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.

Work in progress photos:

Photos:

Video:

Click here to view the embedded video.

Share/Bookmark

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.

Work in progress photos:

Photos:

Video:

Click here to view the embedded video.

Share/Bookmark

A simple, small model of an unique leaf spring catapult designed by Leonardo da Vinci.  

Datasheet:

Completion date: 30/08/2011
Power: wind-up crank
Weight: 75 g

Model of one of the Leonardo da Vinci’s less famous inventions: a catapult using a leaf spring to fire projectiles, which makes it unique in terms of Medieval technology. The original catapult was to use a single wooden leaf spring – an idea probably inspired by a bow. It did not become popular due to high manufacturing costs at the time. There was a number of full-size models recreated today, and they proved capable of throwing stone projectiles just under a quarter mile. My model, whose scale is difficult to determine, can throw a regular Lego ball just under two meters.

It took me a while to find a Lego element of proper elasticity – I eventually settled for two 12 L axles. It seemed that the axles will get bent permanently from the tensions present in the model, but eventually the did not – they turned out to be perfectly straight after disassembly. I believe a catapult using the same principles to work without risking damage to any Lego pieces could be made with two rigid levers mounted on tension bars, but that would look very much different from Leonardo’s original design. I wanted the model to be mechanically accurate; this is also why I didn’t include any arm-stopping mechanism that could potentially increase the range – I simply haven’t found any in the original drawings.

Photos:

Video:

Click here to view the embedded video.

Share/Bookmark

Model of a South African MRAP vehicle. Features pendular suspension, 4×4 drive, 2-speed gearbox and lights.  

Datasheet:

Completion date: 18/08/2011
Power: electric (Power Functions)
Dimensions: length 41 studs / width 24 studs / height 22 studs
Weight: 2.074 kg
Suspension: pendular
Propulsion: 1 x PF XL geared 4.2:1 (low gear) / 2.5:1 (high gear)
Motors: 1 x PF XL, 3 x PF Medium

RG-35 4×4 is a modern small MRAP (Mine Resistant Ambush Protected) vehicle developed by BAE Systems South Africa as a smaller variant of base RG-35 6×6. It belongs to the second generation of the MRAP vehicles, which means that it combines high level of crew protection with impressive off-road capabilities. It was introduced in the first half of 2011, which means that it’s just starting to enter service, with the Canadian Army considering a massive order.

The model was built primarily to test the wheels and gear blocks from the 8110 Unimog set. It consisted of a short, fully studless chassis enclosed in a studfull body. Both axles had pendular suspension with 4 short shock absorbers on the rear, and 4 long shock absorbers on the front axle. The front axle had a Medium motor for steering integrated into it. The 8110′s set ball joints were used to attach axles to the chassis, as I expected them to support at least part of model’s weight thus reducing the friction on the driveshaft. Both axles also included differentials, as I expected them to be necessary for a vehicle with that short wheelbase. However, the presence of the differentials had a bad impact on model’s off-road capabilities.

The chassis, despite being very short and housing tall suspension modules, housed a remotely controlled 2-speed linear gearbox, a straight six piston engine with a separate Medium motor to drive it, and it even housed a motorized front winch unit until I decided to remove it to lower the model’s centre of gravity – and all of this with the right side of the hull recessed to accommodate for a spare wheel. The model had to weight at least 2 kg to be allowed to an outdoor Truck Trial race, and I achieved this weight by adding approximately 0.25 kg using weighed bricks. They were located at the very bottom of the body, thus lowering model’s centre of gravity.

The model turned out to have very soft suspension and additionally I have somehow mistaken the set-up of the gears in the drivetrain, resulting in an unusually low gear reduction. The latter rendered the model practically unable to drive outdoors, and it was eventually destroyed in an accident while I was driving it downhill. The short chassis was a disadvantage when climbing or descending, and the model tumbled forward over its front wheel and crashed.

I believe the model had a great potential, excellent ground clearance and one of the most effective chassis I’ve ever built. This potential was wasted due to my simple error in drivetrain’s construction and due to disadvantages of its short wheelbase.

Work in progress photos:

Photos:

Video:

Click here to view the embedded video.

Share/Bookmark

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.

Photos:

Video:

Click here to view the embedded video.

Share/Bookmark

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.

Photos:

Work In Progress photos:

Video:

Click here to view the embedded video.

Media Reference:

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

Share/Bookmark

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.

Photos:

Video:

Click here to view the embedded video.

Share/Bookmark

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.

Photos:

Video:

Click here to view the embedded video.

Share/Bookmark

Model of a modern French main battle tank. Features advanced independent suspension with adjustable ground clearance, gearless drivetrain, remotely rotated turret and commander’s gun, remotely elevated main gun, and an onboard wireless live feed cam.

Datasheet:

Completion date: 17/08/2009
Power: electric (Power Functions)
Dimensions:  length 58 studs (including barrel) / width 26 studs / height 22 studs (plus aerials)
Weight: 2.48 kg
Suspension:  full independent with adjustable ground clearance
Motors: 4x PF Medium, 2x PF XL

I have a special liking for the tracked vehicles, and especially for modern tanks which happen to be the most advanced tracked vehicles ever built. This is why, having built my last tank nearly a year ago, I was looking for a modern machine that would make a nice model. I wanted something similar to the previous model, the Abrams M1A2 tank, but smaller, lighter and more mobile. Since the Leopard was out of the question (I wouldn’t feel comfortable building a German tank), and the Merkava has an unusually shaped turret that would be difficult to model, I decided to build the Leclerc – a very good and distinctive example of today’s high-tech tank.

If we lay aside the popular jokes on French tanks, the Leclerc is a fairly outstanding and impressive machine. It was build for a very interesting reason: because none of the world’s tank lived up to the expectations of the French Army. As one may anticipate from that, it is in many ways different than earlier main battle tanks such as e.g. Abrams, and very likely sets standards for the future constructions.  There are differences in almost every aspect of its construction: for example when it comes to the defence, Leclerc’s design focuses strongly on the active protection. The tank is protected passively by a modular armour similiar to the one used in Leopard 2, but there are two layers of active protection being currently developed and scheduled to be put into use around 2015: the ‘soft’ layer is capable of jamming computer systems of the incoming missiles, while the ‘hard’ layer shoots down any incoming large-caliber projectiles. Both layers are supposed to be fully automated, with the latter one being capable of shooting down projectiles coming from any direction in time intervals as short as 0.6 second. Even Leclerc’s armament is unusual: instead of Rheinmetall 120mm cannon present in vast majority of modern tanks, it uses longer French-built GIAT 120mm cannon along with a custom French-produced ammunition and an automatic compressed air fume extraction system instead of the usual bore evacuator. The tank’s turret is built around an autoloader system designed specifically for Leclerc, which provides an impressive performance and at the same time allows to avoid many problems usually present with the standard autoloader systems. The most impressive things are many high-tech upgrades scheduled for the Leclerc: those include the aforementioned two layers of the active protection, but also multipurpose armour upgrades, the anti-missile decoys deployment systems, thermal signature reducers, and – probably the most impressive of all – Stealth armour kit.

The construction of the model started with a new suspension concept. I was happy with the performance of the independent suspension used in my Abrams model, but I wanted to make it even more realistic. In order to achieve it I have removed the most unrealistic element, the central tread wheels , and I fitted all the road wheels with thin full rubber tires. Thus the tracks have no solid point of contact with any road wheel whatsoever, and are kept in place only by the road wheels, without any use of the tread wheels which are commonly used in the official Lego sets. At first it seemed an unreliable solution, but it proved to be perfectly reliable – I had less slipped track cases with Leclerc than I have had with the Abrams, and they all happened only because the tread links came apart.

It was obvious from the beginning that the model will make use of the new 8878 rechargeable battery and of the PF speed control feature. It meant two things: that it will have plenty of internal hull space available, and a very simple drivetrain. I have eventually limited the drivetrain to just two short axles connecting motors directly to the respective drive wheels – with the speed control feature nothing more was needed to allow the tank to make turns at any angle, and it seemed to blend power with speed in a promising way. Moreover, such a drivetrain was extremely efficient and durable, since not a single gear was used.

With a lot of internal hull space at hand, I wanted to try an idea of using the independent suspension to adjust the ground clearance. It was achieved by mounting upper tips of all the shock absorbers on lengthwise liftarms, which were moved higher or lower by two coupled pairs of very short levers. That solution worked very well in the early construction stage, easily providing two studs of difference in ground clearance, at which rate the tank was actually able to sit on the ground. It was also possible to change ground clearance at any position, at any moment, even while driving, and the tank’s suspension remained fully functional all the time. The efficiency of this system, which took almost half of the internal hull’s space (there were 4 sets of worm gears all coupled together), was eventually severely crippled by two factors: firstly, the length of the tracks which was limited. The tracks weren’t, obviously, elastic, so their length remained the same as the suspension was raised or lowered. It left a small margin for differences, as the tracks couldn’t be too lose or too tight, and so the range of ground clearance adjustment was limited to approximately single stud. The latter factor was simply the model’s weight, which proved larger than expected and heavily loaded the mechanics of the ground clearance adjustment system. Even though the Leclerc was still much lighter than Abrams, its suspension was loaded a bit heavier because it consisted of just 12 sets of road wheels compared to Abrams’ 14 sets.

The remaining hull space was used to house the battery (in front of the hull, with a small access hatch in the armour under the front part of the turret), three IR receivers (located next to drive motors, partially below rear part of the turret) and a PF Medium motor controlling the turret’s rotation. The last solution was unusual for my tank models, as the previous ones had this mechanism housed inside the turret itself. It made the turret’s internal structure a lot simplier, which was important to me because I wanted very much to model its distinctively flattened silhouette. Thus, the turret ended up housing two PF Medium motors, first of which was used to elevate the main gun. The elevation system used a single linear actuator, much like in the Abrams model, except this time it was located in a central position to make the main gun’s barrel more stable. As for the latter PF Medium motor, I initially intended to use it for a main gun recoil system, an improved version of the one used in the Abrams, but I have eventually decided not to make these two models more similar to each other than they already were. It left me with just a few possible options to use the extra motor, so the motor was eventually used to make a ‘turret in a turret’, that is to rotate commander’s gun, which is a nod towards the realism as the real Leclerc has this gun controlled remotely from inside the tank. Thanks to that, there was a lot of space left inside the other side of the turret, which I have used for something I wanted to use already in Abrams – an onboard live feed camera showing forward view from the turret. I have used a simple micro industrial surveillance wireless camera, exactly the one used much earlier in my Moon Rover. It fit inside the turret very well, and I was particularly pleased with the sound recorded from inside the model – the sound of moving tracks seemed more realistic than I could have ever imagined.

The model enjoyed a fairly good reception. I didn’t really like its aesthetic side which seemed too much like that of the Abrams model, but I loved the performance provided by the powerful drivetrain and the sophisticated suspension system. It seemed to have all the impressive power of Abram’s drivetrain, but moved much more swiftly and fluently. It was my fastest tank model at this weight and the first one to use Power Functions speed control feature.

Photos:

Video:

Click here to view the embedded video.

Media reference:

BrickActu

Share/Bookmark

Fictional 6×6 IFV. Features all wheel drive, full independent suspension, illuminated piston engine, deployable side cannons, and tank-like turret with ability to shoot projectiles.

Datasheet:

Completion date: 31/05/2009
Power: electric (Power Functions)
Dimensions:  length 61 studs / width 28 studs / height 30 studs
Weight: 2.78 kg
Suspension:  full independent
Motors: 2 x PF XL, 4 x PF Medium, 1 x 71427

The initial inspiration for this vehicle was GoW’s Laverne APC. I did not regard its construction as realistic, so I’ve made many changes, including different axles setup.

There was a number of experimental features built into this construction. Among others, I wanted to see how a full independent suspension performs in a 6×6 vehicle with considerable weight. It turned out that only one steered axle in such a vehicle is a bad solution, because the wheels on the rear axles bend while turning. The axles #2 and #3 use 3 studs wide differential bracings I have developed some time ago, and they worked flawlessly. Axle #1 on the other hand is exactly the same module that has been used in my Hellbender model.

Another important feature is the turret. It’s ugly and large (which makes it look like the turrets of self-propelled howitzers) but it houses a firing mechanism developed by Duku and used previously in my Tripod Gun. The mechanism was initially supposed to shoot projectiles through the barrel, but the prototypical barrel made of 1×3 liftarms had so large internal friction that the projectiles couldn’t even exit it. Hence the barrel is non-functional, and the projectiles are being fired from above it. The entire mechanism along with the barrel can be elevated by a linear actuator, but since there is little place under the turret, the elevation is only by few degrees. It shows that if I want to use such a turret in a model of a tank, it needs to be partially ‘submerged’ into the hull to reduce its height.

There are two additional small turrets on the front part of the hull, which rotate accordingly to the front wheels’ angle. However, the synchronization with the steering mechanism is poor.

Finally, there are two deployable side cannons. The initial idea was to use links and a complex setup of several independently moved parts to make the cannons emerge from inside the hull. As the hull’s construction progressed, the available space was becoming more and more limited, so the cannons have eventually ended up in simple casings deployed like a drawbridge. This is a very simple solution, and both casings are moved by a single string and internal winch. In order to solve the problem of string’s backlash, the string was not fixed to the winch drum – instead, it goes through it. Thus the backlash is distributed evenly on both sides of the winch and reduced whenever the string is pulled up.

Personally, I regard this construction a complete aesthetical failure. Still, it featured a couple of new solutions, it was my first vehicle able to shoot and the first wheeled vehicle that used the Power Functions speed control feature.

Photos:

Video:

Click here to view the embedded video.

Share/Bookmark

Model of my favourite vehicle from the Unreal Tournament 3 game. Features 4×4 drive, full suspension, pneumatic rear differential lock, rotating front & rear turret, lights and custom stickers.

Datasheet:

Completion date: 24/03/2009
Power: electric (Power Functions) / pneumatic (fed from internal electric compressor)
Dimensions:  length 46 studs / width 29 studs / height 30 studs
Weight: 2.35 kg
Suspension:  front – independent / rear –  live axle
Motors: 3 x PF Medium, 1 x PF XL
Pneumatics: a single circuit with an autovalve fed from a dual-pump internal compressor

Being an ardent fan of the Unreal Tournament series, I have finally decided to join two passions and build a model of my favourite UT vehicle. Which is Hellbender, underestimated by many, but absolutely lethal if used properly. It was also an opportunity to test a suspension I have developed with Truck Trial races in mind, as well as the 3 studs wide differential lock mechanism I have recently published.

The model is certainly not 100% accurate, as the original vehicle was quite challenging to reproduce. It is, however, entirely functional and fitted with 4 motors total. Power is delivered from two battery boxes, not because of some particularly high energy consumption, but because it turned out to be optimal to locate the battery box on the side, so I have used two battery boxes, one counterbalancing the other. The 4×4 drive is powered by a PF XL motor, and the steering is operated by PF Medium one. Another Medium motor rotates two turrets synchronously. The third Medium motor drives a dual-pump internal compressor via an autovalve, thus controlling the differential lock mechanism in the rear axle. As the rear axle is floating and quite complex already, I found it to be an optimal solution – thus, almost entire pneumatic system is located inside the hull, and there is only a sinle small pneumatic cylinder with two pneumatic hoses in the rear axle.

As for the off-road performance, the model certainly suffers from a short chassis and perhaps too complex rear axle. The short chassis was the reason why the drivetrain is complicated, with steering system located behind the front axle, and the drive being transferred to it from the front. A single, common driveshaft located in the center of the chassis would certainly perform better, as it is a popular solution in the Truck Trial vehicles. The rear axle, on the other hand, has its differential mounted not steadily enough because of the lock mechanism, which results in the gears’ tendency to snap. The model performs well on the floor, but has difficulties with even easy obstacles. It is, however, an interesting study of how the independent suspension based on the 8297 set’s components performs.

The model was presented by me at the official UT3 forums, where it has been acclaimed by some members of the Epic staff.

Photos:

Video:

Click here to view the embedded video.

Media reference:

BeyondUnreal

Share/Bookmark

Functional model of the APC from the James Cameron’s Aliens movie. Features 4×4 drive & steering, full suspension, remotely opened side slidedoor, manually opened driver’s door, remotely rotated turrets, lights and custom stickers.

Datasheet:

Completion date: 11/12/2008
Power: electric (Power Functions)
Dimensions:  length 61 studs / width 22 studs / height 19 studs
Weight:  2.49 kg
Suspension:  pendular with shock absorbers
Motors: 2 x 71427, 2 x PF Medium, 1 x PF XL

My first stricly movie-inspired model, preceded by a long period of a meticulous documentation. I’ve been planning to build it for over a year, and still had to do a lot of shopping before I started. Eventually, it turned out to be my most rare-parts-consuming project up to date.

The model can’t be described without an important point of reference – a model of the same vehicle built earlier by LUGPol user Havoc.  Havoc’s version was not functional, but had quite an accurate appearance, and featured full detailed  interior. My goal was to build a model of the same size, but fully functional. I did not’ however, rely much on the appearance of Havoc’s APC, and built many details in a different way, trying to introduce a number of my own improvements. Overall, my model had less and simplier small details, but better and more accurate silhouette. It was quite amusing to eventually learn that both versions had nearly identical weight.

I have started by choosing a different wheels than Havoc did. The 8448 set’s wheels were better suited in my opinion, because even though they lacked a military-style appearance, they looked very well with 8×8 dishes, and they offered a precious space for the suspension inside. I have used two identical suspension modules, partially based on my pendular steered & driven suspension module, but smaller and fitted with the 3-studs wide differentials. Each module was stabilized by a pair of shock absorbers, and the direction of driveshaft’s rotation was reverted in the middle of the hull, to neutralize the torque effect present in pendular suspensions. The steering lock was limited by the mudguards, but with both axles steered it sumed up very well. While the original vehicle was built from a pushback tug with the crab steering mode present, such a mode did not appear in the movie, and therefore I did not attempt to recreate it.

Full pendular suspension along with a longitudinal driveshaft and steering shaft crossing the middle of the hull has caused a major stability issue. Normally, a pendular suspension is fully stable as long as right and left sides of the vehicle have equal weights. Here, limited size of the hull and imposed location of internal mechanics did not allow me to place the heaviest internal components, that is the battery box plus drive and steering motors, in the middle of the hull. Instead, all internal components had to be moved to one of the vehicle’s sides. Therefore sides of the model had unequal weights, which I have almost fully compensated with nearly 200 grams of additional ballast on the model’s right side, next to the slidedoor.

As for the slidedoor, it was moved by a simple rack & pinion mechanism driven by a 71427 motor. Thanks to the use of safety clutch, it could be also moved manually at any time. The inertia that appears while this type of motor is stopping had added an unintentional effect that made the door appear heavy. The door’s construction turned out to be much more tricky than I have expected, as I was determined to build the door from plates, and therefore it lacked some stiffness. I have solved this problem by using a long horizontal rail attached to the bottom of the door, and additional short upper rail, that kept top of the door pressed against the hull. It required a small horizontal opening in the hull’s lower side, but worked very smoothly.

The rear turret was a tought matter, as it can be slided back to the APC’s rear wall in the movie. I have considered a number of ways to recreate such a movement, taking into account mainly the use of a chain & tread links. The limited size of the model, plus the amount of space occupied by its suspension made me drop that idea completely – such a chain would require at least 16-teeth gears to put it on, and the space behind the rear suspension barely sufficed for the steering system. Moreover, even with the space issue solved, it would be very difficult to make the turred slide steadily while mounted on such a loose structure as the chain. It would be very likely hung at angle while slided back, due to the backlash in the chain. To deal with it, a complex system of rails would have to be employed, resulting in an even greater need for internal hull space. Having considered that, I have used a turret able to rotate, but not slide, and made the rails on the back of the hull appear acid-soaked. Thus the immobility of the turret, which was inconsistent with the movie, could at least be explained in a movie-related way.

Both front & rear turret were rotated by separate motors through a safety clutches. I have used two various motors because of the very limited internal space in the hull’s front part, but both motors ran at similar speeds and rotated the turrets through exactly the same gear ratio. It resulted in very similar speeds of the turrets’ roration, and their independent movement if one of them became locked (which was inevitable in case of the front turret, whose range of rotation was limited by the hull).

The hull was built in a very non-Technic way. I wanted it to appear reasonably smooth – which meant for me using smooth surfaces where possible, but not trying to cover every single stud. This is well seen in the case of the top armour, which was fully covered with tiles in Havoc’s version while I attempted to use large tiles with studs on sides to render the pattern of riveted armour plates.

I have used a large number of stickers to decorate the hull, larger than the original vehicle had, on assumption that a military combat vehicle must bear a number of markings. Stickers in the front part of the APC were consistent with the original ones, and I have found and used military badges designed for the movie in some of the other stickers.

The model was warmly received, and many viewers considered it better-looking than the earlier Havoc’s version. The colour issue was brought up, and I agreed that the model would look better in dark grey, but it would be much more expensive and difficult to build, and still remain somewhat inconsistent with the movie where the original APC’s colour was a very dark green. I have, however, made the model unicoloured, just like the original one was. As for the performance, the model went through a lot of test-driving and performed very well, although its off-road capabilities were greatly limited by the very small ground clearance. Still, it was easy to drive and manoeuvre, and had plenty of torque. I’ve kept its speed low because it runs at such speed through the most of the movie, and I was afraid that it would be very difficult to access the drivetrain, should it malfunction while starting or stopping such a heavy model at a high speed.

Photos:

Video:

Click here to view the embedded video.

Media reference:

Klocki, JoeMonster

Share/Bookmark