Union Pacific Rotary Snow Plow 900081 – Part 3

In this week’s post, as promised last week, I’m going to share with you a bit more progress on with my UP 900081 Rotary Snow Plow kit.

A major part of a rotary snow plow is the fan at the front and for my kit not only do I want it to be functional but I also want it to look right.  And the UP 900081 has a very complex fan.

The red sections look smaller than the silver parts, however, they are the same.  Each blade has wings which fold out to alter the size of the blade.  All the red ones are folded in.  In the close up photograph below you can see the wings on blade number 6.  Blades 5 and 7 have had the wings removed.  You can also see the circular chute the snow is forced down behind the wings. The chute slopes away from the center of the fan towards the back of the fan chamber.  As the blades cut the snow it’s forced down these chutes and as each chute reaches the top of the rotation the snow is blasted out through the hole on the top of the fan chamber.

It would be very easy to simply make a flat disc and add details to the front but I wanted to replicate this detail as closely as I could, particularly the blades and the circular chutes.  3D printing gives me the ability to make this complex shape and maintain strength at a 1:160 scale.  In brass at this scale it would be a very difficult task.

The fan will be printed in one piece with a shaft at the back.  This will pass through the shell bulk head and be connected to a gear which will be driven by the motor.  The fan will also be a separate part from the main body to allow easy painting of both the fan and the fan chamber.  In the render below you can see the fan located in half of the body shell.

The exit chute is directly above the fan.  Above the exit chute will be the directional cover which will force the snow either to the left or right.  This cover will probably be made from etched brass as a 3D printed part will appear to be too thick. The actual wings on the fan haven’t been drawn yet either but I do intend to add this detail.

Because the fan is modeled fairly closely to the original you will be able to see the end of the circular chutes through the exit chute.  However in order to retain strength the circular chutes don’t go back as far as the original.  As a compromise I have added a cut out detail in the side of the fan which you will see as it rotates.

My next task, once the fan and exit chute is finished, will be to work out a reduction gear system so the motor speed is reduced in order to spin the fan at a slower speed.  And in order to do that I need to complete the power chassis and that’s something I’ll share with you in a later post.