P McCatty

Hi everyone, I'd like to introduce my latest MOC. It is an alternate build of the set 60418 Police Mobile Crime Lab Truck. This set's versatile selection of parts (especially the hinges) allowed for plenty of creative possibilities. The story centers on a daring escape attempt using a stolen forklift while the police are distracted at the "Handcuff Café." The primary vehicle is a tractor with a low loader. Its cab seats two occupants, with a small compartment behind them for storing accessories. This tractor turned out great — it even works as a stand-alone model, resembling a racing truck with the bold new tires (5033). The trailer features a "gooseneck" profile (non-detachable) with a functional ramp and stabilizers. The forklift, built with locking hinges, operates smoothly at high and low angles. While it doesn't lift much, it performs well thanks to a carefully balanced counterweight that prevents tipping. As for the café, I repurposed the CSI technician as the attendant, complete with a payment terminal and a movable humanoid sign overhead holding handcuffs. It felt fitting to include a little park bench for law enforcement to relax while they visit this unique hangout spot. Meanwhile, the jail is unguarded but equipped with adjustable CCTV surveillance and wanted posters. The prisoner just needs a little help to escape through the roof hatch — can they make it to the underground getaway in time? Feature List: Cab-over style Tractor Truck with seating for driver & passenger. Includes small storage space in the cab with rear access hatch. Low Loader Trailer, complete with working Stabilizers & Ramp. Futuristic “RC” Telehandler Forklift. Comes with a Pallet & Container for moving materials. Handcuff Hangout Café. Adjustable signage. Nearby Park Bench. Prison Tower with Radio Antenna & Surveillance Camera. Features overhead escape hatch for prisoner. Underground Escape Tunnel entrance. More pix on Flickr HERE l

This is a fantastic solution! I'll be sure to test it out. The jaws of that hinged part at a first glance look robust enough to carry the load, so definitely worth a try. The thought of using a separated universal joint (similar shape) did cross my mind, but I didn't bother to take it apart This is a very clean option though. This is a good idea too. It was a while back that I first designed the axle so I may not be remembering correctly, but I think the head of the servo motor in that configuration intefered with the turntable at the back of the axle. There might have been a way to brace it differently to accommodate this though - I probably leaned towards more symmetry in the end. And at a quick glance, the cable may also get tangled up in the engine crankshaft during extreme suspension flex. This could be solved by running it tight to the body of the motor & using a clip, but I wouldn't want to leave that as a source of error for anyone else building it.

Very good observation! I tried a few different solutions, but none of them were robust enough. There was always be skipping under high torque. Examples below are from using the old 16T & new 8T gears. With the aim of keeping the dual wheels at ~ 19-wide, there was nowhere to mount supports around the differential. To get around this, I supported it by framing with 4 x 12T gears. I was actually surprised by how well it worked. The ground glearance suffers a bit, but the assembly is solid. This can also be done by framing with 8T gears, but it results in a bit more friction.

Thank you! Thank you! The pneumatic cylinders are really 3 in parallel, but I used 6 to get the range. They are coupled with a custom assembly that is a variation of THIS. If you notice, the pivot for the dump bed is not along its base, but rather quite low towards the bumper, such that it has an approximate overall "L" shape. This was specifically chosen to maximize the force delivered to tip the bed at the point where it is highest (horizontal). Regarding the tires - yes you are correct, RC4WD isn't cheap but at the same time, they look much better than the standard LEGO tires in my opinion.

Oddly enough, the pneumatics are pretty quiet. But it's the compressor that gives the model character. While it's working it sounds like a real heavy duty truck with the engine idling.

Thank you! Regarding the old-style differential on axle 1, it was chosen to provide clearance for the servo motor that sits directly on top. The curvature of the motor coupled with the 1/2 stud width of the gear was sufficient. There was no room to move it forward, & moving it up by 1 stud would interfere with the engine crankshaft during extreme suspension flex. The engine already sits a bit higher than I'd like. Typically the approach would be to mirror the axles & so the burning question is, why doesn't axle 2 have the same gearing? During testing I found (with using the old-style differential on axle 2) that the input shaft torque was such that it would shred the new style cv-joint. This was overcome by gearing it up another 20-12 & using the new-style differential. With the 1-stud thickness of the differential gear, the original positioning of the servo motor (just like axle 1) wouldn't work due to interference. Fortunately, the steering arms on axle 2 are 1 stud longer than axle 1 to reduce the steering radius & this is typical on twin steer vehicles. With that, I was able to move the servo away from the differential by 1 stud & achieve the needed clearance. Finally, since the axles have dissimilar differentials, the gearing in between them was necessary. A close inspection of the render below may provide some clarity.

Thank you. Much appreciated

Hi everyone. I’d like to introduce to you my latest MOC: Technic RC Pneumatic Dump Truck. It is on 1:17 scale, weighing in at 4.32kg with just over 5,000 parts. It is loosely inspired by the SinoTruk Howo 8 x 4 Tipper Twin Steer. I would love to get your thoughts & feedback! More pictures on Flickr HERE Instructions: BuWizz, 2.4GHz Feature Summary Powered by 2 x BuWizz 2.0 or 2.4GHz Box. RC Drive 8 x 8. RC Twin Steering. Springless Live Axle Suspension Front & Rear with maximum roll stability. RC Compressor. RC Pneumatic Functions. Tip Dump Bed & Driver Cab independently. Dump Bed Automatic Gate Lock with optional Manual Override. Opening Doors with Spring-Loaded Latch. Foot Pedals (Brake & Accelerator), Signal Levers, Gear Shifter, Air Horn Chain, Ignition Key, opening Glove Compartment. Working In-Line 6 Cylinder Engine (Connected to Drive Shaft) Working Steering Wheel full-time, even when Cab is tipped. Opening Hood, revealing Engine Fan. Adjustable Sun Visors, Mirrors, Windshield Wipers. Technic Figure Compatibility. Locking Feature to secure Dump Bed & Driver Cab to Frame to add rigidity & facilitate ease of model transport. Video Comparison Pictures Locomotion All motorized functions are powered by dual BuWizz 2.0 or 2.4GHz Units integrated into the Cab. The model features RC Drive, with a full 8 x 8 train. Propulsion is delivered by 4 x PF XL Motors, geared down at 2 to 1 with the help of Planetary Hubs. There are no Center Differentials, which ensures that all 4 axles are driven full-time. The drive train is also connected to a (cosmetic) inline 6-cylinder Engine, complete with a fan. With an empty Bed, the weight distribution is closer to the front, which limits the traction on the rear wheels. In practice, the 8 x 8 drive configuration results in much better outdoor & overall performance (particularly over uneven terrain). Individual axle-mounted PF Servo Motors steer the Truck through a Rack & Pinion system, & this is independent of Suspension flex. Axle 1 (forward) has a tighter turning radius than Axle 2. There is a mechanical linkage connecting the system to the Steering Wheel in the Driver Cab with a +/- 167 deg range for a more realistic look. This function remains operational even when the Cab is tipped. Suspension All 4 Axles feature Live Suspension. Both the front & rear wheel sets are connected in tandem, similar to a Walking Beam configuration. By combining traverse & longitudinal pendular levers, articulation is achieved without the use of shock absorbers. This also offers maximum roll stability for high center-of-gravity applications. This idea was inspired by the All Terrain Crane by @Jennifer Clark. Pneumatic System The Pneumatic Circuit uses compressed air to control the pistons that operate the Bed & Driver Cab tipping functions. A Compressor generates pressurized air that is then redirected towards the pistons through corresponding switches. At the heart of the Pneumatic system is the Air Compressor. It is driven by a PF L Motor using 2 Pumps aligned out of phase for smooth flow. Compressed Air is fed to the Pneumatic Switches that control the tipping functions. The model features 2 Pneumatic functions: Tip Driver Cab & Tip Dump Bed. The air supply from the Compressor is redirected through Pneumatic Switches, which in turn control the Pneumatic Pistons that operate the functions. The Switches are activated by PF Servo Motors. With the Compressor turned on to supply airflow, the Servo angle (-90, 0, 90) corresponds to the Switch positions (-1, 0, 1), which then moves the Pneumatic Pistons as (retract, neutral, extend). Full credit to @functionalTechnic for the original RC Pneumatic Servo set-up. The Dump Bed tips at up to 45 deg & has a lifting capacity of 2.5 kg, with a total volume of 3,623 cubic cm. Gate Lock The Dump Bed contains a gravity-based Lever that automatically releases the Gate as soon as tipping begins. Conversely, it is timed to lock the Gate once the Bed is horizontal. An optional pin is included that secures the Lever in position so that it doesn’t release the Gate upon tipping. Driver Cab Details The Driver Cab features functional doors with a spring-loaded mechanical linkage to open & lock them. This mechanism fits in a single stud width & once locked, the door is fully constrained to the Cab. The driver side contains Foot Pedals (Brake & Accelerator), Air Horn, Signals, Ignition Key, Gear Shift Lever. The Windshield Wipers, Mirrors & Sun Visors are all independently adjustable. The Hood on the front opens to reveal a working Engine Fan. Finally, Technic Figure compatibility has been maintained using vintage seats. Admittedly the Technician scale isn’t 100% accurate, but it is never a bad idea to include them. Locking Elements Both the Driver Cab & Dump Bed feature locking mechanisms that reinforce the tipping functions. This is ideal for model transport, where it can be easily lifted from above from any of the sections. Typically, it would be carried from beneath or by holding the front & back. Aftermarket Tires While the standard 62.4 x 20 tires work well, but the RC4WD 1.2” variants have always been preferrable. They are a bit larger & have a more rugged look overall. Due to the weight of the model, the supplied foam inserts were not sufficient for the tires to retain their shape. To overcome this, custom inserts were designed & 3D Printed for the Dirt Grabber option. They consist of symmetrical halves that are joined together on the rim & secured with Technic ½ Pins. The ID features inner shoulders that prevent lateral movement relative to the rim. More Pictures

Has anyone successfully opened these up & replaced the battery with a 3S 11.1V Lipo? That would keep the interface & controller relationship, but boost the power from inside. The 4-port box is quite small & there are only a few 3S Lipo cells I've seen that could possibly fit. I'm not sure about the connection point though (JST, Balance Ports etc).

Performance aside, the pin & axle connectivity remains the same. However, where the CADA & Buwizz Buggy motors shine becomes evident in the studless ecosystem. The chamfers on the original motors require extra clearance.

For anyone that may find these digital files useful, here is the download link. Just grab the zipped file. Feedback welcome. https://bricksafe.com/pages/PMcCatty/miscellaneous/downloads

Just putting some final touches on these for anyone that may be interested. Full connectivity enabled. I'm not going to bother adding unnecessary details like buttons, USB port, etc. Out of curiosity, would it be best to share io files or a parts pack?

Give yourself some credit! This is really well implemented. Reminded me of 8460 right away. So it looks like you have Drive, Steer, Outriggers & a Universal motor from the Buwizz Unit on the base. Then the Slew, Boom, Extend, Hook are operated from the Universal through a manual 4S gearbox in the superstructure. Very intelligent use of the clutches. I really like it. Do you have a video by chance? I can't quite make out the gearing from the XL & I'm curious to see how it steers with the M motor. I imagine that operating the Slew function from the Superstructure while it's rotating could be challenging, which is why I think that it was done from a secondary gear box (in the base) on 42082. But with the benefit of bypassing the need for another battery box in the Crane I think that's ok, especially for a model on this scale.

+1. I'm still at 1985 LOL. Taking my time & enjoying all of it.

One thing that has worked for me is using a game controller with an attachment to hold the phone (running the Brick Controller app). So you can operate the model with one hand by assigning the drive & steer commands to a single joystick. Some phones will have the screen dim (not lock) to save power, but the app still runs. Another option is also to reduce brightness. That frees up the other hand to film with a secondary device.

Thank you! I had a ton of fun making these & trying to keep them as universal as possible. Right now I just have the main Chassis & I switch out the Logger & Dumper attachments as needed. I'm tempted to make another Chassis & link them all together as a road train. It's already super long with a single Trailer. And the thought of trying to reverse the whole thing makes my head hurt LOL. For the updated Claw Rig I'm experimenting with RC4WD Dirt Grabber Tires. They look much better, but I'll have to DIY some new inserts so that they can properly support the weight as the Truck is pretty heavy. The Buwizz motor is so powerful that I've been able to haul a loaded Trailer (approx 6kg total) up steep driveways & over uneven terrain quite easily.

1. It may also be a good idea to check the system for leaks. Sometimes the hoses (especially the older, tighter ones) can split near the connection points with repeated assembly & disassembly. 2. In your modification, did you perhaps reduce the mechanical advantage of the pistons somehow? That could be a contributor as well. With the increased range I'd find this unlikely though. 3. With a bit of trial & error, you could mount shock absorbers in the linkage to dampen the downward movement of the crane arm. This helps it to stay elevated even with a loss of pressure & as an added bonus, reduces the "crashing boom" effect.

While ripping around with this Truck, the first thing that became apparent was that I had nowhere to put the objects I was picking up, since the Crane occupies the entire rear section. That's really where this Trailer idea came from. The most straightforward execution came in the form of a 3-Axle Turntable Drawbar set-up, using the built-in trailer hitch. I also went back to basics by keeping everything manual & making the design as simple as possible. The first thing I tackled was the suspension. One possibility was implementing live axles with shock absorbers. And with no gearing it would be less complex than a driven vehicle, but I figured there still had to be an easier way. I followed @Jennifer Clark's builds some years ago & I vaguely remembered a concept on pendular suspension. I quickly found it by revisiting the discussion of her All Terrain Crane. Maintaining ground contact was the main objective. The flex was surprisingly significant - the secondary objective then became preventing contact between the tires & the Frame. Stops were installed to limit the travel on the front axle. And a smooth guide rail directs the wheels underneath the Chassis at extreme steering angles or while being jackknifed, even if the suspension is already flexed. For the rear axles, since they are also connected side-to-side, the tandem acts like a rectangle with ball joints at the corners & the lateral pivot axis in the middle. The movement is therefore limited by the play in the connectors. During development & testing, the model would sometimes (annoyingly) roll away if the surface was uneven. The obvious solution was to use wheel wedges, as I sometimes did while my hands were otherwise occupied. But without a drivetrain, there was a bit of room in the axles to attempt an elegant (but simple) parking brake system. After some trial & error, I settled with a liftarm construct that initiates contact with the tires to apply friction, while the engaging lever pivots in a manner that locks the system in both the open & closed positions. Initially, the Drawbar was a simple A-Frame with a Steering Arm & Ball Joint pin at the end. After a few inadvertent detachments, a more heavy-duty solution was developed, maintaining 3 degrees of freedom. It is now strong enough to support a 3kg Truck by picking up the Trailer. The first Lift Stand prototype was a spring loaded swinging lever mechanism. With uneven terrain & various possible heights required for the hitch, a more controlled, adjustable deployment was required. The small Linear Actuator was perfect for this. Adding in Caster Wheels now makes for easy positioning. Finally, the length of the Drawbar is intentional because it improves maneuverability while in reverse. Shorter Drawbars are more sensitive to steering input as I found out in a frustrating series of trial & error exercises. The Logging section took shape as its own attachment because of the frequent need for removal to access the base trailer. Then came the idea of making a Dumper attachment. In order for this all to work, the Chassis had to be fairly universal. The switch can be made in 2-3 minutes with almost no disassembly of the base. Attachment points for the Logger were trivial. Coming up with a tipping mechanism for the Dumper in the available space was a lot more complex. Early prototypes involved the use of actuators. Complete solutions were developed for both Linear & Pneumatic options. Due in part to the weight of the Dump Bed (500g), neither actuator delivered sufficient performance (even with intermediate linkages) in order to lift any significant payload, specifically from the rest position where the required force is the highest. I finally settled on a crank based worm-rack sliding mechanism that works exceptionally well, reaching 45 degrees & with a payload capacity of 1.25 kg. At first I used a manual stop to keep the Gate in place. Eventually I figured the spring loaded concept that I originally had for the Drawbar Lift Stand was perfect for this application. There was enough room under the Dump Bed to install a shock absorber & corresponding linkage to lock the Gate. And it remains this way even when tipped, allowing only for manual release. The second option uses a 9L Link that attaches to the Frame which automatically releases the Gate lock when the Bed is tipped. When hauling logs, we always want to avoid fines on the highway & a tie-down system is essential. The Logger has 4 cable attachment points, so that ideally each log will be secured in at least 2 places. It was a little tricky to keep it all compact enough to enable ratchet release with a full load against the angle beams & also avoiding the massive suspension flex while strapped down.. This was a fun project to undertake & it's nice to step away from electronics for a bit. If you've read this far I would love to hear your thoughts & feedback. I was thinking of adding a Tanker & Flatbed options but there aren't too many playable functions involved with those. Instructions (for both) available HERE Feature Summary Springless Pendular Suspension Lockable Parking Brakes on rear Axles Adjustable Drawbar Lift Stand with Caster Wheels Heavy Duty 3D Coupling Jackknife capability Easily Adaptable Universal Chassis Logger: Ratcheting Tie-Downs x 4 Dumper: Max Tipping Angle 45 deg Dumper: Max Tipping Capacity 1.25 kg Dumper: Manual & Automatic Gate Lock Options

Assuming the Servo has a perfect return-to-centre, it appears that you have a set of bevel gears for the change in direction towards the rack & pinion. If you have the Servo directly connected to the pinion you would be fine, but due to the bevel gears, your axle driving the pinion is 9 degrees offset. In a nutshell, having the Servo in that orientation requires an additional gearing stage to reverse that effect. The picture below is the quickest example I could think of since I've encountered this before. The intermediate axle is at 45 degrees and the steering axle at the rack & pinion is in sync with the Servo. Backlash is minimal. Alternatively if you're stuck with the gearing you have & you're (conveniently) using a Buwizz, you can move the steering curve up or down by a small amount to eliminate the offset.

Aesthetics isn't my strong suit so I'll defer to others with more experience on that. With that said I like the way you enclosed the model. I bet you wish you had those 9L Links in white . If I could make one suggestion, it would be to revise the front suspension by using the 5L or 6L Steering Arms (with tow-ball sockets). The knuckle has much better security & you can also (vertically) brace the upper & lower arms with a connector for a solid overall assembly. I did an RC Mod of 8858 Rebel Wrecker a while back & the front wheels would routinely fall off using the original linkage, which is what prompted the switch.

I really like that. Well done! With the V1 there is a slight angular offset (I'd guess maybe 1 or 2 deg) but it is within the tolerance of the parts. And it's easily stackable side by side if you use longer through axles. If you put 2 x 3L bars in place of the 3L axles, then put the 3L axle through that steering joint, would it be the same result? I don't have all of the parts in front of me right now. Either way, it appears that for a brick-built bracket on these cylinders, some derivative containing a 45 deg part orientation works well. Note also that V2 has exact operating stud lengths (22 to 34), whereas V1 & similar would range from 22.4 to 34.4 as there is a sqrt(2) offset between the blue pins.

At the risk of bumping an old thread, while working on something unrelated I came up with 2 other solutions for connecting the 2 x 11 V2 Actuators end to end. I figure this might be great for a tipping bed mechanism. Hopefully someone can find either of them useful. Version 1 Version 2

Beautiful execution.

Quick question on the rear suspension. If you pull down, do the shock absorbers disengage at the ball joint (specifically at the axle connection)? I know it will be mostly under compression, but at an extreme tilt I feel like one side may slip out. I ask because I've run into that situation before using the 9.5L shock absorbers.

Slightly off-topic but you can add the Buwizz Motor to your custom parts in lieu of recoloring the older Buggy version. Courtesy of @Philo LINK