Large Scale Central

Magic Carpet drive, or similar

Modeling
#1

I have been looking at NWSL’s Magic Carpet drives… the only model the catalog says is currently available is the motor block style. I see they used to sell nose hung units, but not any more. Are there any other sources of nose hung drives in #1 scale?

I remember talking to a guy several years ago that got into live diesels. He said the traction motors on his unit (can’t remember the brand), worked like prototype traction motors, in that they rolled free when no current was applied. Does that ring any bells for anyone, and if so, where could I get some?

#2

i remember them.
but it is a long time ago, that i saw the last ad for them.

you being a good modeler, you might try to copy the idea from IT-Uncle, over there on mls.

#3

Hartland has a single axle drive. I think NWSL has gear boxes and you could hook your own motor to that.

#4

(http://burlrice.com/_LS_C420/3d_trucks_exploded.jpg)

(http://burlrice.com/_LS_C420/3d_trucks_dryfit.jpg)

I printed these in nylon, thinking they’d just be a prototype to see if everything would fit together, then I’d print them in steel later. After looking at them, I think they’ll almost work as the finished product. I still plan on doing the gears in brass or steel. The side frames seem stiff enough to support a loco, even if they are nylon. Now I’m just waiting on bearings and springs.

#5

In the copier world, small gearboxes and most gears are nylon. So if its the same quality of nylon, I don’t see why they wouldn’t work.

#6

My only concern with the nylon for the side frames would be cold flow over time. The continuous weight of the loco will eventually sag the nylon.

My tuppence.

Bob C.

#7

I’m guessing there is going to be a difference between injection molded nylon, versus SLS printed nylon. Printed nylon is porous, which makes me want to think it would wear quicker.

#8

Burl, I would have to agree with your thoughts. The nice part is that if the nylon fails, you have the file ready to go so you could just reprint in steel and be back in action. Nice work.

#9

(http://burlrice.com/_LS_C420/3d_trucks_assembled.jpg)

Assembling the parts reveals several issues:

  1. The springs are way too strong. OD, length are alright. May have to go with a smaller diameter wire.

  2. SLS nylon has too much flex for a final product – will have to go with steel for the frame, and lower arm. Nylon would have been nice, especially where the brass plate bolts underneath the journals (self-tapping screws vs. drilling & tapping for machine screws).

  3. The journal & the swing arm were printed separate. I’m wondering now if it wouldn’t be better to print it all as one piece. Assembly would be much easier. I was initially thinking about casting the journal in resin to get better detail.

  4. The gearbox cover (not pictured here) needs some registration tabs. Also, the gears would be much easier to assemble if they had some spacers added to them.

  5. I’m also considering making nylon spacers to gauge the distance between the inside of the wheel and the big gear. Hoping to keep trial and error fitting to a minimum.

#10

Oh but it does look nice.

#11

My bearings came in over the weekend, so now I can see how the traction motor assembly will go together. I shot for a 8:1 gear ratio. Like Ray’s WadaWorks trucks, this allows the wheels to roll freely when there is no current to the motor.