The Tiny Brushless Cross Hot-Rod

[vergogneless]

Heyy everyone ! 

 

Allow me to introduce to you this tiny off-road-oriented hot rod.

 

 

 

 

It is an evolution of my previous model:

 

 

My primary focus was addressing the main issue of front ground clearance. On the trophy truck, it measured a mere 1 stud, resulting in rather evident problems when encountering slightly uneven surfaces.

With this new model, I have managed to attain a ground clearance of at least 2 studs throughout, and even 3 studs at the center, thanks to the negative caster angle.

It is also more compact.

The suspension system offers improved travel as well + an amazing articulation.

All of these refinements make it significantly more versatile and capable. Additionally, jumps will be more comfortable.

 

 

 

 

Regarding its dimensions:

• Length: 15cm
• Width: 7cm without wheels (11cm with wheels)
• Height: approximately 8cm
• Weight: 398g (including the battery)

Now, let us delve into the specifications:

• A2212 1000kv Brushless Motor
• Surpass Hobby KK 35A
• Gray Geek Servo 360
• Dumbo RC X6FG + mini X6FG receiver (with an integrated gyro!)
• 2S 400mAh battery
• Carbon fiber rear axle
• Gear ratio: 1:1.66

 

Please take note that I am employing a brand-new ESC, slightly pricier at 20€ instead of 10€, but it comes with numerous advantages:

• Fully ready-to-run, no need for soldering connectors.
• Smoother operation (no jerking, etc.).
• And above all, a genuine brake! It is no longer just forward or reverse; there is now a brake positioned in between. We are steadily approaching a hobby-grade RC experience.

And the final little plus:

• It is fully programmable using the 7€ programming card. I will test it later and provide feedback accordingly.

 

And the ULTIMATE final little plus:

• It is perfectly fitted for the Lego system.

 

As for the design, I believe it is subject to change; this is merely a preliminary version, as they say. I must admit, I am not particularly skilled in this realm, in general. There may be further adjustments based on real-world testing as well.

I have designed an entirely new mount for the motor to better protect the gears. I can cover it entirely from the underside with a small piece of tape.

 

 

 

 

The steering system has also undergone engineering revisions. It is the best I have ever created or seen in my current configuration. It involves cutting a steering rack to obtain a component typically only available through 3D printing.

Flexible rubber 2x1 pieces (45590) are used to continuously push it toward the gear while allowing ample clearance to avoid putting strain on any part.

The steering exhibits near-perfect precision, absolutely no play. The cap is literally locked.

 

 

 

That should cover the presentation for the most part, I believe.

 

A series of videos is, of course, planned, as usual!

 

Please do not hesitate to reach out if you have any questions or require specific clarifications.

[LegoTT]

I like this for the reference of the rc part, they are not that expensive

 

[vergogneless]

9 hours ago, LegoTT said:

I like this for the reference of the rc part, they are not that expensive

 

Indeed, a mini motor that is no larger than an XL motor once mounted, and yet is as powerful as 6 buggy motors, all for less than €6... :D

An RTR ESC for €20 (or €10 as an alternative for the DIY enthusiast)

A servo motor for €7

A battery for €7

A radio transmitter + receiver for €33 (bearing in mind that for the next project, one only needs to purchase a receiver for €7 if you wish to keep your previous model, as the same remote is retained!)

Therefore, the first brushless project costs between €63 and €73
And subsequent projects cost between €37 and €47.

[vergogneless]

I conducted the initial tests yesterday, and overall, it is highly promising.

 

However, I did identify certain issues, such as:

• Front hub loss in the event of an accident
• Increased fragility of the roof, which was only supported from behind, making it detach too easily in case of an accident

 

*I have changed the front hub, so it should no longer move, I believe. We will see with further use.

 

 

This allowed me to secure the wheels differently; the rim is now directly attached to the hub, without any "washers" between them. The support is more effective.

 

 

*I have also revamped the overall design to address the fragility issues and, hopefully, make the entire ensemble more harmonious.

 

 

 

 

 

 

I presume the rear wing may suffer, but I am willing to take the risk :D

 

As for the driving experience itself, it is incredibly exhilarating. The suspension system is optimal for this weight and scale. With the increased ground clearance at the front, I no longer fear scraping or wonder if "Is it passable or not?"

And the mind-boggling power remains unmatched. One never tires of it. Even the accelerations in a 1:1.66 ratio are seamless, thanks to the meticulously tuned power curves of the ESC right out of the factory.

Speaking of this new ESC, it allows for better power management, thus delivering superior performance. I am eagerly anticipating reaching top speeds.

 

Once again, I must emphasize the remarkable work of the gyroscope, without which all of this would not be possible. Its surgical precision makes it absolutely indispensable :D

[vergogneless]

Greetings everyone!

Big update, as I'm back with the promised video!

There have been several changes since the last publication.

Indeed, I (finally) received my little 3S 450mah 70C battery :D It's slightly larger than the previous 2S 400mah 25C battery, but the power increase is astounding.

Because of this, I decided to use it for the first time on this model. But with this power boost, I had to slightly revise the design to ensure that the whole setup could handle this power without any issues.

Firstly, I changed all four wheels. I'm using the same tires as on my Trophy Truck (43.2x28s), they are wider and have the necessary grip for off-road driving. I've truly fallen in love with them, the driving experience is far superior. They feel like better quality than the newer Lego tires!

At the same time, I widened the front and rear axles for more stability.

I also made the necessary modifications to increase the steering radius by modifying the bodywork.

Several changes and improvements have also been made to the overall design.

And finally, I modified the rear axle to switch to a 1:3 ratio, more suitable for off-road terrain. Ultimately, the power gain from the 3S battery enables reaching excellent top speeds!

 

I invite you to enjoy all of this through the video:

 

 

[FriedlS]

Very awesome! I love these compact rc cars!! Thumbs up 👍 

[vergogneless]

11 hours ago, FriedlS said:

Very awesome! I love these compact rc cars!! Thumbs up 👍 

Thank you for the encouragement! :D
I have truly found my passion with the small-scale models.

The new little one is already under construction, at a 1:28 scale