Model of an Italian WW2 military truck designed for Truck Trial races. Features 6×6 drive and full pendular suspension.

Datasheet:

Completion date: 06/08/2010
Power: electric (Power Functions)
Dimensions: length 53 studs / width 25 studs / height 33 studs
Weight: 2.166 kg
Suspension: pendular, stabilized with shock absorbers
Propulsion: 1 x PF XL motor geared down 8.337:1 (low gear) / 5:1 (high gear)
Top speed: uknown
Motors: 1 x PF XL, 2 x PF Medium

My first Truck Trial vehicle equipped with a gearbox. It caught my attention when I was looking for something more complicated after building several simple 4×4 vehicles. There were two main reasons that made me model this particular truck: its excellent approach and descent angles, and its pair of spare wheels. It was a rare solution, present in a number of WW2-era vehicles, to have a pair of spare wheels mounted on the sides of the chassis, relatively low, and with ability to rotate freely. It was helpful while climbing over obstacles, as these wheels had a good chance of preventing the chassis from getting stuck on the obstacle. For some reason, this solution apparently did not survive to this day.

Technically, the Fiat was supposed to continue and develop the solutions from my two previous Truck Trial vehicles – Hummer H1 and Jeep Wrangler Rubicon. It was built around a brand new studless chassis, unlike the two mentioned vehicles which had studfull chassis. It was also equipped with a simple linear 2-speed gearbox that was controlled remotely with an extra PF Medium motor, and it had unusual rear axle with 4 wheels. While the original vehicle has three regular axles, I decided to combine the two rear axles into a single pendular module that would have 4 wheels suspended on it. It has two advantages: firstly, while the module itself has a transverse pendular suspension, the wheels had a longitudinal one, so their flotation was better that it would be in case of two separate pendular axles. Secondly, a combined module needed much less space inside the chassis, thanks to which I was able to put the model’s battery behind it and the gearbox in front of it. Finally, the Fiat’s chassis used pendular axles mounted on the large Technic turntables, with both drive and steering transferred through the middle of these (drive transferred through a solid driveshaft and steering transferred by an empty differential sitting on it), which eliminated the problem of shock absorbers pressing on the driveshaft and thus creating a significant friction on it. Using the turntables resulted in slightly worse ground clearance, but has greatly improved the structural robustness.

The gearbox was made of a module attached to the PF XL motor, that was supposed to slide inside the chassis back and forth by a single stud, thus shifting the gear. By attaching the drive motor to it, I was able to eliminate a complex transmission system between the fixed motor and the sliding gearbox (this idea was first presented by  Emilus). The gearbox has a very sturdy structure and performed well during the initial test. Only double bevel gear wheels were used inside it, to minimize the problems with engaging/disengaging.

The model was equipped with a single body, which was completed just hours before the race. Despite appearing tall, the body has relatively low centre of gravity thanks to an openwork structure above the cabin and the cargo box. I didn’t have time to care about details such as doors, but at least I made the windshield able to be folded down, just like in the real truck. The cabin had a very basic interior and a simple inline piston engine driven from the driveshaft.

The truck’s performance in the race was arguable. On one hand it has shown good agility, surprising stability and I was able to drive it with great precision. On the other, it was pestered by constant problems with the gearbox, because the gears inside it started to slide along the axle under stress. I was able to temporarily fix it with tweezers until at some point the axle popped out of the drive motor and there was no way to put it back in without taking major portion of the body apart. It has forced me to give up and withdraw from the race.

At first I felt like fixing the gearbox would solve the model’s only problem, resulting in an excellent Truck Trial vehicle. Thus I was obviously planning to use it in the next race. Unfortunately, as I started to rework the gearbox, more problems occurred. The redesigned gearbox needed serious modifications of the chassis. Once the chassis was completed, the rear axle and the drivetrain started to fail. I have made several attempts at solving these problems, until I noticed that the knob wheels in the rear axle’s drivetrain are being worn down very quickly, most likely because of the resistance generated by four wheels. At this point I decided to give up on the truck, on assumption that combining two rear axles with large tires into a single module with drive transferred to by just a pair of knob wheels was a bad idea. The combined resistance of four wheels was simply too much for the knob wheels to handle.

The model became quite popular with the other Truck Trial contestants because of its unusual look and wheels set-up. It became known as “the revenge of Mussolini”, and my decision to give up on raised many protests.

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Model of a Scania R500 truck modified as a racing version. Features full suspension, powerful propulsion system with two independently powered RC motors, lights, custom stickers, cabin with full interior and opened doors.

Datasheet:

Completion date: 05/07/2010
Power: electric (Power Functions)
Dimensions: length 48 studs / width 18 studs (not including the side mirrors) / height 27 studs
Weight: 1.86 kg
Suspension: front – independent / rear – dragged axle
Propulsion: 2 x RC buggy motors powered from separate batteries through separate IR receivers, geared down 1.66:1
Top speed: 7.92 kmph
Motors: 2 x RC, 1 x PF Medium

I’m really fond of modern Scania trucks. I have built a model of a Scania dumper truck in 2009, which – while being technically simple – has gathered a significant acclaim because of the quality of its aesthetics and because of the number of details incorporated. I was not fully happy with it, however, because I found the cabin’s look inaccurate and simplified. This was the primary reason why I started to toy with an idea of building a much more accurate Scania model in a racing truck version. Right from the very beginning I wanted it to be red with some chrome and metallic silver elements, which is why I was not convinced of realizing this model, as it had to be expensive to build. Over the time, however, I have gathered a number of chrome and metallic silver elements, and I have determined that it would take less red parts that I initially thought, as Scanias usually have their lower part of the cabin plain black.

Building this model became eventually achievable when I designed the complete exterior of its cabin using the MLCad software and when I bought four metallic silver wheels (to go along with the two I already had). With MLCad model serving as a very accurate shipping list, it became only a matter of time before the red racing Scania would be built.

I have built a number of racing trucks before, which provided a significant building experience. Based on it, I didn’t want to focus just on the aesthetic side of the model – I wanted it to perform well too. The key to surpass the performance of any of my earlier racing truck was the use of RC buggy motors for propulsion, as they offer somewhat more mechanical power than PF XL motors do, and they are also more suitable for fast vehicles, with less gearing or no gearing whatsoever needed. To use two RC motors at the same time while keeping the model’s weight reasonable I had to use the 8878 battery as a power supply. Since it was downright impossible to power two RC motors to a single battery because of their extremely high power consumption, I had to no other choice but to get a second 8878 battery. Thus, the model needed some serious investments before I even started to build it.

The model’s chassis was initially built with both RC motors using no gearing whatsoever – both motors were simply connected directly to the rear axle. Thanks to their convenient shape, it was possible to use them as the main bearing structure for the whole rear suspension which dramatically increased the internal space available inside the chassis. Thanks to it, chassis housed not only two 8878 batteries and two IR receivers, but also PF Medium motor for the steering, with all these elements located between the front and rear axle.  The use of two IR receivers was necessary – since the drive motors were independently powered, they couldn’t be connected electrically and the only connection between them was rigid rear axle. With the initial rear axle set-up it was possible to use a differential between the motors but I dropped this idea for two reasons: firstly, a rigid axle was more efficient (no elements prone to slipping) and much less prone to a mechanical failure, and secondly the rear wheels had only limited traction while turning, since majority of the model’s weight was located above the front axle.

The independent front suspension was based strictly on my previous experiences with the models of racing trucks and used a blend of suspension components from the Lego sets 8448 and 8297. To handle the weight of the cabin, the front suspension was made very stiff, with two hardest shock absorbers set almost vertically above each front wheel. I have also used thin wedge belt wheels between the actual wheels and the chassis to prevent the expensive metallic silver wheels from rubbing away against the chassis – as it already occurred earlier, with slower and lighter racing truck models. The steering system had to be adjusted to the speed and the weight of the model, which is why it used a relatively insignificant gear reduction and no safety clutch whatsoever.

As for the aesthetic side, I came to think that the main disadvantage of my Scania dumper model was the fact that its distinctive front grill was completely flat, with air intakes simply marked with bricks of a different colour. Therefore I have put a lot of effort into inventing a system of recessed air intakes, which was eventually achieved with the use of 2×2 tiles. With plenty of internal space available in the cabin, this system could be used with a relative ease, providing an excellent aesthetic effect, as anticipated. Other than that, the cabin houses not only its own interior, but also a PF switch which controls all the lights (the lights are coupled with the drive motors and go brighter as the truck speeds up, so the switch is used primarily to turn this feature off when not needed, and thus to save energy which is so highly demanded by the RC motors). With 10 PF LEDs installed in the cabin, the switch takes a lot of space to contain 10 PF plugs with their respective wires. I was able to fit it in efficiently by mounting it on its side, so that the plugs are kept horizontally below where passenger’s seat would be located normally.

An important thing to know is that the real racing trucks are usually subjected to very radical visual modifications which make them look pretty much unlike any stock vehicle. Being a huge fan of the original Scania design, I wanted to avoid this. Therefore my approach was to use a stock Scania R500 as the model’s point of reference, with a few typically racing elements added so as to minimize their impact on the model’s look. Eventually, it ended up with five such elements: the four extra headlights (which are not really used for racing, but I viewed it as an opportunity to experiment with the PF LEDs a bit), the racing air intake on top of the roof, the engine moved back from under the cabin, the large spoiler instead of a fifth wheel, and a custom rear bumper. Additionally, the cabin’s interior has been arranged in a ‘racing’ fashion, with a mock-up of two blue N2O bottles replacing the passenger’s seat and with a distinctive safety net in the driver’s window. The net itself is not a Lego element – I made it as a sticker, by printing a black square with a dark grey grid on it, carefully cutting it to net-like shape with a modelling scalpel, and then painting its other side black with a felt-tip pen (I could also print the black square on both sides of the same sheet, but since large portion of it was meant to be cut out, it felt like a waste of ink). Eventually, the paper net was fixed to the door with a thin stripes of a Scotch tape on its edges.

The other, more traditional stickers, have also been intended to reflect the racing ‘nature’ of the model, with the most obvious example being a note in front of the driver’s window that says “Tävlingsfordon”, which is Swedish for “Racing vehicle” (all stickers use Swedish as a nod to Scania’s country of origin). The sticker above the windshield says “Sagodjur”, which can be translated as “Griffon” (the animal used as Scania’s brand mark) and which was intended to look like driver’s nickname, while both front and rear registration plates feature a miniature Scania’s griffon head and a number 5AR13L, which is an obvious reference to my own nickname.

As the model was getting close to its final weight, the propulsion system started to show signs of weakness. To solve this, I have moved the rear axle back a little while keeping the motors intact, and  added a 1.66:1 gear reduction between the motors and the axle, with gear wheels doubled to handle the significant torque. It has greatly improved the overall performance of the model by making it faster and decreasing its accelerating and braking times, but it also made the chassis seem a bit longish and it made the rear suspension very soft. The manoeuvrability of the model, on the other hand, was not noticeably affected by this change. I have ran a number of tests with Lego speedometer mounted on the truck and the top speed it recorded was 7.92 kmph. This is more than any of my earlier racing trucks could achieve, but I feel like it could be surpassed by this very model. The model clearly has plenty of power in the drivetrain and appears to best build up its speed in long runs. It led me to believe that it could break 8 kmph given a long section of a perfectly smooth floor (unlike the floor I had to run tests on). Anyway, 7.92 kmph is a fairly good result, as it requires model’s wheels to rotate at over 600 RPM (that is 10 rotations per second) and – given the model’s 1:17 scale – corresponds with the speed of 135 mph in the real life.

The truck was highly acclaimed for its aesthetics and performance, both emphasized by the video which took me 4 hours straight to produce. It was my second construction to use a slow motion footage (shot with Casio Exilim FS-10), and my first construction to be accompanied by 1200×800 px photos rather than usual 800×600 px, as I really liked the look of the model and the results of its photo-session.

The model will be kept intact at least until a public event that takes place on July 10th, giving my fellow LUGPol members the chance to see, and perhaps even to drive it.

Photos:

Work in progress photos:

Video:

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Media reference:

Legocn.net (Chinese only), Town Truck Brick! (Spanish only)

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My first Truck Trial vehicle for 2010. Features 6×6 drive and full independent suspension.

Datasheet:

Completion date: 10/04/2010
Power: electric (Power Functions)
Dimensions: length 66 studs / width 25 studs / height 31 studs
Weight: 2.624 kg
Suspension: full independent with swinging half-axles
Motors: 1 x PF Medium, 2 x PF XL

My first 2010 Truck Trial vehicle had a rather difficult creating process. Even though I started to build it more than a month before the race, the final version was created under two weeks time. It was mainly because of the chassis, which wasn’t stiff enough to handle the torque of two PF XL motors, and got completely rebuilt three times.

The goal of the Tatra was to have a realistic suspension with swinging half-axles which are typical for all Tatra trucks. It was achieved by removing differentials and transferring the drive with the knob wheels. The modern Tatras have their half-axles offset a bit – this was not modelled in order to keep the steering system simple and sturdy.

The steering system was located entirely between axles 1 and 2 and consisted of two complex sliding beams with links. The beams were sliding in different directions for axle 1 and 2 and were controlled by a driveshaft whose direction of rotation was inverted in between these axles. Because of insufficient internal space both beams were given the same gear ratio, resulting in an identical steering lock of both axles.

The drivetrain was kept as simple as possible, and the main portion of it, including the drive motors, was located between axles 2 and 3. Both drive motors were located between two stringers of the vehicle’s frame, one behind the other, and were not connected directly but by a common driveshaft located beneath them. Since the space between axles 1 and 2 was occupied by the steering system, an extra driveshaft was needed to transfer the drive to axle 1. It was located above the axles, under the cabin, and it transferred the drive to a V12 piston engine located inside the cabin as well. Thus the transmission of the axle 1 was located in front of it and in order to prevent such a vital mechanism from damage, a cover made of liftarms was installed before the axle.

The body of the truck was rather simple, with the cabin built almost exclusively with the new Technic panels to reduce its weight. The cargo case was simple and shallow, and there was a transportation handle built into vehicle’s frame behind the cabin – a solution I’ve used in some of my earlier Truck Trial vehicles, and which proved very useful as every Truck Trial race involves a lot of carrying the vehicles around. The cabin had a safety cage built on it, which was meant to give it extra stiffness and a more Tatra-like look, as the real Tatras participating Truck Trial races are always equipped with distinctive external safety cages.

The Tatra suffered from the same thing that most of my earlier Truck Trial vehicles did – insufficient amount of testing. The problem with this kind of vehicles is that they can be only fully tested once finished, because test are most revealing at full vehicle’s weight. As you can guess this implies that a finished vehicle has to be taken back apart if it fails tests, and to avoid this arduous procedure it is a common practice to test just the chassis alone with extra load on it simulating the anticipated body’s weight. It doesn’t always work as it’s difficult to precisely anticipate the final weight of the body if it wasn’t built yet, and it’s almost impossible to simulate its exact weight distribution. I have to admit that being short on time, I have only given a minimal amount of testing to the final version of the Tatra – this was also because I was afraid of damaging it right before the race.

During the race, the model experienced two problems – the first was a failing transmission to the front axle, which snapped. There were also minor problems with axle 3, which meant that only the middle axle worked at full efficiency, and it didn’t really help while climbing obstacles. The reason was a faulty construction of the chassis – the suspension itself worked fine, all the snapping occurred in the transmission system inside the chassis. The second problem was sideways stability. While building this model, I have given a lot of attention to make sure its weight distribution prevents it from falling forwards or backwards – and I succeeded. The sideways stability, on the other hand, proved much below what could be expected. It seems that the problem was not related with this particular vehicle but with this type of suspension in general, as exemplified by another Tatra model, the T813 built by Lomero and used in the same race. His Tatra had the same suspension type while keeping a considerably lower silhouette which suggested a better stability. Surprisingly, it kept tumbling over a couple of times per each section of the race. It convinced me that it’s practically impossible to model the Tatras’ suspension system in such a way that the resulting model is stable.

Finally, the model’s drivetrain was pretty much obsolete in terms of the rules used in Polish Truck Trial. The rules take power-to-weight ratio of each individual vehicle into account in order to prevent builders from winning by simply adding more drive motors. Each vehicle is given its own points conversion rate based on its power-to-weight ratio, which basically means that you can win with a vehicle that can race despite having a very low power-to-weight ratio (resulting in high points conversion rate) or with a vehicle that has a high power-to-weight ratio but is very fast and can complete the race in short time. Tatra was neither of these cases – it had a relatively high power-to-weight ratio because of two PF XL motors, while not being really fast. The current tendency among the top Truck Trial builders is to use complex gearboxes with 3 or even 4 gears available. Thus even a truck which is much heavier than Tatra can be driven by a single PF XL motor whose gear ratio is changed as needed by the means of the remotely controlled gearbox. This results in a models that are slow but still capable, while having an extremely high points conversion rate. Two good examples of such trucks are Emilus’ GINAFs and Atr’s Volvo – both being large, heavy, and driven by a single motor.

Upon observing the race, I’ve decided to abandon the Tatra project. While the transmission problems could be solved given a sufficient amount of testing, the suspension system would still not provide satisfying stability. With the next race being only two weeks away, I decided that I would focus on building a new, small, lightweight and efficient vehicle rather than fixing Tatra. This is also the reason not to document the Tatra’s technical solutions – I think it’s better to build something more successful and then document it once it’s solutions are proven in a race. Right not I have a complete front suspension of my next Truck Trial vehicle, which looks very promising, and if it succeeds in the race, I intend to publish a complete instruction for it.

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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.

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Model of a dump truck based on Scania CB8x4. Features full suspension, two axles steered with a different steering lock, elevated cargo case, full interior, lights and custom stickers.

Datasheet:

Completion date: 23/11/2009
Power: electric (Power Functions)
Dimensions:  length 68 studs / width 20 studs / height 29 studs
Weight: 3.35 kg
Suspension:  independent on axles 1&2, double pendular on axles 3&4
Motors: 1×71427, 1x PF Medium, 2x PF XL

My first model after a short break. It was supposed to be relatively simple technically, but elaborated aesthetically. Basically, I wanted to built an improved version of my 8-wheeled dump truck created 2 years earlier, and my very good source of inspiration was Scania tractor unit by Pedro Agnelo. It was Pedro’s great work that made me want to built an entirely black truck with some dark gray elements. The trick that makes cabin’s door open easily (double opposing hinges) is also takes from Pedro’s model.

The first and second axle have been fitted with an independent suspension based on the 8297 set’s components. Both axles have been suspended on shock absorbers, with the axle #1 using doubled shock absorbers to support cabin’s weight. This solution – a very hard suspension of the front axle – made the entire model very stable; almost unbelievably stable for a model driven by pendular axles. The steering system was controlled by a 71427 motor located in front of the axle #1 (a place where a PF Medium motor was too long to fit in), with the usual 9:1 gear reduction and a safety clutch. Both front axles are steered by a single common steering shaft, which was a very good solution for two reasons. Firstly, it kept the steering systems of both axles synchronized at all times, and secondly if any of the steered wheels became stuck or reached the maximum steering lock, the whole steering system of both axles stopped without losing its synchronicity. The ratio of the steering lock of the two axles was 2:1, and it was achieved by using gear wheels of different size for steering. Two IR receivers have been hidden between the mudguards of the two front axles.

Axles #3 and #4 have been suspended on a special pendular module with a transverse and longitudinal swivel points.  Both axles have been pendular with a longitudinal swivel point, so that one wheel could rise above the other. Both axles have been attached to a central structure with a transverse swivel point, so that one axle could rise above the other. It was a compact and strong suspension system with a very good off-road performance, but it was unsprung which resulted in its poor stability as well as in the tendency for the wheels to slip under the torque (the suspension would rise one wheel off the ground if a sufficiently high torque was applied). Moreover, the truck suffered from a disadvantageous weight distribution: axles #1 and #2, which were not driven, handled most of its weight. Therefore the truck performed better while driving backwards than forwards, and some extra load above the rear axles was needed to improve its traction.

The drivetrain was unusual and realistic at the same time. There was a driveshaft connecting axle #3 with the motors in the chassis, but since the height of the axle  wasn’t constant due to the suspension type, it needed an extendable section. It was located between two universal joints and consisted of a number of wedge belt wheels connected by short axles. This is an old solution, found e.g. in the linear gearboxes, but it worked perfectly well here, even though it was handling a serious amount of torque.

It should be mentioned that the gear reduction in the drivetrain was really minimal, and the truck’s speed dependend heavily on the raw power of two PF XL motors. This approach has paid off – the truck was faster that my previous Kenworth Mammoet driven by two PF XLs too, despite being much heavier. However, when some demanding obstacles have been met, the motors would become so strained that they made the Lego battery go off for a moment.

The truck’s cabin housed the drive motor, full sets of lights including rooflights, and the battery along with a full interior that included a detailed cockpit, a steering wheel, seats, pedals, and even flags on the rear wall. The doors could be easily opened thanks to the double opposing hinges system invented by Pedro Agnelo. I have initially thought about using the cabin to house an automated trafficators system, but since I didn’t have a sufficient amount of lights, so I’ve decided to use it for an interior instead. The cabin couldn’t be lifted and its bonnet was fixed, not openable. The ‘Paul’ badge visible in front part of the cabin’s interior is a nod to the recent Lego 8258 set, which is a 4-axle truck too, and which has stickers with driver’s name intended to go in the very same place (the interesting thing is that set contains a number of badges with various names to pick from, including Paul as well as Wabra – the set designer’s surname). One thing I wasn’t happy about was the use of stickers to imitate the air intakes on the sides of the front Scania logo. I’ve decided to use stickers because I couldn’t find any brick of appropriate shape, but the result was way below my expectations.

The cargo case was elevated by two linear actuators driven by a single PF Medium motor located above the second axle. A 3:1 gear reduction was used, but no clutch, since the amount of torque required to lift the case up would make any clutch slip. Please note the very robust way in which the actuators have been attached to the chassis – it was intended to limit the torque losses caused by the actuators bending under the load. Moreover, they needed little space inside the chassis – basically just some openings in the mudguards of axle #3.

The cargo case was large, robust and heavy. I wanted its sides to be perfectly studless and to look interesting, which was achieved with a modular system of tiles. The system itself was just two layers of tiles thick, but to obtain proper stiffness the sides of the case have been made up to five layers thick. It could be built practically up to any length or height too. I believe the look of the case sides was worth the final, surprisingly high weight of the model.

I was pleased with the model despite its technical simplicity. While it was not large enough to house e.g. a gearbox, it was still quite functional, it looked very well, and its mechanical elements have been nearly invisible. Despite some rear suspension problems the truck was relatively fast and handled very well. I believe the key feature of this model was the realistic look, which is more than I need to justify the mediocre number of its technical features.

Photos:

Video:

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Media reference:

Bricks’n'Gears, Fascinating LEGO Model Of The Day, kockak.hu

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My fourth Trial Truck vehicle. Features 6×6 drive, two axles with different steering lock, full independent suspension and front winch with a quick release lever. The first vehicle powered by the Lego 8878 battery in Polish Truck Trial.

Datasheet:

Completion date: 05/09/2009
Power: electric (Power Functions)
Dimensions:  length 53 studs / width 27 studs / height 24 studs
Weight: 1.875 kg
Suspension:  full independent
Motors: 1x PF Medium, 1x PF XL

My another attempt to create a successful Truck Trial vehicle. Having my previous experiences with Unimog U900 and Star 266 in mind, I focused on a vehicle that would be small, light, low and simple. I have chosen to model the Alvis Stalwart truck because it was one of the shortest off-road vehicles with three axles. I liked the idea of having six wheels so close to each other, because if offered good traction and good weight distribution.

The chassis was complex but compact, built almost exclusively with liftarms. It consisted of two steered axles both of which were copies of the module I have used in the front axle of my earlier Hellbender model. The third axle was not steered. The intervals between all three axles were identical, which meant that the second axle was supposed to have 50% of the first axle’s steering lock.

The problem was that two aforementioned modules  were located in ‘mirrored’ positions in order to simplify the drivetrain. Therefore the steering driveshaft had to have its direction of rotation reverted between the modules. It was achieved with a simple setup of small bevel gears, but it also created a significant backlash. Initially there was 16-teeth gear in the first axle’s rack & pinion mechanism, and an 8-teeth gear in the second axle’s one. In theory it provided the desired difference in steering locks of two axles, but in practice that difference was heavily degraded by the backlash. I have solved it eventually replacing the 16-teeth gear in the front axle with a 12-teeth one. Coupled with the backlash, it created just about the perfect steering lock difference.

The drivetrain was somewhat complex, with two separate driveshafts for the third axle and for the two first ones. The model was driven by a single PF XL motor located just above the third axle, and the 8878 battery was located at the very rear end of the chassis – together with the PF XL motor it counterbalanced the weight of the cabin.  I expected the front winch to be a very important part of the vehicle – it was driven by the drive motor through a driving ring with a quick release lever. When the lever was engaged, the winch was driven accordingly to the direction of vehicle’s movement. When the lever was disengaged, the winch was disconnected from the motor and the string could be quickly extended by hand. There was a number of pulleys used inside the chassis to reduce the friction of the string, and the entire winch was enclosed within model’s frame. The winch proved so powerful and robust that when forced to stop, the string split before there was any mechanical damage.

The model was a bit heavier than expected, but it had a very good weight distribution and the suspension worked flawlessly with its weight. It was also quite manoeuvrable and very, very stable. I expected the low ground clearance to be a problem, but it was helped by the bottom of vehicle which was covered by a protective layer of smooth liftarms, so that the model could slide over obstacles to some extent. The main problem of the vehicle was failing drivetrain plus non-lockable differentials. A lot of slip situations occured, and the drivetrain would snap when a really high torque was needed. It could have been helped by the use of the winch, but it worked way below the vehicle’s travelling speed, which proved fatal – the winch was simply to slow to take the load off the wheels. It would work much better if the release mechanism disengaged wheels from the drivetrain as the winch was engaged.

The model has lost its first and only race, but in some aspects it performed much better than any of my previous trucks – it remained stable at all times, it did not suffer any damage despite the use of many delicate parts such as CV joints or universal joints, and it did not formally malfunction – it simply suffered from the drivetrain being unable to handle high torque. It was also acclaimed by other Truck Trial builders for capturing the original vehicle’s look, which kind of surprised me. Moreover, the experimental use of the 8878 battery turned out to be a success – the model’s performance was not degraded, while its weight with a traditional battery box would exceed 2 kilograms.

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Mao de ABS (Spanish only)

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Model of the Kenworth W900 in a version customized by the Mammoet company. Features full pendular suspension, functional steering wheel, R4 piston engine, openable bonnet, sleeper’s roof and doors, remotely controlled front and rear lights, automated reverse lights and trafficators, remotely locked catch and custom stickers. My first construction powered by the Lego 8878 rechargeable battery.

Datasheet:

Completion date: 29/06/2009
Power: electric (Power Functions)
Dimensions:  truck – length 75 studs / width 19 studs / height 26 studs, trailer - length 111 studs / width 18 studs / height 12 studs
Weight: truck – 2.66 kg, trailer – 0.709 kg
Suspension:  truck – full pendular, trailer – none
Motors: 2 x 71427, 1 x PF Medium, 2 x PF XL

Kenworth W900 is one of the most iconic US-type trucks, and the Mammoet is one of the most impressive companies ever, handling stuff like transportation of bridges or houses on a daily basis. Moreover, it is a Dutch company, just like the Lego, and it uses almost entirely black livery for its vehicles which is very appealing for me. Finally, the Mammoet fleet, which consists of some of the world’s biggest and most powerful vehicles in their class, contains a number of customized vehicles, which makes them even more interesting.

There is one obvious point of reference for this model, that is my Tow Truck, completed almost a year earlier. I have assumed that it would be difficult to exceed its level of technical complexity, and if I tried to, it would most likely result in a vehicle of even bigger size and similiar look. That is why Kenworth was meant to be simplier and built with more focus on its aesthetic side.

First thing about the aesthetics are somewhat missed proportions – although according to Mammoet’s blueprints only the bonnet is 2 studs too long, and the rest of dimensions is more or less correct. Nevertheless, the truck looks long and narrow. I have recreated Mammoet’s livery on the body, but not on the bumpers, preferring to keep them free from paint job. Instead, they were fitted with small warning badges, and on the front bumper has a set of guards that Mammoet company uses in trucks intended to push some loads. There are no warning lights, either. I’ve put a lot of work into the bonnet, which can be opened up together with the front mudguards, which is a realistic solution unlike the one used in my earlier Tow Truck. The sleeper was made taller to fit the mechanics in, the catch was increased in size to achieve more accurate shape, and rear mudguards were added.

The model was designed for use with a standard Power Functions battery box, and only in the last stage of building it received the Lego 8878 rechargeable battery instead. The battery decreased sleeper’s height and truck’s weight (by considerable 160 grams) while not impacting the performance in any apparent way.

The suspension system consisted of three simple pendular modules, with axles #2 and #3 using my 3-studs wide differential bracings, each stabilized by four hardest 6.5L shock absorbers available to handle the truck’s weight and load. The front axle had no shock absorbers at all, because too much place was taken by the bonnet and front mudguards. Since the entire suspension is pendular, the truck is susceptible to a transverse tilt resulting from the driveshaft’s load, but it is greatly limited by the hard shock absorbers.

The model is driven by two PF XL motors facing each other and connected by four bevel gears. I have tested this setup before, and I liked how simple and effective it was. Additionally, the use of two motors facing each other substantially reduces the strain on the drivetrain. When I tested it with a single motor, it had a tendency to pull the driveshaft down or up if it was not reinforced properly. With two motors, the driveshaft remains in place because while one motor pulls it up, the other pulls it down. One of the four bevel gears is an idler gear, used only to keep the other three gears in place. It can be easily noticed that the motors would look better if they were located along the body – they would then look just like the fuel tanks. It’s a nice solution, but it makes the vehicle’s frame and transmission much more complex, and so I gave it up. I have to mention that the truck turns surprisingly smoothly, most likely thanks to the long span between the steered axle and the driven axles. And it feels very pleasant and realistic to drive it with the speed control-enabled 8879 handset.

It may come as a surprise, but there is no gearbox whatsoever. I’ve done a lot of tests with a linear 3-speed manual gearbox, which seemed most adequate due to it size and robustness, but it proved somewhat loose and the model performed much better with no gearbox. I intended to use the speed control feature anyway, so the gearbox was eventually removed.

The catch lock mechanism is very simple and compact. It uses a worm gear to hold the trailer in place, and a linear clutch to avoid damage. It was located just above the last axle, which is why I’ve used a custom casing (the standard Lego casing wouldn’t fit in), and it was driven by a motor located in the chassis, directly in front of the second axle.

Slightly in front of the second axle, there is also the steering system’s power output, intended to be connected to the trailer’s own steering system to couple it with the truck’s steering. I have tested a trailer with such a system, but I eventually faced the choice whether to make the trailer with steered axles or to make the trailer which is strong and looks realistic. I have chosen the latter.

Between the fuel tanks, there is a reverse lights activator in the chassis. It consists of a single PF switch whose movement is limited to a neutral and one extreme position , and which is connected to the driveshaft through a clutch. The reverse lights are powered from the same output as the drive engine, thanks to which they go out as the truck stops.

The doors of the cab can be fully opened after removal of their side bars. Inside the cab, there is a functional steering wheel and a simple cockpit. There are no seats, because the respective space is occupied by the trafficators mechanism. I will now explain how it works. Imagine a PF light powered through a PF switch – it blinks as the switch’s position changes. Such a motion can be easily motorized by means of an eccentric mechanism – that kind of solution was already used in the forementioned Tow Truck, and can be well seen in my Snowgroomer. Now, imagine a ratchet that is sensitive to the direction of rotation – it has been used in my direction sensitive gearbox. We can attach the motor to the ratchet, and then prepare two separate eccentric mechanisms with two separate PF switches and two separate set of lights (of any size – in fact, I would make the rear trafficators work too if I had 9 lights instead of just 7). It will result in a mechanism when only one eccentric mechanism is driven at a time, and it changes as the direction of rotation of the steering motor changes. Thus, it is perfectly possible to use the steering motor for it, as it can easily control one more mechanism, and I have used a separate motor here only to be able to locate the trafficators mechanism independently of the steering motor’s location. The trafficators’ lights are powered from the same output as the steering motor, so they go out when it stops working, regardless of the wheels’ position.

One drawback of this solution is that the eccentric mechanism remains in whatever position it was when the ratched moved to the other one. It means that there is a high risk of having all trafficators come up at the same time, because the ones that should be off will have the PF switch stopped in ‘on’ position. It can be prevented with rubber bands that pull the eccentric mechanisms to a specific position once they no longer mesh with the ratchet, but I did not use such means of prevention because of the available space limitations. Please note that the truck already houses approximately 5 meters of electric wire.

Under the bonnet, there is a R4 piston engine with moving pistons and rotating front fan. It is small because of the limited space under the bonnet which results from its specific construction. As you can see on the photo below, there is an interesting area near the front axle where the model’s smooth external surface ends and a Technic structure can be seen beneath it.

Finally, the trailer. I wanted it to wear a different colour scheme. Trailers of this type usually have red and white warning stripes on the edges of main platform. I didn’t have the needed number of red and white parts, and I disliked the look of these colours combined so I replaced them with two shades of grey. The trailer has no steering system nor suspension of any kind, and it is attached to the truck in a fairly simply way. I have to admit that the truck took a terrible amount of work to build and I really didn’t like the idea of even more work with the trailer, especially since it was difficult to show or film together with the truck due to its length. Therefore the trailer is an addition to the truck rather than a proper model.

Overall, the model enjoyed a fairly good reception, despite many people pointing the proportions issue out. The trafficators feature was widely acclaimed, and there was even a number of people who were very critical about the proportions and accuracy of the truck, but still regarded it as an impressive model. Few people declared that the focus on the truck’s aesthetic aspect was much greater than expected of me, and that its functionality was degraded because of this.

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Media reference:

Bricks ‘n’ Gears, kockak.hu, TechnicBRICKs

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An experimental halftrack vehicle. Features three types of suspension, a 4-speed manual gearbox and openable doors.

Datasheet:

Completion date: 13/04/2009
Power: electric (Power Functions)
Dimensions:  length 54 studs / width 17 studs / height 16 studs
Weight: 1.41 kg
Suspension:  front – independent / rear –  torsion bars + pendular bogie
Motors: 1 x PF Medium, 1 x PF XL

Having built a dozen or more tracked vehicles, I eventually felt compelled to try a halftrack. Halftracks are an interesting blend of tracked and wheeled vehicles, combining the advantages of both. Namely, they perform better off-road with tracks than typical wheeled vehicles, and they can steer much easier than typical tracked vehicles thanks to the wheels (which results in a simplier construction rather than in a better performance).

There is a number of problems involved in building a halftrack, and I was curious as to how they would affect a small, lightweight model. Basically, the real halftracks often have the front wheels driven for better traction and better steering. There is usually a differential between the tracks, which serves the same purpose, and some of the heavy German halftracks were fitted with automatic brakes that would slow down one track while turning.

There was a single technical solution that greatly affected the look of the vehicle: the torsion bars. I was earlier suggested to try this kind of suspension, popular even in heavy tanks of the WW2, but it did not occur to me at that time how to make such a bar bend without sustaining any damage. Only sometime later it hit me that the elastic 16-studs long axles from the Jumping Giant would be an ideal and natural choice. It’s just their limited length that was not ideal, and hence the width of the entire vehicle was limited by the transverse 16-studs long axles used as torsion bars.

With the vehicle’s body only 16 studs wide I’ve given up the intent to make the front wheels driven. Instead, they were just fitted with a simple independent suspension, and the suspension of the tracks was complemented by a central pendular bogies because I only had two axles that could serve as torsion bars. The drive was transferred through the usual 4-speed manual gearbox I’ve used many times before to the tracks’ front return rollers without the use of a differential. I have assumed that it would be catastrophic to drive a lightweight vehicle with a slippery tracks via a differential – the slip situation would be more than likely to happen.

Eventually, the vehicle had a surprisingly efficient steering system – which was due to the tracks’ poor traction rather that to its construction. The turning radius was even slightly better than it would be with two regular rear axles instead of tracks. I suppose that given a sufficient speed it could be a great drifting truck.

As for the look of the truck – I had no clear idea what should it look like, but I definitely didn’t want it to look like German military halftracks of the WW2, which are often considered iconic for this type of vehicle. That is why I pursued the look of a vintage truck, which eventually proved to have a lot in common with the US Army’s halftracks (M3 and its successors in particular). Still, I was unhappy about the bonnet which had to be tall and wide to cover the shock absorbers of the front suspension. Actually, the front of the truck was so massive that its center of gravity ended up below the cab – despite the fact that all motors and the battery box were located between the tracks. I felt that the back of the truck should be openable, but that was impossible because of the battery box being fixed there. The battery box and the motors were left uncovered deliberately: this way they could appear to be the truck’s load, and the cargo space seemed much larger than it would with these parts covered up.

The truck was technically very compact, which resulted in some limitations. There was no place for working lights nor for the reinforced drivetrain, the latter resulting in an inconsiderable vehicle’s top speed.  The suspension system, however, worked pretty well. The torsion bars functioned in a proper and realistic way, even though they were probably too weak to support the entire truck’s weight. Still, there was a margin of calibration available, as I created a 2 studs long ‘torsion space’ – that is a space between the actual suspension and the point where the torsion bars were fixed to the chassis. If this space was reduced to a single stud, the suspension could probably handle a significant weight. Tests with the gearbox proved the torsion bars to be a bit unreliable; they tended to produce vibrations at lower speeds and worked smoothly only at the higher ones. I suppose that this effect is proportional to the size of tracks’ links, which means that the newer tracks system would require even higher speed to run smoothly with this suspension system.

Although I have initially considered it a minor, highly experimental project, the Crusader performed almost flawlessly and was more fun to drive than many more advanced vehicles. Moreover, to my sincere surprise its aesthetic aspect was much acclaimed at the LUGPol and beyond.

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Media reference:

Klocki, The Brothers Brick

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My third, unsuccessful Trial Truck. Features 4×4 drive, full indepent suspension and R6 piston engine.

Datasheet:

Completion date: 31/03/2009
Power: electric (Power Functions)
Dimensions:  length 46 studs / width 25 studs / height 31 studs
Weight: 1.95 kg
Suspension:  full independent
Motors: 1 x PF Medium, 1 x PF XL

An unfortunate result of my attempt to enter 2009 Truck Trial season with a brand new vehicle. It was intended to be small, lightweight and as simple as possible. Therefore I’ve decided to model the shortest version of the legendary Unimog truck being produced at the time.

The truck was built in a traditional way, with layers of bricks and plates reinforced by vertical liftarms. There were no differentials at all and the suspension utilized the 8880 set’s suspension components, replacing the universal joints with knob wheels as the universal joints get damaged in the Truck Trial quite often. The number of motors and electric components was limited to a single battery box and a single IR receiver controlling drive & steering. For the sake of stability both battery box and the drive motor were located low under the chassis, with the battery box moved close to the rear axle in order to compensate for the cabin’s weight. I have initially intended to build the cabin with liftarms and panels, but I didn’t really like the look of it and eventually chose to build a ‘fullbrick’ cab. I have, however, failed to maintain the proportions and the resulting cabin was too tall and placed a bit too high.

The decision about the cabin has dramatically increased truck’s weight – from approx. 1 kg with bare chassis and 1.4 kg with cargo platform to the final 1.95 kg. It had a great impact on the stability and performance of the model. Eventually it turned out that the truck was having serious problems with everything but driving straight ahead. A meticulous analysis revealed that it was because of the bracings keeping the knobs inside the suspension’s rocking levers. While they performed quite well before, now they tended to bend under the truck’s full weight. As a consequence the knob wheels became slightly displaced, and came into contact with other parts of the suspension. It has crippled the truck so severely that I decided to abandon this chassis design entirely, seeing no space for improvements. My first idea was to rebuild the truck from a scratch, but after a careful consideration I have canceled the Unimog project and started to build a 4×4 truck with longer chassis and two differentials. So after all,  this model has never been driven outdoors.

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Another take on racing trucks. Features fully modular design, return-to-center steering system, full suspension, speedometer and lights.

Datasheet:

Completion date: 20/01/2009
Power: electric (Power Functions)
Dimensions:  length 43 studs / width 18 studs / height 25 studs
Weight: 1.69 kg
Suspension:  front – pendular without shock absorbers/ rear –  dragged axle
Motors: 1 x PF Medium, 2 x PF XL

After a long break, I’ve come back to the subject of the racing trucks. I wanted something faster and better-looking than my two previous trucks, something that I could call ultimate in terms of performance. The only way to achieve the latter goal was, in my opinion, a fully modular design. Therefore, the truck was built out of three basic modules: a cabin, front part of the chassis with the entire steering system, and rear part of the chassis with entire drivetrain and detachable battery box. Thus it was quite easy to make adjustments to the drivetrain and the steering system.

The drivetrain was powered by two PF XL motors connected by a rigid axle (one of them with polarity switched). The rear axle was driven via a small number of double bevel gears, and a chain that transferred the drive to a 4-studs wide differential. The construction of the rear axle was quite uncommon: its structure consisted of several axles and Technic triangles, the differential was moved to the side, and the space gained this way was occupied by a Lego speedometer sensor. The axle was suspended on two stiff shock absorbers, and given a very small travel distance.

The steering system used the mini pendular steered suspension module developed shortly earlier, with the rubber band layout that enabled return-to-center steering. This function lacked some precision, limited steering lock and disabled the proportional steering, but it served its essential purpose.

The modular design involved a single disadvantage – a necessity to locate most of the PF elements behind the cabin, so that they could be easily accessed when e.g. the steering motor had to be disconnected along with the front chassis module. It has significantly degraded the aesthetic impression given by the truck’s cab.

The performance of the truck was way below my expectations. The drivetrain provided excellent speed when the truck’s weight was only a little bit over 1 kilogram, but with the final weight of 1.69 kg the speed was only half as good. After adjusting the gear ratio I was only able to draw close to 4 kmph (compared to the initial 7 kmph of the 1-kilogram heavy chassis). Therefore, despite a number of innovative features and the satisfactory look of the truck, I considered it a major disappointment. It made me think that perhaps the assumed scale of the vehicle and the final weight it imposed were too high for the PF system to provide a decent speed. Certainly a smaller, lighter and suspensionless truck could run much faster.

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Model of a racing truck inspired by Volvo FH12. Features full suspension, lightweight body and lights.

Datasheet:

Completion date: 27/08/2008
Power: electric (Power Functions)
Dimensions:  length 45 studs / width 19 studs / height 25 studs
Weight: 1.58 kg
Suspension: front independent / rear dragged axle
Motors: 5 x PF Medium

Promptly after my first racing truck was completed, I started to build a completely new one, trying to eliminate all the flaws I have noticed in the first one. The result is a truck, which is much lighter, though almost identical in size, more stable and slightly faster. The dimensions and the look were based on the Volvo FH12 this time. The drivetrain was entirely different, with 4 PF Medium motors connected directly to a common drive shaft. Thus, I intended to test whether or not a greater number of weak motors performs better that the few strong ones. The rear axle was driven via an universal joint and the new type of the differential. Instead of pendular rear suspension, I have used a dragged rear axle to improve the truck’s stability at the cost of its off-road performance, which was not much needed. The front suspension, though still independent, was rebuilt from a scratch. All the 8435 set components were removed, and replaced by a combination of the 8297 and 8448 suspension parts, which offered slightly larger steering lock and much better robustness. The chassis was much less massive and used panels and axles instead of bricks to save on weight. The spoiler was replaced by a trailer catch, just to compare the aesthetic effect, as both solutions are present in the real truck racing. The chassis housed a vertical battery box behind the front axle, while the IR receiver was moved to the cabin. The cabin had some basic interior, and its front wall was made from vertical plates instead bricks, again – to save on weight. For the same reason the number of lights was significantly limited, and the lights off/on switch completely removed.

The truck still had the excellent manoeuvrability of its predecessor, this time supported by much lighter body and better weight distribution. The drivetrain’s performance was clearly worse, it could barely hold all the torque, and the improvement of truck’s speed was possible only thanks to the smaller weight. Given full weight of the previous truck, the drivetrain would probably completely fail.

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My first racing truck. Features full suspension, dual motor drive, and lifted cabin.

Datasheet:

Completion date: 16/08/2008
Power: electric (Power Functions)
Dimensions:  length 47 studs / width 18 studs / height 26 studs
Weight: 1.92 kg
Suspension: front independent / rear pendular with shock absorbers
Motors: 1 x PF Medium, 2 x PF XL

In August 2008, I’ve come across the European truck racing, and this sport appeared to me as very potent in the terms of a LEGO Technic competition. To try out some assumptions of such a competition, and demonstrate my idea, I have built an exemplary truck.

The assumptions of the LEGO Truck Trial competition were as follows:
- trucks scaled to the 62.4 x 20 S wheels, or different wheels of similar size
- maximum width of a vehicle: 19 studs, exluding side mirrors
- full suspension on all axles
- at least one axle driven, at least one axle steered
- must refer to an existing racing truck; therefore I’ve assumed that truck with more than 3 axles won’t be used, as there are no such trucks in the real sport
- no weight limits, and unlimited number of motors used to drive

The idea, presented at LugPOL, prompted several builders to build their own racing trucks, most of which did not comply with the assumed rules (a lot of people complained about the suspension system requirement, which I have viewed as crucial for realism). As of the end of 2008, not a single contest took place.

The truck was driven by two PF XL motors connected by an adder. The rear axle was driven via the new type of differential from the 8297 set, and had pendular suspension stabilized by shock absorbers. The front axle was not driven, and had an independent suspension based on the components from the 8435 set, with very hard shock absorbers (to support the weight of the cabin and to improve stability of the truck, which could rely on the rear axle only). The dimensions and the look of the truck have been to a large extent based on layout of Scania R 340. The battery box was located above the front axle, and the cabin could be lifted to access the box. The truck was equipped with a large array of lights, both front and rear. The IR receiver was located in the chassis and well exposed.

For the lack of any official contest, the truck went through a lot of test-driving. It performed well, with a drivetrain which provided speed below my expectation, but proved entirely capable of handling all the torque involved in driving such a heavy vehicle. Because of the large accelerating gear ratio in the drivetrain, the truck suffered from a large inertia while stopping. I have assumed that a braking manoeuvre must be used to eliminate that, namely the motors were switched to reverse to stop the truck. Again, the drivetrain endured a huge torque generated while stopping truck this way, and since that time, I required all my racing trucks to be able to endure such a manoeuvre.

The disadvantages of the truck was a significant weight, and a tall center of gravity, which did not cause any trouble here, but I have anticipated that it would, if the truck was faster. Moreover, there was a noticeable part wear in the front suspension, which resulted probably from the large weight of the vehicle, located mainly on the front axle.

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