JLiu15

Thanks! It might not be big, but I still managed to fit plenty of mechanisms in there.

Thanks! The model isn't finished yet in that rendering - the articulated joint still needs the bellows. I will model it at the very end as they are gonna be attached to the body panels.

Simple model of a ripsaw controlled by BuWizz. Features drive with 2 RC motors, suspension, and a dual-missile turret that can be elevated and lowered. Functions/features: Drive (2x RC motors, 1 per track) Suspension Dual-missile turret Turret elevation It's been several months without publishing any new MOCs, and this is largely due to me working on my huge New Flyer XD60 articulated bus model. I placed two major orders of pieces directly from LEGO back in August, and as their parts take several weeks to ship I decided to work on a smaller project in the meantime. Since my Azure Racer XL I wanted to create another MOC using RC motors and BuWizz, so I decided to go with a tracked vehicle this time. However, I did not want it to be just another boring tracked vehicle with drive only (like my Lime Tracker from 2017), and I realized a ripsaw would be just big enough to house a turret that can be elevated and lowered. The building process actually started out with the body instead of the tracks. The model has a rather modular build, with individual parts (tracks, chassis, body) built separately and joined together. The turret mechanism was built in the rear of the body, and it is elevated by two small LAs. To reduce complexity, the turret motor is attached directly to the turret and moves with it when elevating. This however required more space in the chassis to allow it room to move. Both the turret elevation and missile firing are driven by PF M motors, and the turret consists of the new spring-loaded turret in a brick housing from the 51515 set. The missile firing motor has a 2L liftarm attached to it that hits the release button on the left/right missiles depending on the direction it turns. Overall, both turret functions worked well. As for the tracks, they have a suspension system with bogies attached to arms with shock absorbers. This part was a challenge, as the tracks needed to sit high but also be reinforced enough to resist the forces from turning. After several attempts with the tracks falling off, I was able to create a setup with the optimal tension in the tracks to prevent them from falling off during serious driving but also not too tight as to add excessive friction. I was initially worried that driving the tracks straight from the RC motors' outer outputs wouldn't be enough torque, but it looks like the finished model performed fine. In the end, the model performed well other than being a little bit top-heavy, but I feel like I could've modeled the shape better to make it resemble a real ripsaw more. I tried to be loose with the design, using curved panels over flat panels and stacked liftarms wherever possible, but still I feel like it can be improved. And as for the color, I think DBG would work best for a ripsaw like this (a Google search for "ripsaw" would show several dark gray ripsaws), but given all the pieces I'm ordering for my New Flyer XD60 model I didn't want to spend anymore on pieces for a side project, so I went with white for the model. Photos: Video:

UPDATE 8/19/21 I've made more progress on the model. I've built the core of the chassis, which is pretty simple but also robust. 2 C+ XL motors are used for propulsion, and thanks to their abundance of pin holes they make for very good structural elements. All of the downgearing is done by the 28:12 reduction at the differentials and the ~5.4:1 reduction at the planetary hubs, which should be sufficient as my Bergmann Swivel Tip Dumper model last year had enough torque with just one XL motor and 28:20 reduction at the differentials. Add another XL motor, greater gear reduction at the differentials, and a lighter body, and I anticipate the performance will be pretty good. The Robot Inventor hub will probably be placed directly above this central chassis section, and thanks to its abundance of pin holes it should also act as a good structural element, especially for bracing the front/rear of the chassis where it'll have to support the force exerted on the shock absorbers. @amorti yes, I believe this medium angular motor has an absolute position sensor, as the output has a marking on it indicating where the zero position is. This also exists on the Spike Prime medium and large angular motors, as well as the C+ large angular motor from the 42114 set. @gyenesvi I've always felt like 4-link suspensions aren't as robust, due to all the links involved. Better to have shock absorbers directly attached to the axle IMO, especially when you anticipate a lot of force exerted on the suspension. And yes, the ball joints were designed for the purpose of protecting u-joints, so the u-joints will be fine. Photos:

Yup, that's like the main purpose of the ball joints - to protect u-joints in live axle suspension setups.

The model won’t be too big. As for the suspension, it’s just like the live axle suspension found on the 9398.

The steering uses a rack and pinion mechanism, but the rack is placed on its side. I will most likely be controlling it with the Robot Inventor app, as I did with my Heavy Duty Skid-steer Loader MOC. The 6-port hub is able to handle C+ motors, so I believe it should be able to handle C+ XL motors. Can they fit inside the ball joint? I'm using the ball joint from the 9398 set, and AFAIK only 3L u-joints could fit in there.

With my Ripsaw Tank MOC essentially done by now (just waiting for some final pieces to arrive) and my PAB order for my New Flyer XD60 articulated bus model still yet to arrive (with more pieces coming for that), I've decided to start another MOC in the meantime. This will be my second model combining Control+ and Robot Inventor after my Heavy Duty Skid-steer Loader. It will have two identical axles, each with a steering motor (medium angular motor) to control steering, and thanks to their absolute positioning feature I don't think I'll have to calibrate it every time, like on e.g. the 42099 set. I was originally planning to use Control+ L motors for the steering, and have this be a Control+ MOC, but found the medium angular motor to fit better with the absolute positioning being another plus. I plan on creating a control profile in the Mindstorms app with different sliders for normal, crab, and 4-wheel steering modes. The drivetrain consists of heavy-duty differentials and planetary hubs, so this eliminates the need for significant gearing down inside the chassis. For propulsion, I plan to use 2 Control+ XL motors, with a fake engine driven by a separate motor. This way, the fake engine can run at all times and there will be less friction in the drivetrain. I anticipate building the chassis to be pretty straightforward, as the entire chassis is essentially a mirror image with two identical axles. As for the bodywork, I'm leaning towards a red car-like body. If so, I will probably name this MOC "Red Beryl C", where "C" is for Crawler. It would be the third model in my Red Beryl series, after my Red Beryl GT of 2018 and Red Beryl X of 2019. Let me know what you think, and any suggestions you may have. Photos: The front axle, with planetary hubs, long shock absorbers, and a medium angular motor for steering: The front axle, with the wheels attached. Note that this is the underside, with the heavy-duty differential visible:

UPDATE 8/12/21 The majority of the body is now finished and attached to the chassis. I was concerned that the weight of the body (although it's not exceedingly heavy) would worsen the performance, but I tested it and the performance was pretty much unchanged, which is good. I feel like I could've done a better job with the body, but I tried to be a little more liberal with applying body panels rather than making it look like a box on wheels. The addition of the cab section and tracks should also improve the looks, as right now it's kinda boring with just part of the body and no tracks. The BuWizz is still in the cab area, but positioned lower in order to lower the center of gravity. At this point, all that's left to do is the cab area and some final touches, and the model is complete. If you guys have any suggestions for me, please let me know. Photos:

UPDATE 8/10/21 I've built the chassis of the model. It features 2 RC motors (1 driving each track) and a suspension system. Reinforcing it was a bit difficult, but with some cross bracing it held up pretty well in my tests. So far, this thing goes crazy fast, and this is with my BuWizz low on battery. I was concerned that there won't be enough torque (as the rear sprockets are connected directly to the RC motors' outer outputs), but it manages to climb obstacles pretty well too. Finding the right track tension was a challenge here. It couldn't be too loose, as it would fall off the sprockets especially given the speed, or too tight, as it would cause excess friction or even warp the sprockets' attachment. I have came up with a setup that uses differently sized sprockets in the front and rear, and it's actually the smaller sprockets that are driven. I think this would also give the model slightly more torque than if I had used the larger sprockets in the rear. Note that the road wheels and return rollers will be attached later. Lastly, I also made a small change to the body. The BuWizz is no longer mounted here. It'll be mounted lower in the chassis to lower the center of gravity, but probably face-up to prevent dirt from potentially damaging it. If you guys have any suggestions for me, please let me know. Photos:

Thanks! Part of the reason behind this project is to test out the newer missile turrets from the Robot Inventor set :) I mean, it's better than nothing, and adds more functionality than just driving which would get boring after a while. Yes. For such a small MOC, I don't think incorporating a gearbox will be easy. It'll probably take up the entire space in the rear.

Hey guys, I'm starting a smaller project here with the aim of maximum playability. Currently I'm waiting for a huge Pick-A-Brick order to arrive for my New Flyer XD60 project, so I've decided to do a small project in the meantime, especially since I haven't published anything since January. This will be a small and simple ripsaw model equipped with a two-missile turret, using new missile elements from the Robot Inventor set. The model will probably be modular, with the body and chassis largely built modularly and connected together when finished. Currently I have the turret and some of the body built. The turret can also raise and lower, but unfortunately cannot rotate as the BuWizz unit only has 4 ports (and two will be taken by the drive motors). As for the drive motors, I plan to use 4 L motors with one connected to each sprocket, although I might also go with one RC motor per track. Overall, I see this model as an upgrade from my Lime Tracker of 2017, as this one will be driven by the more powerful L motor and feature BuWizz. I think this will be a fun little MOC to drive around. It's nice to build something else after months of work on a single project, and it'll be a great way to pass the time as I wait for parts to arrive for that project. Photos:

Great review! Just wondering - the bed color is bright green (like 42039) instead of regular green, correct?

I made a few more renderings of my model. The modeling process is almost entirely complete now - I've added the part that sticks out of the roof in the rear (still not sure what that is), as well as the supports for the bellows. The bellows won't be added until the physical build is complete, as I have to ensure they work smoothly which only really works in a physical build. I'm overall really satisfied with the result, and I'm glad I decided to go for a studfull design. This allowed for a degree of detail not achievable with just Technic pieces.

UPDATE 7/2/21 I've made a lot of progress on the rear section of the model. The bodywork here is essentially complete, and all I'm really missing now (at least for my digital model) is the bellows. The rear end was modeled using a modular approach - several submodels were put together to prevent this area from looking too dull. While I still think I could've done better here, given the limitations of LEGO, I feel that this area turned out realistic enough. I do wish LEGO released trans-orange 4L bars though, as the real bus has orange light strips for the turn signals. I still have to model the part that sticks out on the roof just before the rear end (which you can see in the photos of the real bus I have below). I was only able to find two reference images for the roof of the bus, and this part isn't very clear on them, but the general shape of it seems pretty simple, though. If you guys have any suggestions for me, please let me know. Photos:

I think you're right - the Typewriter set contains a lot of Technic pieces in rare colors, such as lime green, teal, and (I think) dark tan - probably due to excess parts produced for the Sian, 40448, and Bugatti/Land Rover seats, respectively. And from the images we have so far, I think there's a good chance the beams used to build the bed are bright green.

It looks like this piece to me.

I'd love if we get an entire series of LEGO sneakers in the future. As a fan of sneakers myself, some popular sneakers I'd love to see done in LEGO would be Vans Old Skool, Converse Chuck Taylor, or Nike Air Force 1 (although the standard white design might not offer as much contrast when built with LEGO pieces). All in all, I think LEGO did a great job replicating the original sneaker, and I love that even the box is based on the typical blue Adidas shoe box.

No way they're the same as 42056. They're way too wide for these tires (same as 42124). These are likely 42096's in orange.

Personally, I am loving this set. 42124 tires, 42096 mudguards in orange, 42125 mudguards in black, and tons of orange pieces. However, I think the 1989 Batmobile's front tires could've worked better here. The real vehicle's tires have a relatively flat profile, while the 42124's are more balloon-like.

You could even put the Zetros tires on here when the set comes out for a more off-road look

Looks great so far! I love the rim/tire combo with the tires from the 1989 Batmobile.

I think it was from a Facebook post.

Thanks for the suggestion! I like the offsets, and how it won’t impact the steering. The only challenge I see is doing the front right wheel well. Between the wheel well and the door, there’s only one stud of space, and this design requires two studs on either side of the wheel well to attach the black angled Technic pieces. But still, this design is better than anything I had thought of. I’ll see if I can incorporate this design without overcomplicating the build or compromising the structural integrity of the body.

I made a rendering of my model so far. Right now, it's about 70% complete (at least for my digital build), and has over 3500 pieces. I really like how the bodywork is turning out. I'm gonna have to order a lot of white System pieces soon, but the resulting detail is miles better than what I could've achieved with Technic panels and beams. And of course, with this being a model of a New Jersey Transit bus, I put my rendering on a Jersey blue background.