PP wheeled crawler

[Tamas Juhasz]

Nowadays I really wanted to make a crawler to have fun, and to try out what these can do with PP wheels. Those wheels were very important, you can increase the capability a lot, and another very good propertie of the PP wheel: it keeps the center of gravity low because of it's "huge" mass. This is the final version:

http://www.brickshelf.com/cgi-bin/gallery.cgi?f=509357

I built it mostly after the Hpi crawler king:

http://clodzone.com/wp-content/uploads/2009/05/hpicrawlerkingjeepwrangler2.jpg

Suspension:

The Hpi has 3 point one, so I used also that, allows extremely large rotation between the axles:

I used the swingarm from 8297 and two 9L link under. There is also an upper stabilization in the swingarm to prevent outcoming.

The wheelbase is similar to Hpi's, if it would be bigger, the ramp angle would be worse, and that's very important.

The springs are connected with links to the axles, so I get a bigger suspension travel, and the softness is changable.

Driving, steering:

A single XL motor drives, like in the real ones, and there isn't much more space to an another motor. Has a hand operated two speed gearbox, first gear with 8,333:1 ratio, second with 2,777:1:

http://www.brickshelf.com/cgi-bin/gallery.cgi?i=5560527

The steering motor is built in the front axle to be simplier and more reliable. I only had to take care not to oversteer to prevent the steering connections's damage.

Body, accessories:

Has a very simple and lightweight body, so I could keep the whole weight(1731g) under 1750g. In the front there are 3 leds, so in the dark the crawler is also functional:

..and there is a safety net in the left side, and the hungarian flag in the rear.

Driving performance:

You can see everything here:

This is the maximum, I think a TT would be better with a really strong suspension and bigger wheelbase/ground clearance. But in the obstacles seen in the video there weren't problems with it. In about the middle, a 8t gear in the left rear wheel damaged, - I changed later to a stronger teeth 8t gear - , that's the reason for the clacking sometimes.

Main attributes:

1731 g

847 piece

1. gear: 0,4 km/h

2. gear: 1 km/h

l/w/h: 377/237/220 mm

Edited August 4, 2012 by Mbmc

[Aussie BJ]

Very very nice and inspiring. Great little touches with the flags, net and exhaust. I just want one!

Brendan.

[Zerobricks]

Interesting suspesnion with links. Performance wise its great, though a bit slow.

[Kisvakond]

Nice work, Tom!

I really like:

- the two-speed gearbox: it is quite the same like on the RC cars: bottom positioned and strong

- the extra big wheel travel (thanks to the 3-link suspension)

- the Monster Truck.. eer.. Bigfoot.. eer.. RC Crawler "look-alike" (if we except from the profile/form & shape of PP-tires) & the 3-link crawler suspension is also nice!

- the lightweight body (which is possible by using the big, heavy & wide PP-tires)

- the low center of gravity is perfect (again, credit goes to the PP-tires)

- the mixing of linked-hard & spring suspension

It performs quite well, it can be clearly seen in your vid!

I think, you prove: the PP-tires really a good alternative for building even a real RC Crawler look-alike thingy, because it has many positive effect on the requirements of a crawler spec.

Well Done!

Edited August 4, 2012 by Kisvakond

[z3_2drive]

NICE! I saw the video yesterday and thought wow, that suspension is amazing! good performance for the weight and tires, Mine was just for simplicity, performance and little weight. This is what I was talking about, the geometry of the suspension has to be correct, and here my friend, it is spot-on! Those wishbone links are in line with the middle of the U-joint as they're supposed to be. Really cool model

[DLuders]

It looks awesome with those Lego Power Puller wheels and tires, and the flag is a nice touch!

[timslegos]

Looks like a very capable model indeed! The netting is a nice touch as well. I must get some of those PP wheels.

tim

[Burf2000]

Thats pretty cool!

[kieran]

Every time i look at this it gets better and better

[Tamas Juhasz]

Thanks.

The instructions for the axles is available:

http://www.brickshelf.com/cgi-bin/gallery.cgi?f=509835

(if somebody needs the BS picture downloader program, I can upload)

This crawler was the first version, the better performing V2 will be uploaded soon. I like even more the PP wheels after every ride on rocks/soil, they perform surprisingly well.

Edited August 9, 2012 by Mbmc