CPT (Cone Penetration Test) Truck 4WD (2020)


Building instructions (PDF):
(675 pages)

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Example instructions (PDF):

Parts Inventory:
(3.693 parts)

'How does it work' video:

4WD driven truck with tracks for off-road support and front/rear LED lights. Full remote controlled by LEGO® Power Functions or Sbrick modules.

These trucks are not very frequently seen and used for soil investigation of ground surface layers by pushing cones - with measure instruments - into the ground. As investigation is mostly done in rough terrain, the trucks are equipped with a track system that raises the truck - having all wheels cleared of the ground - so the truck can crawl.

I expected not that many difficulties in designing this model, however, that turned out otherwise. The track system leaves hardly not space for the truck chassis itself; the chassis between the front and rear wheels is only 3 till 5 studs wide! To design a sturdy chassis within these dimensions was a real challenge! Especially, as the truck is 4WD, the drive-trains to the front and rear wheels needed to fit in, together with a central differential. The model is powered with 2 PF XL motors for driving and a PF Servo motor for steering.

Raising the truck is done with 4 PF Linear Actuators. As the first tests showed a 'wobbling truck' during crawling, because the PF Linear Actuators do have some horizontal slack. An additional reinforcement was needed to prevent this by using a gear-rack housing (part 18940). Not a straight forward design either.

Finally, I managed to have the cabin tilting functionality powered by a single PF L-motor. And, last but not least, the model has front and rear LED lights that can be turned on/off with a switch located aside the shelter. And of course a shelter door that unveils a folding ladder.













The technic specifications of the 'CPT Truck' are:
* Full remote controlled (LEGO® PF or Sbrick modules)
* Steering (PF Servo motor)
* 4WD, differential unit on front and rear axle, central differential,
  powered by 2 PF XL-motors
* Working V8 engine with 3 fans
* Independent powered tracks, by 2 PF L-motors
* Track unit raised/lowered by 4 PF Linear Actuators and PF L-motor
* Automated cabin tilting by PF L-motor
* Front and rear LED lights, manually switched on/off

Non-technic functions are:
* Cabin door open & close
* Seats can be folded; to unfold a sleeping bed in the cabin
* Raise-able wind deflector
* Cabin grille open & close for mini fans access
* Shelter with door and folding ladder



Details applied:
* Cabin interior with seats and dashboard, and coffee machine
* Fuel tanks
* 4 Spotlights, flashlights, horns and airco-unit on cabin roof
* Fire Extinguisher and exhaust pipes
* Air compressors behind the front wheels


The dimensions of the CPT Truck:
* Length: 51 cm
* Width: 15,5 cm
* Height: 23,5 cm / 25,5cm when raised
* Weight: 4 kg

* Total number of parts: 3.693

Photo-shoot (The Netherlands):
* Donkereindse Bos, Wilnes


























Technical inside (cut-away render):
The first 3 renders are made within Stud.io. Last render is the most outstanding one, made again by Blakbird!




With 6 remote controlled functions, the CPT Truck offers many hours of play, even off-road.

And, the model is able to be used with LEGO® Power functions or Sbrick modules; both being clearly described in the Building Instructions.







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