You are looking at the popular 42000 LEGO® Technic Grand Prix Racer set MINDSTORMS®-motorized with EV3! This racer is Remote-Controllable. The result is GrandPrixRac3r! It took me roughly ~11 hours total to build and has ~900 pieces. Finally, what I have been talking about doing for so long is finally a reality. And I am happy.
GrandPrixRac3r’s drivetrain is geared down 1/1.16 for a little torque to move the heavy racer without sacrificing much speed. Two EV3 Large Motors are hard-coupled (powered together on one axle) and drive knob gears that transfer the power to the differential. The differential of course distributes power between the rear wheels. Knob wheels were used due to their extraordinary strength. CV Joints are also used between the diff and hubs. This allows the axle in between the two CV Joints to slide and adjust a little as needed when the suspension is de-pressed or idle. And as a disclaimer, the differential assembly was already present on the set. 🙂 After serious calculations, I estimated that GrandPrixRac3r drives a touch under 1 MPH. This may seem a little number, but in reality, it travels pretty decently due to its large size.
GrandPrixRac3r’s steering is seamless. It is completely streamlined-covered by the large panels. In fact, it is almost impossible to notice unless you know it’s there! Perfect fit! 🙂 The EV3 Medium Motor drives a 12z bevel gear that steers the special Technic steering rack. You can see how it steers in the additional pictures how the steering rack is used to turn the racer. It uses linkages for the job. The steering is perfect: just the right amount of speed and very good torque for turning. I decided against return-to-center steering; easy precision steering was much more convenient for the situation.
GrandPrixRac3r’s chassis is very rigid; the original set was already rigid enough, but I re-enforced it further to handle any more possible stress from the weight of the EV3 Brick and the Large Motors (the Medium Motors weren’t that much of a problem at all). Please look at all the pictures to see the rigidity and how everything fits in! Let me drop this in: as you can see, the front is structurally joined with the rear by use of interlocked beams expanding through the middle of the racer finally ending up to the suspension system, thus giving a let-go point of the shocks’ stress. I am very proud that it worked, as I encountered problems at first; which brings me to the NeXT step: GPRac3r Suspension!
GrandPrixRac3r’s suspension is a kind of racing suspension commonly known as independent suspension. This suspension is original to the set with the exception of some rear chassis-suspension tweaks to make it work properly. Because of this, GrandPrixRac3r sits a full 1-stud higher off the ground at the rear of the vehicle. Which isn’t a problem at all. I like independent suspension because it can negotiate obstacles independently! Just view to pictures to see the suspension at work.