Model of the Kenworth T900 truck in the Australian road train variant. Features proportional steering using the NXT unit, remotely locked fifth wheel, working turn signals, three trailers, lights and custom stickers.  

Datasheet:

Completion date: 14/05/2012
Power: electric (Power Functions / NXT)
Dimensions: truck: length 67 studs / width 20 studs / height 31 studs, trailer #1: length 103 studs / width: 18 studs / height: 28 studs, trailer #2: length 122 studs / width 18 studs / height 9 studs, trailer #3: length 97 studs / width 18 studs / height 24 studs
Weight: truck: 2.891 kg, trailer #1: 2.378 kg, trailer #2: 1.440 kg, trailer #3: 2.194 kg
Suspension: none
Propulsion: 1 x NXT motor geared 3:1
Motors: 3 x NXT motor

This model was based on the Kenworth T900 truck converted to an Australian road train version. At the same time, it was an experiment on merging NXT functionality with a Model Team look.

I have started by modeling a pure T900 truck, adding some modifications typical for road trains along the way. The result is neither a stock Kenworth T900 nor a classic road train, but it still fits within the wide array of customizations popular among Australian drivers (and sheep).

The heart of the model was a NXT unit located at the back of the sleeper module. Since the chassis was entirely taken by two NXT motors (yes, they are this big), the sleeper was actually where almost all mechanical and electric elements were housed. Among them was a third NXT motor used to lock and unlock the fifth wheel, the 8878 rechargeable Power Functions battery for powering lights and turn signals, a Power Functions IR receiver for controlling the turn signals and HiTechnic IR Link sensor for allowing the NXT unit to send commands to the IR receiver.

It may come as a surprise that the model had an IR receiver housed inside next to the IR link sensor, but it resulted from sensor’s poor IR range. I was initially hoping to be able to install the sensor on an external NXT controller, thus having a chance to add IR receivers and turn signals in the trailers too, but with a model of that size the sensor simply wouldn’t reach the truck and all trailers at the same time. Also, with all the effort put into steering the model over a Bluetooth link, it would be a waste to be limited by the poor IR range.

The model had just a few functions. Both rear axles were driven by a single NXT motor geared 3:1, and the front axle was steered by another NXT motor without a clutch. There was no suspension, as it would affect the look of the model and it was hardly needed since it was never supposed to leave my apartment’s floor.  The fifth wheel was locked and unlocked using a horizontal 40-tooth gear with a short beam on its side, driven by the third NXT motor located in the sleeper. By rotating the wheel, the beam would block and unblock the fifth wheel’s only “exit”.

The front turn signals were controlled remotely and operated by the software, that is by the NXT unit turning them on and off repeatedly using the IR Link sensor. I did not install rear or any other turn signals for the fear of compromising the truck’s look with too many exposed wires and LEDs, but I have added working turn signals indicators on driver’s dashboard. I have also used the speaker of the truck’s NXT unit to honk (or rather beep) on command, and to beep while on reverse. It was a very simple thing and I have omitted it when trying to shorten the video.

The sleeper module was literally bursting at seams with electric elements and wires. There were three access hatches in it: top one for the 8878 battery, rear one for the NXT unit’s front panel, and a side one for taking the entire NXT unit out for battery replacement. The wires, especially the stiff NXT wires, proved problematic because they had to be arranged so as to allow moving the NXT unit out and back in. Eventually, the whole space at the back of the cabin was taken by wires and the side access hatch tended to stick out a little.

The entire set-up, that is the truck and three trailers, was controlled by a very simple external controller using another NXT unit. I have initially attempted to use the Hailfire Droid’s wheel as a steering wheel, but it proved unusable because using it to drive any regular gear wheel created very high gear acceleration which generated plenty of resistance. Gearing down in the latter stage was not an option, as a very considerable backlash in gear wheels was created. I was also tempted to build a pedal-like device to control the throttle, but with the NXT wires being quite short and impossible to connect in series, it proved pointless – I would have to keep such a pedal right next to the NXT unit.

The controller  was a variation of my NXT brick-to-brick remote, allowing proportional steering and drive with a speed control, as well as controlling all the remaining functions with touch sensors and NXT unit’s buttons. It was running the RobotC software, resulting in delay in the other NXT unit’s reactions over Bluetooth link. A secondary, more comfortable way of controlling the model was to use a computer with a gaming pad. Using a Bluetooth link and the RobotC software, it allowed to control the model with minimum delays and the gaming pad provided plenty of buttons and two analog joysticks which were used for speed-control for both drive and steering.

I was not fully happy with the model. Its functionality was troublesome, with a lot of effort required to start and connect the two NXT units, with delays in steering, and most importantly with the enormous amount of space taken by the NXT elements. Its look was somewhat compromised, with some simplifications in the bonnet and cabin’s roof area, and with the side air filters shortened to allow to open the bonnet up – the only alternative here was to cut the front bumper to move the bonnet’s hinge lower, which I didn’t want to do. I was afraid it was the kind of model that makes a good first impression, and goes downhill from there. Still, it was an interesting experience in using the NXT elements and in merging them with the PF ones.

Gaming pad control program:

#pragma config(Sensor, S4, HTIRL, sensorI2CCustom)
#include "drivers/HTIRL-driver.h"
#include "JoystickDriver.c"
tPFmotor SignalLeft = pfmotor_S4_C1_A;
tPFmotor SignalRight = pfmotor_S4_C1_B;

task Signals()
{
  while(true)
  {
    if(joy1Btn(2) == 1)
    {
      PFMotor(SignalRight, 7);
      nxtDisplayCenteredTextLine(5, " < [>]");
    }
    else if(joy1Btn(4) == 1)
    {
      PFMotor(SignalLeft, 7);
      nxtDisplayCenteredTextLine(5, "[<] > ");
    }
    else
    {
      PFMotor(SignalRight, 0);
      PFMotor(SignalLeft, 0);
      nxtDisplayCenteredTextLine(5, " <  > ");
    }
    wait1Msec(250);
    PFMotor(SignalRight, 0);
    PFMotor(SignalLeft, 0);
  }
}

task main()
{
  bMotorReflected[motorB] = true;
  bMotorReflected[motorC] = true;
  StartTask(Signals);
  while(true)
  {
    getJoystickSettings(joystick);
    motor[motorB] = 0;
    motor[motorC] = 0;
    motor[motorC] = joystick.joy1_y1 / 1.28;
    motor[motorB] = joystick.joy1_x1 / 1.28;
    nxtDisplayCenteredTextLine(0, "BATTERY: %3.1fV", nImmediateBatteryLevel / (float) 1000);
    nxtDisplayTextLine(2, "B: %d", motor[motorB]);
    nxtDisplayTextLine(3, "C: %d", motor[motorC]);

    if(joy1Btn(1) == 1)
      motor[motorA] = -100;
    else if(joy1Btn(3) == 1)
      motor[motorA] = 100;
    else
      motor[motorA] = 0;
  }
}
									

NXT-to-NXT control sender program:

#pragma config(Sensor,S1,touch1,sensorTouch)
#pragma config(Sensor,S2,touch2,sensorTouch)

bool leftturn = false;
bool rightturn = false;
bool soundhorn = false;

task BatLev()
{
  ubyte valueReceived[1];
  valueReceived[0] = 0;
  while(true)
  {
    cCmdMessageRead(valueReceived, 1, 1);
    nxtDisplayCenteredTextLine(0, "BAT: L%3.1f / R%3.1f", nImmediateBatteryLevel / (float) 1000, valueReceived[0] / (float) 10);
    wait1Msec(50);
  }
  return;
}

task Buttons() //0 = Gray Rectangle  1 = Right Arrow  2 = Left Arrow  3 = Orange Square
{
  nNxtButtonTask  = -2;nNxtExitClicks = 2;
  nxtDisplayCenteredTextLine(2, " <  > ");
  while(true)
  {
    if(nNxtButtonPressed == 1)
    {
      if (rightturn == false)
      {
        nxtDisplayCenteredTextLine(2, " < [>]");
        rightturn = true;
        leftturn = false;
      }
      else
     {
        nxtDisplayCenteredTextLine(2, " <  > ");
        rightturn = false;
        leftturn = false;
     }
    }
    else if(nNxtButtonPressed == 2)
    {
      if (leftturn == false)
      {
        nxtDisplayCenteredTextLine(2, "[<] > ");
        rightturn = false;
        leftturn = true;
      }
      else
     {
        nxtDisplayCenteredTextLine(2, " <  > ");
        rightturn = false;
        leftturn = false;
     }
    }
    else if(nNxtButtonPressed == 3)
    {
      soundhorn = true;
    }
  wait1Msec(350);
  }
}

task main()
{
  StartTask(BatLev);
  StartTask(Buttons);
  bFloatDuringInactiveMotorPWM = true;
  btConnect(1, "NXT2");
  while(true)
  {
    ubyte valueToSend[7];
    valueToSend[0] = nMotorEncoder[motorA];
    valueToSend[1] = nMotorEncoder[motorB];
    valueToSend[2] = SensorValue(touch1);
    valueToSend[3] = SensorValue(touch2);
    valueToSend[4] = rightturn;
    valueToSend[5] = leftturn;
    valueToSend[6] = soundhorn;
    cCmdMessageWriteToBluetooth(valueToSend, 7, 1);
    nxtDisplayTextLine(3, "Drive: %d", valueToSend[0]);
    nxtDisplayTextLine(4, "Steering: %d", valueToSend[1]);
    nxtDisplayTextLine(5, "Touch BLUE: %d", valueToSend[2]);
    nxtDisplayTextLine(6, "Touch RED: %d", valueToSend[3]);
    wait1Msec(50);
  }
}
									

NXT-to-NXT control receiver program:

#pragma config(Sensor, S4, HTIRL, sensorI2CCustom)
#include "drivers/HTIRL-driver.h"
tPFmotor SignalLeft = pfmotor_S4_C1_A;
tPFmotor SignalRight = pfmotor_S4_C1_B;
// config start
//bMotorReflected[motorA] = true;
//bMotorReflected[motorB] = true;
//bMotorReflected[motorC] = true;
bool buzzOnRev = true; // buzzing while on reverse
int steerAcc = 10; // steering accuracy margin (degrees)
// config end

int turnSignals = 0;

task Signals()
{
  while(true)
  {
    if(turnSignals == 1)
    {
      PFMotor(SignalRight, 7);
    }
    else if(turnSignals == 2)
    {
      PFMotor(SignalLeft, 7);
    }
    else
    {
      PFMotor(SignalRight, 0);
      PFMotor(SignalLeft, 0);
    }
    wait1Msec(250);
    PFMotor(SignalRight, 0);
    PFMotor(SignalLeft, 0);
  }
  wait1Msec(50);
}

task BatLev()
{
  while(true)
  {
    nxtDisplayCenteredTextLine(0, "BAT: L %3.1fV", nImmediateBatteryLevel / (float) 1000);
    ubyte valueToSend[1];
    valueToSend[0] = nImmediateBatteryLevel / (float) 100;
    cCmdMessageWriteToBluetooth(valueToSend, 1, 1);
    wait1Msec(50);
  }
  return;
}

task main()
{
  StartTask(BatLev);
  StartTask(Signals);
  nVolume = 3; // starting volume
  ubyte valueReceived[7];
  valueReceived[0] = 0;
  valueReceived[1] = 0;
  valueReceived[2] = 0;
  valueReceived[3] = 0;
  valueReceived[4] = 0;
  valueReceived[5] = 0;
  valueReceived[6] = 0;

  while(true)
  {
    cCmdMessageRead(valueReceived, 7, 1);
    nxtDisplayTextLine(2, "Drive: %d", valueReceived[0]);
    nxtDisplayTextLine(3, "Steering: %d", valueReceived[1]);
    nxtDisplayTextLine(4, "Touch BLUE: %d", valueReceived[2]);
    nxtDisplayTextLine(5, "Touch RED: %d", valueReceived[3]);

    // motorC (drive)
    motor[motorC] = 0;
    int afactor = valueReceived[0] / 5;
    if (afactor > 1 && afactor < 25)
    {
      afactor = afactor * 10;
      if (afactor > 100) afactor = 100;
      motor[motorC] = afactor;
      if (buzzOnRev == true) PlaySound(soundException);
    }
    else if (afactor > 1 && afactor > 25)
    {
      afactor = (51 - afactor) * -10;
      if (afactor < -100) afactor = -100;
      motor[motorC] = afactor;
      if (buzzOnRev == true) ClearSounds();
    }

    // motorB (steering)
    motor[motorB] = 0;
    int bfactor = valueReceived[1];
    if (bfactor > 1 && bfactor < 75) bfactor = bfactor;
    else if (bfactor > 1 && bfactor > 75) bfactor = (256 - bfactor) * -1;
    nxtDisplayTextLine(7,"Mtr B: %d/%d",nMotorEncoder[motorB], bfactor);
    bfactor = bfactor * 4;

    if (nMotorEncoder[motorB] < (bfactor + steerAcc)) while(nMotorEncoder[motorB] < bfactor) motor[motorB] = 10;
    else if (nMotorEncoder[motorB] > (bfactor - steerAcc)) while(nMotorEncoder[motorB] > bfactor) motor[motorB] = -10;
    else motor[motorB] = 0;

    // motorA
    motor[motorA] = 0;
    if (valueReceived[2] == 1) motor[motorA] = 100;
    else if (valueReceived[3] == 1)motor[motorA] = -100;

    // turn signals
    if (valueReceived[4] == 1) turnSignals = 1;
    else if (valueReceived[5] == 1) turnSignals = 2;
    else turnSignals = 0;

    // horn
    if (valueReceived[6] == 1) PlayTone(784, 50);
    else ClearSounds();

    wait1Msec(50);
  }
}

									

Work in progress photos:

Photos:

Video:

Click here to view the embedded video.

Media reference:

8 studs, The Brothers Brick, The LEGO Car Blog

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My motorized variation of the LEGO Black Pearl set. Features drive and steering, rotating ship’s wheel, manual  anchor winches and lights.

Datasheet:

Completion date: 19/04/2012
Power: electric (Power Functions)
Dimensions: length 90 studs / width 34 studs / height 74 studs
Weight: 1.714 kg
Suspension: none
Propulsion: 1 x PF Medium motor geared 1:1
Motors: 2 x PF Medium, 1 x micromotor

I have been a fan of the LEGO 8184 Black Pearl set ever since it was released – it’s a jet black, shapely ship with an undead crew. However, since LEGO sets are usually cut down to meet certain budget restrains, I decided to build my own ship loosely based on it.

I don’t own the 8184 set, I simply bought a number of unique pieces from it, including black hull sections, sails and some minor pieces. I have also looked through the 8184′s building instruction to see how to build the bow and masts of my ship. The final result is in some parts very close to the original set, while quite different in others. It can be argued whether it was a custom construction or simply a modified set, but it should be noted that the ship was larger and much more complex than the original LEGO Black Pearl.

I was using only one inspiration when modeling the hull – the Revell’s Ghost Ship set,  which is somewhat exaggerated but still fairly realistic. The resulting ship lacked the nice shape of the original Black Pearl, instead it had a massive and tall rear superstructure, which was necessary to house all electric and mechanic components. The main problem was that side and rear walls of the superstructure had to be 3 studs thick each, to accommodate for windows with lights and red walls used as backgrounds.

The ship was able to drive and steer, and featured a ship’s wheel which rotated while steering. The propulsion system consisted of a single PF Medium motor installed under the hull, driving wedge belt wheels with 1:1 gear ratio. The steering was carried out by another PF Medium motor rotating a vertical axle at the back of the hull, with wheels with tires on the bottom end, and with a big decorative rudder attached. At the same time the ship’s wheel was rotated by a micromotor coupled with the second PF Medium motor, using a single knob wheel which proved able to mesh with it. I was very close to making the cannons fire remotely, by installing a motor that pulled their triggers with small sections of string. However, it turned out that the cannons’ triggers have to be instantly released to fire, and if there is any kind of delay resulting from the motor being unable to release all tension in an instant, the “cannonballs” stopped in the cannons’ exits. I was unable to find any simple solution to it, but at least by removing that mechanism I have gained more space – including space for the battery powering the ship, located under fake roof between the stairs at the back of the deck. I have been also toying with the idea of a chassis capable of rocking the entire ship, imitating waves, but I decided that such a chassis would have to be so tall that in the end it would barely look like a ship, more like a trailer with a ship on top of it.

Making the ship really float was out of the question, as the hull wasn’t even remotely watertight, and even if it was, the model would sink under its own weight. It was also way too top-heavy to float properly. Instead, I had a lot of fun working on the crew, which included, among others, an undead fisherman, a rotting cook, a joker farting fire, a painter with inclination to decorate ammunition, and even a pooping parrot, which could be considered an ex-parrot

The whole idea behind this model was slightly absurd, but making it come true was really fun. The ship looked truly majestic traveling across my room, and my only regret is that there was no simple way to take it out on a lake. It was also one of very few models to feature two hamsters in the video: Furball and Noodle.

Photos:

Video:

Click here to view the embedded video.

Media reference:

8studs (Polish only), Classic Pirates

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Model of a generic reach stacker. Features drive, steering, elevated and extended boom, elevated cabin, rotated head and motorized jaws.  

Datasheet:

Completion date: 01/04/2012
Power: electric (Power Functions)
Dimensions: length 38 studs (not including the arm) / width 22 studs (not including the arm) / height 22 studs
Weight: 1.565 kg
Suspension: none
Propulsion: 1 x PF XL motor geared 1.4:1
Motors: 2 x PF XL motor, 3 x PF Medium, 2 x micromotor

Reach stackers are highly specialized industrial machines that can be considered a distant variant of a telehandler. They are being used primarily in cargo terminals in ports around the world, where their task is to transport and arrange containers. I have been planning to build such a machine for a very long time, and I finally succeeded.

The model showed a generic, typical reach stacker rather than some particular model. The interesting thing about reach stackers is that they are absent from the offer of most of the European machinery manufacturers, except for the Liebherr company which produces reach stackers with arched booms, which would be extremely difficult to model with LEGO pieces.

The model was intended to be as simple, small and functional as possible. I have used no suspension system in it; I was unable to determine whether real reach stackers have any suspension systems, but it seems unlikely for machines that are designed to carry heavy loads around perfectly flat asphalt areas. For example, most front loaders have no suspension on their front axles to make them more stable with loads, and they are supposed to work in rough terrain.

Most of the model was built entirely studless, with exception for the sides of the hull, consisting of studfull bricks connected to the bearing frame. Thus, they were used to strengthen the chassis in its crucial section between the mounting points of the boom and of the linear actuators.

The model’s front axle was driven by PF XL motor through a single differential, and its four wheels were mounted on two small Technic turntables which acted as bearings, taking load off the axle. It seemed to work, as the model proved to be very agile, with and without the load. The rear axle was steered by a PF Medium motor with a very simple steering mechanism lacking a clutch or a return-to-center function. It had an extreme steering lock, merely thanks to removal of any parts of the body that could collide with wheels.

The boom, made of studless panels and self-container, was elevated by two large linear actuators driven by a single PF XL motor. A PF Medium motor installed at the back of the boom was used to extend it, through a system of a worm gear meshed with racks on the boom’s extendable section. The head at the tip of the boom included two micromotors, one for rotating it and another one for closing and opening its jaws. Since the head was intended to balance itself under own weight, just like in real machines, a weighted brick was attached to its side opposite the latter micromotor to counter-balance it. The head’s rotation range was full 360 degrees, and its jaws had a gripping range from 9 to 31 studs. Finally, a PF Medium motor and a small linear actuator were used to elevate the cabin and move it forward, but due to lack of space in the hull, the range of movement was minimal and the function was quite unimpressive.

One function that I toyed with and eventually abandoned was tilting the head forward and backward. Real reach stackers have such function, although it appears to be very rarely used. I did not expect to really need it, and it added plenty of technical difficulties, requiring another motor near the boom’s tip, or a pneumatic system routed to its tip, or perhaps an extending driveshaft inside the boom.

There were few interesting technical solutions that I’ve tried – other than using turntables as bearings, they included the construction of the boom which can be made much longer, and the jaws extension mechanism which was very simple, compact and yet reliable. In general, the model had a sturdy chassis and boom, but rather delicate head and jaws. Despite that, the jaws worked flawlessly with any kind of load, and the maximum load capacity of the model proved to be almost 0.5 kg, limited only by the torque of the PF XL motor elevating the boom and by the clutches in the linear actuators.

I have also used this opportunity to test my IR Link sensor which allows the NXT brick to control Power Functions devices. I have built a simple NXT controller with one joystick, using three motors and two touch sensors and working in two modes: drive mode and boom control mode. The controller worked rather well using my program written in ROBOTC which is included below, but the IR Link sensor was a disappointment: its range was shorter than that of PF remotes, and it caused delays in the reaction of PF motors. Still, controlling the model in such way, definitely more realistic than with regular Power Functions remotes, was an interesting experience.

Control program:

#pragma config(Sensor, S1, HTIRL, sensorI2CCustom)
#pragma config(Sensor,S3,touch1,sensorTouch)
#pragma config(Sensor,S4,touch2,sensorTouch)
#include "drivers/HTIRL-driver.h"
bool sending = false;
bool drivemode = true;
tPFmotor DriveMotor = pfmotor_S1_C1_A;
tPFmotor SteeringMotor = pfmotor_S1_C1_B;
tPFmotor BoomElevationMotor = pfmotor_S1_C2_A;
tPFmotor BoomExtensionMotor = pfmotor_S1_C2_B;
tPFmotor CabinMotor = pfmotor_S1_C3_A;
tPFmotor HeadCatchMotor = pfmotor_S1_C4_A;
tPFmotor HeadRotationMotor = pfmotor_S1_C4_B;

task Buttons()
{
  nNxtButtonTask  = -2;
  nNxtExitClicks = 2;
  nxtDisplayCenteredTextLine(0, "Not sending...");
  while(true)
  {
    if(nNxtButtonPressed == 3)
    {
      PlaySound(soundBeepBeep);
      if(sending == false){
        sending = true;
        nxtDisplayCenteredTextLine(0, "Sending...");
      }
      else{
        sending = false;
        nxtDisplayCenteredTextLine(0, "Not sending...");
      }
    }

    if(nNxtButtonPressed == 1)
    {
        drivemode = false;
        nxtDisplayCenteredTextLine(2, " DRIVE [BOOM]");
    }

    if(nNxtButtonPressed == 2)
    {
        drivemode = true;
        nxtDisplayCenteredTextLine(2, "[DRIVE] BOOM ");
    }

    if(nNxtButtonPressed == 0)
    {
      sending = false;
      PlaySound(soundBeepBeep);
      wait1Msec(400);
      PFMotor(DriveMotor, 0);
      PFMotor(SteeringMotor, 0);
      PFMotor(BoomElevationMotor, 0);
      PFMotor(BoomExtensionMotor, 0);
      PFMotor(HeadCatchMotor, 0);
      PFMotor(HeadRotationMotor, 0);
      PFMotor(CabinMotor, 0);
      StopAllTasks();
    }

    wait1Msec(400);
  }
}

task main()
{
  StartTask(Buttons);
  nxtDisplayCenteredTextLine(2, "[DRIVE] BOOM ");
  int LeftMotor = 0;
  int RightMotor = 0;
  int UpperMotor = 0;
  int RightButtons = 0;

  while (true) {
    if(drivemode == true)
    {
      LeftMotor = (nMotorEncoder[motorA] / 7) * -1;
      if (LeftMotor > 7) LeftMotor = 7;
      else if (LeftMotor < -7) LeftMotor = -7;

      RightMotor = (nMotorEncoder[motorC] / 10) * -1;
      if (RightMotor > 2) RightMotor = 2;
      else if (RightMotor < -2) RightMotor = -2;

      if (SensorValue(touch1) == 1) RightButtons = 7;
      else if (SensorValue(touch2) == 1) RightButtons = -7;
      else RightButtons = 0;

      nxtDisplayTextLine(4, "Left motor: %d", LeftMotor);
      nxtDisplayTextLine(5, "Right motor: %d", RightMotor);
      nxtDisplayTextLine(6, "Buttons: %d", RightButtons);
      nxtDisplayClearTextLine(7);

      if (sending == true)
      {
        PFMotor(DriveMotor, LeftMotor);
        PFMotor(SteeringMotor, RightMotor);
        PFMotor(CabinMotor, RightButtons);
      }
    }
    else
    {
      LeftMotor = nMotorEncoder[motorA] / 20;
      if (LeftMotor > 0) LeftMotor = 7;
      else if (LeftMotor < 0) LeftMotor = -7;

      UpperMotor = nMotorEncoder[motorB] / 20;
      if (UpperMotor > 0) UpperMotor = 7;
      else if (UpperMotor < 0) UpperMotor = -7;

      RightMotor = (nMotorEncoder[motorC] / 20) * -1;
      if (RightMotor > 0) RightMotor = 7;
      else if (RightMotor < 0) RightMotor = -7;

      if (SensorValue(touch1) == 1) RightButtons = 7;
      else if (SensorValue(touch2) == 1) RightButtons = -7;
      else RightButtons = 0;

      nxtDisplayTextLine(4, "Left motor: %d", LeftMotor);
      nxtDisplayTextLine(5, "Right motor: %d", RightMotor);
      nxtDisplayTextLine(6, "Upper motor: %d", UpperMotor);
      nxtDisplayTextLine(7, "Buttons: %d", RightButtons);

      if (sending == true)
      {
        PFMotor(BoomExtensionMotor, LeftMotor);
        PFMotor(BoomElevationMotor, UpperMotor);
        PFMotor(HeadRotationMotor, RightMotor);
        PFMotor(HeadCatchMotor, RightButtons);
      }
    }
    wait1Msec(200);
  }
}
									

Work in progress photos:

Photos:

Video:

Click here to view the embedded video.

Media reference:

8studs (Polish only)

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Model of the legendary 60′s racing car. Features full suspension, remote-controlled drive, steering and turn signals, lights and custom stickers.  

Datasheet:

Completion date: 17/01/2012
Power: electric (RC unit)
Dimensions: length 67 studs / width 31 studs / height 17 studs (not including antenna)
Weight: 2.35 kg
Suspension: full independent
Propulsion: 2 x RC motor geared 5:1
Motors: 2 x RC motor, 1 x PF Medium, 1 x micromotor
Top speed: 2.2 kmph

Ford GT40 is a classic racing car with a beautiful history. It was built for one purpose only: to defeat the Ferrari team in the Le Mans race – a goal set by Ford after failure to buy out the entire Ferrari company (Enzo Ferrari changed his mind in the last second). To understand the gravity of this challenge you should know that the Ferrari team won Le Mans six times in row starting from 1960.

The basic design of the car was purchased by the Ford from Lola Cars company owned by Erica Broadley and located in Huntingdon, UK. It can be therefore considered originally a British car. However, Ford spent several months working on car’s aerodynamic properties, under supervision of former CEO of the Aston Martin company, before it was considered race-ready. The finished car was the fastest car of its time, and it won Le Mans race four times in a row between 1966 and 1969 year. When it debuted in 1966, three GT40s have won three first places in the race. Keep in mind that we are talking about race that involved brands such as Ferrari or Porsche – it’s difficult to think of any modern Ford car completing such a task.

The original GT40s were built in a limited number, and the number of “civil” versions was even smaller, making it one of the world’s most often copied cars in the years to follow. It can be roughly estimated that the number of replicas today is several times greater than that of the original cars. Around 2002 the Ford company decided finally to create a new edition of the car, which was supposed to be as close to the first GT40 as possible. In reality, it was largely different, including being taller than 40 inches – a number the GT40′s name originated from – and it was therefore named Ford GT. Due to many differences some Gt40 enthusiast consider the new edition “softened” or completely ignore its existence. You can see the differences between new version (in front) and the old one (in back) below:

If you are looking to learn more about this legendary car, you can see a dedicated Top Gear episode here, and you can listen to how it sounds here.

Ford Gt40 is called the most beautiful car ever made by some – which is arguable, given the fact that its look does not stand out so much from the look of other cars of its era. In fact, it’s strikingly similar to some cars built around the same time (e.g. Lamborghini Miura P400 version S) or even slightly earlier (e.g. Porsche 904 GTS). As large models of supercars give little room for functions (no space) or for performance (weight), my goal was to make the model look real and authentic. Out of many versions of the GT40, with many details looking much differently, I have chosen the Mark II version – one that had a history of engine failures, but that also included many interesting and unique details, including air intakes on top of the rear bonnet. Some other details, such as the absence of side mirrors, show that it’s a racing version of the car. My decision to build the body of the model fully studless was strengthened by seeing a Ford GT40 model by Arvo brothers. I consider them to be among the world’s top studfull builders but their studfull model does not appeal to me – and I don’t think I could possibly top it.
Most of all I wanted to model the shapes of the car properly, looking for a balance between using beams, panels and flexible axles. I was looking for something between the approach of the LEGO 8448 set (body made of just general contours with gaping holes) and that of some older cars by Crowkillers (fully enclosed bodies made primarily of beams).  Some compromises proved necessary – the roof was a single part, without parts of it being attached to doors, because I was unable to find a good-looking solution to that. The front bonnet did not open and the rear bonnet was inaccurate – it should open with all side air intakes attached to it, but it only opened with the top two.

Most difficult part of modelling the body was the front of it, particularly the front mudguards and headlights. If you look at front of the Gt40, its mudguards follow a complex curve which slightly rises towards the sides of the car. I wanted to model this feature, which I consider crucial in making the model look accurate, and I think I achieved that using large panels set at complex angles, with flexible axles drawing the outer body contours. The headlights, on another hand, are nearly rectangle-shaped and come with vertical ribbing, typical for headlights of all cars of that time. I eventually used blocks of 1×2 trans-clear plates, which I think look accurate, but they absorb much of the light of the Lego LEDs behind them.

The model had only driver’s seat in the cabin, and it was moved to the side because of the RC unit occupying the center. The dashboard was completely inaccurate – it rested on top of the bearing frame, so there was no space to experiment with shaping it. The exhaust pipes were tilted downward a little more than they should, allowing the rear bonnet to open up further. Behind the cabin, there was a simple, static mock-up of the engine with some details, but less than I intended to include – I didn’t want to make the model heavier than it already was.

The construction of the model was 95% studless, with only rear axle using studded bearing structure around the differential. The bearing frame was built around the RC unit which was moved forward into the cabin, practically right next up to the front axle. The frame was rigid, but not completely – therefore the rear bonnet could be locked to the back of the cabin, thus providing extra stiffness to the top-rear part of the body.

While the model was not technically complex, it was challenging to integrate all the functions I wanted it to have with the RC unit and with the way it works.

The propulsion system consisted of two hard-coupled RC motors connected to the rear axle’s differential with 5:1 gear reduction (that is larger reduction than shown on photos – I had to increase it after taking photos). The transmission system also included a Lego speedometer, with the display integrated into passenger’s side of the dashboard. The model is rather slow – I was hoping to keep its weight under 2 kg, and with the final weight being much larger the motors were so strained that the batteries in the RC unit lasted about 5 minutes.

The suspension used typical Lego double wishbone independent suspension, with two short yellow shock absorbers per each wheel. It was soft, particularly the rear axle which carried most of the model’s weight. Just like in the original car, the front suspension is slightly narrower and the rear wheels wear bigger tires – in this case, tires were enlarged by putting two rubber treads over each of them. It should be noted that the model drove better without the treads that with them.

The steering system used steering output of the RC unit. The RC steering module could not be used because it was much too narrow. The steering wheel was attached to the RC unit’s output too through a series of gears. The steering lock was small – the RC steering unit rotates by small angle, and I couldn’t gear it up because there was no space for large gear wheels under the low bonnet.

The front and rear lights, using three pairs of Lego LEDs, were connected to the same output as the propulsion motors. They only shone when the model was driving, and they blinked when it started because of the RC motors taking all the power available.

The turn signals system, which took quite a lot of work to include, was based on my earlier mechanism. This time, however, it was remote-controlled rather than automated. I simply wanted to try remote-controlling it freely, and besides it would be nearly impossible to use it with the RC unit’s steering output. Instead, it was connected to the RC unit’s auxiliary output and it consisted of two parts connected only with wires – which was necessary to fit it in. First part was a micromotor driving an old 9V switch, located vertically at the back of the cabin, between the RC motors. The second part was a PF Medium motor rotating two PF switches, coupled with old toothed half-bushes so that turning one switch on turned the other one off. I wanted to control them with another micromotor, leaving enough space for passenger’s seat, but it proved too weak.  The turn signals could be made with just two pairs of Lego LEDs, except that their wires were too short. I had to use four pairs instead, and since the GT40 has single turn signals, I ended up with two spare LEDs in front and two in back. I have installed the front LEDs into the dashboard, creating turn signals indicator in front of the driver, and I have simply hidden the two rear ones.

The model had its imperfections and compromises, but in general it was fun, looked good and it was a great experience in studless building. I can say it was slower than I expected but looked better than I hoped. I think the photos of it are among the best I’ve ever made, and I also put a lot of work into the video, with a good effect. It was a good lesson for my future supercars, because it was example of a very typical supercar, with central engine, low ground clearance and rear axle drive.

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Media reference:

8 studs (Polish only), TechnicBRICKs, Technic Delicatessen, The LEGO Car Blog

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Model of the famous WW2 German heavy tank. Features drive, steering, rotated turret, elevated main cannon and lights.  

Datasheet:

Completion date: 21/12/2011
Power: electric (Power Functions)
Dimensions: length 25 studs (36 studs including main cannon’s barrel) / width 14 studs / height 11 studs (not including antenna)
Weight: 0.694 kg
Suspension: none
Propulsion: 2 x PF Medium geared 1:1
Motors: 3 x PF Medium, 1 x micromotor

The Tiger tank is the probably most famous German WW2 tank, and one of the most famous tanks in history. It entered service as a heavy tank in 1942, and it was exceptionally advanced for the time, as well as deadly effective. The tank’s powerful gun and thick armour made it an unprecedented threat to both Soviet and Allied tanks. There is also another side to the Tiger, which states that the tank was over-engineered, extremely expensive and time-consuming to both produce and to maintain, and its fuel consumption was monstrous, especially for the crumbling economy of the after-1942 Nazi Germany. It was also designed in accordance with a doctrine of armoured warfare that was already obsolete – it was intended to win by superior firepower and thick armour, while the Soviet tanks, much cheaper and easy to produce in large numbers, were already winning by manoeuvrability, sloped armour and by working in groups. To make things worse, the Tiger was rushed into service without proper quality control and on-site technical support, resulting in many tanks disabled by technical malfunctions or being abandoned after getting stuck because there were no means to haul them out. Still, it was an impressive and fearsome tank, even if its significance has been exaggerated by the Nazi propaganda. One could say that it was a great tank itself, but it required maintenance and logistics on a level its creators were unable to provide.

As for the model, I was initially going to build it in large scale, with tracks of the newer type, but my primary goal was  to properly model its distinctive overlapping road wheels. This element is often ignored and simplified in the models of the Tiger, and I wanted to get it right. It turned out difficult to do at large scale, but I figured out that I could simply use Technic discs at a smaller one. Since there pieces don’t exist in dark bluish grey colour, I had to settle on next closest to it, that is pearl dark grey.

The model has undergone a rigorous technical control. 

After deciding on a small scale, the main challenge was to make the model fully remote controlled despite its very small size; the finished model’s hull was only 20 cm long and it could fit on the palm of my hand. My secondary goal, besides that, was to properly model the shape of the air filters on the rear of the tank, which are half-round but Lego builders often make them all-round or even rectangular. I achieved this by using four 6191 bricks, which was also a challenge as they only appear in dark bluish grey in a single Lego set, one brick per set.

Eventually, the model had to house four motors, two IR receivers, a battery and approximately 2 meters of wire, plus the large Technic turntable which would provide a stable base for the turret while allowing to install a motor in it. I won’t be dwelling on how hard it was, let’s just say that there were times when the functionality of the model depended on whether I can move some element half stud further or not.

The model was quite simple technically. It was driven by two PF Medium motors located in the middle of the hull, which drove rear sprockets with 1:1 gearing (the only ratio possible as there was no space for any large gear wheels). There was a battery in front of the hull, and a third Medium motor next to it, which drove the turret’s turntable through a worm gear. There was a single wire that entered the turret and powered a micromotor installed inside it, which drove another worm gear and thus controlled the elevation of the main gun’s barrel. There was no suspension whatsoever, and the two headlights on top of the hull had Lego LEDs inside them and shutters made of the bases of Lego levers.

The look of the model was not meant to be consistent with one particular of many versions of the Tiger, I just wanted it to be characteristic, which means that it’s close to the tanks from the early production batches. Its side number – 131 – was not random; the 131 Tiger tank can be found in the Bovington Museum in UK, and it’s probably the world’s only Tiger tank in driving condition today.

The model did not look perfectly; the hull was too tall by roughly 3/4 of a stud, and the turret had a gap beneath it to allow the worm gear to mesh with its turntable. This could be avoided if there was enough space in the hull to ‘sink’ the turntable inside it, but there wasn’t. The turret was 9 studs wide, built around a micromotor and held together by its roof rather than by its bottom. Its look was affected by mechanical parts inside it – its front was too tall and its rear end is a little too far to the back. Finally, the main gun’s barrel’s dimensions had to be heavily approximated at this scale – for example, the longest section of it should be 0.75 stud thick while the thickest section should be 1.5 stud thick. There are simply no Lego pieces with such dimensions that would have the required look.

The model was fun to play with, but clearly suffered from small size and low weight. It’s almost my lightest tank model ever, one third lighter than my T-72M tank and almost as light as my very simple Mark I tank – and it has more road wheels than any of those; 24 to be exact, with only 16 visible from the sides. Therefore its traction was poor and it was difficult to drive over my floor, where any unevenness (and there are many) affected its direction. I believe it would perform much better with more weight, stronger chassis and a simple suspension system, as proved by my earlier T-72 tank model, which had exactly the same tracks and propulsion system. This means that this model is probably example of the level of “miniaturization” that is already bad for its functionality.

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Experimental static vignette illuminated with LEGO LEDs and an EL wire.  

Datasheet:

Completion date: 29/10/2011
Power: 12V (external transformer)

A vignette is a static scene that fits in 8×8 studs area and is usually populated by minifigs. As a Technic builder, I have never built one before, until having a blue EL wire at hand resulted in a sudden and unexpected idea.

The vignette used two levels of dungeons to depict a sorceress from the Diablo game making her way upwards using a lightning bold spell. The EL wire, which simulated the bolt, had been completed by four LEGO LEDs that illuminated lava leaks and a torch on the vignette’s lower level. The upper level was populated by four incomplete skeletons (there was only a leg left of one of them), armed with weapons just like in the game. There two levels of dungeons also included some tenants: a spider on the upper lever and a somewhat concealed bat on the lower one. The two levers were connected by shattered floor and maintained different colour themes. I have also taken a liberty of taking the Diablo 3′s tagline: “And the Heavens shall tremble” and changing it a little:

This was a very simple creation that allowed me to try some light effects. It was nevertheless fun to build and my hamster fitted well in it

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My fifth Monorail creation, features a single station with three levels, two Monorails and 100 minifigures.  

Datasheet:

Completion date: 05/10/2011
Power: 9V (Monorail) / Power Functions

This creation’s goal was to have three levels of tracks on a single station, and to populate it densely with minifigures. The white Monorail was built first, and I wanted to model it after LEGO Intercity sets, but I came across a number of problems specific to Monorail. For the Monorail to be able to drive up and down the ramps and to fit inside the station, the front and rear of the cars had to be short, and the cars themselves had to be narrow and low. Initially there was sliding door on the side of each car, that would open by coming in contact with rubber axle joiners located at the platform just a moment before the Monorail came to stop. It worked well, but created more problems: the cars were too wide (with doors 1 stud thick) and for the doors to work properly, they would have to arrive and depart in the same direction on all three levels. I have eventually decided that the doors aren’t worth the extra complications and removed them.

The tracks set-up could appear complex, but as demonstrated at the end of the video it was possible to make a Monorail go through all three levels back and forth without stopping. This creation was simple yet enjoyable, and it was my first creation to include some LEGO sets: namely the 7239 set as the fire truck and 7279 set as the thieves/police team with a quad.

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Model of a Cold-War era Soviet main battle tank. Features suspension, rotated turret, elevated main cannon and lights.  

Datasheet:

Completion date: 10/09/2011
Power: electric (Power Functions)
Dimensions: length 39 studs (52 studs including main cannon’s barrel) / width 19 studs / height 16 studs (not including antenna)
Weight: 1.057 kg
Suspension: torsion bars
Propulsion: 2 x PF Medium geared 1:1
Motors: 3 x PF Medium, 1 x micromotor
Top speed: 1.14 kmph

T-72 is one of the most popular tanks in the modern world. It has been produced for 40 years now, and the production still continues with over 25,000 total tanks built. It was designed with cheap mass production and maintenance in mind. It offers interesting blend of simplicity and good characteristics, and it generally follows the Soviet doctrine of focusing on quantity rather than quality of tanks. While the T-72s can be easily gathered in large numbers, they usually lose 1:1 encounters with Western tanks.

I have chosen this particular tank because it’s a great example of Cold-War era Soviet tank design, with flattened hull and small, bowl-shaped turret. The US intelligence nicknamed the turret “Dolly Parton” because its shape supposedly reminded her breasts (you are strongly advised NOT TO search for photos of Dolly Parton, for the sake of your good taste). I had two goals while building it: to test the torsion bars suspension in a lightweight model, and to see how small fully motorized tank model can I build.

As for the aesthetic side, there was a number of minor shortcomings. I wanted to properly model the distinctive shape of the turret, because Lego models of the T-72 usually have turret shaped like a slightly gnawed disc. I think I achieved that, at the cost of attaching some details to the bottom of the turret, thus increasing the gap between the turret and the hull’s upper surface. The turret also had very little space inside – so little, in fact, that the majority of the main cannon elevation system had to fit in a 2 studs wide gap.

Other than that, the central section of the main cannon’s barrel should have been slightly thicker, but the only idea that occurred to me was to wrap it in a paper of similar colour and let it pass for a sticker.  I also had the impression that the hull is slightly too tall, even though I was sure it had the right proportions. I could have remedied it easily by decreasing the suspension’s angle and thus the ground clearance, lowering the entire tank, but the large ground clearance is distinctive for the T-72. Perhaps the reason was that the side skirts started a little higher than they do in the real tank.

The T-72 is unusual in how its details are distributed: there is a lot of details on top of the hull’s rear, but almost nothing on the side skirts and above the tracks. I have added some extra details to simulate the kind of “luggage” that some tanks carry on them – in some cases it seems that the tank’s crew grabs virtually anything that comes around and attaches it to the armour.  I have also used Lego LEDs to emphasize the large number of searchlights on the turret, which is very distinctive for the T-72, and I used some Lego plants to simulate the so-called environmental camouflage, just to see the result.

The model was very simple technically. There were two PF Medium motors in the back, connected straight to the rear tension wheels. Together they provided reasonable speed and a surprisingly high torque. The were also two IR receivers in the back, and another PF Medium motor between them, used to rotate the turret. Because of how small the turret was, its entire rotation system along with the turntable was located in the hull. The central part of the hull was taken by the turntable, and the front was taken by the 8878 battery lying transversely on its side. The battery could be accessed by removing the entire glacis plate. The remaining space, which was sparse, was taken by wires and the suspension system.

This was my second tank to use torsion bars suspension – the previous one was almost 3.5 kg heavy, with nearly 0.25 kg load per road wheel, and its suspension worked perfectly. Here the suspension was very similar, except that the axles used as the torsion bars were kept at fixed angle by the toothed half-bushes and toothed connector joints. It saved some space, but it wasn’t working really well because there were gaps at the half-bushes, which I had to fill with tiny scraps of paper. The average load was less than 90 grams per road wheel, and the entire suspension was therefore very hard – it was actually difficult to notice that it works.

I was happy with how the model turned out, even though its aesthetic side had a few compromises to it. It was a good, very agile model to play with, but I think it proved too light for this kind of suspension.

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My third walking vehicle. Features 8 legs based on Theo Jansen’s walking mechanism, driven by two motors.  

Datasheet:

Completion date: 31/08/2011
Power: electric (Power Functions)
Weight: 0.492 kg
Suspension: none
Propulsion: 2 x PF Medium motor geared 1:66:1
Motors: 2 x PF Medium

I wasn’t satisfied with my previous walker which tried to adapt the Klann linkage, so I turned to something else: the Theo Jansen’s mechanism. I started by studying a so-called kinetic horse which uses Jansen’s linkage to move four legs. I recreated the linkage using 5 and 7 studs long liftarms, and I’ve been experimenting on a 4-legged walker for a while. I was trying to make it steered by articulation, but it proved to be unstable. I have then created two identical 4-legged units and connected them together. I wanted the whole walker to be steered by controlling four left and four right legs independently; I have been experimenting with a studless subtractor in the propulsion system, but it resulted in the walker being slow, large and clumsy.

Eventually, I settled for a lightweight body with two Medium motors controlled independently. I have shortened the legs, as longer legs needed longer chassis to maintain the same level of stability. I have also equipped them with rubber tips to improve traction on flat surfaces. The walker created this way turned out to be very efficient, agile and fast, even if very simple. I consider it my best walker up to date, but this is rather thanks to relying on Theo Jansen’s work than on my own solutions.

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My second walking vehicle. Features 8 legs loosely based on the Klann linkage, driven by a single motor.  

Datasheet:

Completion date: 23/08/2011
Power: electric (Power Functions)
Weight: 0.495 kg
Suspension: none
Propulsion: 1 x RC motor geared 3:1
Motors: 1 x RC

My second walker, intended to use legs with spider-like pattern of movement. I have developed a chassis that used the Klann linkage to move legs, and it walked well and fast – however, it jammed every once in a while and the legs were too fragile to support even medium loads. I have then reworked the legs design to a form that loosely follows the principles of the Klann linage, but in a simplified way. The resulting chassis was small, sturdy and worked smoothly. I have been testing it with two separate motors for propulsion, each driving four legs on one side, which could allow the walker to turn like a tank. Unfortunately, the chassis steered poorly, and proved unstable as it was impossible to keep all legs properly synchronized with two independent propulsion motors.

Eventually, I settled for just one motor, but a fast one. I have also equipped the chassis with two long arms that could be fixed in various positions, thus affecting the walker’s centre of gravity and its walking path. Under certain circumstances it could allow to make the walker turn, but much more often its movement was largely chaotic.

This was definitely not a successful walker, but still a funny build. It allowed me to observe how eight synchronized legs work when set at a number of various phases and angles. I think it wasn’t a good MOC, but it was a good lesson that hopefully would allow me to properly realize the Klann linkage in the future.

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Model of a South African MRAP vehicle. Features pendular suspension, 4×4 drive, 2-speed gearbox and lights.  

Datasheet:

Completion date: 18/08/2011
Power: electric (Power Functions)
Dimensions: length 41 studs / width 24 studs / height 22 studs
Weight: 2.074 kg
Suspension: pendular
Propulsion: 1 x PF XL geared 4.2:1 (low gear) / 2.5:1 (high gear)
Motors: 1 x PF XL, 3 x PF Medium

RG-35 4×4 is a modern small MRAP (Mine Resistant Ambush Protected) vehicle developed by BAE Systems South Africa as a smaller variant of base RG-35 6×6. It belongs to the second generation of the MRAP vehicles, which means that it combines high level of crew protection with impressive off-road capabilities. It was introduced in the first half of 2011, which means that it’s just starting to enter service, with the Canadian Army considering a massive order.

The model was built primarily to test the wheels and gear blocks from the 8110 Unimog set. It consisted of a short, fully studless chassis enclosed in a studfull body. Both axles had pendular suspension with 4 short shock absorbers on the rear, and 4 long shock absorbers on the front axle. The front axle had a Medium motor for steering integrated into it. The 8110′s set ball joints were used to attach axles to the chassis, as I expected them to support at least part of model’s weight thus reducing the friction on the driveshaft. Both axles also included differentials, as I expected them to be necessary for a vehicle with that short wheelbase. However, the presence of the differentials had a bad impact on model’s off-road capabilities.

The chassis, despite being very short and housing tall suspension modules, housed a remotely controlled 2-speed linear gearbox, a straight six piston engine with a separate Medium motor to drive it, and it even housed a motorized front winch unit until I decided to remove it to lower the model’s centre of gravity – and all of this with the right side of the hull recessed to accommodate for a spare wheel. The model had to weight at least 2 kg to be allowed to an outdoor Truck Trial race, and I achieved this weight by adding approximately 0.25 kg using weighed bricks. They were located at the very bottom of the body, thus lowering model’s centre of gravity.

The model turned out to have very soft suspension and additionally I have somehow mistaken the set-up of the gears in the drivetrain, resulting in an unusually low gear reduction. The latter rendered the model practically unable to drive outdoors, and it was eventually destroyed in an accident while I was driving it downhill. The short chassis was a disadvantage when climbing or descending, and the model tumbled forward over its front wheel and crashed.

I believe the model had a great potential, excellent ground clearance and one of the most effective chassis I’ve ever built. This potential was wasted due to my simple error in drivetrain’s construction and due to disadvantages of its short wheelbase.

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Model of a Spanish armoured personnel carrier. Features full independent suspension, 6×6 drive, 2-speed gearbox, remotely opener rear ramp, deployable tracked drone and lights.  

Datasheet:

Completion date: 14/08/2011
Power: electric (Power Functions)
Dimensions: length 56 studs / width 29 studs / height 24 studs
Weight: 2.306 kg
Suspension: full independent
Propulsion: 1 x PF XL geared 6.5:1 (low gear) / 2.3:1 (high gear)
Motors: 1 x PF XL, 3 x PF Medium, 2 x micromotor

BMR-2 is a modern Spanish armoured personnel carrier. It’s a fairly typical vehicle for its class and I have chosen it mainly for its short chassis with first and last axles steered. I was hoping it would work well in an outdoor Truck Trial race. Unfortunately, it turned out that this kind of a steering system won’t work for a vehicle of that size, weight and with these tires without differentials. I haven’t been able to build it on time and therefore I abandoned plans to try it in a race.

The model had a full independent suspension that used 8297′s set components. Axles #1 and #3 were steered through a common steering shaft, by a Medium motor geared down 9:1, with a safety clutch. All wheels were driven by a single PF XL motor through a remotely controlled 2-speed linear gearbox.

The chassis was entirely studless, with majority of internal components located above the middle axle. The body consisted mainly of plates supported by a frame of Technic bricks. This solution resulted  in an unusually low weight – something I was expecting and which prompted me to try using only one shock absorber per wheel. The suspension created this was was very soft, and even though it worked, the model displayed apparent tendency to ‘sit down’ on the third axle.

Close to the end of the building process I have realized that I can save up some internal space at the back of the model. It led me to realize an idea that followed me for a while (or was it planted?) – a small tracked drone deployed from inside. In a way, this was a MOC within a MOC, and thus: a MOCception The drone was extremely simple, built around two micromotors with chains instead tracks. The micromotors were powered and controlled by two long wires connected to a separate IR receiver inside the transporter.  The drone could be deployed once the rear ramp was opened and it could operate outside its carrier. It worked well, but due to its extremely low weight it was somewhat struggling against the wires. I have also integrated something like a simple passenger compartment into the upper hull’s surface, and it turned out to be perfectly fit for a single dwarf hamster.

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