Wednesday, December 27, 2006

A gearbox that works (and more)

It's been a few days, and in anticipation of 15,000 Brickshelf Gallery hits, I'm writing another entry.

The gearbox design in the last post was terribly inefficient. It had to many gears and much friction; two motors could barely move the truck at high speed. Having an axle push onto a postage scale, I could measure the torque at each point along the drive train. There was much loss at many points. I've rebuilt it now, to a much more compact design.

After getting the gears in, I squeezed in a pneumatic shifter. The switch will be somewhere in the cab, allowing you to switch between 16:24 and 24:16 on the fly. For those of you familiar with the technic driving ring setup, you know it clicks when changing gears. I had to file off the ridges on the axle connector so the small piston would have enough power to slide it.

Although theres some gear slipping still to be fixed, I'm confident this truck will be able to handle a road train!

Next on the TODO list? Get the stairs working slick, fix gear slippage, and thread all seven pneumatic hoses up through where the cab hinge is- to where the compressor will be. Also I should make sure a trailer wond knock into the back of the gearbox on turns.