The Sabino Compound Engine

[cnr6400]

 

[Bearcar1]

Good heavens above Chris!! Those valves are exquisite pieces in and of themselves!!! Gees, you make it look so easy and we all know that ain't right....     Simply gorgeous work you have shown us all. I will be stealing a few of your setups, thank-you.


BC1
Jim

[crueby]

Thanks Jim!  Valves like these are something I've been struggling with for years, finally getting them figured out on the last couple projects. Tough to keep them small and more than on/off adjustments, but still get flow through.

As for the setups, steal away! I've stolen (um, I mean, learned techniques) from plenty of others here!
 

[Craig DeShong]

All this piddly little stuff sucks up lots of shop time, but it is what makes a exquisite model from the mundane.  Great detail Chris.

[crueby]

All this piddly little stuff sucks up lots of shop time, but it is what makes a exquisite model from the mundane.  Great detail Chris.

Also since I really enjoy the shop time, and am not a bean counter on a schedule, the extra details are that much more fun to have in the shop!   

[crueby]

So, yesterday afternoon I got the rest of the pipework needed for timing the valves installed (still more for the final engine, but these are whats really needed to test). There is a compression fitting below the starting valve (vertical one to the left of the main valve) to allow the two sections to be installed/removed. The one leading left around the top of the engine is just set in place in the end of the valve, that one is the steam bypass. The barb fitting on top is screwed in, removeable for display.


So, a little teflon tape on the fittings to seal up the threads, added some plastic tube to a compressor fitting and pressure control valve, and things are ready to apply some pressure!

At this point the valve centering and timing of the eccentrics had just been set visually to get them close, didn't really expect it to be able to run. And it didn't, but it did snap over most of a turn:
<a href="https://www.youtube.com/watch?v=Fv2Tf0oAasw" target="_blank">http://www.youtube.com/watch?v=Fv2Tf0oAasw</a>
So, first adjustments needed were to get the valve travel centered, so they opened and closed on the same positions on both the up and down strokes of the pistons. For this adjustment, I didn't care about if the valves opened just at/after TDC or BDC, just that they opened the same amount in both directions. To get a better view of when they were opening/closing, I removed the drain valves from the cylinders and taped a bit of tissue paper over the openings, then turned the crank over by hand with low pressure. Handy way to tell which valve(s) are open when.
<a href="https://www.youtube.com/watch?v=znOONvKPl04" target="_blank">http://www.youtube.com/watch?v=znOONvKPl04</a>
With the valves centered on their travel, adjusted by moving them up and down on the valve rods, an initial check was done on the eccentrics using forward gear setting. The HP valve was pretty close, but the LP valve timing was about 15 degrees off, which is why it would stop on that first test. That was adjusted by removing the engine from the base, turning it on its side, and loosening the set screws in the eccentrics with a small hex wrench through the hole in the bottom of the eccentric follower strap, shown back when I made them. That got things a lot closer, so that the engine would actually run. Well, stumble, it has a pretty good limp still!
<a href="https://www.youtube.com/watch?v=qw0V8Yh61uM" target="_blank">http://www.youtube.com/watch?v=qw0V8Yh61uM</a>
Some more adjustments to both eccentrics, helped by the shop elves, got it better:
<a href="https://www.youtube.com/watch?v=dheblsyi4iQ" target="_blank">http://www.youtube.com/watch?v=dheblsyi4iQ</a>
A bunch more time testing/tweaking the timing, fixing one sticky spot on the LP piston gland, and one more adjustment to the HP centering, and its running much better!
<a href="https://www.youtube.com/watch?v=buMftk6N6B0" target="_blank">http://www.youtube.com/watch?v=buMftk6N6B0</a>
 
Then switched over to reverse direction, and the eccentric positions there were remarkably close, this is with no adjustments for reverse:
<a href="https://www.youtube.com/watch?v=uEvtlqP5_YU" target="_blank">http://www.youtube.com/watch?v=uEvtlqP5_YU</a>
 
Very happy to see things running finally!! Did have to put a few drops of thread locker on some screws here and there when I noticed some of the reverse linkages loosening up. All of these runs involved doing some testing with the starting valve - being a compound steam engine, running it on compressed air works but air does not expand anywhere near as much as steam does, so the pressure on the LP cylinder is lower than when on steam. So, it does like to have the starting valve cracked open a turn or so to add a little more pressure/flow into the receiver passsages. It will run with it closed, but opening it evens out the motions and speeds it up slightly.

Still some more tweaking on timing is likely to be done, but its a runner!  Still lots to do to finish up the build, more pipework on the drains, oilers, builder plate on the side, paint touchup, etc. Thanks for following along!

 

[Rick Doane]

Congratulations Chris!  Absolutely fascinating.   

Regards....Rick

[Kim]

Yes!  Congratulations!  It's so fun to see it run that first time! (Well, EVER time, but especially the first time )

It's been a long road to see it run, but you got here.  Now all you have to do is finish up all that other little stuff 

Kim

[cnr6400]

She's a runner! and a great one on air even. On steam it will likely smooth out even more. 

When you had the engine going astern-full I panicked a bit after a few seconds-  (conditioned response) - in previous lives the ship would have chewed up and spit out about 50 feet of wharf in that time! 

It's been a treat to watch your progress on this one Chris, as always. 

[propforward]

Add me to the list of admirers. What was it - 3 months ? From concept to running engine, and a darn fine and intricate model. Astounding and impressive.

[crueby]

Thanks very much for following along and the kind comments Kim/Jeff/Rick/Stuart! Its been a really fun project so far, just a little more to go. Its been more like 6 months of building, plus time last fall getting the original one measured and the CAD model/plans made. And the 50 years wanting to build it but not having the skills/tools!

Final-final work on it can't finish for a couple weeks, when the castings for the smaller elbows and tees show up from Shapeways. Should have the rest done and waiting for those final bits, in the meantime I'll get started on etching the nameplate for the side of the cylinder block and making the oilers. And relaxing out on the porch!
 

[horst.b.0]

Congratulations, Chris, it‘s a beautiful engine with all these details!
 

[Admiral_dk]

Congratulations (even if a bit belated) - very enjoyable to finally see it run     

A bit more tweaking on forward plus more running and She will be ready for a Ship / Boat (even if She never ends up in one) 

Per

[crueby]

Thanks very much Horst/Per!   


Per - hardly belated, didn't get it running and videos posted till today.
 
Spent some time this afternoon with the picture of the builder plate on the side of the engine, looking for a font and size/spacing that matches it the best. Just printed out a sheet of images on some Press-N-Peel Blue transfer film, tomorrow will get one transferred over to a piece of brass sheet and etch it - will post pics on that process afterwards.

Actually, printed it twice, first time forgot to mirror the image, needed since it is ironed onto the brass.   

[ozzie46]

Yooowwwsaa!!!! That's what I'm talking about!!!!  Congrats.

Ron