Strain, mass, and poor part design.

I finally unpacked the first chunk of Lego last night and started rebuilding the Legobot's drivetrain. While it looks workable now, it's amazingly weak. The Lego turntable design has a few minor flaws that will probably plague my design for at least another few days.

See, the turntable have girders on the top and bottom platform which cannot be removed. This means that I'm forced to deal with additional spacing between the arms and the gears. This space means less reinforcement, which means that at high speeds, my current design is liable to fly apart. D'oh.

So I have a decent concept, but I need to compress is some more. Maybe Sunday. I've got a holiday party tonight, and who knows what tomorrow.

Or maybe skip the transformation...

If I make a transforming motorized robot, it will *not* also be bipedal. While that would be amazingly cool, it's very tough to make a transforming robot with that much flexibility, due to the lack of small motors, and the power draw.

So, I'm already working on the transforming 'bot. That much is relatively easy, it'll just run on a tricycle system to get around, and I'll probably work shock absorbers into the design and boost the torque to make it handle any bumps in the way.

Once I'm done, though, there are still other issues.

1) I really want to make a minifig-scale Eva unit. I'll eventually do so, but motorizing that isn't going to happen. The Eva design is just too light and graceful to allow motorization. Maybe a Zaku lends itself to motorization, but an Eva does not. In fact, it's not even much of a robot on the inside, it's more of a humanoid beast in armor.

2) I want to make a pure motorized biped using only Lego parts. I've got some ideas to implement autobalancing hips and autocorrection for the ankles relying on nothing more than gravity and decent design, but I'll need more parts, likely from the new 4x4 offroader, or the Super Street Sensation. They've got a lot of interesting parts for allowing a drivetrain that allows shock absorption, steering, and actual power transmission to the same set of wheels. Again with the need for special parts (some of which come with Bionicle sets!) but this time adapted for joint design. Also, the more ways that I can run everything through concentric axles, the better. I've already got a design using turntables and differential boxes for combining 3 axles with the same center (don't ask, it's amazingly complex to describe,) but it can't go through a bend yet.

Other good part sources:

Throwbots: Good for ball joints and some (not many) custom connectors.
Roboriders: Good for gearboxes, they may work well for a worm gear based armature.
Bionicle: Good for ball joints, but more importantly, the cheapest source of the newer ball gears.

The nice part is that they're all under $10 a set, making them the best bargain for building mecha.

The other stuff that might be nice are angle blocks, and three or four sets like the Silver Champion, C-3PO, and some others that I'm missing to get the styling pieces. They're an excellent quick way to do some of the trickier parts of the body plating. Since the overall bot is going to be huge, more large armor plates means less time on styling, and less mass for the armor as well.