Corliss Engine Model

[arnoldb]

Thanks for the animation Jerry.

You've now thoroughly wet the appetite 

Kind regards, Arnold

[steamer]

I like it Jerry!   When ya starting?

Dave

[Captain Jerry]

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]

That'll work!

Dave

[Captain Jerry]

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]

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]

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]

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]

CJ,

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

Best Regards
Bob

[Captain Jerry]

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]

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]

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

Really tempting the fates posting that!

[Jo]

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

Jo

[Jasonb]

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

J

[steamer]

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