The most common limiting factor for makers of powered Lego tanks always used to be tracks.
The simplest Lego tracks were the one-piece rubber "Technic Tread Crawler" tracks that came with the Universal Motor Set. The rubber tracks fit all of those plastic-box pre-Technic motors, and they work well enough, within their limits.
I, like umpteen other kids lucky enough to have two motors, just stuck 'em together side by side with one driving a track on the left and one driving a track on the right and, with two battery boxes, then had myself a skid-steer machine.
(Which would never go quite straight, because the battery voltage and motor performance on either side never quite matched. But it was close enough for government work.)
The little rubber tracks were very limited, though. If you wanted less-power-sapping tracks of arbitrary length, you had to use the Technic Link Tread pieces.
The Link Treads were basically just Technic Link Chains with a broad bar attached to the top. They were small enough to mesh with standard Technic gears, which made them rather delicate. Not to mention a bit fiddly for even small fingers to snap together.
The Technic Link Treads weren't actually the first Lego chain/link pieces. That honour goes to Technic Link Chain Old, which was much sturdier because it meshed with the old big spiky gears. The spiky gears were replaced by the finer-toothed ones around 1980, though, because the old ones didn't mesh terribly well with each other, and couldn't be made small enough for intricate mechanisms. (The biggest ones might make a pretty nice scale waterwheel, though.)
Recently, Lego came out with some much beefier tracks to go with the cool new Power Functions line. (I was proud of my pneumatic 8851 Excavator, back in the day, but the all-electric 8294 Excavator, complete with linear actuators, knocks it into a cocked hat.)
The new tracks don't mesh with standard gears, so they need special driving wheels. But apart from that, they seem to be an excellent solution to the problem of making a tracked Lego vehicle that can traverse something more challenging than short-pile carpet.
But, via the excellent Technic Bricks, here's an even beefier solution.
Yep; that's a tank with treads made out of short, straight Technic "lift arm" pieces. Heck, you could probably make a clunkier version of these tracks out of good old studded beams.
This track design looks to be highly scalable, very strong, and easily repairable with cheap parts. And it doesn't need to crawl like this; you could probably drive these tracks quite fast, if you used a couple of the stronger motors.
19 September 2008 at 7:26 am
Hi,
TBs editor right here! ;D
I agree the new TECHNIC tracks that appeared with Power Function elements, are quite versatile. However these polished and big plastic parts, slip to much on many kinds of floor (wood, ceramics,...).
Hope LEGO or someone else come with some rubber pitons, that fit into the track holes. ;)
19 September 2008 at 9:41 am
Surprisingly capable, and unsurprisingly awesome. The multi-colored tracks are a neat touch...
19 September 2008 at 2:23 pm
I can think of a few solutions to the traction problem besides the one actually used in the videos, which is link-pins just sticking out of the tracks like spikes on sport shoes. It'd be easy enough to attach rubber tyres to the pins, but the tank would of course leave the tyres behind whenever they got caught on anything
One obvious but sacriligeous option would be to cut up small tyres and cement them onto the outside of the track components.
Another would be to tie rubber bands (even official Lego(TM) rubber bands, if you like :-) around the middles of the track links as you assembled the track. If you left one stud worth of "air space" in the middle of each link (and thereby forced the track to be even bigger, in order to go around its drive and guide wheels moderately smoothly), you could non-destructively add quite a good pad of rubber to each link.
Hey, there's a thought - would the train-wheel rubber rims, or stationery rubber bands of similar dimensions, fit nicely around these links lengthwise?
I can't help but think that Technic Bumpers could be used for this purpose too, but mounting them solidly might be a big hassle.
Perhaps there'd even be a way to work the various Technic Arrows into a track design - I'm thinking something very directional, with the arrowheads all sticking out towards or away from the direction of travel - but I suspect they're going to remain in their current role as Instant Walking-Robot Feet.
19 September 2008 at 3:30 pm
Yu have the original Excavator? You lucky sod! That's the one Lego kit I've always wanted, but never managed to lay my hands on...
Maybe I'll get the new one, for old times' sake...
...and I just looked on ebay and found the old one for sale... aaargg
19 September 2008 at 9:34 pm
Now this takes me back.. I had the both the Universal Motor Set and the Gear, Axle & Brick set that had the link chain and spiky gears. I found the motor perked up considerably when powered by a monster 9V battery from an old radio. It made great dragsters when combined with the large diameter steel axle wheels. Sadly my fun came to end when it ran onto our shag pile rug, tangled itself up and stripped its internal gears. I think I still have it, anyone got any of the internal bits?
22 September 2008 at 7:53 am
Linear actuators baaah. I liked the pneumatics.