Unimog 437

August 19, 2018 5 Comments


If my previous builds are any indication, I am a big fan of Unimogs. So it was just a matter of time before I built another one. Rather than building one this time, I built a modular system that allows for a number of different versions.

Full instructions can be found here.

This build started with a desired to make another small build with the great Fischertechnik tires I acquired. I wanted to build something small and playful like RM8s FJ or Sheepo’s Defender. As has been happening with many of my recent builds, I wanted to give the MOC some playable options and easy modifications. A Unimog was a perfect option, and who am I to turn down a Unimog? So I gave myself the following constraints: 4×4, I4 fake engine, steering, manual and PF drive options, removable cabs, removable bed, and two chassis. I set off to work.

The axles came together fairly quickly. I decided quickly not to do portal axles, because I wanted the complexity of the MOC to be elsewhere. Both axles have a differential, two soft springs, and are stabilized longitudinally via steering links and laterally via panhard links. All for shocks are mounted on crankshaft parts to get the ride height of the Unimog just right. There is about 1.5 studs of travel for each wheel, which provides adequate articulation.

The axles are connected to a fixed axle that powers a I4 fake motor. Since I wanted the MOC to be easily switched between manual control and PF, the driveline got a little over-complicated quickly. The steering axle and drive axles cross each other twice. This allows for the steering to go to the top for a HOG, and backwards so a PF servo motor can be added. A 16t gear is available at the top of the chassis to power a PTO, or add a PF XL motor to give the Unimog propulsion. The long Chassis can fit a full a full Power Functions pack. When the power pack is not installed lots of open space is available for other additions. I added a three way tipper lift mechanism for both the long and short wheelbase chassis.

Attachment points were added for the rear bed and for the cab. I created three cabs, and each can be added to both chassis (though the Doka looks best on the LWB). Two axles with stop can be pulled to free the cab. I created three beds and a power pack. Four axles with stop are required at each corner to secure the bed. A camper and a crane bed are not far behind on my building queue.

The Unimog turned out exactly as I wanted. The suspension and steering are light and smooth under manual operation, and work great with PF. I am excited about the ability to offer and develop multiple beds and cabs. Instructions are posted, so I look forward to seeing other options people develop to make their own Unimog.

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Mack Magma

March 28, 2017 5 Comments


I consider myself a LEGO purist. I do not cut parts, paint them, and I do very little with custom stickers. But I confess, I’m bending my purist tendencies as of late with all the great custom tire options available. After getting these RC4WD tires, it was time to build another trial truck.

The full gallery may be found on Flickr.

When I build a trial truck, start with three questions: What functions will it have, how many Power Functions receivers will that require, and how many battery boxes will be needed in what placement. Using these decisions I draw up a basic sketch of Power Functions part placement, and I get to work. This truck would have steering, a 2x PF L motor drive, and a two speed transmission. As with other trucks I make, I started with the axles first. The axles were simple as they required no additional functions. Both front and rear have a knob gear in then center, then a 12t to 20t reduction, and a final 8t to 24t reduction in a portal axle setup. The front as a simple steering setup, and the steering universal joints between the first and second gear reduction.

Both axles are strung together with a frame that houses the suspension and electronics. Both axles have pendular suspension, and are linked together with liftarms front to rear. It is a system that is simple, and incredibly effective. A PF M motor is placed in the front to power the steering, and another M motor sits beside it to power the transmission. Two PF IR receivers and two rechargeable battery boxes are placed with one on each side of the chassis. Both PF L motors are mounted side by side in sliding housing in the rear of the chassis. Each motor drives a set of 12t and 16t gear. These separate axles combine to either a 20t or 24t center mounted gear. When both engines are connected 12t to 24t gear, an overall 10:1 ratio is achieved. When both engines are connected to the 16t to 20t gear, an overall 1:6.25 ratio is achieved. With the power of the L motors, this gives a good low ration, and an appropriate high ratio.

As this was a quicker build, I did not spend too much time on the bodywork. A simple flat bed was installed, and the cab is sparse. I selected a simple America style cab from this design idea to build in blue. The grille is big and square, and the rest of the cab generally follows the idea. Both the cab and the bed can be simple removed.

The truck has plenty of power, and the transmission worked without error. The steering was easily controllable. The larger tires gripped very well, as they are soft with big knobs. They were a little taller than LEGO’s tires, and combined with the softer sidewalls, made the truck a little less secure in its footing. But the truck did not roll over easily, and the soft tires made it grip the ground well. I will be using these tires again.

Until the next MOC, happy building.

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Unimog U90

January 14, 2017 1 Comment


About 3 months ago I purchased a set of four Fischertechnik tires from ebricks.ru. After seeing a review of them by RM8, I reached out to him, and he mailed me a set. After a little time, I finally have something to show with them.

Unimog U90

After playing with a number of ideas, I decided to do another Unimog. It’s easy to motivate myself to build a vehicle I love. This time, I wanted to do the unloved U90 (418) version. It was not a terribly successful version, as many find the hood…not one of the best. But few people have built this version, so I was up for it. I put to to a vote on Eurobricks, and the decision was to build it in green. Off I went.

The scale required a 27 stud wheelbase and a 19 stud width. I built the front and rear axles and tied them together. Through a couple of edits, I finally added the suspension and figured out how to get portal axles into the truck. The Power Functions XL motor was mounted just over and in front of the rear axle driving power to all four wheels. The Servo motor was placed directly ahead of the XL for the front axle steering. I added a four cylinder fake engine over the front axle. The rechargeable battery box was placed over the rear axle.

Unimog U90 Driveline

The suspension is a live axle setup, with four hard shock absorbers at each corner. Each wheel has about 2 studs of travel. Not much for a Unimog, but enough for a 418. At this point I started a draft of the cab, and a draft of the bed. At this point the truck had an identity crisis. Move forward with green or find another option.

Unimog U90 Bed Tilt

Building LEGO Technic with green is not the easiest. The color lacks 1×5 and 1×11 beams. Both of the these parts would be needed for the bed and the cab. I could make some things work for the 1×11 in the hood, but there was no other option (read, inexpensive option) for the 1x5s needed for the bed. I toyed with other colors for the bodywork; orange, white, blue, yellow. None of them had the right pop I was looking for. Other than the orange, but, as other have said, orange has been done too many times. Then it dawned on me, “why not use plates?” I had my solution. With one bricklink order, I was done.

The truck drives well, and is easily controllable. The front portal axle can use a little strengthening, so serious trial abilities are lacking with this truck. Both the bed and the cab can be easily removed. I ran out of space for a ram to elevate the bed, but it can tilt three ways. I was pleased with how the truck turned out. It looks great. The driveline coule use some improvements, so I will make those improvements on the next truck.

 

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Concept John Deere Bulldozer

November 4, 2016 1 Comment


In what is becoming a little bit of a theme, I submitted another design for a Lego contest. In the long line of Eurobricks.com contests, the Technic Challenge 10 called for a pneumatic build. Challenge accepted!

Full Gallery Here

Concept John Deere Bulldozer Left

The contest had very few constraints other than the build had to use Pneumatics. As I have mentioned before, working with pneumatics is not my preference. I don’t like them, so it was good for me to step out of my comfort zone.

I was feeling especially creative this time, so I thought about a number of concept ideas. Pneumatics do not tend to work smoothly when lifting arms so I decided against an excavator and a loader early. Additionally, I was not willing to invest in additional parts for this project. After a couple of drafts, the idea of this bulldozer was born. Taking some inspiration from some of John Pope’s design, the basic idea was there. The dozer would have different tracks, a three movement blade, a crazy engine, and a forward thinking design.

Concept John Deere Bulldozer Blade

I started with the tracks. After moving the axle points four wheels countless times, I came up with a design I liked. I made another one, and linked them together. The I worked on the blade. The dozer would have a lift, tilt, and side to side angle adjustment. After playing around with some idea, I found a solution I liked. Two pneumatic rams were on the front to lift the blade on the top. Then two links were connected low on the two sides of the blade, and then on each side of the dozer. These points on the dozer were moved fore and aft by on pneumatic ram each. These side rams would move the blade left or right individually, or together they would tilt the blade up or down. Additionally, it allowed all the tubing to be internal.

Concept John Deere Bulldozer Open

I added a small compressor powered by a Power Functions M motor, and the battery box under the cab, and added the 16 cylinder engine (coupled V-8 and Flat 8). The cab was easy to get the shape I wanted, and gave me some space for another pneumatic ram to open the hood. I then decided to add a ripper since I had one pnuematic left. The new 1×11 ram a great addition, but a little more power could have been used for the ripper.

Concept John Deere Bulldozer Chassis

I was pleased with the look the bulldozer. The functions worked well, but on reflection, the were not exciting enough to be competitive for a contest. After two pneumatic builds in a row, I find some of the frustrations I have with them remain, but I am discovering some charms as well. We’ll see what comes next.

Happy building.

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T-55A

December 9, 2015 4 Comments


The T-72 that a made a couple of years ago is still the most popular MOC I have made; at least in terms of internet analytics. This year, I committed to making another tank, so I figured keeping in line with old Soviet armor would be rather apropos.

The main gallery may be found on Brickshelf or at Flickr. Instructions may be found here.

T-55

The T-54/T-55 line of tanks have been produced in greater numbers than any other tank. The MOC represented here is a T-55A, representing types that were assembled starting in 1970. This series included an updated NBC and antiradiation system, an upgraded engine, and also added back in the 12.7mm anti-aircraft DShK on the loader’s hatch that was part of the original T-54 spec.

As with most of my MOCs, I starting scaling the tank before any building took place. I knew I wanted to use the newer, larger track links, and I knew I wanted to use the old mid-sized wheels. This set my scale, so I got to work. Starting with the chassis and the hull I worked first on the driveline and suspension. I used simple 2×4 liftarms to connect the road wheels to a suspension axle which activated a shock absorber inside the hull. Each road wheel has its own shock absorber. Fitting them all in took some creativity, but they are all mounted inside on the left and right sides of the hull. In the end, each wheel has about 3 studs of vertical travel.

T-55 Chassis

In between each suspension bank are the remaining mechanics.  After the suspension was set, I worked on the turret functions. Right from the beginning, I knew the tank would have a rotating turret and an elevating gun. It was clear having the elevation mechanics for the gun in the turret would be tight, so I decided instead to have the functions placed in the hull rather than in the turret. Using a vertically mounted mLA, connected directly to the breach of the gun, I was able to develop a method that would elevate the gun throughout the full turret rotation. The turret rotation was driven by a 8z gear connected to the turntable, and reduced by a worm gear. Both motors for the elevation and rotation are placed directly in front of the turret.

T-55 MechBehind the turret are two PF L motors mounted transversely side by side. They drive a 1:1 gearbox which connect directly to each rear drive sprocket. The IR receivers are placed above the gearbox. For those keeping score at home, the internals are (f to r) the battery box, the turret motors, the turret mechanics, the drive motors, and finally the IR receivers.

Working on the exterior of the MOC is what took the most time. The hull came together pretty quickly, with the exception of the details over each track. Most of the finishing time came with the turret exterior. Most Soviet tanks have the distinctive mushroom turret, which considering LEGO’s cube orientation presented some challenges. The turret of the T-55 also has a slight triangle orientation when viewed from the top. Like the T-72, I designed the turret with four side orientations (left, right, front, and rear), and one top orientation. Starting from the rear, I added a basic curved structure. The sides each had a couple levels of slopes, each tapering in toward the gun. The front was a little more complex. There are two “slope blocks” made of 4 curved slope bricks, and a supporting structure. One slope block is mounted on each side of the gun. The support structure is a mess of bricks with a stud on one side, headlight bricks, and plates. The top of the turret is plates on the front, and two sloped plate sections under each hatch. The two hatches are mounted to the turret support under the sloped plate sections. The AA machine gun is placed on the top, and various external mountings are placed in various ways around the turret.

T-55 Turret Detail

After making a lot of non-powered MOCs, it was nice to get back into Power Functions. I was pleased that everything worked flawlessly. The drive had adequate traction and power. The suspension worked well, and provided good floatation and travel. The turret rotation was smooth and allowed for precise directions changes. The gun elevation worked great, though I had to limit turret rotations to under four before the clutch on the mLA would snap. After a number of smaller builds, and frustratingly long builds, I was nice to finish something that worked well, provided constant entertainment throughout the build, and turned out quite nice.

Happy building.

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Audi allroad

November 8, 2015 1 Comment


There are not many projects I start that I do not finish. I can count a couple. But, sometimes there are projects that take a long time to complete. I either loose motivation, lack parts (read budget), or find something else to do. If I were wise, I would toss the project, and move on to something better. But there is value to trudging through the slog and completing something difficult. The Spitfire is a great example of this. The Audi Allroad has been on The Queue for about 16 months, and it’s finally done.

The full gallery may be seen on Brickshelf or on Flickr.

Audi allroad

After completing the OCTAN F1, I thought I could use the suspension for an all-wheel drive car. I was sure I could make the front suspension with steering work at this scale.

allroad Suspension

I wanted it to have another fun feature, so using a bunch of differentials, I developed a simple three speed transmission. Three power functions motors are connected via two differentials which connect to the drive axles. Each differential acts as a subtractor between each motor. When one motor is running, the power moves through two differentials, and the car moves slowly. When two motors are running, the power moves through one differential, and it’s a little faster, and when all three motors are running the car is running the fastest as no differentials are splitting the power. I got it to work, and within a day, I had a working chassis.

allroad Driveline

Once this was done, the MOC sat on my desk for a long time. This past fall, Thirdwiggville welcomed another citizen to the village, and this gave me lots of time late at night to get back to working on this project. I spent a couple of weeks working on the body work with the perspective of “finish this.” So the body work could use a little more polishing; doors, mirrors, better lines, maybe an interior. But I was happy to finally get this done.

The MOC worked well. The suspension functions quite well at this scale, and the transmission was simple and effective. It could be a little quicker, but I was not going to make a substantial gearing change after the MOC was built.

Two final thoughts. I need to stop building supercars because they take a lot of time and effort for me, and I find little motivation for the body work; I do not think the body work looks good, and I lack motivation to work on it. Second, I needed to test the driveline earlier in the build process. I spend too much time fiddling with gear ratios after everything was build. But this project is done, and I am happy it is.

Happy building.

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MD600N

August 26, 2015 4 Comments


One of my first memories of a helicopter was watching a Phoenix Police MD520 land in Roadrunner Park, a block away from my house. The high pitch whine of the main prop was incredible, but another sound was missing. I gathered all my seven year old courage, and asked the pilot, “where is the tail rotor.” I got a lesson in aerodynamics that day, and to this day I can still identify an MD520 by sound. It still remains my favorite helicopter, so I figured it was high time for me to honor this aircraft in LEGO.

Full gallery can be found here. Instructions may be found here.

MD600N Front

What excites me about building with LEGO Technic is creating functions that allow motor, movement, and control. Helicopters are mechanically complex, so I find myself drawn to recreating them. I learned about how they work when I built my first helicopter. With this new helicopter I started with the rotor head. I first built Effermans great swashplate design, and figured out what should stay and go. A four blade rotor head seemed not quite right, so after a little work, I managed to get a six blade head. It was with this decision, and discovering in the chosen scale there would be very little internal room, that I decided to switch to making an MD 600N.

MD600N Starboard

I then got to work setting dimensions, and getting the scale of the airframe correct. The length of the rotor blades dictated the scale, and the interior was going to be tight. The major challenge was getting the control functions connect to the cockpit. This is not a new challenge, as it seems to be the case with every large plane I do. I have a lot of experience with it, and so I came up with some solutions. The challenge with a helicopter is the collective. Every movement that is transmitted, must be able to retail its movement while also being effected by the collective. This works well with the swashplate, but at the controls is where this gets difficult. Using the basis of Effermans design allowed for a simple setup where the collective moves an axle on which the the left/right and fore/aft controls mount.

MD600N Cockpit

_MG_2539

Moving the collective moves the other two controls in a way that is independent from joystick inputs, and allows for complete swashplace articulation at any collective pitch. The controls connect to the swashplate above the main cabin and move forward. From there all three fuctions move down to the floor of the cockpit in between the pilot/copilot seats, and the second row seats. The collective is connected here to a lever on only the pilot’s side. The left/right controls connect via an axle to the joystick, and the fore/aft controls connect via a 9L link to the joystick. Both joysticks are linked together.

 

MD600N Chassis

The final control adjusts the yaw of the aircraft. The MD600N uses three methods to give anti-torque to the main rotor. In forward flight the 1)  tail planes give directional stability. The tailboom also has 2) two slits that provide a “Coanda Effect” from the main rotor downwash. Finally, at the end of the boom is a 3) movable jet direct thruster (all are nicely discussed here). This thruster rotates to force more or less thrust against the torque of the main rotor, much like the more common tail rotor. In this MOC, the thurster rotates on a small turntable, and has an axle running through the boom the controls the rotation. The axle connects to the floor petals by way of a flex cable, and a liftarm running below the cockpit. Both pedals are linked together.

Once all the controls were set, I could work on the body. I wanted the helicopter to be blue as I see it in my memory (almost). This presented some parts challenges, but not as many as I expected. The two suicide doors open to the main cabin, though I did not add any to the cockpit. Many liftarms and connectors were used for the rest of the cabin. I wish current Technic parts could facilitate the rather bubbly lines of the MD600N, but I was pleased with how it looked in the end.

As with many of my large aircraft, this helicopter suffered from gummy controls. The range of motion of the controls reflect the scale for the model, but do not allow for great playability or demonstration of features. For something like a helicopter, I am interested in powering the controls surfaces and inputs controls via Power Functions much like this. Next time I guess. But the Helicopter looks great on my shelf, and it brings me back to a great time in my childhood. I hope you enjoy.

Happy building.

 

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Kenworth T47

November 1, 2014 1 Comment


The Kenworth T55 is my favorite Trial Truck I have built. It’s not the best looking, or the most capable, or the most reliable, or even the most popular but it’s the one I keep coming back to. My latest truck is a continuation of the Kenworth series of trial trucks. The T55 would pull a stump, the T47 is quicker, has better steering, and more compliant suspension.

T47

Right from the beginning I knew the truck would have a similar cabin at the T55. It would continue with the four wheel steering, and I added an independent suspension. The dimensions would stay close to the same. From there anything else was fair game. I started with the axles. The new suspensions arms made it a little bit easier to make a good independent design. A CV joint was used at the steering knuckle, which allowed for the steering pivot to be near the wheel. Each wheel had about three studs of travel.

The XL motor was placed on the left of the center line and the rechargeable battery box was placed on the right. A newly acquired Servo Motor was placed rear on the centerline directly in front of the rear axle. I had a little more space left, so I added a simple two speed gearbox. A little more space remained so I added a flat six engine.

T47 Engine

Part of my attraction of the T55 has been it’s coloring, and it’s shape. I wanted to keep the attraction similar, but in a way that would differentiate the trucks. I have been acquiring some green lately, so I thought would be a great color. The cab is basically the same, but now it can tilt so you can work on the engine.

The off road performance was not great on the T55, and the T47 was similar. The independent suspension had too much play at the wheels to be great at steering, and the articulation was not very supple. The truck was great to drive around my house, but when I took it outside it did poorly. The suspension design is better than my last independent set up. There was no slipping of the gears. I think my next design will use the same knuckle, but design a different steering connection. This truck again proves the use of knob wheels rather than a differential for a trial truck. Feel free to make your own, and let me know what improvements you developed.

Happy Building.

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CAT 573C Feller

June 10, 2013 2 Comments


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.

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Talon Track

February 19, 2013 1 Comment


Every once and a while I see something so creative I have to build something like it.  I happened with my HH-65.  It happened with my Zil 132.  And to some extent it happened with my Spitfire.  But when I saw the Urban Buggy from Chrismo, I though I have to make something like it.  It was such a fresh and creative design.  It had such great lines, a perfect stance, and a unique driveline setup.  But while imitation and outright plagiarism are the most sincere forms of flattery, I thought something of my own design would be a better contribution to the LEGO community.  I present my Talon Track Car.

You may find the full gallery here, and the instructions here.

I designed this car to be fast and stable, just like a track car.  I started with a drivetrain that would be reliable and effective.  A PF XL for drive, and a PF M for the steering.  I placed the PF M in the front mounted directly on the suspension unit, with a return to center spring in the middle of the mount.  The system is set up differently than in my Rumble Bee, but uses the same return part.  Each suspension arm would have a single shock absorber.  Directly behind the steering motor was the XL for the drive.  It was geared up with a 20z/12z ratio, with the driveshaft connecting directly to the 20z gear that turned the differential.  The rear suspension used an independent setup that was developed a long time ago for my Red Car Bigger (great name, huh).  If it’s not broke, don’t fix it.  The suspension was planted.  I placed the rechargeable battery box and the IR receiver behind the rear axle.

The car was quick, and didn’t have any problems, but faster would have been cool.  The return to center system worked well, especially for the quickness of the car, and the quickness of the steering.  It was easy to control.  The car was robust, and crashed well.  So go ahead and build your own.  Enjoy.

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