The Sabino Compound Engine

[tghs]

I take the disc brake looking thing on the crank is a type of added flywheel? are the ecentric disc split and bolted to the crank?  there are some complex angles going on between the bed and block,, looks like lots of fun..

[crueby]

This morningsaw first-swarf for the Paine engine build. Building from bottom up, so the engine bed is the first item. Here is what it will look like:


Its a fairly standard engine bed layout, with a few twists. That little ledge on the bottom of the side rails at the inner opening is something that I didn't spot at first, noticed it when going over the photos one more time the other day. Gotta love digital cameras for field work, can take LOTS of pictures knowing that they will be useful later. And no matter how many are taken, there will be at least one more view needed...
I knew from looking at the engine from the upper gallery, where you can get this sort of view:

that the two end openings were narrower than the middle one. When we got in to actually measure things, we found that not only were all three openings different widths, the cross rails themselves were different widths, the one on the left end in the photo (towards the propellor) is widest, the one on the right in the photo is the narrowest. And as is common with maring engines, the front posts are smaller and most likely were designed to be removeable to allow the crankshaft to be pulled out to the side to allow for replacing the main bearings.
On the CAD render above, there are two 'ears' sticking up on the LP end cross rail. These are where the thrust bearing assembly bolts on to take any fore/aft load from the prop shaft - that assembly is another piece that I never was able to get a good look at till we got down into the engine room.
So, given all the shapes of the rails and the size of the whole thing (4-5/8" wide, 6-3/8" long, and 1-3/32" tall), I decided to piece up the bed from six bars, to be notched together at the ends of the cross rails. Making it out of one piece would be do-able, but it would require a massive piece of bar stock to start with. Ron and I did look into getting some of these cast, but getting it 3D printed and investment cast from that is very pricey, and making our own mould would require making the master anyway. Decided it was more fun just to make it from scratch.
Given the sizes of the rails, I started with two lengths of 1/2"x1" for the two rails on the HP end, and two lengths of 5/8"x1-1/4" for the rails on the LP end. Two more longer pieces of the 5/8" bar will be used for the fore/aft side rails. First step is to thin down the cross rails to proper dimension. The bar stock is nominally 1/2" and 5/8" thick, but measurement shows that the thickness does vary slightly down the length, plus the bars have a little bit of crown to the wider sides. Not much, but just enough that getting it all to lay flat is an issue - very common to rolled bar stock that is not ground flat. Started out by drilling a couple holes near one edge that will be milled away later when shaping the cross rails, and bolting it down to a tooling plate on the mill table to take the first side down. I put in two sets of holes, so the area under the screw heads in the first location could be taken off too. That whole area will be removed in later shaping.

First one side was taken down, measurement re-checked, and then bar was flipped over to remove material on the other side. These bars were all stress relieved, so no issues with the bar warping when the first side was taken off. Here is the rest of the stack of raw bars ready for the same operation, just with different dimensions:

A bunch more milling to go to get the bars to thickness...

[crueby]

I take the disc brake looking thing on the crank is a type of added flywheel? are the ecentric disc split and bolted to the crank?  there are some complex angles going on between the bed and block,, looks like lots of fun..

That disc is around the end crank web, and does not add enough to do much as a flywheel. The rim of the disc has a row of rectangular recesses for barring the engine around.


The propellor itself is the flywheel - it is a four-blade bronze beast, four feet in diameter, with a 60" pitch. I found this picture from a news article:

The eccentrics are each in two pieces, bolted together onto the crank as you asked. There are also set screws through its hub to the shaft for adjustment.


The engine bed does have some fun curves to the cross rails, and the two round bases for the front vertical posts are angled. The main sides/top are all square to each other. The two rear post rectangular mounting plates are square to the base, so they won't be hard. The thrust bearing mounting ears will be fun to make. Down each side of the bed are rows of gusset plates - they'll be milled in to the solid bar with small end mills. Ooh, that reminds me, I wanted to order some more of the smaller ones...

[Roger B]

Looks a fun project and a good looking engine      I will be following along (or more likely trying to keep up  ) 

[crueby]

Looks a fun project and a good looking engine  I will be following along (or more likely trying to keep up  ) 

I'll trail some ropes behind the ship so you can waterski along with the build!   

[tghs]

thrust bearing ears, I know all about them... bet they have a big hook spanner to turn the engine..

[crueby]

thrust bearing ears, I know all about them... bet they have a big hook spanner to turn the engine..

Slim looks like he is well versed in adjusting the thrust bearing ears. Though it doesn't look like HE has ears...?! 




Ron and I looked for whatever bar/spanner/lever they used to bar the engine over when we were there, didn't see one.  Dave, if you see this, what did you use for that?

[ddmckee54]

Chris:

I suspect that if you look at pictures of the side frames and zoom in on the areas closest to the disc you might see that the paint will be really beat up.  That would be from sticking a pry bar into the hole in the disc and levering against the frame to turn the engine over, one hole at a time.

You can take out the starter and do the same thing on most car/truck engines with the starter ring gear on the flywheel.

Don

[crueby]

Chris:

I suspect that if you look at pictures of the side frames and zoom in on the areas closest to the disc you might see that the paint will be really beat up.  That would be from sticking a pry bar into the hole in the disc and levering against the frame to turn the engine over, one hole at a time.

You can take out the starter and do the same thing on most car/truck engines with the starter ring gear on the flywheel.

Don

Don, like this picture I just found in the ones taken on the measurement trip set?!

 

[cnr6400]

 

Maybe they can't leave the bar out in the open cause the ship is open to kids and adults....   

[crueby]

Maybe they can't leave the bar out in the open cause the ship is open to kids and adults....   

open bar should only be on the evening cruises!        

[crueby]

Yesterday afternoon got the rest of the rail blanks taken down to thickness, then this morning sent the shop elves up to the bandsaw to rough in the notch the ends of the cross rails to minimize the amount of milling needed. The ends of the cross rails will be notched into the bottom of the side frame rails.

got the four bars lined up in the mill vise, and milled the end notches to final size. The tall center section is the width of the openings in the finished engine bed. In this picture the left side is milled to size, about to do the right side.

Then drilled holes in the short end sections. The inner holes will be used to attach to the side rails. Where the blue lines are is where the end sections will be trimmed back to. The outer holes will be handy for attaching to the jig to be made/used to put the arc in the top surface.

Next will take the top surfaces down near to the height of the flat for the crank bearing caps. Going to leave a little extra height for now, and will take a finish truing pass after the frame is assembled so that the bearing cap flats are sure to be all in a line. I need to remember not to take down the arched area on the cross rail with the thrust bearing ears!

[cnr6400]

 

Nice to see the solid gold being machined!

[crueby]

Nice to see the solid gold being machined!

The elves are busy bagging it up to take to thier bank...

[crueby]

Got the flats milled in on top where the bearing caps will go, and put small notches down the sides to mark where the top of the side rails will be. That little notch marks where the arc starts that tapers the rails up to the level of the caps. The elves inspected it, and gave the parts their approval mark (looks suspiciously like a bottle-cap impression)

Next time will set up the rotary table and make a holding jig to cut the arcs, so that the cross rails look like the ones in the CAD picture: