Freightliner M2


For some reason, I often find myself building two trial trucks at the same time.  While I was building my ZIL 132, I also wanted to try something with floating axles.  The model would use 6 wheels, a 3 speed transmission, and fully suspended live axles.  I also wanted to model the Freightliner M2 Business Class truck as closely as I could.

The model started as my trucks usually do; with the axles.  The second and third axles would be identical, and would be connected with a simple pulley wheel universal joint between the two.  To keep the speed through the universal joints high, and the torque low, I used as 12z/20z gearing after the universal joints, then the knob wheels to rotate the axis, then the normal 8z/24z gearing on the portal axles to finalize the drive.  This also allowed me to keep fewer knob wheels as the second axle had the drive shaft from the transmission pass uninterrupted to the rear wheels.  The final drive ratio for the two rear axles were 1:5.

The front axle was a little more work.  I wanted to have the steering motor mounted on the axle so I would not need to have a steering shaft connect to the front axle.  This proved too difficult, as it would raise the PF XL motor that I was going to use for the drive to high on the truck.  I decided it would be better to mount the steering motor on the frame and connect to the front axle via a CV joint.  Once I made this decision, the front axle became easier.  I used a 1:3 gearing on the portal axles, a knob wheel, and then a drive shaft back to the transmission.  The steering axle would exit just above the drive shaft on the axle to move to the right for the steering motor.

The frame was pretty simple.  Once I had the transmission placed, and the axles spaced, it was simple to place the suspension components, and the shock absorbers.  Each axle had two steering links mounted vertically which connected to a 3×5 liftarm which would activate a shock absorber; very much like Lyyar’s design.  Each axle had a steering arm to keep the axle from swaying laterally.  Finally, all three axles had a number of 9L links to keep the various movements maintained.

The transmission was going to be placed behind the PF XL motor which was under the hood.  The changeover mechanissm would be placed in the center of the truck with the changeover motors mounted longitudinally, on both sides of the truck.  The PF XL motor was place directly above the first axle, and was mounted on a moving frame that was moved by the changeover.  This allowed a moving frame to work its way through the three gears.  The ratios were 1.25:1, 1:1.25, and 1:2.  This allowed for final ratios of 1:4, 1:6.25, and 1:10, which was more than capable for most terrain.  The drive and steering Battery Box was mounted over the second and third axles, and the gearbox 8878 battery box was just behind the changeover in a little box on the bed of the truck.

Finally, like always, a simple body was mounted.  I had a little trouble getting the look I wanted on the front of the hood, as the suspension components kept getting in the way.  I added a bed, covered the changeover and motors, and a couple more details and everything was finished.

The model was not my best driving truck, as six axles do not want to always work together.  The suspensions was supple, and I was getting no drive or steering input on the suspension.  The truck worked well over various terrain, but struggled on some on step obstacles.  The transmission mounting worked well at changing gears, but gears did not have a strong support, and I found they liked to skip at times.  I liked how the suspension worked, but I do not think it brought enough of a valued to use this system again.  It had moderate improvement on dealing with terrain, but it placed a lot of stress on a number of parts, such as the frame, the axles, the driveshafts, and the universal joints.  The next truck will use a pendular set up again.

The full gallery may be found here.

Power Functions 4×4 8081


For most LEGO enthusists, when they purchased the set 8081, they quickly modified the set with a Power Functions drivetrain.  It makes sense.  LEGO models are a little more exciting when they are motorized.  But I guess I went a little backwards.  I wanted to do the fun stuff first, and make the most complicated and compact drivetrain I could make.  I posted the instructions here, and they can also be viewed on Rebrickable.com.

But the comments kept coming from people who wanted to see my model motorized.  So I thought it might be a fun addition.  I added a two PF M motors, a 8878 Battary Box, and an IR receiver.  I tried to keep the modifications simple, so I could easily add the motors to the MOD, and take the system out if I wanted to.  The drive motor was placed on a simple mount that connected to the frame.  The power was fed thought a 8z gear to a 24z gear which then connected directly to the V8 driveshaft.  The driveline was unchanged from the V8 down.  The steering motor was mounted laterally in front of the rear seats.  A 20z double bevel gear drove a 16z gear, then a worm gear moved the final 8z gear which was mounted on the existing HOG steering axle.  I removed the passanger seat which is where I placed the battary box, and created a simple mount for the IR receiver.  The added weight required a new shock absorber, so I added that as well.

The model worked alright.  The drivetrain did well to handle the new power, and I could easily control the Crusier.  The steering motor was a little too powerful for the upside down facing steering rack.  It skipped a little under load, which was a problem over rougher terrain.  The drive motor was a little taxed, so a PF XL would have done a little better.  I guess I could add that, but I am ready to move on to my next model.  Stay tuned.

The full gallery may be found here.

Red Sedan


When I got out of college, I started getting back into LEGO; the end of my “dark ages.”  I wanted to make a large supercar, just like everyone else.  But after my first attempt, there were a couple of things I wanted to improve, and the first car did not really look right.  OK, so what needed to change?  I needed to stretch the car, and make the stance a little better, add some features, and make it as real as possible.

See full gallery here.

I used the dementions of the 2005 BMW 5 series as my template.  From these demensions I used the F1 Racer wheels and tires to set the scale, then I determined the wheelbase, got the width, and I went to work.  I first made the rear suspension unit, and then the dual cam V-8.  Then I linked the two with a 4 speed transmission, and a long driveshaft and added a simple parking brake.  It took a little work, but I then added the front suspensions.  I have found it best to use technic beams to mount the front suspension. The A-arms are then attached to this structure, with the shock absorbers placed on this structure and braced with liftarms.  I then connected this directly to the front of the V-8, and connected it to the rest of the chassis with a simple frame.  I used the old steering mounts of the old 8865 supercar, and connected them to the steering wheel through an upside down mounted steering rack.  Of note, the car was going to be big and heavy.  I had to find a way to get two hard shock absorbers at each wheel which limited the suspensions options I had.  In addition, I added a front and rear sway bar, which took a little more space, but it worked.

Then the body.  I worked first on the doors, and the front bumper.  I used a dual pivot design for the doors so they would open even though bricks do not work well with pivots.  Then I did the front and rear quarterpanels, and set the rear bumper in such a way that a full size spare tire would fit.  I then worked on the interior.  I designed a simple tilt steering using a worm gear, and a universal joint.  I made sure to use the great front seat design by Pixsrv, added a rear bench seat, funished the trunk and added all the little compartments in the center console and glovebox.

I finished with rest of the body work.  The roof had a sun roof, and the trunk would have a damped shock to hold open the  trunklid, and added small details and some mirrors.  It was big, and it was done.  I was pleased with my first large car.  It still my most popular on Brickshelf.com.

All in all it was a great experience to learn about how to make a large car, and all the challenges that go with that.  Frankly, since this design, most of my cars have been a little smaller, as it makes the suspension and steering work a little bigger.  Lessons learned.

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.

Mercedes Benz Axor Refuse


I am a big fan of garbage trucks.  For some reason I find the combination of a smaller truck,with many features all with a complicated compaction device is a great basis for a complicated LEGO Technic model.  Plus, trucks are fun.

The hardest part was going to be the rear compaction device, so that is where I started.  I decided to use a Geesink Norba design as it would give me the largest opening for the trash in the rear because the mechanicals would be on the bottom on and the top of the opening.  13 studs wide is not much space.  In addition, this would allow me to have the rear hopper pivot up to let the trash out when it was full.  I would need to have three functions going though the pivoting hopper.  One at the pivot, and two connecting at the base when the hopper was closed.

The dumpster lift would be driven through a knob gear when the hopper was closed on the bottom.  The compation device would be operated with a gear on the bottom and a mini linear actuator on the top.  This mini linear actuator would also function as the opener for the rear compactor.  All the motors would be housed on the bottom, with one motor placed next to thebattery box.  The extractor would be operated by another mini linear actuator using a scissors mechanism to move the ejector plate.

The chassis was constructed with a PF XL in front of the steering axle.  The motor would power both the drive, and the extractor changed by a changeover.  The steering motor is placed on the right of the truck.  On the left, another PF M motor powers both the dumpster lift and the lower hopper compaction device.  All power came from a 8878 rechargeable battery box, through two PF IR receivers, and powered four motors: One XL for drive and the extraction plate, one M for steering, one M for the dumpster lift and lower compaction, and one M for upper extraction and hopper opening.

The model worked well, particularly steering and the drive.  However the extraction and the hopper opening was a little less reliable.  The hopper was too heavy for a single mini linear actuator, and the compaction device was not stiff enough.  It happened to get caught on some of the internal edges on the inside of the hopper.  The next garbage truck will need to be built a little more sturdy.

The full gallery may be seen here.

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