Posted on 1 Comment

WIP Liebherr LTM11200 (part 2)


Here is the second post about my current project (or more accurately one of my current projects), the full RC Liebherr LTM11200 crane. It is the superstructure:

Liebherr LTM11200 Superstructure

This superstructure is packed with functions, 13 in total. All are RC, but only 4 motors are used. Combined with the 4 motors of the carrier this gives a total of 8 motors for the entire vehicle. And that is exactly the number of motors that can be individually controlled with the LEGO Power functions system.

In the center of the structure a big gearbox is used to switch between 4 groups of 3 functions each. Just as in the carrier each function is colourcoded in either red, yellow or black. Red is coupled to the XL motor and is used for the heavy jobs, like lifting the boom and rotating the superstructure, whereas yellow and black are coupled to L-motors. The switching is done with a M-motor.

The grouping is as follows:

  • Group 1
    • Yellow: Rotating the arm of the cabin
    • Black: Raising and lowering the cabin
    • Red: Tilting the cabin
  • Group 2
    • Yellow: Winch 1
    • Black: Winch 2
    • Red: Boom function 1 (which will be extending the boom. This way it is possible to extend the boom and wind down the winches at the same time)
  • Group 3
    • Yellow: Boom function 2
    • Black: Boom function 3
    • Red: Rotate the superstructure
  • Group 4
    • Yellow: Boom function 4
    • Black: Raising and lowering the counterweight
    • Red: Raising and lowering the boom

The superstructure also has one manual function, namely opening the cabin with a slidedoor.

As with the carrier a lot of attention has gone into the structural integrity of the build. The whole structure is formlocked where possible and longitudual beams are running along the bottom and topside to guide the forces towards the mounting with the carrier. As you can see in the video I used a brickbuilt rollerbearing for maximum support of the superstructure.

I made a short video to showcase all the functions:

And here is a final shot of the superstructure mounted onto the carrier in limited weight transportmode:

Liebherr LTM11200 Carrier and superstructure

That’s it for now.

Leg godt,


Posted on 4 Comments

WIP Codename Silvestros


Here is another work in progress project that I have been working on for some time now. It is 1:8 scale supercar. This project is a cooperation with Marco van Overbeeke.

Marco is a talented freelance automotive designer who has earned his stripes in the hypercar market. Recent projects are the Dendrobium electric hypercar (exterior and interior together with his brother Andries van Overbeeke) which debuted at Geneva 2017, and the livery design of the Lunar Red exterior of the 2019 Aston Martin Valkyrie for Kris Singh. You can find more of Marco’s work on his website and instagram.

Here is a first bodywork sketch he made for me:

Exterior sketch Silvestros
Exterior sketch Silvestros

At this moment I am perfecting the chassis. I have redesigned the chassis three times from the ground up. Reason for that is that there is quite a complex mechanism inside. This car will namely feature 4 wheel steering that is dependent on the gear it is in.

When you are in first gear the front and rear wheels steer in opposite direction. When you are in fourth gear the front and rear wheels steer in the same direction. And when you are in second or third gear the behaviour is something inbetween. When you are in reverse only the front wheels steer. This whole behaviour is controlled with linkages. connected to both the steering wheel and the sequential gearbox (with working paddle shifters next to the steeringwheel).

Here is picture of the chassis as it is now:

Chassis V3 for the Silvestros
Posted on 7 Comments

WIP Liebherr LTM11200 crane


This time I don’t have a finished model to show, but instead I decided to show a bit more about the building process of a new model. I wasn’t actually planning to make this model this year, but as the Dutch say: The blood crawls where it can’t flow. Every now and then a model gets stuck in my head and I just need to build it. And this model got stuck about a month ago…

In this case it is a redesign of a model that I designed and abandoned a couple of years ago. Here you can see one of the few photos I made of it, to get a sense of what the final model will look like:


It is a fully remote-controlled model with 20 functions, 7 in the carrier, 9 in the superstructure and 4 in the boom (driven from the carrier). It is a model that is close to, if not over, the edge of what is possible with LEGO.

In this post I will concentrate on the carrier. Compared to the original model I have made a couple of changes:
Most noticeable is the colour scheme, which is changed to a white-orange livery (since yellow is not as abundantly available as it used to be).
But inside a lot more has changed. I have swapped two M-motors to L-motors (which weren’t available at the time). I have redesigned the outriggers (and I will have to do that again since they are not working to my liking), the function-switcher (to use the modern 3L driving rings), I colour coded the functions (for ease of operation) and I made all kind of small changes to ease the building process (if there is enough interest I might make building instructions).

In this video you can see how the carrier looks and works now:

As you can see retracting the outriggers still requires some redesigning to make them go in more smoothly. Switching the steeringmodes is also not a foolproof system (and I don’t know if it ever will be). The mechanism relies on moving a central axle with gears between two positions two studs apart. There is a mechanism in place that ensures that it is only possible to switch between modes when the wheels are straight. However, this mechanism is located quite far to the front (between the 2nd and 3rd wheel pair). Because of the torsional (lack of) stiffness in the long axle the last wheel pair can be one teeth off during the switch. So after a few switches the alignment between the different wheel pairs can get lost.
Another issue are the two driven wheels. When in normal steeringmode the steering angle of these wheels are only determined by some elastic bands. So sometimes they start to wiggle about. When in crab steering mode only one steeringrack is engaged, whereas the other is moved through a linkage with quite some play. As a result these wheels also don’t steer very well when in crab steering mode.

So, still some work ahead of me… If I have found some solutions I will post them here again.

Leg godt


Posted on Leave a comment

Aston Martin DB9 Volante


Here is my next exclusive commissioned model:

Aston Martin DB9 Volante
Aston Martin DB9 Volante

It is the Aston Martin DB9 Volante. The model is packed with features:

– Independent suspension on all wheels
– Steering with Ackerman geometry and caster angle
– A 5+R manual gearbox
– A V12 fake engine
– Adjustable seats
– Openable doors, hood and bonnet
– And a convertible roof

Aston Martin DB9 Volante
Aston Martin DB9 Volante

The roof mechanism is not automated like on my Ferrari 458 Spider, but it does fold itself in exactly the same way as the real car.

Aston Martin DB9 Volante
Aston Martin DB9 Volante

The doors use a special 4-link mechanism to make the door completely flush with the bodywork when the door is closed. I have made a small video in which I showcase the various functions.

Posted on 5 Comments

Ferrari 458 Spider


Here is my next commissioned model, the Ferrari 458 Spider:

Ferrari 458 Spider

It is a 1:10 scale replica with the following working functions:

  • Steering with Ackerman geometry
  • Independent suspension on all wheels
  • A fake V8 engine
  • A 4 speed sequential gearbox
  • Openable doors, hood and trunk
  • Convertible roof
Ferrari 458 Spider

It is a right hand drive model. I really enjoyed designing and building this model. The convertible roof was a particular difficult challenge, especially in combination with the gearbox and the engine that all had to fit in the space behind the seats.

Ferrari 458 Spider

I also made a small video to showcase the different functions. It can be found here.

Leg godt,

Jeroen Ottens

Posted on 1 Comment

Mercedes-AMG GT R


It is time to present my next commissioned model. It is a 1:10 replica of the Mercedes-AMG GT R.

Mercedes-AMG GT R
Mercedes-AMG GT R

This time I also made a short video showcasing its functions.

This model features the following functions:

  • independent suspension on all wheels
  • steering with HoG and working steering wheel
  • V8 fake engine
  • working lights (with custom lighting bricks)
  • opening doors and hood
  • adjustable seats
  • adjustable spoiler
  • detailed interior and engine bay
  • a 4D+N+R gearbox
  • an active aerodynamic spoiler in the front which opens when 4th gear is engaged
  • four wheel steering with speed (read gear) dependent behaviour:
    – in 1st gear the wheels steer against each other
    – in 2nd gear only the front wheels steer
    – in 3rd gear the rear wheels steer a bit with the front wheels
    – in 4th gear the rear wheels steer with the front wheels
Mercedes-AMG GT R
Mercedes-AMG GT R

This model was a real challenge in terms of packing all this functionality into it. It has over 2200 parts, despite being a 1:10 model. The mistress is of similar scale, but has only 1600 parts, whereas the 1:8 DB11 has ‘only’ 2700 parts. Still, I am very pleased with the end result. Especially the gear dependent four wheel steering setup works like a charm.

Mercedes-AMG GT R
Mercedes-AMG GT R

This is the first model that has custom stickers (not shown since my client wants to build the model himself so I didn’t apply them) and custom lighting. Here are some shots with the lights on:

Mercedes-AMG GT R
Mercedes-AMG GT R
Mercedes-AMG GT R
Mercedes-AMG GT R

The model was commissioned with an exclusivity clause, so there will be no instructions.

Posted on 9 Comments

F14A Tomcat


It has been a while since my last post, my apologies for that. I haven’t been idle though. In the coming months I hope to be able to show some of the models I designed for my customers in the past months. But let me start by introducing the model I have been working on for the past year. Here is my replica of the F14A Tomcat in LEGO Technic:

F14A Tomcat
F14A Tomcat

The Tomcat is an incredible plane, and I tried to pack my version as dense as possible with the features the real plane has as well:

Driven by one M-motor and using a manual gearbox the following functions are electrified:
– The engine turbines (directly coupled to the M-motor)
– The rotating Gatling gun on the port side
– A small pneumatic pump
– The canopy
– The landing gear
– The eight landing gear bay doors
– The adjustable main wings (in the photo below they are moved out, in the photo above they are swept back)

F14A Tomcat
F14A Tomcat, with main wings out

Next to that there are six pneumatic valves controlling the following functions:
– Switch between the internal small vacuum pump and the external large vacuum pump
– The bleed doors in the air-intakes of the engines
– The delta wings at the side of the air-intakes
– The arresting hook
– The front and rear flaps on the main wings
– The two air brakes on the main wings and the three air brakes at the end of the fuselage

F14A Tomcat
F14A Tomcat with main wings swept back

The plane also features a couple of manual functions:
– A knob to control the pitch of the aircraft. The rear horizontal wings and the joystick are controlled with this knob.
– A knob to control the roll & jaw of the aircraft. The rear horizontal wing, the vertical control surfaces and the joystick are controlled with this knob. If the landing gear is down, the front landing gear is steered with this knob as well. A special differential control mechanism is used to combine both pitch and roll control and feed only one signal to each wing.
– The nacelles that contain the turbo engines can be opened and the engines can be taken out.
– A double lever to activate the ejection seats. The canopy is ejected at the same time as well.

F14A Tomcat
F14A Tomcat rear view

And finally some fun facts:
The model weighs around 4 kilograms and is just shy of 4000 parts
It is 87 cm long, 101 / 66 cm wide (main wings open / swept back) and 33.5 cm high when put on its stand
It has ten small pneumatic cylinders and nine shock absorbers
It has 549 axles, 110 gears and 111 panels
Most of the functions are color coded so that you can distinguish them during the building process

F14A Tomcat
F14A Tomcat


Posted on Leave a comment

Ford Focus ST


Here is my next commissioned model, a Ford Focus ST:

Ford Focus ST

It is in a smaller scale then I usually build. It still has the following features:
– Steering (with a virtual pivotpoint and Ackermann geometry)
– A 3 cylinder fake engine
– Opening bonnet, trunk and doors
– Adjustable seats
– Working steeringwheel

Ford Focus ST

The model is very sturdy and can be handled from any angle.

Ford Focus ST

The model is packed with half stud offsets to be able to capture the lines of the original car despite the smaller size.

Posted on 10 Comments

Aston Martin DB11


Here is a model I made on my own account. The new Aston Martin DB11:

Aston Martin DB11

It is build in a bigger scale than my other supercars, using the LEGO 42056 Porsche wheels. The model is filled with functions:

  • Independent suspension on all wheels
  • Steering with functional steeringwheel and HoG in the back
  • Swiveling frontlights (right lamp turns right when steering right, left light turns left when steering left)
  • LED lights front and rear
  • Sequential gearbox operated with paddles next to the steering wheel and HoG in the rear. It is an 8D+N+R gearbox (ie eight speeds forward, one reverse and one neutral).
  • Highly detailed V12 fake engine
  • Adjustable front chairs (forward, backward and tilting backrest)
  • Aerobrake in the back coupled to the gearbox
  • Opening doors, bonnet and tail

Aston Martin DB11

Instructions are available for 20 euros.



Posted on Leave a comment

McLaren 675 LT Spider


Here is my second commissioned model, the McLaren 675 LT Spider.

McLaren 675 LT Spider

The model is remote controlled with the LEGO Power function system. It has four remote controlled functions:

  1. Drive (with a working steeringwheel as well)
  2. Steering
  3. The rear spoiler
  4. The convertible roof

It also features indepedent suspension on all wheels and buttefly doors.

Shaping the front was one of the bigger challenges in the styling. Let me know what you think of it.

McLaren 675 LT Spider

Instructions are available for 14 euros. For that you get instructions for both a red and a white version:

McLaren 675 LT Spider

I also posted a video to show all the functions on Youtube.