Sariel.pl

Small model of the iconic Peterbilt 359 truck, inspired by the HTC races organized by the DoubleBrick community. Features pendular rear suspension, openable bonnet, engine’s model and lights.

Datasheet:

Completion date: 14/01/2010
Power: electric (Power Functions)
Dimensions:  length 49 studs / width 13 studs / height 23 studs
Weight: 0.96 kg
Suspension: front: none / rear: pendular stabilized with rubber axle joiners
Motors: 1×71427, 2x PF Medium

This is a rare example of a construction inspired entirely by a competition specific for a given community. Namely, it was inspired by the Hard Truck Contest invented and successfully introduced by the DoubleBrick community. The exact description of the contest can be found via respective link, it suffices to say that the contest brings together small models of trucks (usually 14 studs wide), built with an accuracy and attention to details that make them a wonder to behold. I’ve spent some time watching the videos from the HTC races not to follow the course of the competition, but to simply enjoy the view of the beautiful models. I was hoping to get the builders from my country interested in similar races, and the best way to get their attention seemed to build a prototypical vehicle.

Having previously built model of the Kenworth W900, I have chosen another one of the most iconic American trucks, the legendary Peterbilt 359. When scaled accordingly to the size of the wheels used in HTC races, it turned out to be just 12 studs wide. The original HTC vehicles are 14 studs wide – I don’t know the reasons for which such a standard was accepted, perhaps it was simply more convenient or based on trucks with different wheels size, but I decided to take the challenge of building a 12 studs wide model. And it was quite a challenge – it was my goal to use identical wheels on all axles, which meant that I only had 6 studs of width available to make the front axle steered (original HTC trucks often use narrower front wheels).

As the idea of making the front axle suspended seemed mad, I focused on the rear axles’ suspension. Since the axles are based on the 5×7 open liftarm frames with differentials inside, it was natural to make them pendular. Concerned about the truck’s stability at high speeds, I have used rubber axle joiners as the suspension stabilizers – they were simply attached to the truck’s frame above the rear axles, and acted as shock absorbers whenever the suspension changed its angle. It should be noted that it’s an obvious solution to use some sort of a simple supporting structure between the frames of axle #2 and #3, but I wanted to model the original wheel span, and the model was simply too small to add an extra space for such a structure. It has slightly degraded its performance – the driveshaft connecting axles #2 and #3 is being pressed by the truck’s weight, and hence the truck is somewhat slowed down.

I have started to built this model with its both ends, separately with front and rear axles. It resulted in an uncommon frame design – the front half of the frame is purely brick-built, while the rear one is 100% liftarmic. Both halves are connected under the sleeper module, but the rear half lacks the stiffness typical for bricks.

The chassis design is pretty typical – both drive motors are located in front of the rear axles, and the steering motor is located behind the front one. Due to limited length of the chassis, I have used  a 71427 motor for steering. It’s located below, and partially inside the cabin, while the drive motors have been hidden under the mock-ups of the side fuel tanks. The final drivetrain’s gear ratio is 1:1.43.

Extra attention was given to the bonnet – I wanted it to be openable and to have a model of the engine underneath it, just like I’ve seen in the original HTC models, but I also wanted to take one more step and use PF lights in the headlights. It was eventually achieved by resizing the bonnet’s width from 7 to 6 studs. This is wrong in terms of the scale, but it makes the bonnet much more structurally solid.

I have deeply enjoyed building this model – perhaps partially because it took just roughly 4 days to complete. It was a valuable experience, showing that e.g. brick-built exterior may look pretty but is quite heavy – this is a really small model, but it weights almost 1 kg (just to give you a point of reference, 1 kg is a minimum required vehicle’s weight according to the rules of Polish Truck Trial). Still, it was reasonably fast and fun to play with, despite its pretty limited functionality.

Photos:

Video: