Author Topic: Corliss Engine Model (Read 27347 times)

Captain Jerry · « **on:** August 01, 2012, 03:55:06 AM »

My subconscious keeps whispering the word "Corliss Engine". These were the giants that made steam engines more efficient and kicked the industrial revolution into high gear. They are easily recognized by the complicated linkage that controlled the four separate intake and exhaust valves on each cylinder using a wrist plate on the side of the cylinder.

Has anyone designed or built a Corliss Engine model with cylinder dimensions of 3/4" bore x 1" stroke or smaller? Or can anyone point me toward plans for a slightly larger engine that could be scalled down?

Jerry

sbwhart · « **Reply #1 on:** August 01, 2012, 07:35:31 AM »

Jerry

I've had an ankering to do a Corless about that size, but keep getting put off at the small size the valve trips would have to be the only way I can think of getting round the problem is the have the valve trips over scale.

Good luck with your quest.

I have some full size info if that would be of help.

Stew

Jasonb · « **Reply #2 on:** August 01, 2012, 07:47:31 AM »

Anthony mount has a new corelis design which will be in EIM, not sure of teh bore but possibly a bit larger at 1" to 1.25" though most of his engines can be scaled up or down and its vertually all fabricated. Bruce Eng will have the plans

http://modelengineeringwebsite.com/Guildford_2012.html#2

Jo · « **Reply #3 on:** August 01, 2012, 08:32:24 AM »

Hi Jerry,

I am currently building a Cross Compound version of Arnold Throp's Corliss engine:

It is a big model and very heavy (there is also a four cylinder version of this engine on the plans

). This is the progress to date on my engine:

.

Her HP cylinder is 1 1/8" bore, 3 7/8" long. Arnold when he wrote up this engine, justified why he had built this engine so large by saying that the problems of making a smaller one and getting to to work can be severe, for instance the steam ports on my engine are only 1/32" wide!!!! The same argument was given to me a couple of weeks ago when I discussed the size of Anthony Mount's new engine with him.

Coles also do a set of castings for a Corliss that was documented in Live Steam.

I am not sure of the cylinder size for her, I would have to look it up at home.

Jo

ausdier · « **Reply #4 on:** August 01, 2012, 01:17:51 PM »

Here is one I have nearly finished drawing.
It has a 1-3/8" bore and a 3" stroke.
It comes from a series by Charles Heckel in the 1938 "The Model Craftsman"

Captain Jerry · « **Reply #5 on:** August 01, 2012, 03:41:30 PM »

Ausdier, Jo and Jason,

Thanks for the responses and the links. Those beautiful models and the obvious skills of the makers make it clear that this kind of model could be a lifetime project for a much younger man than me.

Stew

Scale...That is the problem, not to mention the number of fiddly pieces at any scale. Neither my equipment nor my shop are large enough to build an engine with fully functional valve gear at a size that I can see. I have been modeling the mechanics of this in Alibre' and it is clear that even if I could produce the pieces at the microscopic sizes necessary, they would not have the strength to perform.

I am thinking that the closest that I could come to a working engine at this size is to ignore some of the finer points of the design and produce a simulated version with lots of compromises, sort of an Elmer Verburg approach. I would have to design a trip mechanism or ignore it completely and just do an engine with four rotary valves and no trips. That might be enough of a challenge for me.

I'll keep thinking about this so I would appreciate any suggestions or advice.

Jerry

arnoldb · « **Reply #6 on:** August 01, 2012, 04:07:02 PM »

Cap, I've also been harboring some ideas about this one... for quite a while.

Like you, I've also come to the conclusion that for a small one, some of the details will have to be dropped, and an Elmer-like design will work well with barstock.

The porting through the cylinder block could be tricky to figure out.
One option would be to make it from two pieces of brass - so that the steam passages can be milled on top and a block soldered over to cover them again.
Alternatively, one could drill them all and use plugs like Elmer did frequently to seal up the unnecessary holes. Then the block could be made from a single block of just about any material.

I don't think making the rotary valves will be too much of a problem.

Simplifying the valve gear itself and getting that to work might be the most difficult part; and I'd have to agree that it might be feasible to completely ignore the trips (or just fit optional dummy ones) for a small scale version.

Kind regards, Arnold

sbwhart · « **Reply #7 on:** August 01, 2012, 04:57:54 PM »

Jo

That looks a wonderful engine.

Ausdier

They look very nice designs well drawn up I'll just have to get to grips with 3D one day trouble is I'd rather spend the in the shop cutting emtel than learning how to 3D

Same as you guys I came to the conclusion that the best way for a small size corless would be to fudge it, with a simplified version, but that kind of takes the magic away from the system.

I saw a model by Neil Carney of a Corless pumping engine at an exhibition that looked like it had a working Coreless next time I meet Neil I'll ask him how he made the valve gear.

Stew

Jo · « **Reply #8 on:** August 01, 2012, 07:21:33 PM »

Just got home and dug out the Cole's design:

She has a 1 7/8" bore, but her ports are a massive 1/16", so I reckon you could build her half scale.

Jo

Captain Jerry · « **Reply #9 on:** August 01, 2012, 07:27:31 PM »

The more I think about this it becomes clear that for an air operated engine with no expansion, early cut-off is not important and could not be used to govern speed so there is no need to spend time on that part of the design. If a working governor is to be fitted, it will have to be of the throttle control type but may be just ornamental. I guess the trips will just be dummy or left as a footnote.

At the moment, I am favoring a one piece aluminum cylinder block with drilled passages and since I am going to simplify the valve linkage, I think I will keep it on the small side, 5/8" bore x 1 1/8" stroke.

I'll try to post a preliminary model of the cylinder tonight.

Jerry

Captain Jerry · « **Reply #10 on:** August 01, 2012, 07:30:22 PM »

Really, Jo. Half scale of a massive 1/16" port, becomes a miniscule 1/32" port. What do you cut that with?

Jerry

Jo · « **Reply #11 on:** August 01, 2012, 07:32:08 PM »

The same cutter I am going to use on my engine to cut the ports

Jo

Captain Jerry · « **Reply #12 on:** August 01, 2012, 09:13:38 PM »

This is a section view through the cylinder block

. It presents no production problems that I can see. Another option would be to have the main steam and exhaust galleries milled as closed end slots from top and bottom and sealed with a bolt on plate, much like Arnolds idea except the block is only one piece. That might be better than the drilled galleries that are shown which will have to be sealed at the ends which might interfere with the cylinder heads.

Jerry

steamer · « **Reply #13 on:** August 01, 2012, 10:38:28 PM »

it can be done........

http://craftsmanshipmuseum.com/images/Corliss1.JPG

By Jerry Keiffer....

ausdier · « **Reply #14 on:** August 02, 2012, 05:21:47 AM »

Here is some what of an idea I had as how to do accurate ports for the main cylinder.
Machining the ends and soldering the blocks in first.
Next machine the valve ports.
Then the bore for the cylinder.
Machine the cylinder and solder in place.
I hope the pictures are some help.

Captain Jerry · « **Reply #15 on:** August 02, 2012, 06:47:22 AM »

Ausdier

That looks very good to me and is probably closer to full size practice than my simplified approach. I sure hope you build it and let us watch here. I'll be in the front row of observers.

For my simplified design, it looks like milling the steam and exhaust galleries from the top (and bottom) and covering with top and bottom plates will be better than the first approach that I showed. Like this:

I'm still looking at options but I think I can make this work:

Jerry

Jasonb · « **Reply #16 on:** August 02, 2012, 07:27:31 AM »

If you look back at that picture I posted of Anthony Mounts engien its easy to see how that was fabricated. Rather than having a rectangular cylinder block each valve looks to have been machined from round bar, ports cut/drilled in the main cylinder and then the 4 cylindrical valve blocks soldered on

Captain Jerry · « **Reply #17 on:** August 02, 2012, 07:57:10 AM »

Jason

I have looked at that picture that you posted until my eyes crossed. In addition to the unique cylinder fabrication there are lots of unusual features. The usual wrist plate expected on a Corliss engine is replaced with very long link rods that reach from the crankshaft to the cylinder and the governor seems to work on the mechanism at the crankshaft end. There are fewer fiddly pieces at the valve but the control mechanism is impossible for me to work out.

Jerry

Jo · « **Reply #18 on:** August 02, 2012, 09:46:44 AM »

Jerry,

There are as many ways in which the Corliss valve trip was implemented as there were manufacturers, I assume it was all to do with avoiding patents. My model engine has the Musgrave's trip gear:

Fundamentally they all do the same thing.

Jo

arnoldb · « **Reply #19 on:** August 02, 2012, 03:53:06 PM »

Jerry, I like that cylinder block

- pretty much what I had in mind.

To throw some more fat in the fire, here is more detail on the Corliss - might be worth a bit of a review.

Jo, thanks for posting the Mustgrave trip gear; first time I've seen that one

. Looks like it uses separate exhaust and steam eccentrics ?

Kind regards, Arnold

mklotz · « **Reply #20 on:** August 02, 2012, 04:03:50 PM »

Arnold,

When I click on your link I get an Oklahoma bridges error page.

arnoldb · « **Reply #21 on:** August 02, 2012, 04:10:49 PM »

Thanks Marv - I fixed the link.

Kind regards, Arnold

lazylathe · « **Reply #22 on:** August 02, 2012, 04:33:27 PM »

No too hijack the thread or anything...
I was recently on holiday and they had this giant steam engine on the property.
I think it is a Corliss but am not sure?

I have attached a small pic of it.

Andrew

ausdier · « **Reply #23 on:** August 02, 2012, 05:23:27 PM »

Sure is Andrew.

PS thanks to everyone who likes my models.

If someone needs a bit of help with design work before making chips I may be able to help.

Captain Jerry · « **Reply #24 on:** August 02, 2012, 05:27:36 PM »

Arnold,

That is worth more that a bit of revue.

I'll burn the midnight oil for a while trying to digest it. It is exactly what I was trying to uncover when I started this thread. Thanks for the link.

Jerry

Captain Jerry · « **Reply #25 on:** August 02, 2012, 05:28:23 PM »

Thank for the picture, Andrew. Not a hijack at all. This is not a build log, since I have not even decided if or when I can attempt a build. This is just a general discussion of all things related to Corliss engines hoping to get a better grip on the basics. Any and all contributions are welcome. Bye the way, that is a nice picture of a Corliss. What kind of work was it doing. Engines that have been worked hard in exposed conditions like that have a very different appeal from the museum displays. I like both.

Jerry

Captain Jerry · « **Reply #26 on:** August 02, 2012, 05:38:39 PM »

Quote from: arnoldb on August 02, 2012, 03:53:06 PM

Jerry, I like that cylinder block - pretty much what I had in mind.

Kind regards, Arnold

Thanks for the tip, Arnold. It is an approach that I had not considered and is much better that my first approach. I will continue to work on this concept and fiddle with dimensions before any chips fly.

Jerry

lazylathe · « **Reply #27 on:** August 02, 2012, 05:58:51 PM »

Thanks Jerry!

If i had known about this thread three weeks ago i would have taken better pics....

Anyway here are some more with an explanation of what the engine did.

And one of me for scale reference...
I am right about 6' 3".

Andrew

Captain Jerry · « **Reply #28 on:** August 05, 2012, 06:43:01 AM »

So I spent more than a few hours with this and I think I have a workable design that is simple enough for me to attempt. The valve gear does not implement trips and I have not designed a governor as yet but both might be revisited at some point. I also need to add a base to support the cylinder and an outboard bearing stand.

I'll start looking for material but I'm taking a trip to Alaska next week so I probably won't get underway before September.

Jerry

Captain Jerry · « **Reply #29 on:** August 05, 2012, 03:22:52 PM »

Here is an animation. Let me know if the link does not work.

http://screencast.com/t/9jkdTYcnyn

Jerry 383

arnoldb · « **Reply #30 on:** August 06, 2012, 09:39:20 AM »

Thanks for the animation Jerry.

You've now thoroughly wet the appetite

Kind regards, Arnold

steamer · « **Reply #31 on:** August 06, 2012, 11:51:37 AM »

I like it Jerry! When ya starting?

Dave

Captain Jerry · « **Reply #32 on:** August 06, 2012, 11:08:51 PM »

I should be through with the design changes soon. The geometry of the valve timing and the wrist plate are an interesting challenge. This is what It looks like now:

The fiddly bits around even this simplified version might be a challenge, so this is what I fiddled with in the shop today. The holes are 3/32" spaced .56". I've seen better and I've done worse.

Jerry

steamer · « **Reply #33 on:** August 07, 2012, 03:04:21 AM »

That'll work!

Dave

Captain Jerry · « **Reply #34 on:** August 07, 2012, 11:43:44 PM »

I keep wasting my time refining the design for this engine but with no plans to work with, I am afraid that I will paint myself into a corner. The problem that I hit on today was how to adjust the valve timing. I full size, this would be possible in one of two ways. Adjusting the length of the link between the wrist plate with threaded rod ends ( one with LH thread ) or rotating the lever arm on the valve shaft relative to the valve edge.

The first method is out because of the size of the link, and I don't like the second because I think the arm would work lose unless it is fixed permanently. And that brings up another problem. If the lever arm is fixed permanently to the shaft ( solder or locktite ) how can the valve bonnet which acts as a retainer get installed?

I am open to suggestions.

Jerry

sbwhart · « **Reply #35 on:** August 08, 2012, 07:45:05 AM »

Quote from: Captain Jerry on August 07, 2012, 11:43:44 PM

I keep wasting my time refining the design for this engine but with no plans to work with, I am afraid that I will paint myself into a corner. The problem that I hit on today was how to adjust the valve timing. I full size, this would be possible in one of two ways. Adjusting the length of the link between the wrist plate with threaded rod ends ( one with LH thread ) or rotating the lever arm on the valve shaft relative to the valve edge.

Jerry

Jerry I've found that when you get to this stage with a design its better to start to build it as i find that these sort of irritating little problem you see on a drawing become more solvable when you've got a few solid parts arround you, quite often the answer becomes extremely obvious.

Great looking engine you've got on the board, looking forward to the build.

Stew

steamer · « **Reply #36 on:** August 08, 2012, 10:30:23 AM »

Stews comments resonate....I was thinking though if you make 1 link you could adjust, like the side rods on a model locomotive...you could find the correct length for each link in turn and build matched link accordingly. Clearly this adjustable link would be a piece of tooling, and not a part of the model...but it might allow you to experiment......just a thought.

Dave

Jo · « **Reply #37 on:** August 08, 2012, 12:47:43 PM »

The link doesn't look that small

, I cannot see why you cannot make them adjustable. On my Stephanie the barrelled adjustable radius links are 5/64" at the widest point of the barrelling, 10BA where they go into the rod ends. Other than the length most of the other dimension look remarkably similar.

Jo

Maryak · « **Reply #38 on:** August 08, 2012, 01:28:25 PM »

CJ,

Why not make the links like a mast stay turnbuckle, fine adjustment and lockable.

Best Regards
Bob

Captain Jerry · « **Reply #39 on:** August 08, 2012, 08:56:46 PM »

Stew, I think you are right. Its almost time to start. But I can't do it here. This is just for 20 questions and for building up courage to actually start. I leave Monday for two weeks in Alaska so I'm sort of putting off the actual start until I get back. That doesn't mean I can't experiment with a part or two.

Dave, I get what you are saying about using one link as a trial part (even if it is ugly) and that might work for a rough start but until all four valves are working the engine can't be run for fine tuning. I may have a better way.

Jo, thanks for suggesting that I have skills that match yours but that is only a distant dream. Here in the world of rank amateur where I live, I need a solution that I can complete 4 times that look alike. I don't want the success of this project to depend on that happening.

Bob, a nice barrel style turnbuckle is exactly what is called for. I have a couple of six inch stainless ones in my spares locker left over from cruising days but that would mean building an engine with a 12 foot diameter flywheel to match the scale and my lathe won't handle that. At the scale I'm going to build, I would be happy if I could produce a good non-working replica.

I've got great-grand-daughter duties today, but tomorrow I'm going to see if this will work.

The crank arm and pin at the end can be a permanent assembly. The outer sleeve, with the valve edges, can be rotated to any position and locked with the SHCS in the end. All four valves can be made to the same design and set up as required at assembly. The SHCS will be covered with the bonnet on the back side of the cylinder block. Of course it is not to scale or contemporary practice.

Jerry

Captain Jerry · « **Reply #40 on:** August 10, 2012, 01:23:54 AM »

How's this?

I think this will work out fine. The valve timing is easily adjustable and the adjustment should be reliable, with no creep. I don't think there is anything else that should cause any problem.

I will be back from vacation in two weeks and the construction of this engine will begin in a new thread in the "work-in-progress."

Jerry

rleete · « **Reply #41 on:** August 10, 2012, 01:26:28 AM »

Quote from: Captain Jerry on August 10, 2012, 01:23:54 AM

I don't think there is anything else that should cause any problem.

Really tempting the fates posting that!

Jo · « **Reply #42 on:** August 10, 2012, 09:55:22 AM »

I am holding my breath waiting to know how wide the valve ports are

.

Jo

Jasonb · « **Reply #43 on:** August 10, 2012, 10:20:15 AM »

Do you think the valve spindle needs some form of seal, a small O ring and groove would probably be the easiest.

J

steamer · « **Reply #44 on:** August 10, 2012, 10:25:42 AM »

Quote from: Jasonb on August 10, 2012, 10:20:15 AM

Do you think the valve spindle needs some form of seal, a small O ring and groove would probably be the easiest.

J

Yes....

Dave

Jo · « **Reply #45 on:** August 10, 2012, 10:51:34 AM »

My Throp designed corliss engine has O ring seals.

Jo

Captain Jerry · « **Reply #46 on:** August 10, 2012, 04:01:03 PM »

Jason and Dave

I have been thinking of seals. O-rings maybe:

But I would be happier if I could find 1/4" OD with 1/32" cross section. Then I wouldn't have to groove the inner shaft. I may use graphite packing.

Jerry

Captain Jerry · « **Reply #47 on:** August 10, 2012, 04:11:26 PM »

Jo

The valve bore will be connected to the cylinder bore by three or four 1/16" holes. In the following drawings, the valve edge should open about .045" across the width of .375". That should be plenty, don't you think? In the second drawing, upper right valve and the lower left valves are full open (the piston should be at mid-stroke)

Jerry

Jo · « **Reply #48 on:** August 10, 2012, 05:30:21 PM »

Should be plenty,

but you are loosing that beautiful sharp cut off of the Corliss design . But I won't tell anyone if you don't

.

Jo

Captain Jerry · « **Reply #49 on:** August 10, 2012, 06:29:52 PM »

Jo

I really wanted to experiment with full working Corliss quick cutoff but after extensive research, the fuel savings just don't justify the effort. I may have to reconsider if fuel continues it upward spiral.

Jerry

arnoldb · « **Reply #50 on:** August 10, 2012, 06:52:14 PM »

Quote

the fuel savings just don't justify the effort. I may have to reconsider if fuel continues it upward spiral.

Jerry, on this small scale you might just be able to get away without any seals at all if you made the valve a good fit in it's bore and use thick oil or even a light grease when assembling it. I know that's taking the ?ber simplistic way, so that would depend entirely on you.

A really worthless N$0.02

Kind regards, Arnold

Captain Jerry · « **Reply #51 on:** August 10, 2012, 11:58:28 PM »

I'll start with ?ber, Arnold.

May be stick with it.

Jerry

Captain Jerry · « **Reply #52 on:** September 02, 2012, 01:43:09 AM »

OK! Enough procrastination. I'm ready to start building something. I said I would start in September so here goes. I'm going to start a new thread in "Work in Progress". The engine will not be a full working Corliss design but it has a historical precedent, properly known as a "Four Valve Non-Releasing Steam engine". I hope to see you there.

Jerry

steamer · « **Reply #53 on:** September 02, 2012, 02:09:40 AM »

Count me in Jerry!

Dave

zeeprogrammer · « **Reply #54 on:** September 02, 2012, 04:35:27 AM »

I'll be watching.

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Author Topic: Corliss Engine Model (Read 27347 times)