Author Archives: Justin Watkins

More remote control

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In my quest to build a reasonable remote controlled car in LEGO Technic, I tried rebuilding the 2015 off road set 42037. There is space to fit an L-Motor and a servo in the chassis (at the expense of the pistons mechanism for the engine). The battery box fits in the back of the roll-cage, and the IR receiver sits in the driver’s seat.

From a space perspective, this seemed a promising start. The motor shaft has an 8-tooth gear which drives another 8-tooth gear on the differential shaft. I tried various options for holding the drive shaft firmly in place so the gears wouldn’t cog.

This option is sturdy enough that the motor shaft remains in place. In the car, I used 2L and 3L technic liftarms. A stronger connection can be made using 2L (shown in blue) and 3L  (shown in grey) thin lift-arms which have cross-holes for a blue pin-axle.

In the above picture, the dark grey 8-tooth gear is on the motor shaft. (with the yellow half-bush). The light-grey 8-tooth gear is on the tan crown gear that meshes with the differential.

Unfortunately, after a few minutes of play, the L-motor is powerful enough to cause damage to an 8-tooth gear: the teeth are forces sideways (in an anti-clockwise direction in the photo below).

Unfortunately there isn’t space to move the L-motor up vertically without seriously changing the structure of the car. Back to the workbench.

40 years of tractors

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Lego Technic tractors 40 years ago, LEGO introduced “Technic”, a range of sets aimed at older children. The red tractor (set 851, introduced 1977) was one of the first sets in the new Technic range. Most of the bricks are standard LEGO pieces, but the Technic range also introduced axles, gears, and bricks with holes to mount the axles. The tractor featured working steering, and the implement at the back rotates when the tractor is pushed along.

There have been about 10 tractors in the Technic range over the years, of various sizes and qualities. In 2016, LEGO released a new model (set 42054), based closely on a real tractor, the Claas Xerion, with a logging crane attachment at the back. This model includes an electric motor to power lift and rotation of the logging attachment, and the rotation of the cab.

The two models embody two separate developments over the last 40 years. Tractors themselves have changed dramatically, in terms of size, power, driver comfort, controls and many other aspects. And LEGO Technic has also changed over that time. The Claas model contains hardly any “traditional” bricks, and instead uses stud-less beams connected with pins and axles for its structure, as seen in most of the current Technic range. This leads to a very solid robust model (unlike early Technic models, which relied a lot on clutch power between the bricks, and were often flimsy).

The instructions for both models are distributed in paper form. The instruction book for the red tractor also includes instructions for four or five alternative attachments for the back. The book for the Claas only includes the instructions for the tractor and the logging attachment: plans for an alternative attachment are available on the Internet. The World Wide Web didn’t exist when LEGO introduced the Technic range.

I enjoyed rebuilding 851 for nostalgia. The build is somewhat frustrating in places because it is flimsy. The instructions are also less detailed : kids had to do more thinking and counting on their own back then. I enjoyed building 42054 for different reasons: it is quite challenging to assemble, like a 3D jigsaw puzzle, and quite robust from the start. It felt like half the instructions concerned the construction of one sort of frame or another from smaller elements. Then it all comes together at the end, and there are a number of “aha” moments when one realises what certain features are for. Especially that rising rotating cab. The guy who designed that is a genius.