Extending a 4080 frame

Hello, after tinkering for quite a while I'm finally getting motion on my platform. I'm using my Simlab TR1 frame (4080 extrusion base) and adding linear SFX-100 (150) style actuators based on Odrive. I'll be adding a build log shortly but hoping to get some insight from the crowd here on the best approach to extending my frame.

Unfortunately, the compact nature of my rig means there's not enough clearance to mount the actuators on the front or rear without hitting the seat or other mount points. I think my best option is to add about 10 in each to the front and rear to mount. Alternatively I could add a spacer but unsure what that would look like.

I was considering butt joining a frame extension to the existing frame using flat plate connectors (8hole) for strength. Does anyone have experience with this? Would it be rigid enough or would it be a weak point? Alternatively I was thinking of mounting the extension to the outside of the existing frame parallel and just drill bolt holes through the extrusion for access. I'm hoping to add a little extra extrusion as possible so any thoughts are appreciated. I think the butt joint is my preferred option for space and to maintain clean lines on the rig but not if it compromises strengthen in a way that adds risk of joint failure.

I'm traveling but once I get a moment I can share some drawings to illustrate.

I would love to have custom brackets made but I think the extrusion route is going to be most cost effective right now.

Thanks

Thanks @noorbeast, that is indeed the rig that I have. Here are a couple of quick mockups of what I'm thinking in terms of the extensions. The final rig length would be ~1600 mm x 500 mm

The extension toward the front seems like it would have slightly less stress on the joint, but there's only enough room for me to add one flat plate across the joint on each side of the rig for a total of two. Essentially I would move the pedal mount, steering wheel mount, and seat mounts all forward so that I have enough space to mount the actuators.



On the rear extension concept the joint is directly under the seat which gives me a bit of pause since it's right under my center of mass, but I can reinforce it with two plates on each frame member so there's plenty of aluminum on the joint to really resist any motion. I suspect it will be fine but makes me nervous. In this concept I'm moving everything backwards to make enough space for actuator mounting. Note, I didn't have the wheel mount uprights on when I captured this image.



The third idea that I have is to overlap extrusion the same way that I have in this image for testing. I used wood to mock up the extension just for testing purposes but I think you can get the idea. It's not the traditional way to attach extrusion, but I feel pretty confident that I can add enough rigidity and strength to make it work. It would also space the actuators a bit farther out. In the final design I would mount them on the exterior but have them on the inside on this just during the tests.





My preference is for the butt joint if feasible.

Hello,
you can add 4 spacers (40x80 alu profile, 100mm length) between your frame and the actuators, to get 40mm more clearance between the actuators and your seat. You can connect each spacer with 4 corner brackets to the main frame.
Best regards
Frank

Ahh, yes that's a good point and one I had briefly considered but didn't mention here.
I forgot to mention that part of my issue is that with the frame length as it is the rear actuators would be right at my elbows so I'm looking to get a bit more room as well. Thanks for the idea though.

Hello, you can try to extend your frame with a 40x80 alu profile like this: