Thursday, 20 March 2014

ZiS 22M Halftrack

MOD of my ZiS 5 truck:
Features increased traction, new axle with turntables as joint points, and excellent suspension,  

Production of the ZiS-22 lasted from 1938 until 1940 resulting in only 200 samples built of which a small number was used during the Russo-Finish conflict of 1939/40.

 (photo from, used with permission)

LEGO Model:

Made on ZiS 5 chassis, all the vital components are the same.

Steering and suspension is the same on front axle.
Drive is different, it has faster output from XL motor, because tracks have internal reduction.

For detailed description of the chassis, suspension, cabin and cargo bed and its components, please see my ZiS 5 model.

Back axle:

Back axle has differential, and reinforces all around.
Turntables are used as a connection points to the trucks for three reasons:
1. To release drive axles of any presuure from weight of the truck
2. To have strong 4-point connection of axle and single caterpillar track
3. To allow caterpillar tracks to have infinite rotation (needed for rolling over obstacles)

This axle is extremely strong with turntables, weak point is differential, which can break the central 12 bevel gear under heavy pressure.

It took me few days for axle to make, test and implement into the chassis.
It can be removed and changed with regular axle for wheels in about 30 seconds.

Caterpillar tracks:

Tracks are made to be as real as possible.
In order to achieve perfect realistic look, they have many parts, and single track weights 370 gr.!

These red covers are, like on real one, protection of chain drive system. Yes, real halftrack has indeed chain drive, which sometimes broke and caused problems.

Final setup weight about a kilogram:

 Cargo bed:

For this version I wanted to make canvas bars, so I did it with axle and connectors and a lots of axle joiners.

The rest of the cargo bed is the same, with small modifications to be able to connect with canvas bars.

 From variations, I choose to make cargo bed version, and tractor version.

Model was tested outdoors and it performed ok, without breaking gears. 
The truck weights nearly 3.5 kg,

For best results, it should be kept and used indoors, on flat surface or on carpet. Then it can easily climb over sleepers, carpets or small obstacles.

(click to enlarge)