2GodBDGlory

I don't know if it would work here, but I used some motor cables to simulate that one time.

Yeah, I could probably control a manual lock pretty easily from the gearbox, but I want to try this out, and I guess I don't care that I'm trying to make it work in a compact model where it's maybe not ideal! It'll be 4WD.

Yeah, I am going for something with at least that 3x difference, because I want to have a fairly dramatic speed difference between the two, with a low crawling gear, and a fairly fast cruising gear. You're right, I think I could make a tighter-ratio gearbox work, but I'm trying to avoid that compromise! For sake of space above my rear axle, I'm actually going to be mounting the diff lock in the chassis and then running individual shafts down to each wheel. Because of this, it'll actually be very close to the gearbox, so I don't think it'll be too hard to disable the diff lock in high gear. Yeah, I'd agree, there's not going to be many times when the wheels are spinning, but at the same time creating enough friction to slow the motors down that much. It's probably nothing to worry about!

A while back in this thread, @Zerobricks was showing some sweet 3D-printed versions of the "Racing Small" rim, with much more offset. Anyways, I've been starting planning a small off-roader (Somewhat inspired by @gyenesvi's Bronco), and I was thinking it would be fun to print myself some more accurate rims in that size. The trouble, of course, is that for a 4x4, you essentially need to have some kind of driven, steered hub for the front axle, and the Racing small rim, at 43mm total diameter, really can't quite accommodate them. In order to get around this, for my custom design, I mildly increased the diameter to ~47mm, which is about the minimum I figured I could get away with while maintaining strength and fitting the planetary hub. I've now printed one of them (with more to come), and I think it looks quite promising! Because of the diameter increase, there are some limitations to its use, though: Based on my testing with the three compatible tires I have, I found that the 81.6mm balloon tire works effortlessly (It's always been soft and loose on rims, so I was pretty confident it would work), the 68mm balloon tire works tolerably, and the ~56mm street tire can be jammed on there, but looks weird (though I was testing with a clone one, which might be a bit stiffer). Anyways, though, for actual 4x4s that are going to be using the larger tires, I think it should work fine! As far as hub compatibility, it will work fine with planetary hubs, the old LBG steered hubs with integrated towballs, unsteered hubs, and the old-school black hubs from 8070. Portal hubs work tolerably by my standards, but there is some rubbing. Unfortunately, the new-style black driven/steered hubs won't work, because of the large axle hole parts. (The BMW motorcycle fork hubs won't work either, but they hardly work with anything anyways). I understand that this isn't a solution Lego would use, but I think for fan models it can be a very pleasant compromise. If anyone is interested in printing some of their own, let me know and I can post the file on Thingiverse! Also, Cura's Iron feature is awesome for making a nice top surface!

Nice! Those are both pretty interesting ideas to see!

I was planning out a new MOC in my head, and was hoping to use this diff lock in it, but I think I ran into a snag. I was hoping to include a two-speed gearbox in the MOC, but because the diff lock is based on one specific activation speed, this would essentially mean that if I wanted the lock to function normally in low gear, it would become extremely sensitive in high gear, and likely lock up when turning corners normally, because of the ~3x difference in wheel speed between gears. I suppose this could also be a problem with a single-speed vehicle off-roading at a time where the motors are under enough load that they have slowed down enough to avoid diff locking, though this seems less likely. Does anyone have any ideas for how we could work around this quirk? I've thought about adding some mechanism coupled to gear selection, that could potentially just turn off the lock in high gear, allowing for smooth operation at speed and normal locking function when going slowly, but that adds some regrettable complexity.

Huh, that's an interesting idea that works surprisingly well! The Mack would definitely benefit from having those orange parts replaced, but as you said, they're on their way. Nice work for a first attempt!

It's been a while since I posted any updates, but I've been busy, and I believe the truck is now in its finished state! Features: Spring-loaded landing gear Removable cargo container Container eject function Rear door on container Extending rear spike Expanding rear spike Split opening hood Hidden two-axis joystick operated six-shooter gun Opening cab doors Sliding rear "Ray door" Aesthetics: Because this truck was supposed to be a sort of cheap beater modified for service by my cash-strapped Space Police officers, it's a bit older looking, and has some details added that I thought would add some character, like the "Legoland" brick used on the left side of the sleeper, and the checkered flags. I added my classic KO 55M4NN license plates from the Arocs, a random stamp on the rear of the container ("Shipping label"?), and then raided my stash of former-custom-laptop stickers (now replaced with ones printed on more durable paper) for an "I Heart Motorized Bicycles" one with the motorized bicycles part being completely illegible, a Republic logo (Because there's still Star Wars fans in the distant future!), and a big 'ol Eurobricks Technic sticker for the side of the container. Other than that, what we've got here is a weird amalgamation of classic big rig style, Y-wing engines, a shipping container, and some little winglets holding headlights and keeping the wheelless nose from looking too awkward. The red stripe was a late addition, but makes it pop a bit more. I'd've (Dual contractions are the height of conciseness and lucidity) liked to add some red 1x8 tiles on the grille plates to continue the line, but ~95% of my System collection is back home in Canada and inaccessible to collegiate me. Interior: There ain't much, but there's two front seats, a steering yoke, and a couple sideways rear benches, plus some weapon storage. Spring-loaded landing gear: The landing gear is of a design where it locks into the stowed position with the rubber band, but when nudged will spring down. The front two legs are on their own system, but the rear four are connected via a bunch of 16T gears inside the track. They're nothing too fancy, but are helpful to support the truck! Removable Cargo Container: The container can be removed... Also, bonus pictures of the door on the rear, allowing access for the crew to pass between the truck and container when they're attached Container eject function: Two pullback motors and a spiffy ratcheting system provided (just barely) enough torque to run a big conveyor belt, which would eject the container sitting on top of it. I was also very pleased to use a couple of my old 2605 springs as a belt tensioner! Rear Door on Container: See two things above. Only mentioned here to keep my outline consistent! Extending Rear Spike: This is where my design begins to take inspiration from Star Wars: The Clone Wars' "Droch-class boarding ship," as mentioned in my first post. The big 'ol spike extends out the rear when a knob on the side is rotated, busting off the rear doors (which are mismatched colors because, as everyone knows, it's hard to recover doors that you just ejected randomly into space while conducting a hostile incursion into a criminal warlord's flagship, and even harder when fleeing after said incursion, necessitating frequent replacement) Expanding Rear Spike You may have a handy container to eject from your ship, with its own rocket engines capable of steering it at an enemy ship, and a massive extending spike you can use to impale said ship, but if your spike can't expand outwards after the impalation, you're going to have a hard time getting your boarding crew inside. Thankfully, this MOC suffers from no such problems! This mechanism was harder to make work, and is probably best elucidated (Meaning "made clear," BTW. I like using strange words, dang it! I guess I like people understanding me too...) via these three images from this MOC's WIP days: Split Opening Front Hood No, this isn't some weird strategy for engine access! Anachronistic as the general style of this truck is, Space Trucks don't generally bother lugging around useless engines, though the odd space trucker will keep it around for the sole purpose of creating clouds of black smoke at whim. Carrying around sufficient oxygen in space is problematic, though, and although our intrepid Space Police Officers toyed with the idea of using such a scheme as a smokescreen, they decided the needed the space for other more... aggressive... purposes. In this case, that more aggressive purpose is a big fat gun, the joystick for which can be used to open the hood via a swift pull rearwards, which can move the gun up with enough force to open the hood. Alternately, manual grabbing/moving/releasing can also work. The two halves of the hood are geared together so they open simultaneously. Hidden two-axis joystick operated six-shooter gun See preceding image /\ The gun could rotate on a 60T turntable, and be tilted upwards as well, while retaining remote firing capabilities. Opening Cab Doors: This function is too complex to explain within any finite time period, so I'll just include a picture: Sliding rear "Ray door" I had the door on the container to allow access, but if I left a big 'ol hole in the back of the cab to allow access to it, any pilot would soon begin feeling a degree of difficulty in breathing due to the hasty exodus of his atmosphere into the vacuum of space. To prevent this lamentable occurrence, I added a sliding "Ray door," to the rear. Bonus Weapons Demo: I built a few different guns for my Technic figure to hold, just like I did for minifigures in my more youthful days... I then posed that figure with them around the truck Anyways, I'm pretty pleased with this model, and all the wacko functions I got to think up and include! If I neglected to include any images, you can check out the whole gallery here: https://bricksafe.com/pages/2GodBDGlory/tc25-space-vehicle (Yes, I embarrassingly named the page after some future TC25 ) Video here:

If you're looking to get into MOCing, there's probably no better resource than The Unofficial Lego Technic Builder's Guide. If you just want to drool over awesome MOC's, Incredible Lego Technic (by the same author) is also pretty awesome! If you want to study the history of Technic sets, there aren't any published books I know of that cover it, but you could try the website Blakbird's Technicopedia, or download/print the exhaustive history of Technic sets I wrote, through this thread here: Anyways, welcome to Eurobricks!

If we assume that the dimensions are based on the box, I suppose it would make sense for that to be the small angular motor? It would be a great motor to have more widely available!

Very impressive mechanical work there!

Very nice! That color and tire setup does look great, and makes for a nice model of a very cool vehicle! The double-alternate setup is also nice, and it looks well-engineered too!

Yep, that's the one!

That propellor mechanism really looks like a redeeming feature on this model! I built some old helicopter set with a similar mechanism a while back, but that '90s (I think) era design probably wouldn't be as reliable as this nice new one!

Watching that video, it kind of looks like all the frictionless stud-pins are white. Is that correct? I hope that doesn't become a standard replacement for the LBG ones, though it would be better than the blue ones.

It was first released in Green in the one Monster Jam set this year, but are you seeing it in a more neutral color in this set?

That's quite an interesting chassis! Is it supposed to replicate some real car? Are there any advantages to those angled front suspension arms?

Looks very authentic while adding all that functionality! Nice job!

I did some research into whether that would be possible with MouldKing boxes a while back, and it sounded like 9-10V was roughly the max voltage they could safely handle, ruling out a 3S system unless one added some other kind of voltage controller. Cada could be different though, I don't know.

Cool! If I get back into clocks sometime I might have to try out your design.

The most common thing people do is to upload the instructions to Rebrickable, and then link to it here.

Ok, that might be true

Yeah, there's definite downsides to all the options. I'm also waiting for a legitimate proportional control/physical remote/11.1V Buwizz competitor, but I guess it's just not there yet. You might be right that it's Bluetooth; after all, you can also run it from a phone app, and I don't suppose my phone has a radio output? Does Bluetooth have downsides compared to radio for RC cars? It's seemed to work fine for me

Have you looked into the CADA and MouldKing boxes? (I think they're ok to talk about in this thread?) I'm almost certain they're also 2.4GHz, and are plug and play. The CADA one has the pros of being from a (more) reputable brand, and its "white-top" battery has fairly high current limits, though it (like all Chinese boxes) only has the standard 7.4V. The MouldKing one, on the other hand, has the awesome advantage of proportional control, and the possibility for either 4 or 6 ports depending on which box you buy. I've been very satisfied with my MouldKing 6.0 box so far, with four channels of proportional control via joysticks, and two channels of basic control from bumpers.

Thanks! Sorry, I'm not familiar with a resource like that.