2GodBDGlory

Yeah, perhaps. There is a difference between allowing commercially available, refined non-Lego alternatives and willingness to use just anything. Think Buwizz versus a hand-soldered custom battery rubber-banded to a liftarm, or 7L pliftarms versus rough 3D-printed parts. I guess the difference here isn't so much one of principle, rather just a preference for having everything look professional! And to be fair, I've got a pair of AliExpress buggy motors myself, and I've never filed that down (though I never realized it was a problem), and refrained from cutting out part of the housing to fit a large motorcycle tire inside it, though I was tempted.

Easy problem to fix with a file, I guess, once you depart from the path of purity!

The adjustable width is very interesting! What would that be used for in real life?

Very clean looking!

Yeah, the boom is really nice! It looks strong, and the half-stud sides help keep it compact.

From the AFOL's stand point, you're right, there is no point in continuing the bevel version where it isn't needed. After all, we've got heaps of the old ones we can use whenever we need the bevels, and there's enough supply that they should remain cheap indefinitely on Bricklink, no matter how little they get used in sets going forward. The only issue I see is for people building from a more limited supply of bricks. Switching to less versatile gears would be a pain for young builders working from only a few sets, and also be annoying to AFOLs building B/C models for sets.

I was just taking a look at the Bricklink inventory of the old Black Cat Model Team truck (5571), and I noticed something strange. I'd always assumed that that set used the same 62.4x20mm tires that are common these days, in, for example, the 42043 Arocs. However, it turns out that while they look very similar, they are actually slightly bigger, at 68.8x24 mm, and have their own slightly different rim. These old tires only appear in this truck and the 5563 Racing Truck Model Team set, and are quite expensive (I suppose because of the desirability of the 5571 set). I was very surprised to realize that I had never heard of these tires, and so I checked out Sariel's wheel chart, and found that the old one was nowhere to be found, so I guess I'm not quite as ignorant as I thought. Are any of you folks aware of these tires? Have they ever come in handy on a MOC? Old^ New^

Nice find! The introduction of a more neutral color makes me feel better about not getting any red ones yet.

Great writeup as usual! Placing the battery that far forward is a really interesting solution that I may have to try someday! The suspension is also pretty unique. One detail I quite liked was the way you secured the yellow crankshaft part that the steering actuator connects to. The moment I saw the render, I worried that that part would pop off immediately thanks to their very low clutch power, but then I saw you had placed the 1x2 Technic brick overtop of it to prevent that. Nice solution there!

Oops, I seem to have some keyboard shortcut to submit this that I keep hitting accidentally. I'll edit this to my actual question in a minute...

So, for this contest I decided I would build a Mobile Crane of some sort, because it has similarities to the boxy cars I'm used to building, and also has a fairly convenient shape for the volume constraints. At first I thought I would be building a fairly standard crane, probably with six wheels. I planned on using Corvette wheels, but since I only have four of them, I thought I might have to do something weird, like put Model Team wheels on one of the sides. As I looked for inspiration, though, I found a compact-looking mobile crane with only four wheels, which fit my supplies better, so I decided to take inspiration from the Liebherr LTM 1040-2.1 The planned features are: Two-stage extending boom Lifting boom Winch Outrigger extension Outrigger lowering 4-wheel steering Superstructure rotation and possibly if I have room: 4WD and a micro I-6 piston engine Live axle suspension Another design goal is to have all the controls manually operated from the chassis--I would like to have all the controls for similar functions in a similar location, and I feel like having controls on the superstructure will result in the boom swaying around as the control knobs are twisted. However, I've got three functions in the superstructure, and we all know how impractical it is to get three functions through one, so I thought of an unusual idea that might help here. It would essentially be a distribution gearbox placed inside of the turntable, switching between functions in the upper half, but with the switch being controlled from the bottom. The plan is to base it off of the 24/16T differential. The 16T side will constantly be driven from the bottom, but with provision to allow the differential carrier to slide up and down a stud. The 24T side, though, will engage different gears depending on whether the carrier is in the upper or lower position, causing it to operate different functions. We'll see how that turns out... I started by developing a design for a two-stage boom based on the gear rack housing parts: I really liked the design--stuff just fit nicely, and the grooves on the insides of the panels were perfect to help locate the red part as it extended. However, as I began to look at scaling the crane, I realized that in order to build the largest possible crane that would be within the rules, I'd be using 56mm balloon tires, and that if I did that, I'd need to have a far, far bigger boom. This crane seems to have a disproportionately large boom! My planned dimensions for the crane are 13 studs wide, 16 studs tall, and 48 studs long, and my boom is currently sitting at exactly 48! Boom contracted The boom is extended by that 3L worm gear driving a set of 4L racks It is driven through these gears. I'll have to put some kind of pivot in still. It extends really tall! This is the how the middle segment is constructed And this gives a glimpse of the pulley system needed to extend the smallest segment. So far, I really like the boom, but I think the outriggers are going to have a really hard job keeping the crane upright with such a huge boom on such a small carrier! Next I'll probably work on figuring out the details of the rest of the superstructure.

I dare somebody to submit a 1x1x10,000 string of axles and axle connectors to this contest, and pass it off as, say, a really wide steamroller wheel.

Yeah, I think you're right that I'm kind of stretching the limits of what the contest was meant to be, for better and for worse! Good catch about it being 48 studs long; I knew I designed it to be as big as possible, so I do recall thinking it odd that my final volume had that much leeway. I must have just miscounted at the end, so I'll fix that in the post. Thanks!

Good job so far! It's interesting seeing your build process in action. I think this part would work pretty well here; have you considered it? One of these could be helpful under it:

Thanks for the feedback! You're right, those curved panels could have looked good. Unfortunately, I've only got two of that multi-hole type in black, and only one of the fewer-hole type in black, and I don't think I have enough in any other color either, so square it must be! You're right about it looking skinny between the cab and the superstructure, but this was done intentionally. As pointed out in the video, when the boom is lifted, because of a poor pivot point location, the rear end of it sticks fairly far down, causing it to interfere with rotation at times because it will hit the top of the outrigger mechanism. Because the boom needs this extra space, I left it empty there to allow the boom to swing through that arc while raised up, but I don't recall ever actually doing that maneuver once it was finished! Perhaps it would have been better to use that space to reinforce my sagging cab and just rule out that option, but I'm probably not going to change anything at this point. (Too much trouble to take more pictures ) Good observations, though!

Thanks! I do like focusing on features. I'd agree that the proportions are odd, and I think you're right that it's the boom's fault. I believe its length is correctly scaled to the crane I was basing it on, but I never scaled the height of the boom part, and I'm assuming that in order to get the multi-stage setup inside, I had to exceed the height it should have had, cutting down on space below.

Ok, thanks!

Will we have to take a picture with our model in some kind of bounding box for proof of compliance, @Jim? I just finished my entry and will be taking it apart soon, so I just want to make sure I get all the documentation I need before I take it apart. Thanks!

Here's my final update! Since the last time around, all I've added functionally is connecting the steering wheel in the cab to the wheels, but I made a few other tweaks, such as getting rid of the weight brick on the hook, as well as the pulley for the hook, and adding the larger-diameter worm gear to the boom extension to keep it from skipping. Aesthetically, I added the main cab and the operator cab, some lights, and red highlights. Below here I'll just give a normal MOC presentation, rather than a WIP one: ------------------------------------------------------------ Here is my entry for Eurobricks contest TC22, a compact mobile crane. In order to be within the 10,000 cubic stud limit, this MOC was made to a 13 stud width, 48 stud length, and 16 stud height, for a total of 9984 cubic studs. Functionality includes: Steering from steering wheel in cab Outriggers that extend and lower using a rear control knob (actually two knobs hard-coupled together for convenience and symmetry) Rotating superstructure via rear knob Winch via rear knob Lifting boom via rear knob Two-stage extending boom via rear knob Two-output distribution gearbox for boom lift and extension, controlled from one knob and one selector on the chassis, with two outputs on the superstructure. Magnetic "hook" Most of the functions were quite straightforward, but three deserve extra mention. Boom extension. This was the first time I had tried making a two-stage extending boom, so it wasn't perfect, but it was still quite cool. A large-diameter worm gear run off a crank ran a long string of 1x4 gear racks to extend the middle segment of the boom (4x3 studs), while two pulley systems caused the end segment of the boom to simultaneously extend out of the middle one, allowing the boom to extend to a little less than three times its original length. With such a large boom on such a small crane, it looked pretty impressive when extended. Sadly, there was too much friction to extend it effectively from the main knob, and while one could extend it by hand by pushing on a different gear, it would take an immensely long time. Outriggers: The outriggers had to be very compact to fit within the size limitations for the contest. In the end, they were based on two 13L gear racks pressed against each other and connected with gears so they would extend together. Furthermore, the legs were attached to them on a pivot connected to a transverse axle. When the legs reached nearly full extension, this axle would be forced to catch and pull the leg down, allowing for both to be controlled from the same knob. The legs weren't especially stable, but they did help keep the crane stable despite the very long boom. Distribution gearbox: The unusual distribution gearbox was developed in order to allow all three superstructure functions (winch, boom extension, and boom lift) to be controlled from the chassis. The winch was driven by a central axle through the turntable from its own knob, but the other two functions used the gearbox. It was shifted with a small lever on the side of the crane, and would push a setup of a transmission driving ring with a 20T clutch gear on each side up and down. In all cases, this assembly was driven from a single knob on the chassis, but depending on whether it was up or down, it would drive different functions on the superstructure. Because the shift lever could only push the gear assembly up and not down, there was a rubber-band loaded lever on the top to force the gears down when the shift lever got out of its way. Mock-up. Imagine the two sides as connected only by a large turntable. WIP model shifting Overall, I think the model had fairly impressive and interesting functions, and looked decent in my eyes. It definitely had its shortcomings, such as the inability of the boom to rotate while lifted, the extreme difficulty of extending the boom (unless you resorted to an external motor), and the weak chassis (the cab would sometimes scrape the ground.) I don't have ambitions of beating the far more experienced builders in the contest, but I'm glad to have participated, and gone outside my comfort zone a bit. More images at: https://bricksafe.com/pages/2GodBDGlory/compact-mobile-crane

Nice going! It looks like it'll be a really interesting MOC. I would encourage you to give the semi-trailing arm suspension a shot, though! I was just taking a look at it, and I think it would be an interesting challenge and another great touch on this already mechanically interesting MOC.

Thanks for pointing me to that information! It's pretty intriguing that Lego is actually partnering with the Raspberry Pi people to make a lower-cost (higher skill-level, I assume) alternative to Mindstorms.

Very nice! I can imagine that programming that would be quite challenging. One question I have is how you're able to adapt the Lego servo wires to the Raspberry Pi? I was under the impression that that plug type was proprietary for Lego, and not something I'd expect to see for a Pi.

If you follow his link to Rebrickable, there's a video on that page

I just watched your video on Rebrickable, and I'm very impressed with the functionality! Collective and cyclic pitch on the main rotor, plus cyclic on the tail one is very impressive, especially for a B-model of a set without any turntables!

Looking good! I also found 13 studs wide to work well for my mobile crane.