Time for another update on my Liebherr crane. I have made a first version of the 4 stage boom. The thing is massive! It weighs over 4 kg, it has 90 long panels (3×11 curved, 3×11 flat, 5×11 flat) in it and it reaches 2.5 m when fully extended.
Due to the weight it is now impossible to lift the boom with just the cilinders. So I added a system with rope and pullies to lift the boom. There is some fearsome bending of axles in the current setup when the boom is lifted, but it works.
I devised a new way of extending the boom to maximize the size of the inner sections, but also this system is struggling with the sheer weight of it all.
Rotating the superstructure has also become impossible with out a helping hand.
On the plus side, the whole crane can stand on it’s own when fully extended, which is an awesome sight. Also the speed of the ropes is not as slow as I feared.
Even though it looks finished, it is not. There are still quite some things to improve:
The rope for lifting the boom and the extention of the cilinders need to go to the same group of RC operations (if you remember there are 4 sets of 3 functions each in the superstructure).
A driving mechanism for extending the inner sections needs to be made that is strong enough (at least it is self braking now)
The structure where the pulleys in the rear are connected to needs to be strengthened (there are even some form-locked constructions that are being pried apart)
The stabilizer arms need to lift further upwards
The small LA’s in the stabilizer arms need to be replaced with big LA’s (that will bring the total amount of big LA’s in this model to 12)
The rope for the hook needs to be properly guided along the boom
The legs to put the boom on when moving the boom from the carrier to a transport wagon need to be designed and added
Here is the heavy road configuration version (without the extra pulleys to lift the boom):
Finally I am pleased to announce that the work on instructions has started. So please stay tuned.
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:
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:
Yellow: Rotating the arm of the cabin
Black: Raising and lowering the cabin
Red: Tilting the cabin
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)
Yellow: Boom function 2
Black: Boom function 3
Red: Rotate the superstructure
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:
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:
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).
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.