After more or less coming to terms with the failure of my first MOC, I started looking around for another model I could try my hand at and eventually came across Zblj's off-road crane. I thought it was pretty cool but I still wanted to build another tow truck, so I scoured the web for something that might be a cross between Zblj's off-road crane and a wrecker. Luck was not on my side, however, so I decided to just wing it and not worry about how unrealistic my model might be.

Since I love building by trial and error but am not too keen on piecing together massive models only to have to tear them down because of some silly design flaw, I took a sort-of-modular approach. So far I've got a very rudimental rear axle, some outriggers and a distribution gearbox.

This is the rear axle (the pics suck big time as usual).

I'm not too fond of those 2x1 rubber bricks, so I took advantage of the space and used soft shock absorbers instead. The setup is basically a heavy-duty version of the Actros 42043's. Down-gearing is 3-to-1.

Nothing special about the outriggers:

And this is the heart of the truck-to-be:

This module has 5 L motors. Four are hard-coupled to provide propulsion to the vehicle; the fifth will drive the various functions through the gearbox, which is just a basic distribution system with each segment driving a function either way (42042 style). The functions should be as follows:

Right side, top to bottom:

- tow arm

- tow fork

- tow winch

- front winch

Left side, top to bottom:

- cabin tilt

- middle and rear outriggers

- rear spade outriggers (I don't think that's their real name - anyway, the same kind of outriggers on the 42038 truck)

- compressor (one-way switch, of course)

I went with L motors rather than XL ones since the former are easier to incorporate into a build and are less likely to tear apart the U- and CV-joints. The model will probably be around 100 studs long and 23 or 25 studs wide, so I expect it to weigh around 5 kg, which the four L motors should be able to handle comfortably.

To prevent excessive friction and power loss, the crane (whenever I get round to it) will have its own motor and battery box.

Hopefully I'll get the truck done by the end of the year and also be able to take some decent pictures at long last.

Edited September 2, 20168 yr by suffocation

This looks like it is going to be one big MOC. I'm slightly confused about what the compressor is going to drive if the crane has its own battery box and motor?

Hi Jim, the compressor will drive the outrigger rams.

I feel way out of my comfort zone building at this massive scale, so hopefully it'll drive me to learn some new (for me) techniques.

This'll be huge! I look forward to seeing the finished build!

Hi Jim, the compressor will drive the outrigger rams.

Ok, that makes sense... sort of! I'm probably being really stupid, but if the compressor controls the rams for the outriggers, what will the middle and rear ram function and the rear spade outrigger function do?

This is indeed going to be a massive build! Really looking forward to its progress!!! :-)

Very interesting, will be following this thread.

Why everyone is building something enormous lately?

Ok, that makes sense... sort of! I'm probably being really stupid, but if the compressor controls the rams for the outriggers, what will the middle and rear ram function and the rear spade outrigger function do?

I'm terrible at explaining stuff

The gearbox will drive the horizontal arms of the middle and rear outriggers, whereas the compressor will drive their pneumatic (vertical) rams. The rear spade outriggers (I wish I knew the exact name) don't have to extend outwards but just dig down into muddy terrain, so all I'll need there are a couple of LAs.

Oh. How cleverly simple

When I saw the first picture of the gearbox I thought the 3L axle pins were purple!

So you are all about Go BIG Or Go Home with this MOC . Anyway can't wait to see ut finished ;)