42028 Bulldozer – Remote Controlled

 Alternate model, Construction equipment, MOC  Comments Off on 42028 Bulldozer – Remote Controlled
Sep 102015

Hi all, here we are for a new mod !

42028_A42028 is a nice small bulldozer with 2 functions, a blade on the front and a ripper on the rear. With its chains, it’s very realistic, but as usual with technic chains, totally unplayable on a smooth ground. The front blade is manoeuvrable thanks to the exhaust pipe. This is a good idea because it’s so much discreet than the traditional hand-of-god gears. The rear ripper has no real use, it’s just a mechanism added to complete the model, you can’t play with it at all, point.


42028-RC-RenderingMy son was playing with it, when i realized that it would be much more fun if it was fully remote controlled. I started with the tracks, the more elegant would have been to add a subtractor, but the lack of space led me to install two motors, one on each side and driving its own track. I chose to gear down a lot to increase torque, lowering speed, after all, this is a construction equipment, not a race car !
The front blade received also it’s own motor, and lots of gearing down, it’s heavy and the mechanism requires also lots of torque.

The main challenge was the battery box. Firstly I wanted to use a traditional PF battery, but it’s so huge that i could not find a place for it without altering severely the overall look of the bulldozer, mainly by modifying the cabin. Another point is that the new Lego tracks are wide and there’s not much space between them under the cabin.
I remembered then that my son has Lego trains, a quick raid in his bedroom and I stole him a battery box. They’re smaller, less powerful although, but smaller, which was the reason why I took it. I decided to install it in place of the ripper, it’s useless, so, let’s force ourselves to use it ! Another good reason to put it at the rear is that it equilibrates the weight of the bulldozer and improves the contact between the chains and the floor. Last thing, the 2 Power Function infrared receivers, the last free space was behind the cabin, it’s just wide enough, easy choice. This is not very handsome, but it’s my choice. Another possibility was to place them on each sides of the bulldozer, but the infrared signal is weak and I prefer to have them located high over the model than on its sides.

The rests of the modifications were more easy. The tracks are a bit shorter, 30 links instead of 32.

The summary of changes is as follows:
– Removal of the fake motor
– Removal of the rear ripper
– Adding of a motorization of the 2 tracks
– Adding of a motorization of the front blade

Instructions are available for free as a PDF file, you won’t need the original booklets and the part list is in the file. Feel free to download them, experiment and report your comments here !

>> Download :   42028 - RC - PDF (1755 downloads) <<



Aug 032015

A few months ago, I bought a 42000 Formula 1 from Bricklink. It’s a pretty nice model, i like the suspension arms and the way it’s designed. I kept it for the holidays and last week, I built it. It was a rainy week in the west of France, rainy and cold, and I had plenty of time to spare so I decided to disassemble it and to create a new moc from that box.

4After awhile and a good advice from my lady, I chose to create a quad. At first, she wanted a dragster, but it would have required a pair of smaller wheels for the front axle. Choosing to build a quad was a good idea for me, because, like I said earlier, i really, really like those suspension links and quads usually have those kind of levers on their axles.

Here’s the result of 4 periods of 2 to 3 hours of building. The quad has the following functions :

  • Suspended rear axle
  • Suspended front axle
  • Steering axle without rack and pinion, it’s based on a lever linked to the handlebar
  • Openable rear trunk
  • V4 motor located under the driver’s seat

It’s made of roughly 530 pieces, mainly black and white ones, the red ones being left apart because red does not really match to the police colors. To match reality, I did not placed a differential on the rear axle. Technically, it’s a really bad idea because the big flat wheels of the formula 1 won’t allow the quad to turn very well, they stick to the ground and dont slip at all, but at least, it looks real. If you build that quad and wanna play with it, I advise you to be wise and to place a differential on that rear axle, or if you dont want to, just unlink the 2 wheels and to keep only one to drive the fake V4 motor.

If you build it with different colors, i’ll be happy to see a few photos !

Downloads :