[ WIP ] Brushless Lego RC - 1:28 scale

[vergogneless]

Hey everyone!

(video at the end)

This is a somewhat different project from the previous one:

The previous project (the cross hot-rod) truly fulfills a need. Indeed, there is no off-road RC at the 1:24 scale, brushless, for a price around €70. It's just a dream. So, I created my own custom model within this price range. It may not compete with conventional 1:24 brushless RCs, but we're talking at least double the price, if not triple.
And honestly, for less than €70 (actually around €40 since I already had the remote), I don't think I could find anything better at a smaller scale!

Regarding this new project, it doesn't take itself too seriously, but it still means a lot to me. Being a fan of small scales, this time I wanted to replicate what already exists.
I have several 1:28 scale RCs that perform very well (drift, speed etc).
But I still wanted to see how it would turn out in Lego, especially with a brushless motor.

 

Regarding its dimensions:
• Length: 13.5cm
• Width: 9cm with wheels
• Height: approximately 4.5cm (scalable)
• Weight: 221g including the battery (scalable)

 

 

 

 

Now, let's delve into the specifications:
• A2212 1000kv Brushless Motor
• Surpass Hobby KK 25A ESC
• Gray Geek Servo 360
• Dumbo RC X6FG + X6FG receiver (with an integrated gyro!)
• 2S 400mAh battery
• Gear ratio: 1:2

I'm testing a 25A ESC for the first time; I'll see if it holds up over time and if it has enough power. The advantage is that it's lighter and even more compact.

A small novelty regarding the transmission is that I've gone with a 1:2 ratio. It seems to be the sweet spot between acceleration and top speed.

Obviously, I know it would be better with a differential, but unfortunately, I don't have the space.
I also know that 4x4 would be ideal, but it poses the same problem.

However, I do have the gyro doing half of the job, so to speak.

So, I'll make do with what I have, and no matter what, I know the final product will be fun and enjoyable to drive.

I think for the first time, I'll use the ESC programming card to optimize the power curves. At first glance, the motor is completely disproportionate to the scale and wheel size. So, there will be a little tuning challenge.

I've incorporated a makeshift suspension with a rubber band. I think it's sufficient even for outdoor use. I'll see with further testing if I really need an articulated suspension or not. Regardless, it will only run on absolutely flat surfaces.

 

 

 

I've focused my attention on the steering angle, which is particularly important for this type of vehicle.

 

 

In its current state, it doesn't really drift. At most, it slides with panache.
I don't expect much in this regard, but I know it will make up for it in driving pleasure and top speed. On that point, I'm certain it will exceed the maximum speed of its smaller siblings, which is 30km/h.

 

Regarding aesthetics, as you can see for now, it's a mess of cables, but with good management, that will be solved. It also doesn't have any design yet; I haven't decided on the bodywork. But there's potential!

 

And here's a short video of this very first version, which is bound to evolve greatly!

 

Any feedback will be greatly appreciated as always :D

Edited June 1, 2023 by vergogneless

[vergogneless]

A little update to present to you the V2 :D

 

 

 

 

 

 

 

 

It bears little resemblance to the V1, as you can see, there have been many changes and modifications.

 

Firstly, the design. It's a first draft, lacking some finishing touches and details, and there may still be further modifications.

I wonder if I should mix it with another color?

 

Regarding the control and handling. I conducted some tests outdoors and realized that the ground clearance at the front was far too low. Even on a flat road, the slightest pebble becomes a catastrophe.

To address this, I had to do some cutting and sanding. It feels like I'm creating my own parts with 3D printing! I don't think I can do any better; I really need the 2x1 connected to the steering rack.

 

 

After modifying this ground clearance, I achieved what I wanted! I now avoid almost all small rocks, and the few that don't pass through end up getting ejected from under the chassis on their own.

I'm surprised by how straight it runs (thanks to the gyroscope) with excellent acceleration. I haven't tested top speed too much, but I have already surpassed what small Wltoys models, for example, can offer.

The turning angle and tires allow for sliding on the road. It’s fun.

The driving experience is smooth and precise, as usual, I am not disappointed. There is a satisfying sense of power under the finger, especially since that power is genuinely there.

 

I'm delighted to have this little thing to take everywhere, and it works perfectly :D

Moreover, to enhance its "portability," I have ordered the new X6PM-350 from Dumbo RC, which has the same characteristics as the X6FG I am currently using but is much more compact. The only difference is that we lose about 30% of the range, but no one will say that 350 meters is not enough, especially in the Lego world!

 

 

 

As always, a video will be posted soon.

[Krxlion]

I didn't really think you can pull a decent body out of this scale, but you did! Reall great looking small vehicle ;) Regarding mixing colors, black comes really good with white, but you can go with something more unusal. The change of remote control is also a step in good direction. I feel like you can simply take it with you in small bag or something and whenever you find flat road on a walk or something, you can bring this small car out! When I wanted to go out with my MOC - Trophic, I needed to get my trekking 35L backpack, haha. :D

[vergogneless]

@Krxlion 

Thank you very much for your warm message :D

Regarding the design, indeed, it's not easy, and everything can quickly look square. But I keep discovering more techniques to make the overall look more pleasing to the eye and harmonious.

 

Yes, that's why I love small scales so much, you can even have multiple at once, lol. One for the road and another for off-road :D

 

By the way, since my last update, I made a few visual mods, and I couldn't resist making an indoor drift video at home. I'll take care of the editing and I think I'll post it today!

Honestly, it performs well in drifts, and after adjusting the ESC settings, I hope it will be even better!

 

For the big outdoor video, I will try to add some touches of orange :D

 

[vergogneless]

 

Here is the video, feel free to react :D

[vergogneless]

Hi all!

Here is the latest video showcasing all the outdoor sequences.

It's mind-blowing! It has been running for approximately 10 hours since its creation. Not a single part has broken, and nothing has budged. The only thing I have to do occasionally is tighten the front wheels because the way they are secured is not ideal for such extreme conditions.

On another note, I have finalized the design, and in the end, it will remain black as it truly embodies its DNA since the beginning.

 

The next project is already in progress, still at a 1:28 scale, but this time we are switching to 3S! It will also be my very first model equipped with ball bearings throughout :D

[pow]

small and simple. I like that!

In that scale you can easily integrate a shock absorber - getting rid of that rubber band. I build something very similar like your car last year. ...Just for inspiration.

The finished product is on rebrickable: https://reb.li/m/131895

Edited June 8, 2023 by pow
Edit link and some more Information

[vergogneless]

@pow 

Hey, thanks for your message! :)

Congratulations on your little model, it's always great to see what others are doing and the techniques they use!
By the way, I wrote to you on your thread because I had a question!

It's true that I could easily install one or even multiple conventional shock absorbers. I've already thought about it, but I really enjoy the feeling I get with the rubber band, which made me completely set aside the traditional shock absorber. I also have concerns that it might be too bouncy when I reach speeds of over 30 km/h. But it's true that I should give it a try!

However, I'm currently working on a brand-new mini trophy truck with a fully pneumatic suspension, and it's very promising. We're getting closer to a suspension with an oil bath setup.