12 minute read
REVIEW: BUCKET WHEEL EXCAVATOR
from BRICKS issue 18
by mark guest
BIG BUCKETFULS OF BLISS
The largest Technic set to date is a huge undertaking and leaves a big impression when complete
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Words: Ryan Welles Photography: Andrew Tipping
42055 Bucket Wheel Excavator is the biggest LEGO Technic set ever produced, not only in its dimensions but also in piece count. There is a physical limit to how big sets can be, considering the flexible qualities of Technic parts and with this set, that limit seems to be nearly reached. But before jumping to that conclusion: what exactly is a bucket wheel excavator? We all know what an excavator is and by looking at this particular machine, we understand the ‘bucket’ part. However, not everyone will be familiar with this type of monstrous equipment, let alone ever having stood face-to-face with one. This class of machinery is used in mining facilities and is there to perform a continuous rather than continual digging task of removing and transporting material such as rocks and soil into mining trucks. Its length can be as colossal as 80 metres and it can weigh up to 13,000 tonnes. I applaud the experimentation of the Danes to come up with something new in LEGO Technic besides the countless amount of regular excavators and other yellow construction vehicles and there is a charming amount of play value included.
SET NUMBER: 42055 SET NAME: Bucket Wheel Excavator PIECE COUNT: 3927 RRP: £179.99 / $279.99 / €229.99
Gear selector to choose the direction of rotation
BOX AND CONTENTS
This is the biggest box I have ever encountered in the Technic line but that pretty much makes sense with its contents being in excess of 3,900 pieces. It is also a true delight to discover that the box can be opened on either side and this does not require any tearing. Therefore, like last year’s 42043 Mercedes-Benz Arocs 3245, the box can be flattened and stored without taking up too much space. The box contains a flap showing all of the main functions of the excavator. This is a really attractive way of selling the product, because parents will lift the flap to see if this is a suitable building experience for their offspring (or themselves, to be quite honest). Similarly striking is how the LEGO Group now delineate which functions are motorised and which are manual. Oddly, they do not mention how the boom height is adjusted here.
The back of the box is dedicated to the B-model, whose instructions can only be found online. It is called a Mobile Aggregate Processing Plant and is about 88 centimetres in length. It is a machine that can sort the two types of bricks that come with the set to serve as soil or rock. The machine has two motorised conveyor belts and moves on tracks. The white mining truck that comes with the A-model can be kept intact.
Inside the box, we find a hefty 550-page instruction book sealed in plastic with a decent-sized sticker sheet. This marks the first LEGO Technic set that contains an inner white box, familiar to builders of LEGO Star Wars, containing bags 1 to 3 and the Power Functions battery box. The rest of the well-filled main box contains bags 4 to 8 and the XL Motor. The total amount of bags, excluding the instructions and Power Functions elements, is 32. Of the 3,900 parts, more than 1,800 pins are included, as well as over 140 gears (including gear racks and turntables) and over 270 axles. The amount of Technic lift-arms and beams is just as impressive, numbering over 800. Just so you know where your money goes! It is an impressive parts pack for designing your own LEGO Technic creations.
MINING TRUCK
The first three bags contain an assortment of grey bricks used as stones as well as parts to construct a white mining truck.
The huge box has plenty of inspiration and information displayed
The excavator’s eight buckets make short work of moving huge quantities of rock and material from open mines
Twin linear actuators move and control the enormous boom
This features two functions: steering and raising/lifting the open-box bed. The bed itself is big enough to contain the 112 bricks included as cargo. This truck contains 308 parts and is an utterly charming inclusion, adding much to the play value and serving as an appetiser for the massive build that lies ahead.
BASE OF THE EXCAVATOR
Building the base of excavators is usually a rather repetitive task. Although this is not an exception for set 42055, the vast scale of it makes for an enjoying and satisfying endeavour. The four numbered bags contain an impressive quantity of 5x7 Technic beam frames - 53 in fact - adding much to the sturdiness of the lower structure and therefore allowing it to hold all those ‘tonnes’ of LEGO-weight.
The centre of the base is formed by a turntable (of the new bevelled type introduced last year) with an axle going through it that drives the tracks. This is accomplished by a rather straightforward assembly of axles and gears with a double-speed reduction. Like its reallife counterpart, this excavator moves very slowly. Considering the size of the machine, I was a bit surprised to see that only the front axle is actuated. Although smoothly moving the thing on tracks is not much of an issue, it would have made more sense if both axles were linked to the central gear assembly.
The build of the base is concluded with the construction of a central ring of gears. This ring is comprised of a new type of gear rack in the shape of a quarter-circle with inner 35 teeth (making the total circle 140 teeth). There are a total number of 14 of these racks included in this set.
MAKING TRACKS
The third phase of the build focuses on the tracks, comprising two identical elements. To make that happen, three bags are used, one only containing black track pieces. Even though building using only two elements may sound somewhat boring, the construction of these track parts goes surprisingly quickly. A whole row of wedge belt wheels and pins with stop bush are used. Once the 88 black tracks are attached, the base of this massive bucket-wheel excavator is finished. The sky is the limit, so let’s continue building upwards!
COMMENCING THE UPPER STRUCTURE
There are a total number of five bags intended for the base for the upper structure, which is mounted on the central turntable. This is the most interesting part of an already fairly impressive build - so far. After the lowest layer of the upper structure is formed around the turntable, a complex array of gears makes sure all three motorised functions run smoothly and go up to the central gearbox in three parallel vertical axles. Most of this is accomplished with the use of rows of red clutch gears that rotate freely around pins.
The number of gears is impressive and looks very challenging. Also at the bottom of the upper structure, a series of wedge belt wheels is added. These will eventually roll over the arches of new quarter-circle gear racks, even though this is more for support than for making the
upper structure rotate freely and smoothly over the gearracked circle.
Before the upper structure is mounted on the tracked lower section, two parallel linear actuators are fitted. These are operated manually, which some may feel is a weak part of the design but I honestly don’t think that tilting and lowering the heavy main boom with a motor would have been a good idea. There is too much friction involved and moving things by hand is much more reliable and satisfying. After the fourth stage of the build, you will slowly see the bucket-wheel excavator take shape. The build is still pretty low at this stage but you get a good sense of the majestic size of this set. And most of the complex gearing is hidden from view. I was surprised this set is far more impressive and complex than meets the eye and there is much going on in the lower regions of this mammoth.
THE SMALL CONVEYER BELT
Comprised of two bags, the fifth phase gives you all parts for the small conveyor belt which is straightforward to build and is set into motion using one of the vertical axles we built in the previous step. Also, it includes a distribution system formed with a series of simple Technic beams, ensuring that the soil and rocks transported end up on the right belt.
The most interesting aspect of this smaller conveyor belt is its manual movement. It can be rotated almost half a circle around two of the new arched gear racks and is operated with a knob at the bottom rear of the model. It also includes a rather simple yet effective clutch system operated with a driving ring.
Material drops to the lower conveyor for off-loading
Thanks to The LEGO Group for supplying the set to review. None of the opinions expressed in this review are those of The LEGO Group.
This allows the smaller conveyor belt to have three positions. It can either be rotated freely, locked or remain stationary regardless of the position of the central structure: a neat feature that enhances the playability of this behemoth even further.
THE BUCKET WHEEL AND LARGE CONVEYOR BELT
An impressive number of nine bags form a substantial sub-build that forms the bucket wheel and large conveyor belt. It starts with the bucket wheel, made of two large wheels of four arched gear racks and eight buckets. This bucket is a new version of the small bucket that has been around for almost 25 years.
Kept in place by free-spinning wheels, the big wheel is guided by a bunch of small gears. This assembly also contains a bed made out of angled beams to make sure all soil and rocks scooped up by the buckets actually end up on the conveyor belt. This is a very satisfying assembly that is full of interesting twists and turns. It was extremely rewarding to place the giant bucket wheel on the construction that holds it. The bucket wheel is turned by the end of the conveyor belt, although I had assumed it would be the other way around. Although this set-up is completely understandable from a design point of view, it comes with a downside. Because the wheel lacks direct actuation, it becomes rather feeble. It causes a jerky motion and is easily stopped by blockages or when lifting a heavy object.
This is increased by the use of a double pair of white clutch gears near the central gearbox, which come in the next stage of building. To finish off, the large arm pivots around two small turntables that are attached to the chassis. Additionally, a series of gears is added to create the angle between the arm and the upright chassis. These will be connected to the gearbox that is built in the next stage.
CENTRAL GEARBOX, POWER FUNCTIONS
Stage seven of this lengthy construction process comprises a Power Functions XL Motor, battery box and three bags of parts. The weight of the Power Functions provides a suitably-heavy counterweight for the bucket wheel. Building gearboxes can be such fun and the one that comes with this set is no exception. It may not be as complex as in previous Technic iterations but does the job quite well. Basically, the gearbox makes sure you can combine functions in both directions but not all functions can be combined, for the sake of security or lack of realism.
Joining both parts of the arm is a satisfying undertaking. When the arm is finished, it is mounted on the main construction. The attachment of the arm is surprisingly solid and a simple pair of linear actuators are able to carry and move the entire arm. This is predominantly made possible thanks to the balanced design.
“ I APPLAUD THE EXPERIMENTATION OF THE DANES”
FINISHING TOUCHES
Construction of the first-ever LEGO bucket wheel excavator is about to come to an end. The remaining three bags add stuff such as the white cabin which contains two tiny blue seats, side panels and railings. There is even a ladder that can be manually lifted and lowered.
After what can only be described as a fascinating and in some ways, unusual build, a giant piece of mining equipment occupies most of the table. Throughout this review, I have described the various functions of this massive model; now it is time to put it through its final tests.
There are certainly a lot of fulfilling play features, including the addition of the white mining truck but the main function, the scooping and transportation of bricked dirt, only works well if you give it a hand. The bucket wheel does not always move in a constant fashion and is jerky. Most of the other motorised functions are sluggish to the extreme, like the real thing but, as I mentioned at first, this merely emphasises the limits of how big a LEGO Technic set can be. Perhaps it stretches the boundaries of what is possible with axles, gears and beams.
This is a remarkably good deal pricewise and an excellent parts pack for beginner LEGO Technic builders with a modest collection. I also applaud that the LEGO Technic team is trying to break new ground by developing sets that are not yet another excavator or racecar. It certainly brings something new to their palette and in terms of size and extremeness, it will be a tough act to follow.
The Bucket Wheel Excavator is a truly impressive model
