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.