pic: Everything in the tube drive (too late to turn back now)

Free speeds: 7.2 fps low 17.7 fps high.
Weight: 26.3lbs
Let me know what you think. I already know it would be nearly impossible to assemble.

Looking at the wheel set-up, are you planning on making bumper mounts that will make a hexagonal drivetrain?

What’s that bump in the middle where the gearbox is? What’s holding the bearings near the shifter in? It doesn’t have a flange, so it confuses me.:o

Assemby could be easier with some extra access holes to stick a pair of pliers in to hold stuff still.

I like your packaging much more than mine, but I can see why it would be impossible to assemble…
I’m seconding Chak’s question about what the bump is. Did you mill down the entire outside of the tube except for that part?

EDIT: what size tubes are those?

When you expand the drive rails to 2"x2" (which is my educated guess as those rail dimensions), how much space are you actually saving by going in tube?

Any reason you put the outer wheels on the inner edge of the tube and not the outside? Having them on the outside reduces turning scrub (slightly) and lets you extend your belly pan into the corners of the frame.

Though, having a hexagonal frame perimeter might make it easier to avoid pins.

Methinks they are bull gears (final stage gears). :ahh: :eek: I hope I’m wrong, but I see extraction of pulled carpet threads from gears in 2471’s future.

My apologies for the slow response. I just got off work.

Something like that. I’m partial to octagons for ease of mounting.

What’s holding the bearings near the shifter in? It doesn’t have a flange, so it confuses me.:o

Its flange is bolted to the inside of the tube to save space.

Assemby could be easier with some extra access holes to stick a pair of pliers in to hold stuff still.

That’s true, but I still think this design would take several lifetimes to put together, so I don’t plan on ever building it.

Thanks, and yes I prefer that to a lightening pattern.

EDIT: what size tubes are those?

2" by 2" by 0.125" wall.

Not enough to be worth it. This design was half way between a joke about the “put everything in the tube” hype train, and a fun CAD exercise.

Yep, I mostly did it that way because the gearbox design allowed me too, and I like the bulged side drives.

Have you ever used this technique in real life? Even if you have a facing cutter and a good size mill it would take a huge amount of time and resources. The same result could be achieved by bolting/riveting/epoxying/welding a reinforcement plate in the areas you need on some thinner wall tubing.

In general when working with square tubing it’s a better use of resources to order a smaller size/wall thickness than to machine weight away from a thicker tube.

Could I get a picture of your shifter shaft without any gears on it? Kind of curious how that works out, with the pulleys on either end and the shifter in the middle.

Yes, I have done this in real life. Admittedly to a tube smaller than the one pictured, but it did not take a lot of time or resources to do. Thinning the walls of the tube would be significantly stronger than bolting/riveting/epoxying/welding a reinforcement plate on, and would require less time and resources, because each side of the tube would have to be set up on a mill anyway.

Yeah… I wasn’t able to come up with a solution that I really liked, but this is whats in the model:Picture

Would you be able to put your front and back wheels inside the rails as well? That would utilize more space in them and maybe make the concept more valuable with as much space as possible being utilized

Great idea! I’m surprised I hadn’t thought of that. I still don’t think the design would have enough value to be worth pursuing, but putting the wheels in there definitely saves some space.
Here’s the updated model:Picture

Now, what would it take to get the motors inside the tube? They are fairly high on the list of components that get in the way, so that should be a priority. (2.5" motors fit in 2" tubes, right?)

L=1-1.25cos(x)    //maximum length of remaining material (in inches), measured from
L=0.25            //edge of tube, assuming motor is centered

(Yes, they technically do.)

If you are really ambitious, I bet a few talons could fit in there too! Maybe an accumulator even.

While there are some that would fit, I think it would be more practical to keep the accumulators elsewhere. /S

On a slightly more serious note, there is still unused space in the front and back rails for possible manipulator or slide drive mechanisms.

That would be a cool concept. A drop down slide drive with a full 6w tank. That’d be the ultimate butterfly drive! Have 2 omni wheels on the front and back faced perpendicular to the 6w tank. It’d be super heavy and complex though.