Project Kalamazoo

[gfish]

I've been developing/obsessing over an idea for next year's Burning Man, based around the image of an old 19th century railroad handcar. I have decided to call it Project Kalamazoo, as Wikipedia tells me that is how such devices are known in Australia. Ideally it would carry the two drivers plus up to another four people sitting on the edges. I really like the idea of driving around, picking up random people, letting them swap out on the secondary drive position. That would be really fun, and I'm sure it would catch a lot of attention. I'd definitely need a kind of rough navvy outfit to go with it.

This weekend I got kind of bored and took the opportunity to play with Googles SketchUp and 3D Warehouse. This is the rough design I've been thinking of, with lots of smaller details (like support brackets) left out.



The front wheels are freely rotating caster-style (not shown). The hand pump turns the craftshaft which feeds into a small ATV differential. That turns two sprockets which drive the rear tires. Why add the complication/expense of a differential? Because the drive tires have independent brakes on them, which are also used for steering. This allows a very simple interface which can be operated while still pumping. Also, I like the quirkiness of it. Should be pretty nimble.

The connecting rod attachment point, crankshaft offset and gear ratios are just randomly chosen for this rendering. There are just too many question marks to try to decide upon those now. Once I have the platform built I can figure out just how much torque will be needed, and what pumping range of motion and force is comfortable. It doesn't have to go very fast, after all. Slow and steady is fine once it gets going, as long as pumping isn't too much work. I don't think it will need adjustable gears, but if so it isn't the end of the world. I'll probably be cutting up a pair of old bikes for parts anyway.

I can't start on this until I'm back in Seattle, obviously. And I'm going to want to get my forge back for some of it -- smithing the brackets by hand will be fun and a nice touch, visually. Most of the parts will be pretty cheap and easy. Standard wood floor design, iron pipe for the pump and connecting rod. One important design limitation is that it needs to be able to break down into pieces that can (comfortably!) fit in my car. Hopefully the longitudinal floor joists can be single pieces. They're 3 meters in this rendering, and the driver's mass is dangerously close to the rear axle. Wouldn't want to flip it while driving solo...

Comments

[dymaxion.livejournal.com]

Why not have the front wheels actively steered by rotating the hand pump pillar? Seems more elegant than brake-steering. On the playa, you can almost certainly get away with single-speed, I think.

[loree.livejournal.com]

Is the steering mechanism not pictured, or am I (or you) missing something?

[peteralway.livejournal.com]

For the record, I was born in Kalamazoo.

And oddly, when my family still lived in Kalamazoo, before they moved out to the suburbs, and before I was born, I am told that they owned a kiddie version of just such a device. Alas I have no recollection of it.

[ionan.livejournal.com]

"I'd definitely need a kind of rough navvy outfit to go with it.
"

You probably know this one already, but-
Gentlemen's Emporium (http://www.gentlemansemporium.com/gentlemans.php), specifically, this (http://www.gentlemansemporium.com/store/vict_mens_14.php).

[bakeme.livejournal.com]

how would you brake? with your feet, presumably? what kind of assemblature?

[bakeme.livejournal.com]

also, my friends and i having been vainly dreaming of having some kind of art car for burning man next year. this thing would be awesome.

[irgth.livejournal.com]

I suspect (based on vague fourth hand knowledge of the difficulties engineers have had getting brake assisted steering to work on race cars) that the differential/braking/steering would be very time intensive to get right.

A possible alternative would be to have two hand pumps, each driving one wheel.

Another alternative, especially since cannibalized bikes are going to be a major source of components, would be to change gears to turn (difference in gear ratios for left/right wheels determining turning circle). This would also allow for programming the path of the vehicle (automated gear changes based on distance traveled and/or GPS).

[bigbumble.livejournal.com]

I am very skeptical of turning by braking. My recumbent tricycle (see userpic) has one wheel drive on the left rear wheel. There is very little or no steering effect because of it. If you have rigidly aligned wheels I am confident you will have little or no turning ability by breaking. I suggest you test it first on an Lego or Erector Set type model before you start building.

[zzyzx-xyzzy.livejournal.com]

How about cable-actuated steering? You could have brake levers on your handlebars that pull the front casters around.

[caladri.livejournal.com]

I think you should make it magenta (http://docs.FreeBSD.org/cgi/mid.cgi?18238.938873650.1).

[keystricken.livejournal.com]

This is going to be a smash hit. I'm looking forward to hitching a ride myself.

By the way, you're going to see a suspiciously derivative robot on the website in a couple days...

[ilmarinen.livejournal.com]

Fish, have you seen the build log for the original Contraption? (Originally pump powered, then they added that little hit-n-miss engine last year.) It's on Tribes.net. I'll see if I can pull it up.

-B.