Dozer
My first tracked vehicle, features a subtractor in the drivetrain, illuminated engine block and a pendular suspension.
Datasheet:
Completion date: 06/07/2007
Power: electric (wire-controlled) / pneumatic (fed from internal electric compressor)
Dimensions: length 34 studs (plus blade) / width 22 studs / height 16 studs
Weight: 0.89 kg
Suspension: pendular bogies
Motors: 2 x 71427, 1 x 47154
Pneumatics: 1 circuit with electric compressor
My first tracked vehicle ever, not too big, but packed with features. The most important one is a drivetrain that consists of a subtractor. Subtractor basically connects two treads to two motors so that one motor drives them in the same direction, and the other one drives them in opposite directions. As result, it is possible to drive with one motos and steer with the other, just like in a car. That solution has several advantages, including ability to turn in an arch (while both motors are running), and easier steering, and it makes the vehicle able to drive ahead in a perfectly straight line, which is often impossible when treads are drive by two separate motors. There is a more exhaustive explanation of the subtractor mechanism in the Ideas category, and here is just a basic diagram:
The use of the subtractor makes it possible to use a V8 piston engine driven by the drive engine (kinda difficult if you have two motors, each driving one tread). The engine block, entirely in the trans-clear color, is illuminated from below by a LED brick from Exo-Force sets.
Other features include a detachable battery box, and an internal electric compressor with a manual valve, raising and lowering the blade. The dozer has a very simple suspension, that worked well against any obstacle that relatively weak 71427 motor was able to put the dozer through.
