Best Of SP&S 4-6-2 #626 Project

[peteski]

Sounds like without the shim the worm was too deeply engaging the worm gear, creating additional friction.

[Chris333]

The real kitbash must have included lengthening the boiler. Either that or a whole new one.

[peteski]

The real kitbash must have included lengthening the boiler. Either that or a whole new one.

Must? Really? I always thought that kitbashing meant taking parts from multiple existing models and creating another model not representing any of the part sourcing models.  As in "bashing kits together".  Any additional modifications are optional.

[Chris333]

I was talking about the real 4-6-0 locomotive. They didn't just slap on a trailing truck, they somehow made the boiler longer:

http://www.brasstrains.com/images/products/039813/DSC00039.jpg

[superturbine]

Max,
Perhaps this question has been asked before.  I would question the benefit in having the flywheel attached to a gear head motor.  I would think that the flywheel effect would be negated by the resistant motion of the gears especially with a 4 to 1 gear box.  If that is not the case would it not be better to add tungsten weight to the engine in the fly wheels place.  What have your test shown?

Jason Smith
Tomball Locomotive Works

[Chris333]

Ideally the flywheel would be on a shaft hanging out the back of the motor. Still has some effect just not as much.

It could also be said you don't even need a flywheel with a coreless motor, but just add one because you can and there is room.

[mmagliaro]

Max,
Perhaps this question has been asked before.  I would question the benefit in having the flywheel attached to a gear head motor.  I would think that the flywheel effect would be negated by the resistant motion of the gears especially with a 4 to 1 gear box.  If that is not the case would it not be better to add tungsten weight to the engine in the fly wheels place.  What have your test shown?

Jason Smith
Tomball Locomotive Works

First, to address Peteski's observation.  Yes, the worm must have been riding too low.  I wasn't expecting that, because
it is riding in ONE of the original bearing pillow blocks.  But what I overlooked was that without BOTH pillow blocks,
it is possible for the angle of the worm shaft to be ever-so-slightly off, and that would cause part of it to ride too low.

Now, as to Jason's point.   Normally, you would be right, because a gearhead would have significant resistant motion
in the gears.   But man oh man, you
haven't seen THESE gearheads.  They are so incredibly free-wheeling that when you turn the output shaft in your fingers,
it feels like you are turning, ... AIR.  It feels like there is nothing there.  No gears, no armature, nada, zip.
There's something to be said for a precision stainless case with precision cut stainless gears.

Faulhaber quotes their gearhead efficiency as > 90%.    That means there is almost no friction at all in that thing.

[mmagliaro]

Ideally the flywheel would be on a shaft hanging out the back of the motor. Still has some effect just not as much.

It could also be said you don't even need a flywheel with a coreless motor, but just add one because you can and there is room.

YES and YES.  If there were a backshaft, that would be awesome, because the flywheel could turn 4x the speed of the output shaft.
I put it there because I could.  And I don't lose much weight because brass is a pretty darn good weight.

Some spinning mass on the shaft is always a good thing to overcome slight variations in motor and friction.

[superturbine]

That is awesome, thanks for the info!

[mike_lawyer]

Max -

I should have picked up on that when looking at the pictures.  On my K4 conversion, I mounted the worm on the gearshaft and used the two bearing blocks to hold it in place.  I will try and get some pictures up.

You are right about the motor.  It definitely is really cool with the ball bearings!

[mmagliaro]

Max -

I should have picked up on that when looking at the pictures.  On my K4 conversion, I mounted the worm on the gearshaft and used the two bearing blocks to hold it in place.  I will try and get some pictures up.

You are right about the motor.  It definitely is really cool with the ball bearings!

I thought about that.  I hope you post a picture.  I was thinking that using both pillow blocks and the original
flexi-coupler would be a great way to build it, but I think it pushes the motor back too far.  Please show us what you did!

[mmagliaro]

Here's the next installment.
Refinements on how I mounted the cylinders, and construction and mounting of the trailing truck (which turned out
to take quite a bit of work).
The trailing truck on this engine has 45" wheels, so no "stock" truck will do it.  I had to make up a set from
a diesel (not quite 45", but close, and a lot closer than 33 or 36).   The big wheels in the old Arnold and the
Con-Cor 4-6-4 (some versions) were actually too large!

Next step will be the pilot truck.

[superturbine]

Nice Max,
Of course you do more refined work on pieces I simple epoxy or superglue in place, such as the tab on the trailing truck.
My only thought-
If onlly one wheel is insulated, the axel will have curent and so will the frame, what if the insulated wheel strikes the metal minitrix trailing truck frame (at the inside or outside) in a curve or turnout.  Will it short?

Jason Smith   

[mmagliaro]

Nice Max,
Of course you do more refined work on pieces I simple epoxy or superglue in place, such as the tab on the trailing truck.
My only thought-
If onlly one wheel is insulated, the axel will have curent and so will the frame, what if the insulated wheel strikes the metal minitrix trailing truck frame (at the inside or outside) in a curve or turnout.  Will it short?

Jason Smith

Thanks Jason, for thinking about this!  No, it won't short.  The plastic tongue is the only thing on that entire trailing truck that can come into contact with any part of the engine, so even if the wheel touches the truck frame and the whole truck frame is "live", there is nothing else for it to touch.  It is also impossible for both wheels to touch the frame at the same time (when it slides all the way one way or the other, there is only one wheel that can ever touch).

[superturbine]

Ok cool,  it looks like in your post that only one wheel is insulated.  I was thinking if you have a live axel.. touching the frame and the edge of the insulated wheel touches the frame you would have a short.  But I must have miss understood.