New Technic 8043 Excavator
In the course of human events, the occasional item or product may come along which changes the way we perceive the world, and perhaps even ourselves. Is the monstrous 8043 excavator this item? No, that would be ridiculous; it's only a LEGO model. On the other hand, it is one of the most marvelous and technically complex LEGO models ever produced and belongs on the shelf and in the heart of every true fan.
My copy showed up via DHL courier yesterday and I immediately began building, forgoing all sustenance and personal hygiene in my quest to complete it as soon as possible. Since almost no one on Earth has had a chance to build this yet, I thought I better record my thoughts and the build process as I went along. Read onward, gentle reader, and be prepared to share my epic journey as you watch this model take shape. Grab yourself a tasty beverage, turn on some music, and open your mind.
Larger versions of all the images can be found in my Brickshelf folder (once moderated).
First we'll look at the box. It is a huge box, the same size as that for 8275 and 8421. It has a flap which opens on top to show you the myriad of functions. The back shows pictures of the alternate model, the instructions for which must be downloaded and are not available yet. The alternate looks almost as good as the main though. It is a tracked loader. Like nearly all modern LEGO boxes, you have to destroy the back corners to get it open.
Inside, you'll find 9 poly bags, a bucket, 3 instruction manuals for the main model, a sticker sheet, and a big pile of Power Functions components. Some of the bags contain other smaller bags. Two of the bags are identical copies and contain the same parts. My sticker sheet was slightly mangled from sliding around inside the box and one sticker was stuck to the instruction sheet. I wish they would put the sticker sheet inside one of the books to protect it.
Now lets take a look at the parts. The pile of parts is truly enormous, although nowhere on the box does it actually say how many there are. Ancillary evidence would suggest there are about 1123. This means, by part count, it is not among the biggest Technic sets ever, but it certainly is one of the physically largest once built.
Now we'll look closer at some of the parts. For Power Functions elements, we have 4 M motors, 2 IR receivers, 2 IR transmitters, 1 battery box, and 4 linear actuators. This is more even than the 8275 bulldozer, although no XL motors are present. Along with the linear actuators, you'll see 6 of the actuator brackets. This is more than the number of actuators, so obviously a couple of them are used for other purposes. The 2 extra are used as gearboxes and support the digging arm where it attaches to the superstructure. There are also a large collection of panels here, including 10 of the long angled panels 64681 and 64393 in yellow which previously did not exist in any set.
You can see a large assortment of studless beams, and a smattering of the old studded variety. The 13L beams are dark gray for some reason, perhaps to help in distinguishing them from the 15L beams. If so, this represents an underestimation of the intelligence of children. Any teenager who manages to get one of these sets can probably count to 13 and tell the difference between that number and 15. But I digress. We also get four of the transmission rings and four extensions, parts which were quite rare up to now. There are 10 of the new pins with cross holes, and 8 of the 3L universal joints.
If the measure of a good set is how many gears it has (and there is ample evidence to suggest this is true), then this is the best set ever. A look at the gear collection reveals a total of 71 gears including 14 of the elusive and magical 16 tooth clutch gears, more than in any other set. There are also 4 of the newer larger "idler" gears. The axle collection is also ample. There are not just normal axles, but lots of the more unusual stop axles. The 3L stop axles are now in dark tan like other 2010 sets. The real treasure is the 4L stop axle though. This has only appeared in 2 sets before. In my copious collection of over a quarter of a million Technic parts, I had only 2 of this part. This set adds 26 more to my collection!!
So far as I can tell, there is only one new part included. There are 6 of these new "brackets" or "gearboxes" included. They are similar in size and style to the linear actuator brackets, but are somewhat stiffer. And of course, they are black.
It's time to start building! The build starts with the tracked carrier. These first two pictures show the semi-modular construction. Up to this point, everything is purely structural; no moving parts. That comes next.
Now we start building the drive systems for the left and right tracks. Only the forward sprockets are powered, each with an independent gear system. The first image shows a couple of the new parts used as gearboxes. The gear at left and the long axle which will be pushed through later are the input from the superstructure. The two new bevel gearboxes follow to turn the torque outboard. The second image shows them attached to the assembly. The 8 tooth pinion gears at the front are the drive system. The last image shows another pair of gearboxes driving this torque out to the front sprockets. The rear sprockets are not powered.
After the installation of some unsprung bogies, the tracks can go on. Unfortunately, the bogies are not even pendular so the rolling assembly is rigid. This is find, of course, just not as cool as full suspension.
Now comes a technique which has only been used in one other set. If the motors for driving the tracks were in the base, then the wires would have to go through the turntable up to the battery box. These wires would become tangled when the model slews. To solve this, the motors need to be in the superstructure, but this means the drive system has to pass through the turntable. In order to pass an axle through a rotating part, it has to be at the axis of rotation. This is easy with one axle, but how do you put two functions, and therefore two axles, on the same axis of rotation in the center of the turntable? The answer is a coaxial drive system. The long black axle in the center drives one side of the tracks. The other side is driven by the outer gears which pass through the turntable using the gray idler gears and the red transmission rings. This outer assembly can spin freely on the inner assembly without turning the central axle. Voila, two coaxial functions! The last image shows how these functions are passed back to where the motors will be. The two tan 20 tooth double bevel gears will drive the two sides of the tracks.
Now we'll set the carrier aside for a bit and work on the motor and gearbox assembly. I feel pretty comfortable in saying the is the most complex gearbox assembly in any Technic set. First we'll install the 4 motors side by side and connect them to the IR receivers. The wires are tucked carefully away and the whole thing is made compact and ready for the gearbox. Note that the 3 axles you see sticking out right now are not attached to the motors yet.
Before we do the gearbox, we'll install the battery box and the rear cosmetic assembly which also serves to help hold everything together.
Now things really get interesting. The 3 black axles connect to 3 of the motors. They support the 3 clutch gears in the first picture, but those gears are not driven by the motors unless the driving rings are engaged. The next photo shows the transverse assembly which contains the red parts used to actuate the driving rings. The knob gears in the last picture are connected to the 4th motor which rotates the whole red assembly to simultaneously move all 3 driving rings. When all driving rings are aft, you get 3 motorized functions. When all driving rings are forward, you get 3 other motorized functions. By the time we get to the last picture, there are multiple planes of gears doing seriously cool things. Some day, I'll do some computer images which strip away all the structure to dissect the functions and show how they all work. It's pretty hard to do from the photos alone. The gray axles you see coming out will drive the tracks and the slewing. The gears to drive the digging arm connect to all the gray clutch gears.
The next assembly is a cap for the gearbox which contains some of the gears which will be used to drive the digging arm.
When this is attached, we have a completed gearbox which can now be attached to the carrier. At this point, all the weight is aft of the turntable so the assembly is seriously unbalanced. I wedged the bucket under the gearbox to hold the whole thing up or the excavator would tip back on the tracks. In the second image, you can see the tan bevel gears which control the tracks at the bottom front of the assembly. The other tan bevel gears on the top will be used for the digging arm.
These next few photos show the build up of gears for control of the digging arm. In the first image, you can see the top bevel gears which control the two functions which will be passed out along the boom. The second image shows the set of tan double bevel gears in parallel which will be used on the parallel linear actuators which raise the boom. You can also see the worm gear which slews the whole superstructure using the ring gear on the outside of the turntable.
Now we finally see some linear actuators. These two are in parallel and will lift the boom. They are attached via brackets used as gearboxes. The gearboxes contain the new idler gears which spin freely on the axle. This is a good thing. Like the turntable, since the whole digging arm rotates upward, the torque for the linear actuators has to be passed through this axis of rotation. The problem is that the whole weight of the digging arm is on this axle which would make it almost impossible to turn. The idler gears solve this problem by spinning without the need to rotate the axle.
Now we can start the digging arm, beginning with the boom which has a fixed angle built in. A pair of box beams are used in an unusual way to lock the angle. There's also a lot of universal joints here. The power for the two linear actuators on the boom comes in via a pair of axles which are side by side, by need to be brought into line to pass up the boom. The u-joints are used to accomplish this lateral shift. The pair of linear actuator brackets not only contain the gears to power the functions, but will also support the boom.
Now we'll build the dipper which has an angle controlled by the first boom linear actuator. Finally, the last linear actuator controls the angle of the bucket. The last two pictures show the rotation axes of the various parts of the digging arm by showing it in the two extreme positions. Unlike a normal excavator bucket, the lugs on this bucket are on the back rather than the top. (This is because this part was actually made for the 8459 wheel loader.) As a consequence, some fancy linkage geometry was needed to make the motion right.
Now the completed digging arm can be attached to the superstructure. Like the lower lifting linear actuators, idler gears are used to avoid rotating the heavily loaded support axle.
Now that the functional components are all attached, it is time to get back to aesthetics. The operators cabin is built, and so are the big side panels which will enclose the superstructure and hide much of the detail. The model will remain open on top for a view of some of the gearbox.
That's it!! The model is complete. Here are some shots showing the final model in a couple of positions. As you can see, the reach of the arm is quite long.
While the excavator is super fun to drive operate, this image shows that it is actually lousy at digging holes, the bucket can barely reach below grade at all. On the other hand, it has a very high reach when fully extended. The model operates very nicely. The tracked drive is slow, but it should be. Real excavators use hydraulic motors for propulsion and move very slowly. The slewing is quite fast. The nice part of this is that the slewing speed matches the speed of the model turning when skid steering. This means that if you skid steer and slew in opposite directions at the same time, the carrier spins under the superstructure which remains in place. The ability to use all 3 digging functions at once is very nice, although to be truly realistic, you need to be able to slew without switching functions. "CAT controls" in a real excavator have 2 sticks with 4 degrees of freedom to dig effectively. That's a minor complaint though. We have 6 motorized functions here, or 7 if you count the driving ring switch. This is far more than any other model.
This final image shows how the model compares to a couple of other recent excavators.
I could go into a complex rating system on the parts, functions, price, and so forth, but if you've actually read this far then you obviously have a keen interest in this model. Also, as the Arbiter of Public Opinion I get to choose what's cool and what's not without consulting anyone. Sometimes this is a burden, but I accept the responsibility with humility. My verdict is that this is easily among the very best Technic models ever. Yes it is very expensive, but there are some very good reasons for that. It will teach you everything you want to know about gear systems, transmissions, and mechanics. It will be fun to play with, fun to build, and even the alternate model is available if you get bored. Buy it. Why are you still sitting there?
Edited by Blakbird, 06 June 2012 - 06:25 AM.