[WIP] Gravedigger - Monster Truck Chassis v1 RC with BuWizz

[TheQuoteMan]

Fellow Technic Builders,

Let me share my first serious and almost finished MOC - possible the most recognisable Monster Truck of all times, Gravedigger.

 

Firstly, let's start with the picture of the real ting, in case you are not as obsessed with Monster Trucks/Gravedigger as I am: 

 

And here my version (now with stickers) 

The idea of recreating it with Technic was what drove me back to Lego after my dark ages. Firstly I wanted to just do a simple MOD of 42005 with body and colour swap, but then we've got the Claas tires which are a perfect fit for this project, so it got bigger and bigger.

Anyway, here we are after two years of building:

2XL engines for power, geared up 3 times (one engine per axle)
2 servos for steering 
PF switch controlled by a M engine for switching from crab steering to opposite 
LEGO Lights
Weight: 1281g
Dimensions:
44 studs or 35cm long
15 studs or 12cm wide (chassis)
27 studs or 22cm wide (wheels)
32 studs or 26cm tall

Performance wise is runs 3:1 geared up XL engines powered through BuWizz which combined with low centre of gravity allows for a fun stuff like less or more controlled driving on side two wheels:

And to be seen in a video: 

 

Plus a video of the steering switch at work:

 

The model is not very mechanically realistic, e.g. it has portal axles while the monster trucks use planetary geared axles, but it is my first MOC and it was meant to be fun in outdoor, not off-road play and it is.

There is a mention of the chassis being v1 in the topic. I want to improve it and develop optimal Monster Truck chassis and have a set of bodies to replace on the top. As such, I am recreating the model in stud.io for my reference and possible instructions and the renders of the powertrain are available in links below (I don't want to overburden the post with pictures, anyone who will be interested in them will surely click a link).

Build time so far: 2 years. This is my first MOC, I know it is far from perfect (e.g no torque allowing to climb a ramp and have enough speed to make a decent jump) but is fun for me so far and overall I am happy with the result.

https://ibb.co/mVecNT
https://ibb.co/ew12p8
https://ibb.co/f8rDwo
https://ibb.co/dinWhT

I have also ordered a set of custom stickers for the details and they are on the way.

Can't wait to hear your opinions, guys as the stuff being published here humbles me with cleverness and complexity.

 

Edited July 15, 2018 by TheQuoteMan

[rathodsandeep]

Really cool - liked the turn with wheels in air. Will wait for the version with stickers

[TheQuoteMan]

Thanks rathodsandeep, I am trying to get some control over driving on two wheels. I hope that with gamepad controls it will be a bit easier, as so far 50% of the two wheeled turns end up on side/roof :P

The stickers arrived on Friday. Given that I may damage them slightly I've got two sets, to replace them when damaged. 

 

It looks much better with the stickers on, I think it is almost complete. The last thing to do is to add the visual details of fake V8 on top of the M motor in the rear

Edited July 15, 2018 by TheQuoteMan

[Aventador2004]

1 hour ago, TheQuoteMan said:

it looks much better with the stickers on, I think it is almost complete. The last thing to do is to add the visual details of fake V8 on top of the M motor in the rear

It looks really nice. Is the servo braced well.

[TheQuoteMan]

1 hour ago, Aventador2004 said:

It looks really nice. Is the servo braced well.

After draining the BuWizz from full charge to no power the servos are moved up due to the crashes/flips about a 1/8th of a stud, its barely visible. For me that's good enough.

Here are photos of how I braced
 

 

[Aventador2004]

2 hours ago, TheQuoteMan said:

Here are photos of how I braced:

They look not braced well, You should try vertical 6l beams for support.

[Meatman]

I would be concerned with those #1 connectors in the steering working themselves loose and pulling from the axle. There is no doubt a better way to do that.

Edited July 15, 2018 by Meatman

[TheQuoteMan]

3 hours ago, Aventador2004 said:

They look not braced well, You should try vertical 6l beams for support.

Have not had issues with them so far ans I've been driving it for fun of asphalt since April.

Same with the steering.

I know its not super sturdy and would not stand an offroad drive, but was never intended offroad and its my first MOC, so I will do better next time and with further evolutions of the chassis.

Actually the only flaw I has so far is sometimes the 3l pin with stopper in portal gears comes off, just in one wheel and I am not exactly sure why

Edited July 15, 2018 by TheQuoteMan

[Aventador2004]

Just now, TheQuoteMan said:

I know its not super sturdy and would not stand an offroad drive, but was never intended offroad and its my first MOC, so I will do better next time and with further evolutions of the chassis.

Yes, then again, your model. Just wanted to make sure it works.

[TheQuoteMan]

It does for now, but it's far from perfect.

This is the first rolling chassis that actually works for this MOC, I am sure it can be improved (e.g. have a proper suspension, not just almost hacked springs). Bracing servos and possible alternative steering connections will be looked into when I will be doing an improved version, when I will come up with the courage to tear it down massively or just build a next one, keeping this as point of reference.