap ($22) and have too much backlash. At least I was able to determine that 10:1 ratio will work good. I upgraded to low backlash gearboxes, same brand as the 6 big ones on the base. And now there’s NO backlash in the stick at all! This is going to be great to fly.


We also got back into the shop. We got all the stock cut for the remaining machining and some more painting done.


Hopefully next week a CNC will not be running a job so we can get these cut!

Due to rain cancelling some weekend plans, we were able to spend most of Sunday working on things. Got the first joystick pivot machined and some assembly done

Lovely work.

The red/yellow/orange rods (do they have a technical name?!). Are they off the shelf parts? If so could you tell me where from?

I wish, we had to cut & weld those too. We call them the pushrods, connecting rod, or links. In fact my buddy welded the first one with 2 left hand thread bungs so we had to cut it off and redo it

Thank you for sharing I found your rig design is very nice but need a lot of pro tools to build.

In waiting to see it moves a have a question :what is the ref. of your gearbox for 80ST-M02430 servo motor?

Hi, gearbox is 50:1 from YUN DUAN on aliexpress https://www.aliexpress.us/item/2251832781256249.html

These are the upper pushrod mounts, which will be welded to the tube cockpit frame. We did them on the 5-axis since that made the side holes easier to deal with.

Huge progress update! We started on the cockpit frame!



Today we were finally able to get the tubes mounted to the pivot point blocks. The dimensional accuracy of the bent tubes was phenomenal. We measured out where the blocks would be, 34” apart on the threaded end face, and the main tubes dropped right into the pockets of the pivot blocks. Keep in mind the front blocks are on a bent section! Every check dimension was spot-on. We tacked one together and went for some dinner, and the plan was were going to finish out one frame more. But the larger weld table had so much junk on it, and we need the room for the lower seat tube and front cross tube. We figured then since we knew how this went together at this point we should just do all 3 up to this stopping point. Looks like a Santa sleigh, just in time! Next week we can add all the other parts to them and fully weld them.

I should make another update, things i did last week with the FFB stuff. My friend got the Thrustmaster pendular pedals, which i promptly disassembled:


I was able to draw up this unit that can bolt on the back, and have the FFB motor drive the pedals.


The motor will just pull on a bicycle brake cable instead of the spring unit. It even uses the same mounting bolts so no permanent damage to the unit.



Its a simple solution, i was able to adapt it to my Saitek pedals. It works pretty good!



Now if only i could get XPForce to not hang when i try to choose the axis for this unit. As soon as i pick yaw: Y Axis i get this. and the dev seems to have abandoned the software.

Tonight was a big one! We got 1 cockpit tack welded together and I was finally able to sit in it!


The pedal assembly took some time to fit up but a couple little jack screws held it up nicely. It has a huge adjustment range. It was nice to get real confirmation that all my measurements of plywood pieces 1.5 years ago all worked out. The next 2 should go quicker now that we have a good plan on how to finish these up. Still some machining to do- the servo lift arms and some joystick gimbal components.

Hey. Brand new here. me and my buddy are working on designing a 6dof rig similar to yours.. Currently waiting for parts to show up.

I was curios if you ever got your Thanos working properly? and if so can you share you settings?