Kenworth T47


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.

JCB 714


My repertoire has become quite diverse over the years. I have made large cars, large planes, MODs, and many other types of builds. I enjoy those builds, and I get an immense amount of satisfaction completed them. Recently I have enjoyed making smaller, non-powered, Technic MOCs. I can generate more small build ideas, I can stay motivated better, and I enjoy the playing with final result more. So I made another small MOC, the JCB 714.

The full gallery may be found here. Instructions may be purchased for $5 USD.

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JCB 714

This MOC started when I was browsing the JCB UK website. I thought the 714 would be a fun little project that would have some nice features, and would utilize some of my collection that is not currently being used. I started working on the frame. The MOC would have a four wheel drive system, suspension, steering, and a dumping back. I designed two suspension/steering designs, and while the first one was awesome, it was not as stable as I would have preferred. So I reverted back to the design utilized on the real JCB. It was not as flashy, but it worked well. A turntable is planted behind the steering pivot, with the drive axle moving through the center of both. A liftarm was placed on the left to operate the steering function. The drive axle would connect to both axles through a 12/20 gear reduction which connected them to two differentials. The I3 motor was placed in front of the forward axle.

The rear was more challenging than I expected. First, I had to plant the mLA’s in such a way that they could be connected by a single axle that would not impede the driveline. Second, the mLA’s had to operate in such a way that the bucket could do the full range of motion; nearly 90 degrees. Third, the shape of the bucket did not work well in LEGO, as there were limited flat surfaces. Thankfully the sides were flat, and some of the bottom. The bottom was connect to the dump pivot, and the sides would hold the angled panels. Finally, it had to make sure the rear wheels could still move freely. While there are still some holes in the dump, it works well enough to transport a bunch of bricks.

The cab built up fairly quickly, and allowed me some space to add the rear window grate, and a exhaust pipe. The hood can open, and there are steps to get into the cabin. Safe egress is important.

As I am finding with MOCs that do not utilize Power Functions, the MOC functioned well, every time. No maintenance is needed, gears do not skip, and the MOC works as it is designed. This is part of the reason I am building these kind of MOCs more often. The MOC worked as it was designed, just like a MOC should.

Thanks for reading and happy building.

 

 

Iveco XTR


After a couple of more complex projects it is nice to take a break to do two simpler projects. When I need a little bit of a design rest, I do a trial truck, and usually a fictional one, so I can build as I please.

The full gallery can be found here, and free instructions can be found here.

Iveco XTR

After building a number of trial trucks, I have found some features I like to have on my trucks. Note, these features may be prioritized differently if I was participating in a Truck Trial race. These features I like are linked suspension, PF XL motor for drive, tall clearance, and a center mounted battery box. As I was making this truck for my own pleasure, I forced myself to include all of these features.

I usually start a truck with the axles, and the Iveco was no different. I created the axle with a portal axle build around my favorite piece for both the front and the rear. I also added the space to fit both a differential, or knob wheels for the final drive (though the pictures only show the latter). This would allow me to switch the traction of the truck, and allow for a minor gearing change. While the changeover takes a little bit of time, it’s a nice feature and the gives the truck some versatility. I placed the steering motor directly on the front axle with allowed the middle of the truck to be simplified vastly. In the center of the truck is the battery box mounted longitudinally, and a Power Functions XL motor in the rear. This keeps the heaviest components of the truck in the center and low.

The linked suspension is a setup developed by other that connect two pendualar axles together. Each left side has a linkage that connects the two left wheels together, and the right wheels have the same. This keeps the wheels planted as the pressure from the terrain is balanced across all four wheels. When one wheel has to go up to follow the terrain, the rest of the wheels adjust. It is simple, effective, and keeps the truck a little more planted than a suspension utilizing shock absorbers. Otherwise the truck bounces a little during an obstical.

As you can see in the video, the battery box is getting a little tired, and the snow as a little mushy, but the setup worked well. The truck stayed planted, and it was nice to have two final axle options. It is a simple design that does not require too many hard to find parts, so if you need a good little afternoon project, give the Iveco XTR a build, and tell me what you think.

OK, off to some more complicated builds. Check The Queue. There is some fun stuff coming. Until then, happy building.

Bedford MWD


I have said it before, but my favorite things to build are Trial Trucks.  The combination of the driveline construction, forces on the truck, diversity of body style, and various propulsion systems offered by LEGO combine for a great building experience.  Because of this, I usually am building a Trial Truck, or have one built at all times.  But for some reason, this truck seemed to sit for a long time unfinished.  I struggle with deciding if a truck will be a model of something, or something fictional.  This decision is often made too late in the construction process.  After toying with a Daimler Scout body, I decided I needed to finish this project and the Bedford MWD body was chosen.

The full gallery may be seen here.

01

After some some experience with various designs, I decided to construct a truck around a simple locking differential idea I had recently designed.  Because I would need an extra IR Receiver for the locking function, I decided a simple two speed gearbox (1:6 and 1:10) could use the other IR channel.  I placed all the controls in the middle of the chassis.  The driveline and the steering axle would run through the middle.  On the left side was the Battery Box and the motor for the gear change, and on the right side was the XL drive motor, the gear box, and the motor for the locking differential mechanism.  The steering motor would hang out the back of the chassis over the rear pendular suspension unit.  Both axle were connected by my favorite linked suspension system.

zbedford

Each axle took a little bit of work.  I selected a simple design for the locking differential.  Basically, it is a 24 tooth differential placed directly next to a 24 tooth gear.  A pair of sliding 12 tooth double bevel gears slide back and forth one stud to connect only with the differential, or with both the differential and the neighboring gear locking out the differential.  After toying with some old flex cable, and some pneumatics, I figured I was making it too complicated.  I added a small pivot with a Small Technic Steering Arm, and connected it to a 9L link.  This way both axles could be connected, the suspension and lock could keep operating unaffected by each other, and it all could be controlled by a mini Linear Actuator.

Initial tests were positive, so I then decided to figure out a body for the design.  I worked for too long on a Daimler Scout body.  I had the structure made, but the paneling was just not happening.  After sitting on the project for 5 months, I decided it was time to make something new.  The Bedford design worked well, and helped my get excited again in the project.

Now, once I got outside to drive the truck a glaring problem occurred.  The bevel connection in each axle that transmits the longitudinal drive forces to transversal drive forces kept slipping.  You can hear it in the video.  Because of this, it did not matter if it had locking differentials, or if it had a two speed gearbox, or if it had working suspension.  Anything could stop it.  I though about reworking the axles, but then, I have been working on this for 11 months, it was time to be done.  I’ll use the locking mechanism again.  That worked great.

Thanks for reading.

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.

Mini Feller


Building with Lego is a continuous formation of compromise.  While my ideal of what my Mini Feller would include was significant, what I could actually accomplish was a compromise of space, function, realism, and frankly the amount of frustration I was willing to tolerate.  So while the final result is a watered down version of what I would have liked, it was the result of me compromising amidst the situation.

Instructions can be found here.

I wanted to make a small model go with my Mini Skidder.  The MOC had to be the same scale, have a decent level of fuctions, and work with my Skidder.  A feller seemed like a good option.  As I looked at what function this MOC would have, I ambitiously stated it must have a working blade, working steering, working grapper, and a working tilt function.  All these functions would be controllable on the back or on top of the cab.

The steering was simple enough.  I added a small turntable at the bottom of the chassis to give the frame some support.  The HOG steering axle would come out at the top of the cab, and join the front and the rear with a small link arm.  Simple enough.  Likewise, I added a differential in the rear part of the chassis, geared up the rotation, sent it though a couple of universal joints to the front of the Feller, connected it through a pair of 12z bevel gears, and attached a saw blade.  Again, simple enough I had steering and a working blade.

It got complicated as I tried to add the arm features.  The lifting of the arm would be done with a 8z gear with a worm gear.  Because there was a driveshaft to the front blade, the 8z gear needed to be placed on the axis of the arm, but out of the way of the driveshaft.  The required a 1 stud offset that also needed to be directed back through the steering axis to the rear of the Feller.  I used a CV joint to allow the axle to slip as the feller would steer.

The tilt feature would require a parallel control that would allow the elevation happen while keeping the feller blade parallel to the ground.  This would require another 8z worm gear connection at the lower rear pivot point of the arms.  I was running out of space.  Of the 7 studs to work with, one was used for the universal joint, one was used for the lifting gear, one for the mounting liftarm, and one for the lifting arm.  I could not add another worm gear system, while being able to actually lift the feller blade.  Additionally, adding a link for the gathering arms would also have to work through this pivot point if I wanted to isolate the movement from the lifting and tilting feature.  I had to give.  A compromise was necessary.  I felt the stability of the feller blade had to be paramount, so I added another support arm.  I also felt gathering arms must remain as they are essential to a feller.  Sorry, but the tilt feature got the ax.  It was the correct decision, but it still tasted a little sour.

It was a great little MOC, and I had a good time creating it.  I hope you enjoy building your own.  The full gallery can be viewed here and the instructions can be viewed here.

Thanks for reading.

Mack Marble 5T


I confess.  I took the bait, and started on the 2012 You Design It, We Build It before the final rules had been confirmed.  I should know better.  After all my schooling, you would think I have a good idea about how to follow directions.  The first direction is, wait for directions.  But, with all LEGO building, I enjoy what I am creating, and so even after the rules and directions have been given, I still want to contribute to the LEGO community.  So, my next MOC is another Trial Truck, built with the intention of being easy to play with, easy to build, and tough enough to handle child play.  All with instructions, so you can build one.

See Instruction Page

I built this model based on what I thought could be improved on set 9398.  While this new set was a great step forward for the LEGO company, I felt there where a couple of changes that should be made to make the model a better off-roader.  Because I was working with the assumption that this would be something LEGO would produce, I gave myself a couple of constraints.  First, the model had to be less than, or equal to, the cost of 9398.  Second, the model had to have improved off-roading skills.  Third, the model had to have easy playablity, so the drivetrain had to be reliable, the battery should be easy removable, and it should be easy to drive.

I started the frame before the axles.  I placed the battery box directly over the driveshaft.  An XL motor was place behind the BB and three 16z gears above the driveshaft.  One 16z gear went up to the fake motor shaft.  The driveshaft would connect front and rear to the two axles through the new ball joints from 8110.

I then built the two axles, starting with the rear.  To keep the speed of the Mack similar to the 9398, I would gear down the XL motor to about 1:4.  The driveshaft came out of the ball joints and connected to the differential.  I chose two 12z/20z gear sets as the final reduction.  This would keep the driveline a little stronger, and help keep various axles from working their way out of the gears, much like the design of the 9398.  The final gearing was 1:3.89.  It’s not a stump puller, but it could still move up most hills.

The front axle was a little more tricky.  Basically, it had a similar setup, with a PF M motor placed on in it to work the steering.  This was by design.  To keep the driveline reliable, and limit the failure of steering, I kept the steering part of the axle, rather then having components placed in the chassis, and then connected via a shaft to the front axle.  The steering is a little quick for my liking, but it works flawlessly.  To understand more about the axles, check out the instructions.

Through a little trial and error, I connected the suspension, and tweaked it so it would function in a way that was robust, and allow for great movement.  I am still not pleased with how it turned out aesthetically  but it functioned without problems, it supported the model well, and allowed for sufficient articulation, so I left it.

I then added a simple body, a basic rear bed, and added some engine components such as exhaust,  intake, and a simple turbocharger behind the fake motor.  When I was done, I noticed the cab looked a little like an old Unimog.  This seems to be a theme with me, as I love the look of the Unimog.  On the other hand, I do not like the look of too many cabover truck designs, as such, many of my trucks have the slight setback cabover design that is very similar to the Unimog.  My T55 is like this, and this is why I have built so many Unimogs.

The model worked well.  the suspension and stability was perfect.  The truck was stable, and did not roll over, all while being able to handle various terrains.  The gearing was sufficient and would be great for a playing child.  It was easy to change out the 12z/20z gears in the portal axles to a 8z/24z setup which made the truck a little more strong.

It would be a great model for many LEGO fans due to cost, reliability  stability, and playability.  So I have posted instructions for people to enjoy the model as well.  I think it would have been a great LEGO set, then the rules were released.

Next time I’ll wait for the rules.  Thanks for reading.

Full gallery is here.

International FTTS


It has been a little quiet in Thirdwiggville for the last month.  I have been working on a project that is taking a lot of time and resources, so my posts have slowed, even though my building has not.  But just wait, it’s going to be awesome.

Last summer I wanted to do another Trial Truck that would utilized some features I have never used before.  I wanted something complicated to see how it would work.  I wanted a model that would use four wheels steering, independent suspension, and have a simple two speed gearbox while being low to the ground.  After spending some time at the Chicago Autoshow, I saw a FTTS concept, so I thought this would be a great vehicle to model for this next truck.

This model would be built around an independent suspension.  After seeing it used so effectively in a truck by ATRX, I wanted to give it a try.  Each of the four wheels would use a simple double a-arm set-up with a wheel mount attached at the outside.  The wheel mount would house the portal axle and connect the steering linkage.  After a couple of different designs, I also decided the wheel mount would also connect the the shock absorbers.  This was a little unorthodox, as most independent designs mount the shock absorbers directly from the frame to the a-arms.  I did this for two reasons.  First, the model would be heavy, and I could not get the support I needed when the shocks were connected to the a-arms.  Second, and most importantly, I noticed too much suspension flex when the shocks were mounted to the a-arms.  The force applied to the wheel would go up the wheel, to the wheel mount, through the pivot, halfway down the lower a-arm to the shock.  LEGO is relatively stiff, but all these steps complied too much flex.  I would not have it.  I mounted the shocks on the wheel mount, and created a simple MacPherson strut set-up.  This worked well, as it allowed for full steering movement, long suspension travel, and adequate support of the truck.

The front and rear suspension axles both had a PF-M motor driving the steering.  Each were on independent PF channels connected to a single 8878 Battery Box to allow for individual steering, crab steering, and to solve steering drift commonly problematic with four wheels steering vehicles.  Both axles were connected with dual drive shafts running the length of the truck.  One drive shaft would then connect through a simple two speed gearbox to the PF-XL motor.  The final gearing was 1:6.2 and 1:10 for the truck.  This gave the truck sufficient top speed, with an effective crawler gear.  The Battery Box used for the drive motor and the gear shift motor was placed directly behind the front suspension, and in front of the drive motor.  This placement was perfect for stability.  It helped give great traction to the front wheels, kept the center of mass low and to the center with a slight forward bias.

I then finalized the model with a simple removable body built on a Technic frame.  While the hood was little high, and the rear body a little too short, it looked pretty close to the rear FTTS.  Fans seems to like the look, as it is still one of my more popular model.  See the full gallery here and the Work in Progress gallery here.

The model was a lot of fun to drive, and due to its squat design, it was very well planted.  The truck did not want to role over.  I think it could have used a little more suspension travel, and having four wheel steering was crucial to give it some maneuverability that was lost due to the suspension design.  The gearbox was flawless.  The truck did have some trouble skipping gears at the portal axle.  It seemed to happen when a single wheel was over-stressed as the driveshaft could have used stronger bracing in each suspension unit.  This placed a lot of strain on the particular wheel.  So would I do the independent suspension again.  Maybe, but it would need some strengthening and redesign.  Maybe it’s time for another truck like this.

Thanks for reading.  Something big is coming.

CAT D5K


Construction equipment was pretty much designed for LEGO Technic.  I learned this while designing my MB Axor Refuse Truck.  Yellow bricks are pretty popular and accessible, the equipment usually has many functions which can be replicated, and working models with power functions can be made to reenact various construction projects for great playablility.  After finally getting some large track links, I figured it was time for me to do a bulldozer.

I wanted to model the CAT D5K for a couple of reasons.  First, it used a two wheel track for each side rather than a three wheel track for each side.  Second, I wanted to do something by CAT.  Third, I decided on the D5K because for dozers of this size I think it looked the best due to its stance and overall balance.  Plus, when I started looking at the scale of the dozer I was to model, I learned the D5K would work best with the parts needed such as the tracks and blade, and work with the internal space allowed.

The base D5K really only has three functions: drive, blade lift, and blade angle.  I had no intention to add a ripper, because, frankly, I ran out of space.  Space became an issue very early.  I had 9 studs to work with between the tracks, and I needed to add four motors, a dummy motor, a battery box, and two receivers, all while retaining the appropriate look.  All the gearing had to be compact, and the linear actuators needed to be placed efficiently.  The real D5K has a manual adjustment for the blade pitch, but all of my designs left something more to be desired, so I took it out.

Both tracks would have their own motor, and I wanted to link them to a dummy engine, which required a differential.  I connected the motors directly to a worm gear which drove a 8z gear.  This gear was on the axle for the rear drive wheel, and connected on the other end to a differential which connected both drive wheels.  This differential functioned as a power take off for the dummy motor in the front of the bulldozer.

Two more motors were placed under the dummy motor.  One connected though a 12z/20z gear reduction for the blade angle.  It proved difficult to supply power for the blade angle function through the blade tilt pivot without taking up too much space.  The second motor was used to adjust the blade height.  After a simple reduction, two mini linear actuators were used to move the blade up and down.  It worked well, and was plenty strong.

I added the battery box under the driver’s seat, and placed the two IR receivers in the top of the cab.  It was not optimal aesthetically, but it seemed to work well for control.  And again, I just ran out of space.  I worked on the body, gave the model a working hood, and built a cabin.

The model worked well, but building with tracks is always a little bit frustrating.  Like it or not, LEGO plastic will never be fully smooth, and this is compounded with the track system.  Also, I found that the dummy motor would lose its connection to the drive wheels, as the axles connecting to the differential would slip out every once and a while.  This seems to be a commom problem with Technic builders, so we will see if the new axles will help.  I liked the size of this model, and it had a good amount of functions.  Now I need to use the tracks for something else.

Maybe another tank.

The full gallery may be found here.

Zil 132


A couple of months ago I was struck by a new design by Waler.  It was refreshing to see a well made Trial Truck based on something a little different.  I wanted to make a model of my own.  Thanks to him for the inspiration, and for the great ideas on the cab and the fenders.

From the beginning I knew this truck was not going to be a serious off road contender, but I wanted to redesign the whole drivetrain.  I decided to go with a pendular suspension for the first and second axle and a trailing live axle for the third axle.  All three axles would have a differential and a a set of portal axles.  The first and the third axle would also have steering linked together.  As is often the case with my trucks, I had the pendular axles held by a turntable with the steering function passed through the turntable by use of a differential.  The second axle was held by a turntable in the front, and the steering differential passed through to provide steering to the final axle.  The drive function powered all three axles and would connect to the transmission and motor in between the first and second axle.

The third axle was a suspended live axle that had a trailing setup created with the new 8110 pieces.  This would allow for rotational and vertical articulation while connecting the drive shaft and giving space to the steering function above.  The steering shaft would allow for movement via a CV joint.  The Power Functions M steering motor was placed in the rear, and used a simple 1:9 reduction.

A Power Functions XL was used for the drive funtion and was placed between the front two seats.  The motor was mounted on a sliding assembly for the gearbox function, much like the design pioneered by ATRX.  I used my three speed changeover design to move the motor through three gears, for a final ration of 1:7.5, 1:4.7, and 1:3.  The gearshift worked perfectly.  While the drivetrain was a little complicated, the gearing was rather simple.  The battery boxes were place above the second axle side by side.  This kept the weight centered, and as low as I could get it.

Finally I added a cabin and a cargo area.  The cabin was straight from Waler’s design, as was much of the fender area.  I used technic panels to create the cargo area, which also gave me a space to place the two IR receivers.  This also hid the two battery boxes, and the wiring, and generally cleaned up the truck.  I created two small doors in the top to assist with picking up the ZIL.  I was done.

Over mostly level ground the ZIL was one of my better designs.  The differentials and steering worked flawlessly to make the ZIL drive easily.  The gearbox worked well and eased the drivetrain over slight irregularities.  But once the  pavement turned to dirt the ZIL struggled a little more.  It was not designed to have too much suspension travel, and this showed.  It struggled on some of the bigger bumps, as the tires would scrape the wheel-wells.  Overall, I was pleased with the design, and was happy with the way it turned out.  It looked great, it was fun to build, and it was a blast to drive.

The full gallery can be viewed here.  Also, a big thank you to The Lego Car Blog for posting this model on their blog.

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