US Truck 1 . US Truck with aerodynamic approach scale 1:17,5 with PF. It features solid axle suspension on front and rear axles and Ackerman steering. .
After I finishing my first truck I wanted to build another one. It would be easy to build a copy with another color scheme or change some details, but that's not what I wanted. First I started working on a log truck again, that's the type of truck I wanted to build in the first place back three years ago when I started building LEGO models again. Like the first attempt, this attempt ended up in building a completely other type of truck. The inspiration to build a more aerodynamic truck started with a picture I have of a Freightliner. I spend a holiday in the US, it's decades ago, in which I took a bunch of pictures of US trucks including this Freight. Searching the web I did find loads of other pictures and so I started designing this truck. Like with the first truck I did not try to create an exact copy of an existing truck, I've been inspired by all the famous US truck brands. I do not have enough LEGO to start building it from scratch therefor I used MLCad.
Some details are used too in my other US Truck, but again I wanted it to be completely different so a lot of new details had to be build. I specifically like the filler cap right next to the exhaust. This is inspired by that Freight I mentioned before. Like with the first truck I had to equip this truck with all chrome exhausts, I like that on the real trucks so much, I couldn't stand it... :-)
For more pictures on this model click this to check out my Brickshelf Gallery.
I did not spend much time on the interior mainly because there's not much room left because of the PF that consumed most space. Here you'll see the seats and one nice detail, the cups... :-) The sleeper holds the Battery Box, PF XL motor and the length differential I'll explain later on.
At the moment of taking these pictures no light units where installed, but now they are. This picture also shows the fifth wheel. Again I wanted this part also to be functional, not only the looks. One night I just sat and started thinking and trying and in the end I came up with this design.
The steering system is the same again as in my other US Truck, I did spend so much time developing and improving this system that I thinks it's worth being used over and over again. The only part of this truck that can be opened is the hood, instead of an engine, opening the hood shows the PF M motor, Rubber Belts, Worm Gear and other gears that drives the steering. Because of the partially wedged shaped hood and cabin opening doors where not an option. I'm glad I did not spend time on opening doors because later on it came out that I needed the strength of the day cab and sleeper to avoid the model to bend under its own weight...approximately two kilogram.
One of the reasons it took so long to build this steering system is the Ackerman geometry. I wanted it to be incorporated, but that wasn't easy at all. Once again, by not giving up trying I managed to overcome the problems.
Because of the limited space in this truck frame I decided to give both rear axles their own drive shaft. As you can see on this picture I did separate them by using a length differential. First attempts did not have this, but this leads into creaking and slipping gears so I had to come up with some sort of solution.
Because of the skirts on both sides of the truck I had to make the frame of this truck two studs longer then the original one. This sounds much easier then it is to actually execute this. Instead of using three 1 x 16 Technic Bricks plus two Technic Slope Long (Wing Back) like I did on the first truck I had to reconfigure both frame beams. From the very beginning of building a truck frame I choose to be inspired by real life trucks. Two strong beams starting at the front bumper and ending at the rear part of the trucks are mainly the bases the entire truck is build around...in real life and therefor in my models as well. Because of this approach I had to use Technic Bricks because I needed the holes to attach parts to like drive-line, steering, suspension system and so on. This is mainly the reason why adding two studs like I mentioned before was not that easy, but I managed... :-)