The Sabino Compound Engine

[RReid]

It's just one of life's great feelings when all those individual parts first do their dance in unison and harmony. Congratulations!

[crueby]

It all moves very smoothly!  In both directions!  What could be better?

Kim

THIS:

After playing with it some more, um, er, testing the rotational quality, yeah, thats it!  I looked over and realized that this would be a perfect time to hook up the big propeller that I bought back when getting ready for the build!  This prop is the proper size and pitch to match the original at this scale, and I had figured that at a minimum it would be set next to the engine as a part of the display, and preferably connected up to turn with the engine.

When I bought it (found it at The Prop Shop in the UK, a foundry that specializes in scale props for display and RC), I had them drill/tap the hub for a M8x1 thread which I have taps/dies for but holding a prop like this takes special fixtures so I had them do it. Tonight I made a short adapter with a M8 threaded post and drilled/tapped for the screw pattern to match the end of the crankshaft. Really sets off the model! Right now there is no set screw or loctite so rotating it one way is fine, other way it unscrews, but that can be added later. I'll probably make a simple disk to thread on in place of it for use in hand-turning the engine during testing and valve timing, to minimize the chance of cutting a shop elf (or me) in half - those blades are not real sharp but enough to do damage when spinning fast.

This gives the engine a good sense of scale to the ship - as I recall its a 48" prop with 60" pitch on the real ship. It would not be anywhere near this close to the engine, there is a long extended shaft running back to the stuffing box through the sternpost, but at this scale that would take up a very long shelf to duplicate! So, I'll settle for this Binford 6000 Blend-O-Matic version.

 

[crueby]

It's just one of life's great feelings when all those individual parts first do their dance in unison and harmony. Congratulations!

And so much fun to just sit there and spin it round and round, grinning!   

[RReid]

It would not be anywhere near this close to the engine, there is a long extended shaft running back to the stuffing box through the sternpost, but at this scale that would take up a very long shelf to duplicate!

In Model Railroading that sort of compromise is referred to as "selective compression".

[crueby]

It would not be anywhere near this close to the engine, there is a long extended shaft running back to the stuffing box through the sternpost, but at this scale that would take up a very long shelf to duplicate!

In Model Railroading that sort of compromise is referred to as "selective compression".

Great terminology, that makes sense on things like rail layouts (and models like this).   

[steam guy willy]

Hi "C"  looking really good,,   a great feat of your engineering skills , Lovely workmanship ...and very shipshape as we say over the pond ?!!!

"W"

[crueby]

Hi "C"  looking really good,,   a great feat of your engineering skills , Lovely workmanship ...and very shipshape as we say over the pond ?!!!

"W"

Thanks Willy!   

[Kim]

It all moves very smoothly!  In both directions!  What could be better?

Kim

THIS:

You're right! That's even MORE cool! 

This gives the engine a good sense of scale to the ship - as I recall its a 48" prop with 60" pitch on the real ship. It would not be anywhere near this close to the engine, there is a long extended shaft running back to the stuffing box through the sternpost, but at this scale that would take up a very long shelf to duplicate! So, I'll settle for this Binford 6000 Blend-O-Matic version.

I thought it was the Acme 6000 Blend-O-Matic?  You should check on that 

Kim

[derekwarner]

Chris......

That propeller in asll it's beauty defies visual understanding  ...I do understand steam propellers have an over square [pitch greater than diameter] and a proportionate bore to stroke relationship 

The difficulty I have is the M8x1 mounting 

What is the diameter of the engine output shaft? or the crank pin journal size?.........I sort of assumed these to be somewhere about 20 mm diameter or ~~ 3/4" diameter

Derek

[john mills]

the engine and propellor look really good.the propellor is nice shape.The edge not that sharp but would still hurt if you bump yourself on it.
They can be difficult to hold for machining.I had a 20"dia propellor that i made pattern for to the original specks.it sat in the store for 12 months then on day machine this so it can be installed so they can use it at 6 pm it was for a quench tank for heat treatment.
the face comes  flate to the edge  .some time latter a fitter did some work were it was taken out.he thought the edge was too sharp
so he put a big chamfer on it.
   John

[crueby]

Chris......

That propeller in asll it's beauty defies visual understanding  ...I do understand steam propellers have an over square [pitch greater than diameter] and a proportionate bore to stroke relationship 

The difficulty I have is the M8x1 mounting 

What is the diameter of the engine output shaft? or the crank pin journal size?.........I sort of assumed these to be somewhere about 20 mm diameter or ~~ 3/4" diameter

Derek

Hi Derek,
The M8x1 is the thread I had them put in the hub of the model propeller, not the size of the original shaft end. I picked M8 since its a size I have taps/dies for. So, that thread is what I put on the little adapter screwed to the end flange on the crankshaft so I could bolt on the prop, its not part of the model proper.
Chris

[crueby]

This should clarify things on the propeller mount, a picture of the adapter to go from the flange on the end of the crankshaft to the M8x1 thread that was on the hub of the prop when I bought it. This is NOT a scale version of how the actual prop attached on the real ship.

[crueby]

And the only close picture I was able to find of the real prop, gives a good idea of the size with the guy working on it, I think he was removing barnacles or other critters from the surface of it.

[crueby]

To make it safer and more comfortable to spin the crankshaft over by hand, this morning I took an offcut of brass that was about the same weight as the prop and threaded it to also fir the shaft, along with a countersunk set screw to keep it from spinning off.


Also drilled/tapped the prop hub for a set screw - did that on the drill press with some blocks of wood to help hold it in place - tough shape to hold since it is too tall for the vise on the drill press to reach the hub.

That should work out well.

So, whats next? Hmmm, there is still the grease cup fittings for the eccentrics and con rods, but I think I'll leave those for now, till after the cylinders/pistons/valves are done, they are small pieces that could be damaged with all the handling/adjusting to come for the valves. That means it may be time to start hogging down the big bars of 1144 Stressproof steel for the cylinders!?  I can do the initial bulk removal and squaring up with the bandsaw, then work out the holding plates/jigs for shaping them. Ummmm, better reverse that and work out the holding first in case its easier to get bollt holes drilled on the full bars....

Time to consult the brainy elf, Elfbert Elfstein!   

[cnr6400]

That shop elf looks just like.........     HEY!   

"do a jig or the errors will be big" as one of my tool design / tool making mentors used to say 40 odd years ago.   (he used a different word than "errors" but this is a family show)