Model of the legendary 60′s racing car. Features full suspension, remote-controlled drive, steering and turn signals, lights and custom stickers.  

Datasheet:

Completion date: 17/01/2012
Power: electric (RC unit)
Dimensions: length 67 studs / width 31 studs / height 17 studs (not including antenna)
Weight: 2.35 kg
Suspension: full independent
Propulsion: 2 x RC motor geared 5:1
Motors: 2 x RC motor, 1 x PF Medium, 1 x micromotor
Top speed: 2.2 kmph

Ford GT40 is a classic racing car with a beautiful history. It was built for one purpose only: to defeat the Ferrari team in the Le Mans race – a goal set by Ford after failure to buy out the entire Ferrari company (Enzo Ferrari changed his mind in the last second). To understand the gravity of this challenge you should know that the Ferrari team won Le Mans six times in row starting from 1960.

The basic design of the car was purchased by the Ford from Lola Cars company owned by Erica Broadley and located in Huntingdon, UK. It can be therefore considered originally a British car. However, Ford spent several months working on car’s aerodynamic properties, under supervision of former CEO of the Aston Martin company, before it was considered race-ready. The finished car was the fastest car of its time, and it won Le Mans race four times in a row between 1966 and 1969 year. When it debuted in 1966, three GT40s have won three first places in the race. Keep in mind that we are talking about race that involved brands such as Ferrari or Porsche – it’s difficult to think of any modern Ford car completing such a task.

The original GT40s were built in a limited number, and the number of “civil” versions was even smaller, making it one of the world’s most often copied cars in the years to follow. It can be roughly estimated that the number of replicas today is several times greater than that of the original cars. Around 2002 the Ford company decided finally to create a new edition of the car, which was supposed to be as close to the first GT40 as possible. In reality, it was largely different, including being taller than 40 inches – a number the GT40′s name originated from – and it was therefore named Ford GT. Due to many differences some Gt40 enthusiast consider the new edition “softened” or completely ignore its existence. You can see the differences between new version (in front) and the old one (in back) below:

If you are looking to learn more about this legendary car, you can see a dedicated Top Gear episode here, and you can listen to how it sounds here.

Ford Gt40 is called the most beautiful car ever made by some – which is arguable, given the fact that its look does not stand out so much from the look of other cars of its era. In fact, it’s strikingly similar to some cars built around the same time (e.g. Lamborghini Miura P400 version S) or even slightly earlier (e.g. Porsche 904 GTS). As large models of supercars give little room for functions (no space) or for performance (weight), my goal was to make the model look real and authentic. Out of many versions of the GT40, with many details looking much differently, I have chosen the Mark II version – one that had a history of engine failures, but that also included many interesting and unique details, including air intakes on top of the rear bonnet. Some other details, such as the absence of side mirrors, show that it’s a racing version of the car. My decision to build the body of the model fully studless was strengthened by seeing a Ford GT40 model by Arvo brothers. I consider them to be among the world’s top studfull builders but their studfull model does not appeal to me – and I don’t think I could possibly top it.
Most of all I wanted to model the shapes of the car properly, looking for a balance between using beams, panels and flexible axles. I was looking for something between the approach of the LEGO 8448 set (body made of just general contours with gaping holes) and that of some older cars by Crowkillers (fully enclosed bodies made primarily of beams).  Some compromises proved necessary – the roof was a single part, without parts of it being attached to doors, because I was unable to find a good-looking solution to that. The front bonnet did not open and the rear bonnet was inaccurate – it should open with all side air intakes attached to it, but it only opened with the top two.

Most difficult part of modelling the body was the front of it, particularly the front mudguards and headlights. If you look at front of the Gt40, its mudguards follow a complex curve which slightly rises towards the sides of the car. I wanted to model this feature, which I consider crucial in making the model look accurate, and I think I achieved that using large panels set at complex angles, with flexible axles drawing the outer body contours. The headlights, on another hand, are nearly rectangle-shaped and come with vertical ribbing, typical for headlights of all cars of that time. I eventually used blocks of 1×2 trans-clear plates, which I think look accurate, but they absorb much of the light of the Lego LEDs behind them.

The model had only driver’s seat in the cabin, and it was moved to the side because of the RC unit occupying the center. The dashboard was completely inaccurate – it rested on top of the bearing frame, so there was no space to experiment with shaping it. The exhaust pipes were tilted downward a little more than they should, allowing the rear bonnet to open up further. Behind the cabin, there was a simple, static mock-up of the engine with some details, but less than I intended to include – I didn’t want to make the model heavier than it already was.

The construction of the model was 95% studless, with only rear axle using studded bearing structure around the differential. The bearing frame was built around the RC unit which was moved forward into the cabin, practically right next up to the front axle. The frame was rigid, but not completely – therefore the rear bonnet could be locked to the back of the cabin, thus providing extra stiffness to the top-rear part of the body.

While the model was not technically complex, it was challenging to integrate all the functions I wanted it to have with the RC unit and with the way it works.

The propulsion system consisted of two hard-coupled RC motors connected to the rear axle’s differential with 5:1 gear reduction (that is larger reduction than shown on photos – I had to increase it after taking photos). The transmission system also included a Lego speedometer, with the display integrated into passenger’s side of the dashboard. The model is rather slow – I was hoping to keep its weight under 2 kg, and with the final weight being much larger the motors were so strained that the batteries in the RC unit lasted about 5 minutes.

The suspension used typical Lego double wishbone independent suspension, with two short yellow shock absorbers per each wheel. It was soft, particularly the rear axle which carried most of the model’s weight. Just like in the original car, the front suspension is slightly narrower and the rear wheels wear bigger tires – in this case, tires were enlarged by putting two rubber treads over each of them. It should be noted that the model drove better without the treads that with them.

The steering system used steering output of the RC unit. The RC steering module could not be used because it was much too narrow. The steering wheel was attached to the RC unit’s output too through a series of gears. The steering lock was small – the RC steering unit rotates by small angle, and I couldn’t gear it up because there was no space for large gear wheels under the low bonnet.

The front and rear lights, using three pairs of Lego LEDs, were connected to the same output as the propulsion motors. They only shone when the model was driving, and they blinked when it started because of the RC motors taking all the power available.

The turn signals system, which took quite a lot of work to include, was based on my earlier mechanism. This time, however, it was remote-controlled rather than automated. I simply wanted to try remote-controlling it freely, and besides it would be nearly impossible to use it with the RC unit’s steering output. Instead, it was connected to the RC unit’s auxiliary output and it consisted of two parts connected only with wires – which was necessary to fit it in. First part was a micromotor driving an old 9V switch, located vertically at the back of the cabin, between the RC motors. The second part was a PF Medium motor rotating two PF switches, coupled with old toothed half-bushes so that turning one switch on turned the other one off. I wanted to control them with another micromotor, leaving enough space for passenger’s seat, but it proved too weak.  The turn signals could be made with just two pairs of Lego LEDs, except that their wires were too short. I had to use four pairs instead, and since the GT40 has single turn signals, I ended up with two spare LEDs in front and two in back. I have installed the front LEDs into the dashboard, creating turn signals indicator in front of the driver, and I have simply hidden the two rear ones.

The model had its imperfections and compromises, but in general it was fun, looked good and it was a great experience in studless building. I can say it was slower than I expected but looked better than I hoped. I think the photos of it are among the best I’ve ever made, and I also put a lot of work into the video, with a good effect. It was a good lesson for my future supercars, because it was example of a very typical supercar, with central engine, low ground clearance and rear axle drive.

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Media reference:

8 studs (Polish only), TechnicBRICKs, Technic Delicatessen, The LEGO Car Blog

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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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Experimental static vignette illuminated with LEGO LEDs and an EL wire.  

Datasheet:

Completion date: 29/10/2011
Power: 12V (external transformer)

A vignette is a static scene that fits in 8×8 studs area and is usually populated by minifigs. As a Technic builder, I have never built one before, until having a blue EL wire at hand resulted in a sudden and unexpected idea.

The vignette used two levels of dungeons to depict a sorceress from the Diablo game making her way upwards using a lightning bold spell. The EL wire, which simulated the bolt, had been completed by four LEGO LEDs that illuminated lava leaks and a torch on the vignette’s lower level. The upper level was populated by four incomplete skeletons (there was only a leg left of one of them), armed with weapons just like in the game. There two levels of dungeons also included some tenants: a spider on the upper lever and a somewhat concealed bat on the lower one. The two levers were connected by shattered floor and maintained different colour themes. I have also taken a liberty of taking the Diablo 3′s tagline: “And the Heavens shall tremble” and changing it a little:

This was a very simple creation that allowed me to try some light effects. It was nevertheless fun to build and my hamster fitted well in it

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My fifth Monorail creation, features a single station with three levels, two Monorails and 100 minifigures.  

Datasheet:

Completion date: 05/10/2011
Power: 9V (Monorail) / Power Functions

This creation’s goal was to have three levels of tracks on a single station, and to populate it densely with minifigures. The white Monorail was built first, and I wanted to model it after LEGO Intercity sets, but I came across a number of problems specific to Monorail. For the Monorail to be able to drive up and down the ramps and to fit inside the station, the front and rear of the cars had to be short, and the cars themselves had to be narrow and low. Initially there was sliding door on the side of each car, that would open by coming in contact with rubber axle joiners located at the platform just a moment before the Monorail came to stop. It worked well, but created more problems: the cars were too wide (with doors 1 stud thick) and for the doors to work properly, they would have to arrive and depart in the same direction on all three levels. I have eventually decided that the doors aren’t worth the extra complications and removed them.

The tracks set-up could appear complex, but as demonstrated at the end of the video it was possible to make a Monorail go through all three levels back and forth without stopping. This creation was simple yet enjoyable, and it was my first creation to include some LEGO sets: namely the 7239 set as the fire truck and 7279 set as the thieves/police team with a quad.

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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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My third walking vehicle. Features 8 legs based on Theo Jansen’s walking mechanism, driven by two motors.  

Datasheet:

Completion date: 31/08/2011
Power: electric (Power Functions)
Weight: 0.492 kg
Suspension: none
Propulsion: 2 x PF Medium motor geared 1:66:1
Motors: 2 x PF Medium

I wasn’t satisfied with my previous walker which tried to adapt the Klann linkage, so I turned to something else: the Theo Jansen’s mechanism. I started by studying a so-called kinetic horse which uses Jansen’s linkage to move four legs. I recreated the linkage using 5 and 7 studs long liftarms, and I’ve been experimenting on a 4-legged walker for a while. I was trying to make it steered by articulation, but it proved to be unstable. I have then created two identical 4-legged units and connected them together. I wanted the whole walker to be steered by controlling four left and four right legs independently; I have been experimenting with a studless subtractor in the propulsion system, but it resulted in the walker being slow, large and clumsy.

Eventually, I settled for a lightweight body with two Medium motors controlled independently. I have shortened the legs, as longer legs needed longer chassis to maintain the same level of stability. I have also equipped them with rubber tips to improve traction on flat surfaces. The walker created this way turned out to be very efficient, agile and fast, even if very simple. I consider it my best walker up to date, but this is rather thanks to relying on Theo Jansen’s work than on my own solutions.

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My second walking vehicle. Features 8 legs loosely based on the Klann linkage, driven by a single motor.  

Datasheet:

Completion date: 23/08/2011
Power: electric (Power Functions)
Weight: 0.495 kg
Suspension: none
Propulsion: 1 x RC motor geared 3:1
Motors: 1 x RC

My second walker, intended to use legs with spider-like pattern of movement. I have developed a chassis that used the Klann linkage to move legs, and it walked well and fast – however, it jammed every once in a while and the legs were too fragile to support even medium loads. I have then reworked the legs design to a form that loosely follows the principles of the Klann linage, but in a simplified way. The resulting chassis was small, sturdy and worked smoothly. I have been testing it with two separate motors for propulsion, each driving four legs on one side, which could allow the walker to turn like a tank. Unfortunately, the chassis steered poorly, and proved unstable as it was impossible to keep all legs properly synchronized with two independent propulsion motors.

Eventually, I settled for just one motor, but a fast one. I have also equipped the chassis with two long arms that could be fixed in various positions, thus affecting the walker’s centre of gravity and its walking path. Under certain circumstances it could allow to make the walker turn, but much more often its movement was largely chaotic.

This was definitely not a successful walker, but still a funny build. It allowed me to observe how eight synchronized legs work when set at a number of various phases and angles. I think it wasn’t a good MOC, but it was a good lesson that hopefully would allow me to properly realize the Klann linkage in the future.

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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.

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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 pushback tug. Features a powerful propulsion system, elevated cabin and lights.  

Datasheet:

Completion date: 07/08/2011
Power: electric (Power Functions)
Dimensions: length 40 studs / width 16 studs / height 35 studs
Weight: 2.07 kg
Suspension: none
Propulsion: 2 x PF XL geared 24:1
Motors: 2 x PF XL, 1 x PF Medium

Pushback tugs, also called pushback tractors, are low-profile vehicles used to push and tow aircraft around the airport. They are in common use, as using a pushback tug is cheaper than having an aircraft move under its own power, and safer than having an aircraft move using jet engines. Pushback tugs come in two variants: the older one, with tractor connected to the nose gear by a tow bar, and the newer one which scoop up the nose wheel and lift it off the ground, effectively attaching themselves to it. I have chosen to model the newer variant, which is much more complex and more interesting. It was not modelled after any particular make of a pushback tug, just after the typical look of a vehicle of the newer variant, as I wanted to focus on performance rather than on accurate look.

My goal was to make a model capable of towing 20 kg of load on a wheeled trailer. The trailer was essential to reduce the friction – according to my tests, the model was able to tow roughly 6 kg without a trailer, with the load being simply moved on the floor. As I was unable to determine whether the real tugs have suspension systems of any kind, I decided not to use any suspension in the model. There are two reasons for it: first, the suspension of any kind would make the drivetrain more likely to fail under tension, and second, a suspension system seems needless in a vehicle designed to drive solely on the perfectly flat areas of the airports.

The front axle of the model was steered and the rear axle was driven. The model steered poorly, as its center of gravity was close to the rear axle and as the rear axle had no differential. The propulsion system consisted of two PF XL motors geared down 24:1 each, generating a total torque of 696 N.cm, that is 48 times the torque of a single non-geared PF XL motor. The rear axle was reinforced to handle this kind of torque: it consisted of a number of short axles rather than a single long one to limit twisting, and the gear wheels on it were doubled and connected together with four pins each in order to lower the risk of physical damage.

Tests ran on the model have shown that its construction can handle the required tension (it was built around a massive frame, and the area around the rear axle was heavily reinforced) and that it has plenty of torque (I was thinking of adding another two PF XL motors if needed). Thus the limit of its towing capacity depended only on the traction of the rear axle’s four wheels. I’ve equipped the model with massive body and installed six weighted bricks around the rear axle to make the model heavier and thus improve the traction. The weighted bricks added extra 0.33 kg while taking relatively little space.

The body of the model was simple and had little functions (I decided to make the nose gear attachment mechanism non-functional, and one of several reasons was that it was very difficult to observe how it works in real vehicle). The cabin was elevated, just like in many real tugs, using a motorized scissor lift mechanism and a single small linear actuator.

The model was very simple, but turned out able to achieve its goal: it towed the trailer with 20 kg of load on it. At this point the model was already having problems with traction, depending on the area of the floor, and the trailer was so heavily burdened that its wheels kept slipping off axles every couple of minutes. I was afraid to physically damage the trailer, even though it was built around two layers of massive 16x8x1 bricks, and hence I did not test heavier loads. It would be interesting to see how much such a vehicle could handle if it was carrying the load directly on it, as this would ensure sufficient traction, but such a solution involves plenty of problems resulting from a huge load being placed on the model’s structure. I suppose it is possible to make a Lego vehicle that can carry 20 kg of load on it, but it should be probably significantly different, e.g. with tracks or with wheels with no tires on them.

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My fourth Monorail creation, features a single line and a detachable prison cell.  

Datasheet:

Completion date: 04/08/2011
Power: 9V (Monorail)

This simple creation was inspired by the Lego 6991 set, which features a Monorail car with a cargo unit that is detached upon reaching the end of the line. I decided to create a simple Monorail with police squad escorting a prisoner in a detachable cell.

The Monorail consists of two cars. One was modelled after a typical locomotive, and the other one just included some escort and the detachable prison cell. The cars were built in dark grey colour that would suggest a military theme. The locomotive included one set of flashing light bulbs, with one red and one blue cover, thus making it appear more police-related. The prison cell was built like a sledge that was pushed up a stand by the Monorail, which would then stop and go back without it.

It was an extremely simple creation, but I enjoyed it. The locomotive allowed me to try a couple of building techniques on a Monorail car, and the prison cell worked just like intended.

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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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TechnicBRICKs

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