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Liebherr HS 8040






Length 40s / width 23-29s / height 21s (32/18-23/17 cm) – without boom

Scale: 1:18

Maximum height depending on the lenght of the boom

  I 70 cm – equivalent 11m

  II 87 cm – equivalent 14m

  III 102 cm – equivalent 17m

  IV 121 cm – equivalent 20m

Weight: 2945-4014g

Power supply 2xBB 8878

Controlled by two sbricks

2x M

3x L

2x XL



Driving - 2 Ls

Track sliding - M

Rotation of the uppercarriage  - M

Lifting boom by a winch – L

Two winches for moving the bucket – 2 XLs


Today, I’d like to present you a dragline excavator Liebherr HS 8040. I came up with the idea of building such a machine after watching a movie from Brick Creek exhibition. The whole construction was made in about two months. 

For driving I used two L motors, which power both tracks with ratio 1,67:1. Because of that ratio the excavator is pretty fast (maybe too fast for such a machine). Because of variable track spacing there is no space to add other gear reduction, while maintaining the stability of the structure. The tracks are slided by four small linear actuators, driven by M motor. The mechanism of retracting tracks is based on guides of three studs height and one width. They come into the undercarrige, based on two cnostructions made of 5x7 frames, and connected by the system of sliding tracks. Details in photos below.

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The uppercarriage is mainly based on frames, connected by liftarms and housing made of technic panels. For rotation I used M motor with ratio 120:1. Three winches are made in similar way: the string is wound on a sleeve on an axle, between two 36 gears, driven by 12 gears. For lifting boom there is one L motor, and for moving the bucket there are two XL motors.

I used modular counterweight, like in the real excavator. In the lightest configuartion it weighs 319 grams and consists of a battery box and back cover of the excavator. The heaviest configuartion of the counterweight it weighs 1140 grams. It consists of the lighter configuration and additional battery box, cover and lead weights (8x70g), which are protected against movement while driving the excavator.


Boom is a simply, durable construction made with liftarms. Most angular connections are „legal”, but because of the narrowing of the first and the last section of boom, not all of them are. But they fits with no problem. 

Boom configuartions:

I)             I + IV: 30s + 44s, max height of the excavator 70 cm

II)           I + II + IV: 30s + 21s + 44s, max height of the excavator 87 cm

III)          I + II + IV: 30s + 42s + 44s, max height of the excavator 102 cm

IV)          I + II + III + IV: 30s + 21s + 42s + 44s, max height of the excavator 121 cm

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I built two buckets: a dragline bucket and a clamshell bucket. The excavator can be also used as a crane, but while lifting heavier element it would require bigger counterweight.

49539646412_7392272e0b_t.jpg 49538919888_3e5c9631d8_t.jpg

Before I started the building, I wanted to make something fully modular. I think it worked out :)


Operating the excavator is not easy, it requires a little of experience, which I am achieving. This type of machine is designed primarily to dig below the ground on which it stands (f.e. dredging water reservoirs), that’s why it’s hard to dig from a flat surface.

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I encourge you to like my new fanpage.




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Wow, I really like this! Works smoothly and you put in a lot of functions in such a (relatively) small structure. Well done :thumbup:

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