Unimog U500 (405.201)


Every couple of years I build another Unimog; they tend to be a favorite subject.

Instructions may be found here.

Unimog U500 (405.201)

Right after the LEGO Batmobile 76139 was released, I saw the front tires, and immediately planned this Unimog. The tires were perfect for a U500. I stared working on a draft before I had acquired the tires. I wanted the build to be in the theme of my Unimog 437 in that it was about 1:18 in scale, and had modular cabins and bed options. But I wanted to take this idea to the next level so that front and rear attachments could be added, as well as trailers. Many of my builds as of late are more system focused, in that a main build supports lots of other attachments, trailers, and versions of the same build. With this one, standard attachment points on the front, rear, bed, cab, and hitches allow for a variety of versions and attachments to be added quickly. I’ll make more of these soon.

Rear Hitch, Attachment point, PTO, and PPTO

I quickly set up a front and rear suspension using what was learned on the 437. The MOC has front and rear live axle suspension, four wheel drive, and front steering. A I4 engine is placed under the cab, over the front axle. Unlike the 437, I added a front and rear PTO. The rear PTO has an on/off switch. A center PTO is present as well for attachments that go in place of the rear bed. Finally, I added a Pneumatic pump behind the cabin to run pneumatics on the front or rear of the truck. A value determines if the preasure goes to the front or rear.

U500 Chassis

I added a three way tipper bed on the rear of the chassis, and created a way for the cab to be tilted. Both can be released by pulling a couple of axles out to allow for the tipping. The cab has seating for three, and both doors open. Finally, I added a front winch that is released and wound up using the fake air tanks on the left of the truck.

In the coming months I will make some attachments and trailers for this truck and for a U400/430 version that use the chassis of the U500 with some adjustments.

2016 Unimog U430

The truck turned out how I wanted it too, and had the features work the way as intended. The suspension is a little hard, but that supports various attachments well. This tipper bed and winch are a little addictive to play with. I did not spend much time making attachments for this truck, but I hope to do so soon. Until the next build or Unimog, Happy Building.

Atmos Tractor


I guess I am on a little bit of a tractor kick lately.

Instructions for the tractor may be found here, which links to instructions for attachments, implements, and trailers.

Atmos Tractor

I had recently rebuilt my 9393 MOD, and as I took it apart, I wondered if I could make another tractor with the same implement attachments, improve the esthetics, and use different sized front and rear wheels. Then I thought maybe a pneumatic pump would be fun. My builds as of late have become much more dynamic, in that I like to be able to quickly change them or add a feature. Tractors work great for this, as adding a new trailer or implement can change the build dramatically. Additionally, I enjoy the challenge of making a system that supports lots of additions, while retaining the mechanics that my builds have always had.

Atmos Rear

The tractor came together very quickly for me. In 10 days I went from having a size draft of the tractor to a final MOC. I used the same driveline, albeit stretched, as the 9393 MOD so the mechanical parts were easy. Direct steering is used, and goes through a rear wheel drive system that connects to a two cylinder engine. A PTO is present at the rear of tractor, but not at the front. Adding a pneumatic pump required a stronger frame which was quickly modified, as well as a hose running to an attachment point at the rear.

The bodywork took the most time; about four days. I wanted to keep a simple hood, so I kept the design of 9393. I added some headlights to dress up the front, and the interior left some room for a steering wheel. Shaping the roof and the cabin was a little tricky due to all the half-stuff offsets of the front windshield. The fenders are simple, but match well. Just like that on day ten, the tractor was done. At the time of writing, the tractor can be built in orange, lime, white, and black.

Atmos with Mower

Part of what attracts me to building tractors is all the options one can present with a tractor: implements, trailers, plows, and on and on. The design of the tractor needed to support all of these possibilities. There is a hard point on the front, a hitch on the rear, and a three-point hitch on the rear.

Once these hard points were set, I began to spice it up. It’s no secret that set 8049 is one of my favorites, and since this tractor had a pneumatic pump, I thought a forestry trailer was needed. But then I wanted a snow plow, and a hooklift loader, and a dumper, and some farming equipment. So of course I built them all. You can find links to instructions for the tractor and most of the additions in my instructions tab.

Atmos Tractor with Trailers

The build was great little addition to my portfolio. The system supported a lot of different trailers and implements, some of which are still coming. The design language is consistent with my other builds, and the size is right in my sweet spot. I hope you enjoyed it too. Until the next build, happy building.

CAT 914K


These days, some projects are taking longer than they have in the past. The little Wiggs in my house and a mirad of other reponsibilities are slowing my production. This loader was started a little over a year ago, and it was finally finished last week.

The full gallery can be seen here.

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I was sitting on a train in Chicago, and saw a little CAT 914k out the window, and thought, “I should finally make a loader.” I got home and started to work. My collection recently added the Fischertechnik tires and the pneumatic parts from the LEGO 42053 Volvo, so I started calculating the scale. Once the scale was set I worked on the linkage for the bucket. I spent two full nights working on the linkage to take full advantage of the longer pneumatic rams. I used the longer ones on the lift, and a shorter one on the tilt.

fullsizeoutput_108d

After the bucket mechanism was set, I worked on the chassis. The size allowed for four wheel drive. The rear axle was set in a pendular setup, which allowed for some articulation over varied terrain. The rear differential linked to a small I4 motor that was placed in the rear. The pneumatic valves were placed over the motor. The light on the roof operated the steering.

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While the project took a little too much time to complete, it was a fun project that turned out well. The linkage and bucket range worked well. It also held a load well. The stability of the loader could have been a little better when pumping the pneumatic pump, as the suspension took a lot of rigidity out of the rear. The design allowed for normal LEGO 81mm tires as well.

Happy Building.

International Tow Truck


I have so many pneumatic parts, but I do not build with them often. It was time for me to use them.

DuraStar

Since this would be an intentional pneumatic MOC, I wanted to do something small and simple. I thought a tow truck would work well. As many of my trucks are based on Europian models, I figured it was time to do an American truck. The International DuraStar truck seemed to be a good solution, and they are rather ubiquitous her in the States. It is not too big, and not a pick-up based truck, so it was perfect for me.

I first started with the tow boom. I used the new 1×11 cylinder for the boom extension. I used two of the old 2×9 cylinders for the boom lift. I worked hard to get the boom rigid enough for the extension while remaining small. Still the boom is about twice the width and height of the required scale. It is a little flimsy with a heavy load.

DuraStar Hook

The chassis was more work than it should have been. Working in all the pneumatic parts is simple enough, but giving space for all the tubing and flexibility required much work. Add to the fact that the  chassis needed to be strong enough for a Pneumatic pump, and I thought it would be good to have a working driveline, and it got messy fast. Editorial comment: I like clean designs. It’s hard to have clean designs with pneumatics.

DuraStar Chassis

The rear wheels connect to a 2 cylinder fake motor in the front. I did not use a differential. It fits, but I could not find a solution to keep the wheel axles connected to the differential while retaining the rear dualies. All of a sudden the choice of not having a differential in 42022 makes a little more sense. I added a little car lift on the back. The elevation is controlled by worm gear, and the extension simply uses two friction connectors. In front of the dualies is a pneumatic air tank on the right, and the two control valves on the left. Hoses fill up the rest of the space. Above the air tank is worm gear transmission for the winch.

DuraStar Right

I spent a lot of time working on the hood. The cab came together smoothly, but the hood took some work. Working with something that was rigid enough for my standards took some time. I tried some designs with panel, and some designs with plates and wedge plates. Eventually, I settled on a simple studs-on-top brick and plate construction. The mixture of Technic and system looks a little disjointed, but it represented the shape well.

The truck worked well enough. The steering and fake motor worked smoothly and consistently. The pneumatics worked smoothly, and were able to move the functions of the truck well. The car lift on the back cannot handle too much weight.

Two final editorial comments. I am firmly in the linear actuators camp, as I have said before. Fitting rams, running tubing, and trying to use those little valves just to get position of the pneumatics perfect drives me crazy. Second, I really like the 49.5×20 wheel and tire set. It is a great size and has perfect look. But when I build trucks with them I get frustrated. They look better as dualies on the rear, but there is no good connection to a differential on a 15 or 17 wide setup. Eventually I will find a solution, but at this time, they are driving me crazy, so stay tuned.

Happy Building.

CAT 573C Feller


LEGO takes up space.  We all know this, and yet we still seem to try to cram as many working functions into a MOC as we can.  Sometimes it works out well.  Sometimes we have to scrap a few functions.  Other times, the functions are so dense you really cannot believe you got it to work.  This is the story of my wheeled feller.

The full Gallery may be found here. Instructions may be purchased for $5 USD.  Buy Now Button

CAT 573c Feller

I have been thinking about making a feller for about two years now.  It is a project I have never seen done before, with the exception of two tracked fellers (OK, and my other one).  Over this time, I have been planning, acquiring parts, and making plans, and over the last four months I have been building.  Nothing I have made has been so complicated or so dense.  There is no space left.

As I always do, I stared with the dimensions of the vehicle.  The schematics for the CAT 573C were easily available, so I stared with the chassis.  I knew space would be an issues, so the driveline had to be simple and compact.  The Power Functions XL motor would be geared down 3:1 and mounted just behind the rear axle.  A drive shaft would move through the steering pivot to the front axle.  The rear axle would have simple pendular suspension.  The steering would be completed by two linear actuators placed on either side of the pivot with a PF M motor on top.  Simple enough.

From here, things got complicated quickly.  The MOC would have four remaining functions.  The feller saw, the grapple arms, the feller tilt, and the feller lift.  Since trees are rather heavy, fellers are designed with as many of the system mechanics behind the rear axle.  As such, all of the functions I would add would need to be in the rear, as the front would not have any space.  I quickly learned this would not work.

Eventually, I found what would fit.  The IR Receivers would make up the rear bumper, and the battery box would be directly over them, off to the left.  Two PF Ms would be on the right and would drive two mini Linear Actuators.  These would move two pneumatic valves. These pneumatics would move the lift function and the grapple arms function.  An air tank would supply the pressure from a pneumatic pump placed on the driveline.  Another PF M would be placed over the front axle to give the feller head the tilt functions (it should be noted, 7 designs, and five weeks were spent on this feature alone).  The final PF M was in the feller head, and would drive the feller saw.

After packing, repacking, and packing again, all the features we set.  Then all the cabling and hosing were placed.  No easy task, as I was running out of space, and 25 or so hoses, and 10 cables take up a lot of room.  I added some comfort features to the cable, including a (half) chair and a roll cage.  And so Mr. Technic could get in, a little step.  Then a lot of paneling for the rear, including some access doors on the rear, and the model was done.  Here it is in action.

As you can see in the video, the MOC worked well, but some of the functions did not work as clean as I would have liked.  The drive and steering were fine, with an easy drivability.  There was a lot of mass in the back, so sometimes the torque from the drive motor would cause the back to tip.  The saw worked well enough, and for the most part so did the tilt, but the pneumatic lift struggled.  It was a little overloaded because the saw unit was too heavy.  The grapple arm worked well, but for both pneumatic rams were hard to control.  As always with LEGO pneumatics, they too often are off or on.

Until the next MOC, happy building.