Wilde Beast 4x4 Pickup [MOC]

[Daniel-99]

Hello everyone! I am glad to introduce you my new Lego MOC. It is called "Wilde Beast" and it is a 1:10 scale 4-wheel drive pickup truck. 

 

Technical characteristics

 

1.  1:10 scale, 1.630 kg of total weight
2.  All wheel drive with 4 x Buwizz motors powering each wheel separately
3.  2 x Geek servo for steering
4.  3S Li-Po for power
5.  RC radio + Wixy units for control
6.  Full independent suspension with customizable hardness
7.  Custom wheel hubs with metal bearings
8.  RC wheels 90 mm (12 mm hexes)
9.  Metal U-joints in the transmission
10. Robust 3D-printed steering bones
11. Positive caster angle on all wheels

 

Back to the beginning 
The main Idea behind the build was inspired by real e-cars. This cars has no gearbox, and each wheel gets connected to an e-motor independently.
I tried to replicate this principle with Lego bricks and some custom parts.

Bodywork
This car has is a 1:10 scale pick-up truck body, Though it is a bit too short for a normal pickup. The body was made to be light and it is build on the chassis with a half-stud off-set in order to make the wheels seating symmetrically in wheel arches. (It was an obligatory decision due to the positive caster angle).
There are many things that can be improved in the bodywork, but the current one perfectly satisfy my needs: it is light but make the car somewhat recognizable as a car. Hope to find white fenders to the front wheels some time!
All the driving elements are located in the lower 5 studs of the car, so it is very stable.

Suspension
Wilde Beast has a full independent suspension with positive caster, which is very unusual for pickups. Moreover it was made to be customizable for different purposes. 9L shocks connected to the lower bones of the suspension play main role. At the same time upper bones of the suspension has their own set of shocks which can be customizable! Custom wheel hubs provide a natural King-Pin Inclination.

 

Transmission
"A good transmission - is no transmission"...

This was my main philosophy for this car. The car has 4x Buwizz motors for propulsion, each motor is connected to one wheel of the car via half-axle (which uses metal U-joints). "Gear Ratio": Slow output of Buwizz motor -> 95 mm wheel. Such solution has its own positive and negative aspects.

Positive:

•   extremely low friction
•   stiffness
•   fast cornering (e-differentials)
•   High maximal speed (over 13 km/h)

Negative:

•  Too big stress on motors (a smaller wheels would work well)
•  Car does not go straight due to the difference in motors

Let me explain the last "problem" in more details. The motors used in the car are "the" same from the view-point of a lego builder. Though they are "different" from the physical view point: each motor has individual characteristics, such as resistance, max power, max rotation speed and so on... This difference can not be seen in slow models (with max speed under 7 km/h) but they became critical at speeds over 10 km/h.
As the result, car is always turning to one side and the driver need to correct the trajectory with a steering.

There are only two ways to fix this problem: either to make a mechanical balancing via differentials, or to test each motor separately, and make individual power curve to it. A steering system with build-in hygroscope might also help.

Controls
The car is controlled via RC radio. The whole system is very similar to RC car setup. 3S Li-Po is used for power, it powers controllers for driving motors (called Wixy). The controllers provide the power to Buwizz motors by a signal of receiver. The model is steered with 2 x GeekSevo, though one would be enough here.

To see a detailed description of the system, see here: 

 

Conclusion
The Wilde Beast was a great research project for me. I tried to replicate a real e-car layout and my goal was achieved.
Car is very fun to drive, but the driver needs to pay a careful attention to the road. The main problem of the car is the lack of the e-brains which would allow to calibrate the driving motors...

P.S. I will definitely make another car with same chassis on smaller wheels to reduce the load on motors.

 

[Alex Ilea]

Very cool project! I like how rugged it looks.

[2GodBDGlory]

Very cool! That chassis looks nicely engineered, and the electronics and custom parts are always interesting.

Your criteria for the bodywork make me laugh! "There are many things that can be improved in the bodywork, but the current one perfectly satisfy my needs: it is light but make the car somewhat recognizable as a car."

[Voldemort87]

Very nice chassis layout. Looks tight. Body work proportion can be improved, I think. Looks a bit flattened. 

[Daniel-99]

12 hours ago, IA creations said:

Very cool project! I like how rugged it looks.

 

6 hours ago, 2GodBDGlory said:

Very cool! That chassis looks nicely engineered, and the electronics and custom parts are always interesting.

 

5 hours ago, Voldemort87 said:

Very nice chassis layout. Looks tight. Body work proportion can be improved, I think. Looks a bit flattened. 

Thank you all! I spent a lot of efforts in the chassis and I am glad you liked it.

The body is definitely a bit flattened ;-) I tried my best to build a body over the flat chassis, but there is much to improve.