Walking-beam STEAM ENGINE (for paddle-wheel steamer)

[gregbal]

Currently working on drawings for what I hope will be my next scratch-build ship project -- a Great Lakes sidewheel steamer built in the 1850s. One of the interesting challenges she holds is her semi-exposed 'walking-beam' steam engine which...like most similar vessels of the era...had the characteristic diamond-shape 'beam' (from which the engine gets its name) and its supporting structure poking through into clear view amidships.

Fortunately, the (fairly-standardized) design is well-represented in online images. I picked one lovely detailed drawing and started laying out parts. Once that was done I decided to build a 'dummy' version to test general fit and appearance, and to suss out unanticipated difficulties or parts I wanted to add or modify.

Here's that rather rough 'first shot,' sized simply to the size of the printer sheet without worrying about scale -- though I later calculated it to be around 1/228, 'in the ballpark' for a model which would end up being just over 13 inches in length. I expect to add a bit more detail to any final version, though that will ultimately depend on how much will be actually visible in the ship itself...something that has yet to be determined.
Anyway, I thought I'd share the project so-far, for any that might find it interesting.

Enjoy!

[mbauer]

Very Impressive build. Great photos. Really like the detail, looking forward to seeing more of the build.

Mike

[whulsey]

Not real into ships, but the walking beam engine is great. Should detail it out as a stand alone model.

[Captain]

Looking great. I've found it very rewarding to design a scratch build for yourself.

[CharlieC]

Good start but it isn't a steam engine yet.

The complicated looking linkages on the steam cylinder are designed to convert the linear motion of the steam cylinder piston rod to the circular (actually an arc) of the beam. This engine, from the diagram, also seems to have fairly complicated linkages from the flywheel to the valve chest. There might be an interesting engineering story here - why the valve drive was taken off the flywheel rather than the common practice of a double Watt's link at the end of the beam?

Charlie

[gregbal]

Thanks, guys!

Originally Posted by CharlieC

Good start but it isn't a steam engine yet.

The complicated looking linkages on the steam cylinder are designed to convert the linear motion of the steam cylinder piston rod to the circular (actually an arc) of the beam. This engine, from the diagram, also seems to have fairly complicated linkages from the flywheel to the valve chest. There might be an interesting engineering story here - why the valve drive was taken off the flywheel rather than the common practice of a double Watt's link at the end of the beam?
Charlie

I realize there's a long way to go yet...right now it's just speculative 'parts.' Once I get the vessel itself drawn up, and a scale fixed...then it will be time to 'dial in' the machinery a little more.
The diagram I used was largely chosen at random, simply for its clarity (and the conveniently-included 'Scale Guy' leaning nonchalantly against the frame). I haven't started delving into the details of 1850s technology yet. Sounds like it will make an interesting study.
I appreciate your comments. Any suggestions for a good 'beginners guide' to the subject? (I'm fairly 'up' on the good old internal combustion variety...but steam is a whole new ballgame, for me.)
Regards

[Michael Mash]

Very interesting looking project Greg.
Count on me being in the audience for this one.
Mike

[CharlieC]

Originally Posted by gregbal

Thanks, guys!


I realize there's a long way to go yet...right now it's just speculative 'parts.' Once I get the vessel itself drawn up, and a scale fixed...then it will be time to 'dial in' the machinery a little more.
The diagram I used was largely chosen at random, simply for its clarity (and the conveniently-included 'Scale Guy' leaning nonchalantly against the frame). I haven't started delving into the details of 1850s technology yet. Sounds like it will make an interesting study.
I appreciate your comments. Any suggestions for a good 'beginners guide' to the subject? (I'm fairly 'up' on the good old internal combustion variety...but steam is a whole new ballgame, for me.)
Regards

There are a bunch of documents at:

https://steamshed.com/free-steam-engine-reads/

Think of a steam engine as an external combustion engine - the steam is just an energy rich working fluid. In internal combustion engines the working fluid is created by the combustion of the fuel/air mixture.

There's a huge model steam engine community who create working scale versions of historic designs. I would not be surprised if someone hasn't built a model walking beam engine of the type you are trying to model - might help with the details of the engine.

Charlie

[Vermin_King]

I haven't fully delved into this yet, but when I saw that it was from the Steamboat Arabia, I saved the link -- modelshipworld.com/topic/17090-steamboat-arabia-1856-by-cathead-finished-scale-164-sidewheel-riverboat-from-the-missouri-river-usa/



I remember reading at the museum that it was a walking beam boat, but had no clue what that meant

[aansorge]

Classic Steam Engin Model


I thought I remembered a working paper model on this forum. Not a walking beam design, this one has a long crankshaft driving the large flywheel. But the plans may indeed show how that complicated linkage works.