[MOC] 42150 Mad Mutt RC

[mla2]

A while ago I did various motorized versions of the 42151 Bugatti Bolide, starting with one which uses a Buwizz 3, a buggy motor and a C+ large motor.

This was a fun project and recently I got the idea to try and do the same for the smaller 42150 Monster Jam Monster Mutt Dalmatian. Initially I had the impression that it was too small to fit the Buwizz but at some point I relealized I could make it two studs wider in the middle without really changing its looks . After that things quickly came together and I had a working version, again using a Buwizz 3, a 1:1 geared buggy motor and a C+ large motor.

Unforntunately I couldn't stop myself from trying to make version with a PF servo motor for steering instead of the C+ large motor. I tried many different configurations and in the end I found a clean solution which a) offers the extra space needed by the longer C+ motor, b) allows the very large steering range needed by the PF servo motor, c) has the space for the different plug configurations (1 PF + 1 PU, or 2 PF), and d) does not require different parts to switch between versions. Quite proud of it!  This final configuration uses 90% of the original parts + 150 extra parts.

Being two studs wider meant I could also use tractor tires instead of balloon tires for the version with the C+ large motor. Also I was able to make it work with any buggy motor and not just the slim ones from Buwizz. So in the end it's quite accessible since it would work with only cheap electronics from alternative brands.

The only downside is that the center of gravity is still very high so it flips easily when cornering with high speed, even with tractor tires and being two studes wider. I looked at adding a nice set of balls of steel to the bottom of it but they seem quite light if Bricklink is right: only 24 grams a piece which I don't think is going to make a difference.

Otherwise though it's great fun to drive and super fast. In fact, it's so fast I can't make a video of it at home, I will do one later at the office.

Here's some pictures and renders. I will post free instructions on Rebrickable once the video is also done. Hope you like it any any comments or suggestions are welcome!

C+ large motor:

PF servo motor:

 

Edited February 19, 2023 by mla2

[Zerobricks]

Well done! I was sure these models were too small to be properly motorized, but you proved me wrong.

[mla2]

2 hours ago, Zerobricks said:

Well done! I was sure these models were too small to be properly motorized, but you proved me wrong.

Thanks, glad you like it. Looking forward to a motorization of another of these by you. It will probably add something crazy like 4WD no doubt

Forgot to link the .io file earlier, here it is: https://bricksafe.com/files/mla2/other/mad-mutt/Mad Mutt.io

[mla2]

I've uploaded the instructions to Rebrickable, see https://rebrickable.com/mocs/MOC-140518/mla2/42150-mad-mutt-rc

I also uploaded a short demo movie to YouTube, with a suprise ending

Enjoy!

[Daniel-99]

Rather unusual RC model. It is interesting to see how you managed to squeeze all electric components inside ;-) Though this car seems to be a little bit uncontrollable due to the fast gear and negative caster angel. Good experiment! I guess it would be cool to see two or three of RC models made from Monster Trucks racing agains each other!

[mla2]

Thanks! On the tractor tires it drives straight quite well, but the high center of gravity is a problem in fast corners and also slippery floors are a problem. On a carpet like in the video it works great but it's very fast so you need a lot of it :)

Edited March 8, 2023 by mla2

[Lixander]

Great work! If you want to continue testing, you can make the set wider, by putting the wheels more apart from the body.

It will take more parts, but it will be more stable.

[mla2]

Thanks! It's already two studs wider than the original set.