[MOC]- Soviet Tracked Vehicle BWSM 80

[Samolot]

BWSM 80 was a prototype of a "sanitary" vehicle created by combining the DT 75 bulldozer with a GAZ 53 cab.



I've found its picture in the RU-net already a few years ago, but it waited for its turn in a folder with inspirations.
It used to be orange Porsche that I could build Zila 130 now from blue Bugatti I made Gaz 53. I wonder if a new secular tradition was created?



Three weeks of holiday in the countryside was enough to build this 60 cm model.
There were several challenges in the construction.
Weight, the model could not be too heavy because it had to rise and ride on tracks. It determined the entire construction. I could not use too many PFs, a complicated suspension, fake engine under the hood and details of the interior.

The biggest challenge arose, how to use the two PF-L to master the drive in three variants.
1 Only wheels
2 Only caterpillars
3 Wheels and tracks simultaneously
 For a good balance, the motors and Battery Pack are at the end of the vehicle. In front of the PF L motors  there is a system of three gear boxes, two of them transferring the drive from the PF l motors directly to the caterpillars or to the rear wheels (one motor ) and the front axle turning (the second motor).
The right motor, however, is attached to the second gearbox in front of the drive wheels of the caterpillars. With it, you can drive the right caterpillar "from the front" simultaneously with the wheels.
To drive left caterpillar you need, the fourth box which is placed at a 90-degree angle to the others and uses a blue 2o zgear from Bugatti. It is just transferring power from the right engine to the left caterpillar.

A completely different challenge was to make this 2.5 kilogram move efficiently on relatively short caterpillars. Obtaining the right stiffness required a lot of mass tests. The model lifts up a single PF M handle thanks to a double worm gear with toothed wheels with z 40 and two clutch z 24.

Another difficulty was the fact that when lifting, you have to compensate with the tensioning wheel changing the caterpillar tension. I got the desired effect thanks to the system which, when moving the main lifting arm by 9 studs, shifts the drive wheel axis by only 5 studs. In addition, the tension is supported by four small shock absorbers.

To make the vehicle lightweight I decided to simplify the suspension and the use of leaf springs, there are also no extras such as the fake engine under the hood or the detailed interior of the cabin.
I only added lights in the front.



I hope you like it and I look forward to your comments.
 

The whole Gallery

https://bricksafe.com/pages/samolot/bwsm-80

Lifting 1x PF M
Propulsion 2x PF L
Control 2x PF IR
Lights 1x PF LED

Weight 2.5 KG

Length 60 cm
Width 21 cm
Height 25 cm

Edited November 4, 2018 by Samolot

[jorgeopesi]

What a piece of art, I just fell in love with yours and the real one, solving the problem of the weight over the wheels would be perfect.

[Johnny1360]

Great subject matter, well executed. I'll bet the real one was a mechanical nightmare that spent more time in the garage than on the road. 

[Saberwing40k]

That's one clunky vehicle, but it is a really cool and well executed mechanism, and the color scheme is very pleasing. Getting folding tracks done is a challenge, but you did well.

[Samolot]

Thanks.