Model Engine Maker
The Showcase => Vehicles & Models => Topic started by: crueby on January 19, 2023, 04:49:48 PM
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All done! The paint on the engine bed bolts is done, the name plate is attached, time for final photos and videos to wrap up the build.
To recap, back last spring I went to the antique engine show at Mystic Seaport Museum, displaying my Sabino engine based on the one in their steamship. They were demonstrating a number of the engines in the museum collection, including one like I had never seen before:
(https://i.postimg.cc/hPwP7LKd/IMG-4524a.jpg)
At first I thought it was some sort of anchor winch, but the spiral grooves on the drum didn't match that type. When they operated it, by turning the handle just visible in the upper right of the photo, the drum went back and forth with the handle movement (was designed to have the steering wheel connected from up above onto that shaft). I was intriqued, it was a giant steam servo! After I got back home and mentioned it on the forum here, forum member Michael posted a couple pictures of the real steering engine he restored and owns, rescued from the scrap pile after it was taken off one of the river sidewheelers on the Elbe River in Germany:
(https://i.postimg.cc/gJkxV455/IMG-20220831-174306.jpg)
That started a great conversation, and I knew I had to build a model of it. He supplied drawings of the original engine, lots and lots of photos of it during his restoration, plus videos of it running. This is the type of ship that it was used on:
(https://i.postimg.cc/fbMysBwL/IMG-20220824-053444-1080-x-490-pixel.jpg)
There are still a number of the ships running tours on the Elbe, and there are videos of them and their steering and main engines online.
So, I started drawing it up in 3D CAD to make model plans from, based on all that information, here is one of the screen captures from that:
(https://i.postimg.cc/kgkbyWnL/Steering_CAD_2.jpg)
To help understand how it works, also did this cutaway version:
(https://i.postimg.cc/cL4pc5x5/ShaftsCAD_-_labelled.jpg)
Its quite an interesting mechanism, with the steering wheel turning the inner upper shaft, which moves a follower connected to the control valve. As the engine comes on, it turns the lower shaft with a large gear that turns the outer upper shaft, which via a half-lap drives the follower back the other way, turning off the engine when it meets the position that the wheel is now at. The control valve swaps the steam and exhaust between two pipes leading to the cylinders. The valves on the cylinders are spool type (aka piston valves), and the swapping of the steam/exhaust flow makes them swap between inside admission and outside admission, which reverses the direction on the engine. Quite clever how they did it! Here are diagrams that show how that works. First, a diagram showing the parts:
(https://i.postimg.cc/pXNPyk25/Valve-Base-Parts.jpg)
When the control valve is in the stop position, the control valve sends nothing to the cylinders:
(https://i.postimg.cc/9QCVYMwW/Valve-Stop-Position.jpg)
When the control valve moves up, it sends steam down the lower pipe and takes exhaust back from the other, making the spool valve work in Outside Admission mode, running the engine one way.
(https://i.postimg.cc/gkvmhRJS/Valve-Forward-Position.jpg)
When the control valve is moved down, it sends steam through the upper pipe, making the spool valves work in Inside Admission mode, running the engine the other way:
(https://i.postimg.cc/NjDtJcRR/Valve-Reverse-Position.jpg)
Here is the completed engine (full build log is over in the other section on the forum)
(https://i.postimg.cc/YqgCmJ00/IMG-2832.jpg)
(https://i.postimg.cc/XYkNsdw0/IMG-2842.jpg)
Behind the model the chains lead back to a 'rudder', to show how it operated from the engine. This setup is based on pictures from the real ship.
(https://i.postimg.cc/YCHqNbL3/IMG-2841.jpg)
Closeup of the gear/control mechanism:
(https://i.postimg.cc/8k75TFVh/IMG-2839.jpg)
(https://i.postimg.cc/ZYXqnTTX/IMG-2831.jpg)
Here is a video showing the engine in operation, moving the 'rudder' behind it back and forth with the steering wheel. The engine cycles on and off and self-reverses as needed.
https://www.youtube.com/watch?v=pKp-J9aGXiA
When the engine or boiler is down and the steering engine cannot be used, it has an option to steer manually with no power assist. This clip shows how that works. Dog clutch on the lower shaft is disengaged and the one on the steering wheels is engaged, and the large wheel has a screw that clamps onto the outer upper shaft, locking all of the shafts and screws together. That way the control valve is bypassed, and the large gear on the lower shaft and its attached chain sprocket are moved. The larger steering wheel gives more leverage for the helmsman (or possibly two helmsmen) to move the rudder and steer the ship.
https://www.youtube.com/watch?v=uBDB4yCTMns
Thanks very much to all who followed along and helped out! Biggest thanks to Michael for all his help, information, pictures, and drawings! Without his help this project would not have been possible.
Chris :cheers:
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At the risk of repeating myself I'll just go ahead and say, Beautiful job Chris! Amazing work on drawing up the plans and producing such an interesting and unique engine! :NotWorthy:
Kim
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:ThumbsUp: :ThumbsUp: :ThumbsUp: :cheers: :cheers: :cheers:
Great job Chris!
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Wow, what a great project, !!
Thanks for sharing your your build log, fantastic workmanship, :cheers:
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Thanks if you do that with the magazine.
And what's next?
Will a new curtain rise tomorrow?
Michael
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Thanks if you do that with the magazine.
And what's next?
Will a new curtain rise tomorrow?
Michael
Very possible. Or not. Tune in and see! :Lol:
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Congratulations again, Chris. Another unique model extremely well done. :cheers:
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Another brilliant job, done in a flash.
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Nice one Chris! Looking forward to your next project
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Very nice project Chris and thanks for the explanation of how the rudder was controlled manually without the engine. I was going to ask but you anticipated the question perfectly!
Mike
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Very nice Chris!
Another amazing project complete!
Dave
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As always Chris top notch work and a pleasure to follow along. :Love:
:drinking-41:
Don
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Thanks very much guys!
Mike, I didn't anticipate, George asked about that the other day! :Lol: Early on Michael had to explain it to me too!
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As always a great project worked to a fabulous completion. Thanks for the journey. :pinkelephant: :pinkelephant: :whoohoo: :whoohoo:
Ron
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Thank You for posting this project.
I had no idea such a mechanism existed, but a little thought brings up the idea that something like this would have to exist.
I admire your desire to model things that are not mainstream, but are incredibly interesting in their own right.
I will be waiting to follow whatever you attempt next.
Congratulations on a successful job.
ShopShoe
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Thanks if you do that with the magazine.
And what's next?
Will a new curtain rise tomorrow?
Michael
Very possible. Or not. Tune in and see! :Lol:
Next project is about to start (after some workshop updates like the hangers for the QCTP holders and such). It is going to be a project I've wanted to do for a really long time, one of the Stuart Turner steam hammers. I remember seeing them in the ST catalog (remember catalogs?) back when I was just getting into machining, but never built one. A year or so ago I found out the ST sells the pland sheets seperately from the kits, so I picked up the one for their steam hammer. The price for the kit seemed too high, since I can make just about everything from bar stock, but the main curved column would take a lot of time/material to make, so I ordered just one of those from their replacement parts list, and I'll make the rest myself. The current owners of ST said they didn't have any in stock, and hadn't cast any of that kit since taking over, they are currently updating the pattern to work with their new process (don't know what that is, just repeating what they said) and they should have it cast around the end of the month. They have been very responsive to emails, hoping that is a good sign.
In the meantime, the shop elves have been studying the plans and plotting out how to make things. Hope I can read their handwritten notes, their writing is really small! :Lol:
(https://i.postimg.cc/P5jnqnyM/IMG-2847.jpg)
The cylinder will probably be first, I did a little doodling in Fusion to sketch out how to make it from bar stock, and given the size of bar I have on hand it will likely turn out to be a slightly larger bore than the original but the same general shape. The one change I am going to make is to make the valve be a D-type slide valve rather than the spool valve, I like the D valves a lot better, much easier to get a good seal.
Look for that thread to start in the next couple days!
:cheers:
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On an ocean voyage, and fair weather....one may be suprised how little the number of rudder movements over the miles of ocean covered
Many older grumpy :old: Captains judged the Helmsan by this number of turns to maintain a set compass direction
Still lovely to see this superb model in action.....thanks Chris
Derek
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On an ocean voyage, and fair weather....one may be suprised how little the number of rudder movements over the miles of ocean covered
Maybe, but I think a lot would depend on the particular ship. My late father used to tells us how it was nearly impossible to steer a straight course on a WWII American Navy escort carrier. He was glad they usually had to zig zag to try to confuse the submarines, but still, with the Skipper looking over his shoulder it made him so nervous he requested a transfer to the flight deck (where he nearly lost his arm, due to someone else's accident).
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Another unusual beautiful model completed. Excellent work, Chris, congratulations! And good entertainment for all your followers, thank you! :cheers: