Rockbrick

as always with these things I always wonder how to do this with lego....

8851 B-Model the original....

Now there's an idea! to be honest I was going to use the 8421 Cab but I just went all free-form - then I thought to change the title but I can't Current gearing (Fast output off the RC motor 8z->24z) is for speed - climbing ability one flat shoe only. I will change the gearing down a bit and take her outdoors soon - too heavy too I need to shed some weight

indeed it wasn't as i'd planned to make a similar chassis myself - you saved me loads of time! - my truck is something quick I made to try the chassis out - Now last night I was watching a soyuz capsule recovery in the snow in Khazakhstan - and then seeing the Yemelya Arctic Vehicles that went to Canada... made my mind wander ...

have made the photos smaller as per guidelines (800px wide) apologies....

air pressure / weight ratio is a big factor here...

"France fell in 1940 without the assistance of the Gustav Gun, so new targets were sought. Plans to use Gustav against the British fortress of Gibraltar were scrapped after General Franco refused permission to fire the gun from Spanish soil. Thus, April 1942 found the Gustav Gun emplaced outside the heavily fortified port city of Sebastopol in the Soviet Union. Under fire from Gustav and other heavy artillery, Forts Stalin, Lenin and Maxim Gorki crumbled and fell. One round from Gustav destroyed a Russion ammunition dump 100 feet below Severnaya Bay; a near miss capsized a large ship in the harbor. Gustav fired 300 rounds during the siege wearing out the original barrel in the process. Dora was set up west of Stalingrad in mid-August but hurriedly withdrawn in September to avoid capture. Gustav next appeared outside Warsaw, Poland, where it fired 30 rounds into Warsaw Ghetto during the 1944 uprising" I don't think such a machine should be glamourised in any way even though it was an engineering marvel it was designed to destroy big scale.

nice and compact and looks like lots of fun - and looks like a samurai

Recently after many years on the shelf my 8421 was looking a bit too tired (stickers all peeling, dust everywhere I couldn't reach with the duster, etc.) so I decided to take her apart and put the pieces in a laundry bag and put it through the dishwasher cold soapy rinse... (using regular hand soap ph neutral) then I cleaned all the dirty parts individually with a soft lint free cloth etc.... Anyway the plan is to rebuild 8421 and print my own new stickers (I have a sticker printer which should work well on lego) Before doing that I had always wanted to try ZBLJ's excellent Tatra Kolos Chassis... having most of the parts a quick cheap brickling order away and I used the remaining parts to make the body which ended up very volvo/kamaz looking instead of tatra but hey... The steering although correct as close as possible to the original tatra - has a lot of free play, not for precise truck trials - I had to reinforce the worm drive a bit to reduce the backlash there using the old technic worm gear cage and it handles a bit better now. The rear suspension layout is superb. perfect in every way in motion in looks and in fuinction. As it runs over small bumps all the wheels move but the body stays self levelling. Enough of the chit chat lets see some pictures, Using M-Motor for steering and RC motor for drive: Very short video:

As mad as a box of gerbils Love it!

I am using the faster ouput 8 to 24 its pretty quick but chewing up gears... On my second set already.....

Here's a couple of quick photos ... basically I used the parts from 8421 that I had just dissassembled for cleaning, came out more VOLVO/KAMAZ looking than Tatra but goes to show what a great chassis this is:

Definately prefer the front end of the original concept - the rest of the final version is possibly better with the lower wheel arches...

looks like a self levelling vesion of Sariel's landrover with the pendular suspension

tell me about it - i just took apart my old 8421 as it was dusty and I have cleaned each dirty piece individually... can't wait to make it again but my fingers hurt

love the way it flops the wheels over the bumps and if you stare at the main central line of the chassis it hardly moves... i'm not very good at body work but will try something or other soon it looks weird with no 'head'

why the two seats? one would be enough if it you could tilt it up and out a bit ?

I took apart my 8421 and borrowing some pieces from 8455 I have made this Chassis (I want to design my own cab etc..) I am using the RC motor off 8421 and M motor for steering. I will post some photos in a separate thread eventually but I would just like to say what an engineering masterpiece this is... for the scale its perfect - only thing missing is differentials but they only help inside the house - this beast is meant to be used outdoors anyway The steering although correct as close as possible to the original tatra - has a lot of free play, not for precise truck trials - perhaps I made a mistake making it too - I had to reinforce the worm drive a bit and reduce the backlash as much as possible and it handles a bit better now. The rear suspension layout is superb. perfect in every way in motion in looks and in fuinction.

in that case 8860 8865 had manual gearbox too and 853 but for me the first one with a realistic gearbox was 8880

BOOOM shake the room... that is impressive - the base is perfect - be careful with the cab design

keep it - sell it then buy 2 used ones and play them hard

its like asking why we have to learn some advanced mathematics at school when we will not use it every day (we have apps for that etc...) the point is you are excercising your brain, carving new neural paths in your brain and strengthening existing one which will help you problem solve and be a better builder/designer in the future so keep making ridiculously expensive and large MOCs !

I would imagine as they use hyrdraulic pistons to steer they have one for each side and simply re-routing the fluid will alternate between ackerman and parallel steering or just maybe they never have ackeraman to begin with?

lego know all of this and that is why if you really have a lot of parts and can reverse engineer quite well you'll only be able to do the cheaper sets 100% and what percent of your captive market would that be anyway? new parts and new techniques are always present in the larger (and even simpler sometimes) sets - unique colours etc... the mix they have to release is a careful concoction of marketing - very hard to do and lego get it right most of the time... I just took apart my 8421 for a good clean and cleaned each piece individually - *now* i appreciate why lego went studless - so much easier to keep clean...and re-clean.... before I put it back together I may have a go at some reverse engineering now I have achy fingers and 1441 parts sitting in a box...

Fine I understand now you want to ask questions here and not on the 15 page topic as its become more of a reference article - but my point is if you do read the 15 pages , you might not need to ask the question(s) in the first place as they may have been answered already in the 15 pages. still this is a great thread already with some new designs I had not seen before...