Sherp ATV
Model of a Russian off-road truck. Features 4×4 drive and unique suspension system.
Datasheet:
Completion date: 26/01/2019
Power: electric (BuWizz 2.0)
Remote control: BuWizz 2.0
Dimensions: length 29 studs / width 23 studs / height 20 studs
Weight: 1.197 kg
Suspension: sliding pillar suspension
Propulsion: 4 x PF L motor geared 1:1
Motors: 4 x PF L motor
The Sherp ATV is, due to its simplicity, a very popular subject for LEGO builders – there are literally dozens of LEGO models already in existence. The only reason I’ve decided to build my own was that it occurred to me that a LEGO model could be equipped with suspension, and I just couldn’t pass on trying out this idea.
The model, which was built in just one day, sported an unique suspension system: each wheel had a PF L motor inserted directly into it, and the motor was embedded into a suspension unit that made the entire motor and the wheel go up and down. There were 4 such units in the chassis, one per each wheel, and each was suspended on two soft long shock absorbers. All in all, the vehicle was driven by four ungeared PF L motors, which ensured maximum efficiency – there was simply no LEGO gearing where some friction could build up. The resulting model could go as fast as 7 KPH on flat terrain and proved literally unstoppable on snow – even when it drove into snow too deep to move forward, it was always able to back out under its own power. The steering was achieved as a simple skid steering, that is by difference of speeds between right and left wheels. It worked great on snow, where traction was limited, but not so well on a regular floor, where the wheels were grippy and the skid steering proved jumpy.
Because the model was built for winter conditions, I’ve chosen BuWizz 2.0 as my power supply and remote control device. This was because my experiences have shown BuWizz to be literally immune to cold, whereas the LEGO 8878 battery and regular AA batteries succumbed to it quickly. The BuWizz also provided great range outdoors, far superior to PF IR range, and proportional speed control, which was essential in controlling this model. For optimum performance, I have plugged each of the four PF L motors into a separate port on the BuWizz unit, thus taking up all ports and not leaving any option to add LEDs to the vehicle – there was room for them, but they would require their own power supply. A single BuWizz 2.0 unit handled four PF L motors without any problem, but it would run completely dry after about 30 minutes. I’ve only used the BuWizz in Fast mode, because after my experiences with my Mercedes-Benz Tankpool Racing Truck I was concerned that the Ludicrous mode wouldn’t be able to handle all four motors.
The vehicle performed amazingly well on snow and didn’t get stuck even once. It would occasionally lose a wheel, but it was always the same wheel, which probably meant faulty axle piece. The suspension worked, but due to model’s low weight it was barely of any use. At the same time, the suspension required a massive frame inside the model, taking up pretty much all space inside it, so perhaps it wasn’t worth using after all.
