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

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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 LEGOŽ 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 (LEGOŽ 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!


 

 

 

Play-ability
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 LEGOŽ Power functions or Sbrick modules; both being clearly described in the Building Instructions.