Model of the famous WW2 German heavy tank. Features drive, steering, rotated turret, elevated main cannon and lights.  

Datasheet:

Completion date: 21/12/2011
Power: electric (Power Functions)
Dimensions: length 25 studs (36 studs including main cannon’s barrel) / width 14 studs / height 11 studs (not including antenna)
Weight: 0.694 kg
Suspension: none
Propulsion: 2 x PF Medium geared 1:1
Motors: 3 x PF Medium, 1 x micromotor

The Tiger tank is the probably most famous German WW2 tank, and one of the most famous tanks in history. It entered service as a heavy tank in 1942, and it was exceptionally advanced for the time, as well as deadly effective. The tank’s powerful gun and thick armour made it an unprecedented threat to both Soviet and Allied tanks. There is also another side to the Tiger, which states that the tank was over-engineered, extremely expensive and time-consuming to both produce and to maintain, and its fuel consumption was monstrous, especially for the crumbling economy of the after-1942 Nazi Germany. It was also designed in accordance with a doctrine of armoured warfare that was already obsolete – it was intended to win by superior firepower and thick armour, while the Soviet tanks, much cheaper and easy to produce in large numbers, were already winning by manoeuvrability, sloped armour and by working in groups. To make things worse, the Tiger was rushed into service without proper quality control and on-site technical support, resulting in many tanks disabled by technical malfunctions or being abandoned after getting stuck because there were no means to haul them out. Still, it was an impressive and fearsome tank, even if its significance has been exaggerated by the Nazi propaganda. One could say that it was a great tank itself, but it required maintenance and logistics on a level its creators were unable to provide.

As for the model, I was initially going to build it in large scale, with tracks of the newer type, but my primary goal was  to properly model its distinctive overlapping road wheels. This element is often ignored and simplified in the models of the Tiger, and I wanted to get it right. It turned out difficult to do at large scale, but I figured out that I could simply use Technic discs at a smaller one. Since there pieces don’t exist in dark bluish grey colour, I had to settle on next closest to it, that is pearl dark grey.

The model has undergone a rigorous technical control. 

After deciding on a small scale, the main challenge was to make the model fully remote controlled despite its very small size; the finished model’s hull was only 20 cm long and it could fit on the palm of my hand. My secondary goal, besides that, was to properly model the shape of the air filters on the rear of the tank, which are half-round but Lego builders often make them all-round or even rectangular. I achieved this by using four 6191 bricks, which was also a challenge as they only appear in dark bluish grey in a single Lego set, one brick per set.

Eventually, the model had to house four motors, two IR receivers, a battery and approximately 2 meters of wire, plus the large Technic turntable which would provide a stable base for the turret while allowing to install a motor in it. I won’t be dwelling on how hard it was, let’s just say that there were times when the functionality of the model depended on whether I can move some element half stud further or not.

The model was quite simple technically. It was driven by two PF Medium motors located in the middle of the hull, which drove rear sprockets with 1:1 gearing (the only ratio possible as there was no space for any large gear wheels). There was a battery in front of the hull, and a third Medium motor next to it, which drove the turret’s turntable through a worm gear. There was a single wire that entered the turret and powered a micromotor installed inside it, which drove another worm gear and thus controlled the elevation of the main gun’s barrel. There was no suspension whatsoever, and the two headlights on top of the hull had Lego LEDs inside them and shutters made of the bases of Lego levers.

The look of the model was not meant to be consistent with one particular of many versions of the Tiger, I just wanted it to be characteristic, which means that it’s close to the tanks from the early production batches. Its side number – 131 – was not random; the 131 Tiger tank can be found in the Bovington Museum in UK, and it’s probably the world’s only Tiger tank in driving condition today.

The model did not look perfectly; the hull was too tall by roughly 3/4 of a stud, and the turret had a gap beneath it to allow the worm gear to mesh with its turntable. This could be avoided if there was enough space in the hull to ‘sink’ the turntable inside it, but there wasn’t. The turret was 9 studs wide, built around a micromotor and held together by its roof rather than by its bottom. Its look was affected by mechanical parts inside it – its front was too tall and its rear end is a little too far to the back. Finally, the main gun’s barrel’s dimensions had to be heavily approximated at this scale – for example, the longest section of it should be 0.75 stud thick while the thickest section should be 1.5 stud thick. There are simply no Lego pieces with such dimensions that would have the required look.

The model was fun to play with, but clearly suffered from small size and low weight. It’s almost my lightest tank model ever, one third lighter than my T-72M tank and almost as light as my very simple Mark I tank – and it has more road wheels than any of those; 24 to be exact, with only 16 visible from the sides. Therefore its traction was poor and it was difficult to drive over my floor, where any unevenness (and there are many) affected its direction. I believe it would perform much better with more weight, stronger chassis and a simple suspension system, as proved by my earlier T-72 tank model, which had exactly the same tracks and propulsion system. This means that this model is probably example of the level of “miniaturization” that is already bad for its functionality.

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Model of a Cold-War era Soviet main battle tank. Features suspension, rotated turret, elevated main cannon and lights.  

Datasheet:

Completion date: 10/09/2011
Power: electric (Power Functions)
Dimensions: length 39 studs (52 studs including main cannon’s barrel) / width 19 studs / height 16 studs (not including antenna)
Weight: 1.057 kg
Suspension: torsion bars
Propulsion: 2 x PF Medium geared 1:1
Motors: 3 x PF Medium, 1 x micromotor
Top speed: 1.14 kmph

T-72 is one of the most popular tanks in the modern world. It has been produced for 40 years now, and the production still continues with over 25,000 total tanks built. It was designed with cheap mass production and maintenance in mind. It offers interesting blend of simplicity and good characteristics, and it generally follows the Soviet doctrine of focusing on quantity rather than quality of tanks. While the T-72s can be easily gathered in large numbers, they usually lose 1:1 encounters with Western tanks.

I have chosen this particular tank because it’s a great example of Cold-War era Soviet tank design, with flattened hull and small, bowl-shaped turret. The US intelligence nicknamed the turret “Dolly Parton” because its shape supposedly reminded her breasts (you are strongly advised NOT TO search for photos of Dolly Parton, for the sake of your good taste). I had two goals while building it: to test the torsion bars suspension in a lightweight model, and to see how small fully motorized tank model can I build.

As for the aesthetic side, there was a number of minor shortcomings. I wanted to properly model the distinctive shape of the turret, because Lego models of the T-72 usually have turret shaped like a slightly gnawed disc. I think I achieved that, at the cost of attaching some details to the bottom of the turret, thus increasing the gap between the turret and the hull’s upper surface. The turret also had very little space inside – so little, in fact, that the majority of the main cannon elevation system had to fit in a 2 studs wide gap.

Other than that, the central section of the main cannon’s barrel should have been slightly thicker, but the only idea that occurred to me was to wrap it in a paper of similar colour and let it pass for a sticker.  I also had the impression that the hull is slightly too tall, even though I was sure it had the right proportions. I could have remedied it easily by decreasing the suspension’s angle and thus the ground clearance, lowering the entire tank, but the large ground clearance is distinctive for the T-72. Perhaps the reason was that the side skirts started a little higher than they do in the real tank.

The T-72 is unusual in how its details are distributed: there is a lot of details on top of the hull’s rear, but almost nothing on the side skirts and above the tracks. I have added some extra details to simulate the kind of “luggage” that some tanks carry on them – in some cases it seems that the tank’s crew grabs virtually anything that comes around and attaches it to the armour.  I have also used Lego LEDs to emphasize the large number of searchlights on the turret, which is very distinctive for the T-72, and I used some Lego plants to simulate the so-called environmental camouflage, just to see the result.

The model was very simple technically. There were two PF Medium motors in the back, connected straight to the rear tension wheels. Together they provided reasonable speed and a surprisingly high torque. The were also two IR receivers in the back, and another PF Medium motor between them, used to rotate the turret. Because of how small the turret was, its entire rotation system along with the turntable was located in the hull. The central part of the hull was taken by the turntable, and the front was taken by the 8878 battery lying transversely on its side. The battery could be accessed by removing the entire glacis plate. The remaining space, which was sparse, was taken by wires and the suspension system.

This was my second tank to use torsion bars suspension – the previous one was almost 3.5 kg heavy, with nearly 0.25 kg load per road wheel, and its suspension worked perfectly. Here the suspension was very similar, except that the axles used as the torsion bars were kept at fixed angle by the toothed half-bushes and toothed connector joints. It saved some space, but it wasn’t working really well because there were gaps at the half-bushes, which I had to fill with tiny scraps of paper. The average load was less than 90 grams per road wheel, and the entire suspension was therefore very hard – it was actually difficult to notice that it works.

I was happy with how the model turned out, even though its aesthetic side had a few compromises to it. It was a good, very agile model to play with, but I think it proved too light for this kind of suspension.

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Model of a Spanish armoured personnel carrier. Features full independent suspension, 6×6 drive, 2-speed gearbox, remotely opener rear ramp, deployable tracked drone and lights.  

Datasheet:

Completion date: 14/08/2011
Power: electric (Power Functions)
Dimensions: length 56 studs / width 29 studs / height 24 studs
Weight: 2.306 kg
Suspension: full independent
Propulsion: 1 x PF XL geared 6.5:1 (low gear) / 2.3:1 (high gear)
Motors: 1 x PF XL, 3 x PF Medium, 2 x micromotor

BMR-2 is a modern Spanish armoured personnel carrier. It’s a fairly typical vehicle for its class and I have chosen it mainly for its short chassis with first and last axles steered. I was hoping it would work well in an outdoor Truck Trial race. Unfortunately, it turned out that this kind of a steering system won’t work for a vehicle of that size, weight and with these tires without differentials. I haven’t been able to build it on time and therefore I abandoned plans to try it in a race.

The model had a full independent suspension that used 8297′s set components. Axles #1 and #3 were steered through a common steering shaft, by a Medium motor geared down 9:1, with a safety clutch. All wheels were driven by a single PF XL motor through a remotely controlled 2-speed linear gearbox.

The chassis was entirely studless, with majority of internal components located above the middle axle. The body consisted mainly of plates supported by a frame of Technic bricks. This solution resulted  in an unusually low weight – something I was expecting and which prompted me to try using only one shock absorber per wheel. The suspension created this was was very soft, and even though it worked, the model displayed apparent tendency to ‘sit down’ on the third axle.

Close to the end of the building process I have realized that I can save up some internal space at the back of the model. It led me to realize an idea that followed me for a while (or was it planted?) – a small tracked drone deployed from inside. In a way, this was a MOC within a MOC, and thus: a MOCception The drone was extremely simple, built around two micromotors with chains instead tracks. The micromotors were powered and controlled by two long wires connected to a separate IR receiver inside the transporter.  The drone could be deployed once the rear ramp was opened and it could operate outside its carrier. It worked well, but due to its extremely low weight it was somewhat struggling against the wires. I have also integrated something like a simple passenger compartment into the upper hull’s surface, and it turned out to be perfectly fit for a single dwarf hamster.

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Model of a Liebherr excavator with tunneling arm. Features a blend of electric and pneumatic functions, custom stickers and lights.  

Datasheet:

Completion date: 17/06/2011
Power: electric (Power Functions) / pneumatic (external manual pump)
Dimensions (with arm in driving position): length 40 studs / width 16 studs / height 35 studs
Weight: 1.497 kg
Suspension: none
Propulsion: 2 x PF Medium geared 1:1
Motors: 4 x PF Medium, 1 x 71427

Model of a regular Liebherr excavator with an uncommon tunneling arm. Model of the very same machine created in larger scale was released in 2010 by my fellow LUGPol member M_longer and is available here. M_longer introduced me to this excavator before he started to build it, and I liked it so much that I intended to build it first. Eventually my timing kind of failed, because my model was finished 10 months after his

My version of the excavator was intended to be much smaller than M_longer’s: his was scaled to the new tread system, and I decided to use the old one for mine. The resulting difference in scale means that my model is roughly 40% smaller. Seeing that the model would be quite small for its number of functions, I have been planning to use pneumatics wherever possible and to have an external pneumatic controller permanently attached to the model. This solution is sometimes called a ‘pneumatic leash’ and it was used in many of the models created by my idol builder, Jennifer Clark. I have never really used it before and I thought of this as of opportunity to feel like Jennifer

While I was in the process of cramming the mechanics inside the hull, it occurred to me that I will be able to integrate all four pneumatic valves into the hull at the cost of making its upper surface uglier. I decided it was worth it, and eventually the model’s only external element was a single manual pump, which allowed for more accurate control of the pneumatic system than a motorized compressor would.

As for the aesthetic side, I didn’t want the hull to look like a box, which was pointed out with my earlier Caterpillar excavator, so I decided to build the sides and the back of the hull using body panels and SNOT (studs not on top) technique. I think the model looked generally worse than M_longer’s version, which is disadvantage of the smaller scale, but it did include a number of details that were omitted by M_longer in his model – such as e.g. the side and rear view mirrors.

The model had 5 motorized and 4 pneumatic functions. The propulsion system was obviously motorized and consisted of two PF Medium motors geared 1:1 and located in the chassis. The chassis also housed a third PF Medium motor, which rotated the superstructure. The fourth PF Medium motor was located inside the superstructure and drove two large linear actuators that controlled the elevation of the arm’s first section. As the actuators were effectively handling the weight of the entire massive arm, I have assumed that pneumatic cylinders would be too weak or too inaccurate for this task. Finally, there was a  71427 motor located at the back of the hull, and it was chosen because it’s shorter than a PF Medium motor. Its function was driving the milling head, which was done by a single long driveshaft that went all the way from the back of the hull to the tip of the arm and which was articulated in five places.

The 71427 motor was not controlled remotely, like the other four motors, but was instead connected to a switch located in the front right part of the hull. The same switch controlled two lights on the arm, as there was simply not enough space inside the hull to connect them together with hull’s front and rear lights. As a result, the lights on the arm lit up as the milling head works.

The whole electric system was powered from a single 8878 rechargeable battery located in the rear left part of the hull. The battery was accessible through a hatch in the left side of the hull, and was lying on its side in order to stay aligned with the side body panel.

The pneumatic system consisted of a single large cylinder that controlled elevation of the dozer blade in front of the chassis, two small cylinders that tilted the arm’s second section left and right, two large cylinders that controlled elevation of the arm’s third section and a single large cylinder that controlled the angle of the arm’s head. The arm itself was a fully studless structure partially covered by a studfull shell. Its range of movement was reasonably close to that of the original machine, and it was robust enough to support the model on one side. The milling head could be easily removed and replaced by e.g. a bucket or… something else.

It should be noted that the model’s driving speed and superstructure’s rotation speed were both inflated. I have done this on purpose, because I wanted to use the full potential of the model’s motors, knowing that I can reduce the abundant speed at any moment using the speed dial remote.

I was fairly satisfied with this model. It was compact yet full of various functions, it blended motors, linear actuators and pneumatics using the advantages of  each, and it looked quite good and accurate. Despite having no gear reduction at all, it was perfectly able to push and tow the 8110 Unimog set which weights over 2 kg. I consider it a noticeable step forward from my previous excavators in terms of blending aesthetics and functionality, and – unlike my previous excavators – it appeared free from severe disadvantages to me.

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Media reference:

TechnicBRICKs

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Simple vehicle built for fun. Features 4 driven rubber tracks, chassis elevation system and remote-controlled Zamor cannon.  

Datasheet:

Completion date: 24/02/2011
Power: electric (Power Functions)
Dimensions: length 36 studs / width 23 studs / height 50 studs
Weight: 1.14 kg
Suspension: none
Propulsion: 2 x PF Medium motor geared 1:1
Top speed: 1.60 kmph
Motors: 4 x PF Medium, 2 x PF XL

The idea for this vehicle has evolved quite a bit. Initially meant to be a successor of my Moon Rover, since I am deeply fascinated by all the robotic contraptions NASA sends into space, it has gradually became something built rather for fun than for pretending my room’s floor is another planet. It was also important to me to build it without having to take apart my previous construction, which meant that I could use 3 IR receivers and 6 motors at best.

The Prowler has become an opportunity to experiment with a HD video. Having finally a full-HD-capable camera at hand, I was eager to try producing some high quality panoramic video. I have chosen to use Ulead Video Studio to do so, a decision which I severely regretted later, and I started by trying to produce a full HD video, which turned out to require a machine much more powerful than my PC. Having decided on regular HD instead, I proceeded to work on the video, which became increasingly frustrating, as the Ulead software turned out to work really slow.

It seems that the frustration over the video, which I felt compelled to finish against all odds, has affected the work on the model itself. For instance, the two Medium motors geared 1:1 proved incapable of driving over any serious obstacle, and I didn’t want to modify the drivetrain, because it would mean reworking the whole chassis. The live feed camera, which worked flawlessly the day before I started filming, proved unwilling to co-operate with my PC when I needed it to. I’ve tried for a couple of times, but I was unable to get a signal from it, which is why there is no single image from this camera in this video – I just didn’t manage to film it when it worked. Finally, the Zamor launchers proved quite difficult to control remotely. I wanted to have two of them, launched one after another continuously by a single motor with an eccentric mechanism. For some reason – perhaps because my Zamor launchers were brand new – it turned out to require an enormous amount of torque, rendering the eccentric mechanism completely useless, as it would yield to the launcher’s resistance regardless of how much reinforced it was. I have tried a couple of solutions, and eventually settled down on a single launcher with a primitive control system consisting of a single motorized linear actuator. It meant that the launcher control system could not work continuously, but required switching back and forth. In the end, the Zamor launcher proved largely inaccurate anyway. Since the spheres would not always sit in the launcher in exactly the same position, there was a significant spread when firing them. It was acceptable for just having fun and shooting large targets, but it still took me over an hour to get the short at the beginning of the video right.

I would say that it’s a clearly unimportant construction, perhaps something I needed to relax after a long and tedious work on the previous one.  Still, I have learned something from building it, which means that it was worth building anyway.

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Datasheet:

Completion date: 17/12/2010
Power: electric (Power Functions)
Dimensions: length 40 studs / width 12 studs / height 16 studs
Weight: 0.787 kg
Suspension: pendular bogies
Propulsion: 2 x PF Medium motor geared 2:1
Top speed: 0.8 kmph
Motors: 2 x PF Medium, 1 x 71427

This is a very simple articulated tracked vehicle, loosely modelled after the Swedish Hagglunds BV 206. My inspiration came obviously from Peer “mahjqa” Kreuger and his Stilzkin Igniz offroad vehicle. Since Peer’s model was really hard to top technically or aesthetically, I decided to go for simplicity and small size, a size fit for Lego full-rubber tracks I never had a chance to use before.

The vehicle is composed of two parts kept together by a complex articulated joint. The joint has the ability to change the horizontal angle between the two parts, which is controlled by a 71427 motor geared down substantially. It also has ability to rotate around transverse and longitudinal axis, freely, with the only constraint being the space between two parts of the vehicle. Initially, I wanted to control its rotating around transverse axis with another motor, thus gaining the ability to elevate or lower both ends of the vehicle, but it proved to perform very well without it.

Both parts have identical chassis, with two separate drive motors – PF Medium motors geared down 2:1. I was going to use a single drive motor located in one part of the vehicle and transfer the drive to another by universal joints, but that would require making the central joint much more complex or restrict its movement, so I used two separate motors instead. This solution, coupled with small weight of the model and the excellent traction of the full-rubber tracks, results in outstanding climbing abilities, shown on the video below.

The bodies of the both parts of the vehicle, despite being similar in size, have entirely different internals. The first part houses a 71427 motor with its gearing, and a lot of wires due to three parts of Lego LEDs used. The second part is literally built around the rechargeable battery and a single IR receiver, with the addition of a single pair of Lego LEDs. There are three wires connecting both parts.

The model was very fun to play with, and performed quite well in the snow, even though the steering system was struggling hard to work  with tracks buried in snow. Also, despite its good ground clearance, the model would pile up some snow in front of it while driving, until the point at which the pile was large enough to stop it. Still, its performance against obstacles was extraordinary, and its climbing abilities astonishing given its size. Two disadvantages degrading its performance was the tall silhouette, resulting in the centre of gravity located so high that the vehicle had a strong tendency to tip over, and the small weight which made it difficult to control, as it would change its direction on obstacles sometimes.

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Datasheet:

Completion date: 28/10/2010
Power: electric (Power Functions)
Dimensions: length 70 studs (including main gun’s barrel) / width 26 studs / height 23 studs (not including antennas)
Weight: 3.42 kg
Suspension: torsion bars
Propulsion: 4 x PF XL motor geared 1:1
Top speed: 1.5 kmph
Motors: 4 x PF XL, 2 x PF Medium, 1 x Micromotor

My first dark grey tank with a conventional construction (i.e. with a turret). I broke my ‘no German tanks’ rule, but at least the 2A4 version serves also with Polish army. It’s also the last version of Leopard with it’s original turret, whose distinctive shape (resulting from limitations of then-early modular armour technology) reminds me somewhat of German WW2 tanks. Leopard 2 is the world’s first 3rd generation tank (a brief explanation on tanks generations is available here), resulting from a failed joint German-US Main Battle Tank project (one that gave birth to Abrams M1 too) and introduced in late seventies. It’s a very universal construction with strong focus on mobility, and it has become quite popular, especially within EU. Widely considered as European Abrams’ counterpart, it has seen action e.g. in Kosovo and Afghanistan. The newest version currently in service is 2A6, while a 2A7+ version is under development.

I have started to work on this model in an unprecedented way, that is by buying a 1/35 scale plastic model kit of the Leopard 2A4 (which alone took a couple of months, as models of this versions of this tank at this scale are exceptionally rare, I only found them in Hobby Boss’ catalogue and already out of production) and putting it together for reference. I have obviously used a blueprint for calculating the dimensions too, but the plastic model gave me incomparably better reference, such as details of the portion of the hull that is covered by the turret or the decals compliant with German army’s marking patterns. It also helped me to get the idea of various subtle angles and shapes that were difficult to notice on a blueprint, and provided a clear view of some details that appeared vague on it. I am generally happy with the model’s look which suffered few compromises, except for a single serious one: the two grills on top of the rear hull surface, which should be round. I was forced to place three IR receivers beneath this surface, which made it impossible to accurately model the round shape of these grills – I wish I could do that e.g. like here.

Technically, the model was primarily meant to test a new suspension concept, based on torsion bars – a solution taken straight from the real tanks. Torsion bars suspension uses road wheel mounted on end of short rods, whose other end is set on a flexible element which twists under load, thus allowing the road wheel travel up and down. The simplest application of this solution with Lego pieces was a bit unorthodox: it required regular axles, which have a degree of elasticity, to be twisted.

Just like  in my previous tank model, the 6595 wheels have been used as the road wheels. They were mounted on bent 2×4 liftarms, so that they could rotate and maintain good ground clearance. The other ends of the liftarms were set on 8 studs long axles inserted transversely into the hull’s floor. Both ends of the axles were supported, but the inner ends, in the middle of the hull, were locked so they couldn’t rotate. Thus the axles were firmly braced in the chassis, with one end still free to rotate – the end with the liftarm and road wheel on it. It resulted in axle twisting slightly under load and then twisting back when the load was gone. Contrary to what I was afraid of, no apparent damage to the axles occurred, and this kind of suspension turned out to work excellently and to be extremely space-efficient (all it took was basically a single stud of hull’s height). Moreover, the hardness of this suspension can be easily adjusted by using shorter axles or by changing the locking point on them. In this model, each road wheel was subject to an average load of almost 250 grams and the suspension worked perfectly well with an 8 studs long axle, given 4 studs of space between the liftarm and the axle’s locking point.

The model is driven by an unusual number of four motors, all XL. Each of its four sprocket wheels is driven by a separate motor, and the whole set is powered from two separate battery boxes through two separate IR receivers (set on the same channel), with each battery box powering one left and one right motor. I hoped that the massive torque provided by all these motors together would make the model fast despite its weight, and early version with almost 3:1 gear ratio proved to be very fast. Unfortunately, the performance degraded rapidly with the growing weight, and at 3 kg the motors were unable to move the model at all. I’ve spent almost 2 hours changing the gear ratio to 1:1, viewing it as the most efficient ratio possible and unwilling to experiment with something between 3:1 and 1:1 lest I spent another 2 hours changing it again. It appears that XL motors, despite all their power, become increasingly ineffective when used with accelerating gear ratio. It is also possible that it takes more torque to move heavy tracked vehicle than it does for a wheeled one of the same weight.

Except for the four XL motors and two battery boxes, the hull houses three IR receivers, a single PF Medium motor that rotates the turret and the entire turret rotation mechanism along with a turntable. Placing the turret’s turntable inside the hull had a number of advantages: most importantly, it made the rotation mechanism simpler and more robust, and made the construction of turret’s base much simpler while leaving plenty of free room inside the turret. There are two wires going through the turntable, so it can’t rotate infinitely, and there is a simple liftarm frame the turret is built around. The frame includes a single roller behind the turntable, which keeps the turret’s rear end from touching the hull.

Inside the turret, I wanted to have a self-levelling main gun with remote elevation control. To put these two features together, I have built a module suspended on a transverse axle, which connected the main gun with its counterweight and had a micromotor in between, so that the angle between the main gun and its counterweight could be changed remotely. It worked as expected, joining the two features: changing the angle between the main gun and the counterweight by e.g. 30 degrees would result in the main gun going up (or down) by 15 degrees and the counterweight doing exactly the same, while the whole module kept self-levelling all the time. Two problems prevented me from using this mechanism: firstly, raising and lowering the counterweight required more space inside the turret than was available, and secondly, the micromotor’s wire kept affecting the module’s position, no matter how I arranged the wire. Eventually, I decided to keep the self-levelling feature and to remove the elevation control at all. Tank model with no main gun’s elevation control is certainly at disadvantage, but I thought that since all my tank models had this feature, I can do something different just this once. So, I removed the micromotor from the module, positioned the counterweight as close to the main gun as possible, and added another counterweight below the pivot point to lower the module’s centre of gravity – as it was apparent that the accuracy of self-levelling increases with the centre of gravity being further from the pivot point.

The micromotor which was removed from the self-levelling module served as a propulsion for commander’s cupola. It proved perfectly suited for this purpose, because no gear reduction was needed and the cupola is mounted directly on the motor.

Finally, there is a PF Medium motor in the rear part of the turret. I had a lot of space available in the turret, but all the IR channels were already in use, so I was looking for some additional use of the channel controlling turret’s rotation. Eventually, I have built a copy of turret’s rotation mechanism inside the turret, driven by the aforementioned Medium motor and working in opposite direction. The motor was connected to a switch inside the hull, and the switch was connected to the same IR receiver’s output as the motor rotating the turret. It resulted in a possibility to turn on or off a mechanism that would rotate something on top of the turret against the turret itself, thus keeping it aligned with the hull. The obvious choice was to select gunner’s machinegun as the counter-rotated element. The mechanism worked well, but the difference in resistance met by the motor rotating the whole turret and the motor rotating the machinegun alone resulted in different speeds of rotation, with the machinegun rotating slightly faster than the turret. Thus the machinegun does not really stay aligned with the hull, but slowly rotates in opposite direction that the turret does. It should be noted that since two copies of turret’s rotation mechanism were built, there are actually two turntables in this model: one below the turret and another one inside it.

Despite its few shortcomings, the model met a very positive response, being occasionally called my best tank model yet. I was slightly disappointed by its speed, but delighted at its suspension which worked way beyond my expectations, providing excellent flotation without using a single shock absorber. Personally, I consider this model as a preliminary study for my next tank, the South Korean K2 Black Panther, which will develop some of Leopard’s solutions further and hopefully improve in general wherever possible.

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Video:

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Media Reference:

Rock’n Tech (Portuguese only), The Brothers Brick

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My final 2010 Truck Trial vehicle, built in less than single week after the previous vehicle failed. Features full pendular suspension, 4×4 drive, lights and opening doors, bonnet and rear board.

Datasheet:

Completion date: 03/09/2010
Power: electric (Power Functions)
Dimensions: length 48 studs / width 26 studs / height 27 studs
Weight: 1.985 kg (1.726 kg in roofless version)
Suspension: pendular, stabilized with shock absorbers
Propulsion: 1 x PF XL motor geared down 5:1
Top speed: 0.8 kmph in roofless version
Motors: 1 x PF XL, 1 x PF Medium

When I decided to abandon my Fiat SPA35 model, it was just a week before the Truck Trial race and my first decision was to pass on driving this time and to only take care of filming. Shortly after, I changed my mind and decided to try some simple 4×4 vehicle, just to drive something in the race. The vehicle was intended to combine the advantages of my two previous Truck Trial vehicles – Hummer H1 and Jeep Wrangler Rubicon, while also learning from Fiat’s failure. I wanted to try to model another famous 4×4 vehicle, so the classic Land Rover series 2 (dating all the way back to 1958) was pretty much an obvious choice.

While the complete model appears much like a Hummer/Wrangled hybrid on the outside, it was internally much closer to the Fiat model. The chassis was built completely with studless parts and used large Technic turntables to hold suspension modules in place – both solutions tested in the Fiat for the first time. The Land Rover shared engine location, gear ratio and wheels with the Wrangler and a studfull body with the Hummer. In fact, the Rover used studfull body around a studless chassis, whereas Wrangler used studless body around a studfull chassis.

The suspension has undergone some major changes in comparison to the version used in Fiat. The front axle was reverted to the version used in the Wrangler, and then a single turntable was attached behind it and the steering system was additionally reinforced. Both drive and steering were transferred through the turntable – steering by a solid driveshaft and steering by am empty differential sitting on it. The rear axle was built from a scratch between two turntables. There was no gearbox, and – just like in the Wrangler – the drive motor was located above the front axle, right under the bonnet. The racing rules we use state that every model has to be equipped with a piston engine of accurate configuration and placement, unless the actual drive motor is located where the original engine is. Thus, locating the motor under the bonnet meant that no piston engine was needed in the model, which saved space, weight and drive motor’s power. The steering was controlled by a single PF Medium motor geared down 15:1 and located low in the chassis, in front of the rear axle. The entire underside of the chassis was covered with studless parts, in order to create a single smooth surface that was unlikely to get  stuck on an obstacle, and in order to lower the centre of gravity as well.

Knowing that my Wrangler model had abundance of torque, I wanted the Rover to be much heavier.  Our racing rules take power-to-weight ratio of each individual model into account, therefore more weight at the same power means more points. Thus, I wanted the body to be massive, but at the same time it was my goal to keep the model’s centre of gravity low, despite its significant ground clearance (up to 7 studs under cabin’s floor). Therefore especially the lower portion of the body was built so densely that model came out almost undamaged from some crash tests I conducted later.

The body was equipped with a pair of opening doors, an opening bonnet with a spare wheel fixed on top of it (a common sight in early Land Rover versions), and opening rear board with the IR receiver attached to it. Most of the Land Rovers can be accessed from the back by a single door, and a board is a rarity. I chose the board over door because this way the IR receiver was more exposed, and could be pulled out from the cabin’s inside to some extend if needed. Moreover, the rear part of the cabin has been adapted to house a camera. Due to weak mounting points, this solution worked well only on flat, level surfaces, as proven during the race.

It should be noted that the model’s body was inaccurate: the front radiator grille should be put further back under the bonnet. I couldn’t model it because of the frame that braces the suspension module of the front axle. Moreover, inspired by the Inception movie featuring a tracked Hummer H1, I have created a simple set of four tracks for the Land Rover. The tracks and wheels could be easily swapped in the chassis, and while I did not intend to use the tracks outdoors (our racing rules don’t allow tracked vehicles of any kind), I have used these to drive around my apartment. The general performance was apparently inferior with tracks on, and in particular the traction was much worse than it was with wheels.

The completed model weighed a whopping 2.1 kg until I removed ballasted bricks that were mounted under the bonnet in order to shift the centre of gravity forward. It reduced model’s weight to just below 2 kg, and I decided to leave it like that because there was no time left for changes. The model performed well at this weight, it experienced no mechanical failures and displayed superb traction, but it was obvious that it will be struggling against its own weight.

Land Rover was warmly welcomed by other contestants because of its look and its very short building time. It performed well in the race, no mechanical failures occurred, but its weight turned out to be a real problem. The model ran out of power to climb on several occasions, and toppled over once. It ended up at the last place in the race, much to my disappointment. Yet still, other drivers and viewers were greatly impressed by its look, which led me to believe that it would be a waste to take it apart, and that the model should enter our last 2010 race on October, with open body design that should significantly reduce its weight.

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Media reference:

GadgetSin

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Large model of a Caterpillar front shovel excavator designed for a public display. Features a drivetrain with a subtractor, superstructure rotation mechanism, V12 piston engine, arm with 3 joints controlled remotely by motorized linear actuators, pneumatically opened bucket, remotely elevated operator’s cabin, lights and custom stickers.

Datasheet:

Completion date: 11/06/2010
Power: electric (Power Functions) / pneumatic (fed from internal compressor)
Dimensions (with the arm in ‘resting’ position): length 80 studs / width 28 studs / height 35 studs
Weight: 3.5 kg
Suspension: pendular bogies
Propulsion: PF XL motor geared down 9:1, through a subtractor
Motors: 2 x PF XL, 6 x PF Medium, 1 x 71427

I wanted to build a front shovel excavator controlled by linear actuators for some time already. It took me a while to find a machine with a distinctive silhouette (as many large front shovel excavators are shaped similarly) and my choice was the Caterpillar 90-tonne machine with an unusual cabin elevation system.

The model would be built at much later time if it wasn’t for the people from the Focus popular science magazine, who invited me over to a Picnic of Science held in Warsaw (the largest popular science event in whole Europe). It was a kind invitation, but it also meant a fixed term to build something spectacular and, so to say, public-proof. I had to hurry to make it on time, I even used my absence of leave to finish the model, but I felt it was still not tested sufficiently.

The look of the model is accurate to some degree. The size and all the dimensions are kept faithful, and the colour theme is an exact rendition of one of the two Caterpillar liveries I’ve seen this machine with. The details on the top of the model, however, were intended to look diverse rather than accurate, the V12 piston engine model is completely unrealistic (but it turned out to be a great crowd pleaser, as anticipated), and the arm lacks a single actuator. Additionally, the way the bucket opens up has been changed slightly to make the bucket look better and be more structurally sound.

As for the functional side, it was largely affected by the unexpectedly huge weight of the model. While the chassis was providently built around a really massive studless frame, the drivetrain had to be additionally geared down to handle it. Even with the 9:1 gear reduction, some gears in the subtractor are still being grinded to dust. Not a single gear in the drivetrain was broken, but there was a plastic dust coming out whenever I opened up the subtractor. But in fact, the painfully low speed of the model is accurate as the real machine moves at 4.4 kmph.

There is a studless Technic turntable between the chassis and the superstructure. The stability is provided by four double rollers, consisting of two wedge belt wheels with rubber tires each, and integrated into the superstructure’s bearing frame (located, as usual, in its ‘floor’). The rollers are supported by large tiles on the top of the chassis. I have assumed that use of large rollers will be a convenient way of filling the gap between the superstructure and the chassis, and that the rubber tires will provide a degree of elasticity should the superstructure tilt while operating. Whether these assumptions were accurate or not is difficult to prove eventually. But I was right to only use four sets of rollers (front/rear/left/right one) as they provided sufficient stability for as long as they were part of a sound, rigid structure.

The major drawback of this model is the use of an 8-teeth gear wheel as the final part of the superstructure rotation mechanism. The weight of the superstructure coupled with the friction generated by the rollers’ rubber tires caused this gear to be severely damaged during final tests. Since it was very difficult to replace (read: it required to take half of the model apart) and there was no guarantee that the new gear wheel wouldn’t share its fate, I left if the way it was. Which means that the superstructure rotation works only when aided by hand. The video clearly shows that superstructure rotates as long as the rear part of the hull is being gently pushed (at some point I even use a single finger for that to demonstrate that there is indeed a mechanism working there and that I’m not simply rotating the superstructure by a hand). The use of the 8-teeth gear wheel, which worked fine in lighter models, was a mistake here to begin with. I should have used a worm gear instead, preferably one that would be mounted to the chassis and driven from the chassis.

The rear part of the hull houses the 8878 rechargeable battery which powers the whole model and which can be accessed by a small sliding lid. On its left, there is a big V12 piston engine driven by a separate PF Medium motor coupled with the drive motor (which means that there is no mechanical connection between this engine and the drivetrain whatsoever). The whole V12 is fully enclosed inside the hull, and can be displayed by opening up a two-piece lid. I always wanted to include a piston engine into an excavator model, and with a model that large I finally did. On the right side of the battery, there are four IR receivers and beneath them, there is a pneumatic autovalve which controls the opening/closing of the bucket.

The front part of the hull houses a massive frame around the arm’s main joint. The arm is 6 studs wide at this point, and there is a driveshaft, two pneumatic hoses and three electric wires going through the joint. On the right side of the arm there is a PF XL motor which drives two linear actuators that lift arm’s first section. There is also a PF switch which controls the lights on the arm, and which can be accessed by the means of a small door in the right side of the hull. On the left side, there is a cabin sitting on a scissor lift mechanism, which is moved by a single linear actuator driven by a 71427 motor located under the piston engine. The elevation range of the cabin is impressive, especially when you realize that the whole scissor lift mechanism is just 3 studs tall. The mechanism has its drawback too – it puts a very high load on the motor, so it has to be additionally geared down (hence the low speed of cabin elevating) and the weight of the cabin has to be kept low (hence the number of details is lower than intended).

The arm consists of two sections. The first one is controlled by the aforementioned PF XL motor which drives two linear actuators integrated into the front part of the superstructure’s frame. The second section is controlled by a PF Medium motor located in the hull, between the arm and the 8878 battery, which drives a single linear actuator integrated directly into the arm’s first section. There is another PF Medium motor inside the first section, which drives another two linear actuators that tilt the bucket. The second section of the arm is pretty much empty. The arm was built in the same way as it was with my previous excavator: it consists of a studless frame with directly attached actuators, and a studfull outer skin which provides extra stiffness but is not necessary for the arm to work. I am not quite pleased with the somewhat weird look of the pneumatic hoses on the arm – I could have enclosed these inside the arm, but I felt that an excavator’s arm ought to have some hoses on it. But due to the complex construction of the arm’s first section, there was no way to arrange the hoses in a more realistic manner.

The arm has some excellent movement range. In fact, it is somewhat better than that of the original machine – to the point at which it is not necessary to open the bucket to unload it, as it can be simply tilted.

As for the bucket opening mechanism, it is very simple and consists of just two small pneumatic cylinders. Some minor part of the load is usually left inside the bucket when it opens, but this is caused by the bucket’s inner shape which results from its internal studless frame rather than by the mechanism itself.

This has doubtlessly seen more practical use than any of my other excavators, as it was operated for a couple of hours straight during a public event. It has also successfully faced the devastating curiosity of little children present at the event, but I won’t describe the details lest I sound like a contraception promoter In fact, the failing superstructure rotation mechanism is the only thing that prevents me from calling it my best working excavator model ever. The model has been also highly acclaimed by LUGPol members – so highly, in fact, that I was genuinely surprised.

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Media reference:

Hobby Media (Italian only)

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Re-edition of the model of the Swedish MBT, built two years after the initial version. Features full suspension, remotely tilted hull, remotely controlled dozer blade and lights.

Datasheet:

Completion date: 06/03/2010
Power: electric (Power Functions)
Dimensions: length 67 studs (including main gun’s barrel) / width 25 studs / height 19 studs
Weight: 2.15 kg
Suspension: pendular bogies
Motors: 2 x PF Medium, 2 x PF XL

After almost exactly 2 years, I decided to re-build my perhaps most renown tank model. The S Tank, created back in 2008, has been extremely well welcomed, and no matter how many bigger, more accurate and more complex tank models I’ve built later, there were always some people claiming that S Tank was the best. I, on the other hand, was aware of many shortcomings of this model, and it was my goal to overcome these shortcomings in the following models – a fact that has apparently escaped the attention of many S Tank’s enthusiasts. Eventually, I decided to build this model again using my current level of modeling skills, even though it was against my ‘never build the same thing twice’ rule.

The original S Tank, or Stridsvagn 103, is a fascinating machine all by itself. Designed in 50s, it was the main tank of the Swedish army for the next 40 years, until arrival of the Leopard 2. What was the key of its success and its long-term service? The fact that it was designed with Sweden in mind. Moreover, it was designed specifically for defensive roles. This is why the typical turret was removed completely, because the tank was intended to stay hidden waiting for the enemy to come. To operate in difficult Swedish terrain, the tank was fitted with then-advanced hydropneumatic suspension and a turbine engine (in addition to a traditional diesel engine), making it the world’s first MBT to use turbine engine. Aiming was done by moving the entire tank, using the suspension to tilt the hull as needed. In order to fire its main gun, the tank had to be stopped and its suspension locked – it was clearly a drawback, but it was acceptable given the tank’s defensive role. It should be also noted that in 50s and 60s the fire control systems were relatively primitive, and tanks rarely fired while moving. Finally, the S Tank was equipped with a front dozer blade, which could be used to entrench it quickly and without the need for crew to leave the vehicle.

Thanks to removal of the turret, the tank’s front could be protected by a single armored plate, set at an angle that made it very difficult to penetrate. Actually, at the time it was designed, the S Tank’s front armor was virtually impenetrable for any other tank’s armament. To make a full use of this advantage, the crew included two drivers – the second driver was facing backwards and had his own set of steering instruments. Thus the S Tank was able to drive backwards quickly, while being protected from the enemy by its front armor, as well as being able to return fire at any time.

The S Tank was clearly an unorthodox design, so specific that Sweden remained its only operator, but it could be pretty lethal to any advancing force. Why? Because it had to be spotted before it could be engaged. Now, take a good look at a fully entrenched S Tank:

The new model of the S Tank was supposed to be: accurate, performing well and dark gray. I believe it meets all these conditions. The hull, which was tilted pneumatically in the previous version, is now controlled by linear actuators. It takes much more hull’s internal space, but the stability provided by such solution is peerless. Since my first S Tank was driven by a single XL motor, and the motor was apparently working pretty hard, and now the PF speed control is available, I used two XL motors, each one driving a single track. The tracks’ suspension system consists of 4 large, realistic road wheels (6595 wheels without tires work very well with tracks) suspended on pendular bogies, two wheels per a single bogie. I wanted to use a torsion bars suspension for the first time, but it was impossible to make it work together with the tilted hull. The front dozer blade is operated by a single PF Medium motor instead of pneumatics, and it works better than I expected (this is an application where pneumatics usually performs better than motors do). It should be noted that front part of teh hull houses a traditional battery box rather than the rechargeable battery, and there are two reasons for that. Firstly, a battery box can provide more power for two PF XLs used simultaneously, and secondly I needed something heavy in model’s front part to acquire the proper weight distribution.

As for the visual details of the model, my goal was to model the most distinctive ones. Like many tanks with long service period, the S Tank has undergone several modifications and there are 4 variants of this tank, which differ mainly in details. Few details are fictional, just to fill some empty spaces. Please note that this model uses custom chrome sprocket wheels, rather than original ones that come only in yellow or orange at the moment. These wheels have been purchased at this Bricklink store.

The model took a lot of work and a lot of extra shopping for parts, but I think it was worth it. For me, it is clearly my best-looking tank up to date. It seems that models in dark gray look particularly well on photographs, which is why I attempted to make a couple of macro-like shots, even though I only had a general purpose lenses (macro lenses are expensive beyond human reason). The model performed very well too – it was my fastest tank up to date, and its large road wheels made the suspension’s work spectacular to watch. I have enjoyed driving it over a wrinkled blanket more than I enjoyed driving any other tank under any other conditions. However, there’s a good chance that it would perform better with a torsion bars suspension.

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Model of a JCB skid steer loader. Features drive, steering, remotely raised arm, tilted bucked and working roof lights.

Datasheet:

Completion date: 14/02/2010
Power: electric (Power Functions)
Dimensions:  length 31 studs / width 18 studs / height 20 studs
Weight: 0.73 kg
Suspension: none
Motors: 3 x PF Medium, 1 x micromotor

No a long ago, I have come into posession of the LEGO micromotor, something I wanted to have for years. Micromotors are unique, hard to get at a reasonable price, and impossible to replace in certain cases. When I finally got mine, I wanted to use it to control the horizontal angle of the main gun’s barrel in my T28 model, but the model was almost complete by the time I got the motor. Then it occurred to me that the smallest project on my list could definitely use the micromotor.

JCB 180 is a simple tracked skid steer loader. There are plenty of skid steer loaders and I was never interested in building one, viewing them as simple and technically boring. The JCB 180, however, is one of few loaders with a single arm instead of two, and that makes it challenging.

My goal was to  achieve maximum functionality while showing as little mechanics as possible. I’ve spent quite a while trying to fit a small transverse subtractor into the chassis, but I had to admit that it’s too large at this scale eventually. Therefore the drivetrain is very simple: it consists of two PF Medium motors, each driving a single track. Third PF Medium motor drives the linear actuator that controls the loader’s arm. Having one arm instead of two turned out to be a blessing in disguise, as there was no space inside the hull to drive two linear actuators or to transfer the movement from one arm to another. The roof lights are a good example of how compact this model is: they are coupled with the micromotor, because there was no space to connect them elsewhere.

The micromotor was located at the end of the arm, and it proved quite easy to integrate into a liftarms-based structure. It uses 3:1 gear reduction to change the bucket’s angle. I did some capacity tests with Lucius the hamster (roughly 60 grams heavy), and he was able to stay on the bucket without causing any sort of mechanical malfunction. The capacity, however, is severely limited by the fragile bucket’s construction – the first bucket I made was so heavy that it tilted to the side in a very ugly way. The final bucket was optimized for minimum weight.

The model was built in less than a single day, and it could certainly be somewhat upgraded. But I was satisfied with its functionality and look anyway, and considered it a relaxing build, without the need to make it better & better. It was also Lucius’ first time to appear in the AFOLs’ world.

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Model of the American WW2 super heavy tank prototype. Features full suspension, drivetrain with a subtractor, lights and advanced main gun control system.

Datasheet:

Completion date: 13/02/2010
Power: electric (Power Functions)
Dimensions:  length 73 studs (including main gun’s barrel) / width 30 studs / height 16 studs (not including aerials)
Weight: 2.2 kg
Suspension: pendular bogies
Motors: 2 x PF Medium, 2 x PF XL

T28 was an unusual project. Started in Spring 1945, it was designed to break through German defenses and to counter German super heavy tanks such as Maus or E100 (none completed, fortunately). The designers focused on the armament and armour of the tank at the cost of its mobility, and they decided not to use a typical turret as it would not be needed against fortifications. T28 had one of the thickest tank armours in history, but it was driven by an V8 engine providing merely 500 HP – a very little power for a tank of such weight. It was also one of few tanks to move around on 4 tracks. The outer set of tracks could be removed for transportation by train. The tank could drive on a road on inner tracks, towing the outer ones behind.

Out of 25 planned T28s, only two were built. The war ended before they were operational, and in 1947 they were subjected to evaluation. It went bad – one prototype was completely destroyed by engine fire, and the other one proved that a 500 HP engine can barely move it. Both were supposed to be scrapped, but the undamaged one was found in 1974 in a back field at Fort Belvoir, Virginia. It is unknown where it was earlier, and it is unknown how a tank of this size can remain unnoticed inside a military base

The model is relatively simple on the technical side. It uses only 4 motors, two to drive and the other two to control the main gun. Just like in the real tank, the main gun has limited traverse and elevation. The drivetrain consists of a subtractor and two PF XL motors, one for drive and one for steering, on assumption that it takes quite a torque to steer a tank that wide and with 4 tracks. The model is not entirely accurate – one of departures include a V6 piston engine in the back, instead of fuel tanks. The real machine was driven by V8 engine, but only 6 pistons can be seen through a 8×8 grill, so I used a V6 engine. It has internal lighting, with lights pointed at each piston, and all the lights are coupled with the drive engine, so the faster tank goes, the brighter the engine is.

Another departure is the shape of the front of the hull. It was changed mainly to house the main gun control mechanism. The real tank had its gun mantlet attached to the hull, while the model’s mantlet is attached to the barrel and moves together with it, hence it needs a certain margin of free space around it.

The most challenging element of the model was its suspension system – not because it’s advanced, but because it’s so expanded. Each of the four tracks uses four pendular bogies, each with two road wheels. It sums up to the total of 16 bogies with 32 road wheels. Each track’s suspension is separate and independent, and each track consists of 123 tread links. Together with the spare track section on the armour, it sums up to over 500 tread links used for the model.

The model looked really well, and it definitely paid off to build it in dark grey instead black. It performed well, although the main gun’s barrel was a bit wobbly. It also seemed to experience problems with the drive motor – it could drive backwards and turn very well, but it seemed that driving forwards put more and more tension on the motor. The problem seemed to be getting worse over time, and it is possible that the PF XL motor used for drive was defective. Because of that, the model appeared very slow on the video, whereas given a properly functioning motor it should have been faster. Still, it was my first tank in dark grey, and came highly acclaimed for its look.

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