RC rock crawler (PP wheeled)

[Tamas Juhasz]

Hi again!

This is my latest crawler, firstly it looks like a V2 of my previous one, but it's a different construction:

http://www.brickshelf.com/cgi-bin/gallery.cgi?f=509876

This is more able to climb rocks, there weren't problems in those terrain stages where I tested. The suspension and driving is absolutely different in this one. I didn't copy a real RC crawlers suspension, because we have no metal parts(the Lego parts can deform), and it needed some more reliable and strong one. So the suspension solution is similar like the Unimogs torque tube, but it's a torsion one with two paralell liftarms in front and rear axle. Very reliable and simple, and provides enough equalization in terrain:

The wheelbase increased compared to my previous one, and the ground clearance is also higher thank to the V-shaped bottom. The center of gravity is pretty low, credit goes to the PP wheels, they weight together 744g. In the upper part there is only the RC unit and the very lightweight body. Stability was good, but you have to drive carefully to prevent rollover.

Two 5292 RC buggy motors drive the crawler, top speed is 0,8 km/h, so wasn't boring the test. Final reduction(i): 25:1

Each axle has a built in RC motor, it's very important, because in this way it has no reaction torque(is it an appropriate phrase?).

Bottom:

The 6L links provide the minimum ground clearance, they prevent the decrease. The springs do mostly vertical stabilization, and give flexibility to the crawler, so a take off in stairs isn't problem without body damage.

Outdoor terrain test video:

Of course, it's built with PP wheels, I think other Lego tires are unable(or much worse) for rock crawling.

Hope you like it.

Edited August 11, 2012 by Mbmc

[DLuders]

This is a very capable Lego RC Rock Crawler! The sun does not interfere with the radio control signals like it does with the Power Functions' infrared signals. Are you planning on making instructions for the axles, like you did for your Version 1 crawler?

Edited August 11, 2012 by DLuders

[Tamas Juhasz]

The sun does not interfere with the radio control signals like it does with the Power Functions' infrared signals. Are you planning on making instructions for the axles, like you did for your Version 1 crawler?

Yes, RC is much usable and comfortable. I made instructions for the whole machine, I can upload if somebody needs.

The next step will be this chassis with custom RC wheels. Now the PP wheels means the limit.

Edited August 12, 2012 by Mbmc

[DLuders]

I made instructions for the whole machine, I can upload if somebody needs.

Yes, please do!

[Tamas Juhasz]

Ok, I will upload soon.

Anyway, I really interested in what do you think about this construction. I didn't see a lot of PP wheeled crawler.

[DLuders]

The chassis construction allows for large ground clearance, and the heavy Lego "Power Puller" wheels+tires help keep the crawler's Center-of-Gravity low. The springs on the lightweight, articulated chassis helps keep those tires in contact with the ground.

[Tamas Juhasz]

The instruction is available now:

http://www.brickshelf.com/cgi-bin/gallery.cgi?f=510190

Only 94 picture, but I think it's not hard to see how to assemble. But feel free to ask me if something isn't clear. The rear axle is very similar to my previous crawler's rear axle.

If somebody needs the BS downloader program, I will try to send it. (but earlier it was unsuccesful in email, because it's a copyrighted program and an .exe)

Edited August 17, 2012 by Mbmc

[DLuders]

@ MBMC: Thanks for making the photo-sequence Building Instructions! They are very clear.

[parda]

Nice functional details in this machine!! I'm looking very close to the instructions...