It's been awfully stale in here, partly because I didn't have a CAD environment set up for a while, and partly because life's been busy. But I’ve seen all the follows (thanks everyone!), and it's been a good push to post an update on things.

I've been tinkering with a lot of the finer points of the model, so that I can finally sort out some critical details, like the steering and how parts are actually going to connect together.

Here's how it looks now:

Steering and Suspension

In a binge of looking at the Atom websites and Google Images, I spotted some Atoms under construction, and took note of the placement of the steering rack. Not something usually focused on, or easily visible. It's way up in the nose, past the pedals, on the back side of the boxed in area. They're clever for putting the pinion in the middle, making it one part for the left- and right-hand-drive models.

I figured if it's good enough for them, it's good enough for me, and went with it. It's a nice spot. I had to flip the hubs for the front wheels to move the tie rods up, and bring them more in line with where the steering is. It worked a treat! I'm playing with servo locations now, so I can maybe actually wrap up the front suspension.

Also the upper a-arm mounts need reinforcement, I need to actually insert fasteners, make tweaks and accommodations for the shocks, and all kinds of little things...

Cosmetics

The old seats bothered the heck out of me, they looked okay, but weren't really symmetrical, and weren't that good. So I did away with them! I have the old file, and a vaguely seat-shaped placeholder for now, until I make something better or snag something online. I figure the batteries will be attached in the tub to keep the center of gravity low, and they may well interfere with the bottoms of the seats, so I'll probably be redesigning them anyway. But on the other hand, a scale Stig would be cool to harness in...

The top of the nose finally has a much better shape to it now, as well, and I actually like it. It's not perfect, or even terribly close, but a lot better looking than my many previous attempts, and it's smooth and a solvable shape for SolidWorks.

I'm also finally adding mounts! There's a tab and a couple screw holes in place for the dashboard top, and I added mounts at the corners of the tub. I also flipped the center of the tub to go under the rails that go front to back because before, as one piece, it would have been physically impossible to assemble. That adds two more meaty mounts in the center.

Drivetrain

I redesigned the differential from a pricy, heavy-on-the-rotational-inertia bevel gear setup to an axial arrangement that some larger-scale RCs use. The current one is mostly for mockup at this point, but I did want something to gauge the size of the thing. It's currently 14 and 18-tooth 0.5-pitch (metric) spur gears. It's so much more compact, and there's now ample mounting space on the sides for the two different spur gears for the two speeds. I still have yet to redesign the shifter mechanism, however.

There's still a longer to-do list than I can actually fathom, but for now:

• [S/S] Lay out the remainder of steering. Mainly from the servo to the drag link .
• [S/S] Make room at the back for 50-55mm RC touring shocks
• [S/S] Design a mount for the steering servo and actually place it
• [DT] Redesign the shifter mechanism to operate from the outside, rather than the complicated hollow-shaft setup
• [DT] Switch from carriers with the hex pattern and a keyway to gears with the hex shape cut from the hub.
• [DT] Design the actual shifting mechanism, be it servo or solenoid-driven, and any latching or fancy positioning mechanisms. And the intermediate for the motor speed and shifter so that it can be shifted while in motion.
• [DT] Figure out where the electronics are going. There's room on top and in front of the motor for the ESC, and the receiver and BEC will also need homes.

Much, much lower priority things are:

• Telemetry electronics
• An anti-roll bar, but I think that'll take a backseat for the time being.
• Lights!