Mini 42109 TG Rally Car - RWD

[N1K0L4]

Hello 

My first LEGO RC model was the 42109 Top Gear Rally car. Back when I got it, I was only starting out with building my own stuff, so the first MODs were..., let's just say not the best quality. But the goal was clear from the start, improve the its performance. The first "ok" MOD was 2 years ago when I first got some BuWizz components. I added independent suspension on all wheels and a BuWizz motor powering the rear wheels. It was again a bit questionable build quality, and it had A LOT of slack in the steering, but it was good overall. Few years forward and I again wanted to build something under that body. Than I got an idea of miniaturizing the whole car, making it more practical and agile. 

That's how I got to this model. It's really small at only 27 x 13 x 11 studs, exceeding my expectations for size. Speed is much better now, having more than twice the power and 1:3 gearing it's able to achieve up to 10 km/h. Even though it doesn't have a differential, it's surprisingly agile on grippy surfaces, but you do have to slide the back around on slippery surfaces either it understeers.

Specifications and features:

• powered by BuWizz 3.0 Pro and 2 PF L motors geared 1:3
• steered by PU L motor
• partly openable front hood
• openable rear hatch similar to Group B rally cars
• interior with 2 seats and a steering wheel
• 3 x 3 x 2 stud space under the seats for spare parts

Instructions:
https://rebrickable.com/mocs/MOC-197632/N1K0L4/mini-42109-tg-rally-car-rwd/

Video showcasing the model:

 

You also might be wondering why have I put "RWD" in the titles. That's because I'm working on a AWD version, which is currently finished only as a digital model. When I find enough time I'll build it, but it should be done this year.

I hope you like it!

Nikola

[Aurorasaurus]

Nice model! I'm always surprised how compact you build, it really is impressive. Is this the same configuration you were driving at Buwizz gathering?

[N1K0L4]

36 minutes ago, Aurorasaurus said:

Nice model! I'm always surprised how compact you build, it really is impressive. Is this the same configuration you were driving at Buwizz gathering?

Thanks! Nope, on the gathering I had a AWD version, which isn't the same as one that is still to be built, but the body is the same.

[aFrInaTi0n]

Nice looking and very compact!

 

One little comment: for other receivers than Buwizz it may br nice to switch one motor to be able to connect the two moters om the same PF port. But would need another transfer-gear.

Render of my E-Kart MOC using this:

 

 

As it would also allow for an old PF Servo to be used as consequence

Another minor effect: the wheel axle is less stressed towards the longer distance side to the wheel

Edited October 24, 2024 by aFrInaTi0n

[N1K0L4]

1 hour ago, aFrInaTi0n said:

Nice looking and very compact!

 

One little comment: for other receivers than Buwizz it may br nice to switch one motor to be able to connect the two moters om the same PF port. But would need another transfer-gear.

Render of my E-Kart MOC using this:

 

 

As it would also allow for an old PF Servo to be used as consequence

Another minor effect: the wheel axle is less stressed towards the longer distance side to the wheel

Thanks!

I get what you mean, that was my original idea, but due to its very limited space between the wheels (only 9 studs) this was the only solution. 

If you were to use some other PF power source you'd also need to redesign the other parts of the front because of a different servo motor used.

[aFrInaTi0n]

I already thought it would be too narrow to be implemented.

[LabManager]

7 hours ago, N1K0L4 said:

Video showcasing the model:

Hi! What camera are you using for the FPV ? Can you share how you mount it on a such small car ?

[N1K0L4]

10 minutes ago, LabManager said:

Hi! What camera are you using for the FPV ? Can you share how you mount it on a such small car ?

I'm using a GoPro Hero 4 Session and some tape.

I usually use one 3D printed case with a pin hole for mounting it (I can send you the file if you want), but this time it was too complicated to integrate that.

[bruh]

I like it! how many parts does it share with 42109, other than the 3.0 and two PF motors?

[Alex Ilea]

As I said on YouTube, it is very nimble and cute. 

[N1K0L4]

30 minutes ago, bruh said:

I like it! how many parts does it share with 42109, other than the 3.0 and two PF motors?

23%, from which are most some common parts + parts for the body. You can compare it and see the details on the Rebrickable page too.

14 minutes ago, Alex Ilea said:

As I said on YouTube, it is very nimble and cute. 

Thanks ;)

Edited October 24, 2024 by N1K0L4

[2GodBDGlory]

Oh, that looks like fun!

[gyenesvi]

Really cute one, and I like the way the electronics is squeezed in such a small place, but covered so nicely with a clean body and it even has interior!

[N1K0L4]

On 10/25/2024 at 2:46 AM, 2GodBDGlory said:

Oh, that looks like fun!

It is, I'm just waiting to be able to build the AWD one, that will be even more fun :)

3 hours ago, gyenesvi said:

Really cute one, and I like the way the electronics is squeezed in such a small place, but covered so nicely with a clean body and it even has interior!

Thanks! :)

Edited October 27, 2024 by N1K0L4

[LEGO Train 12 Volts]

Totally cool ...amazing car and lovely video!

[N1K0L4]

8 hours ago, LEGO Train 12 Volts said:

Totally cool ...amazing car and lovely video!

Thank you!

[LEGO Train 12 Volts]

What I find incredible is the agility with which it drifts and the speed at which it runs!

[N1K0L4]

55 minutes ago, LEGO Train 12 Volts said:

What I find incredible is the agility with which it drifts and the speed at which it runs!

Thanks!

TBH, it really understeers on those smooth tiles which is a bit annoying. And the drifting is basically a necessity there. But on grippy surfaces it's really good.