Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

These castings may still be available from myersengineworks.com

Here is their description:

Norbert Keeley designed this engine in the early 1970’s. It comes in a single cylinder and 2 cylinders (Double Murdoch).
An oscillating cylinder steam engine (also known as the wobbler in the US) is a simple steam-engine design (proposed by William Murdoch at the end of 18th century) that requires no valve gear. Instead, the cylinder rocks, or oscillates, as the crank moves the piston, pivoting in the mounting trunnion so that ports in the cylinder line up with ports in a fixed port face alternately to direct steam into or out of the cylinder.
Oscillating cylinder steam engines are mainly used in toys and models but, in the past, have been used in full-size working engines, mainly on ships and small stationary engines. They have the simplicity and therefore, low manufacturing costs.

Castings-single cylinder

• 1 inch diameter cylinder bore
• 6 ½ inch diameter flywheel
• 10 aluminum castings
• Prints

Castings-2 cylinders

• 1 inch diameter cylinder bore
• 6 ½ inch diameter flywheel
• 17 aluminum castings
• Prints

Here are pictures and video of this one.

Enjoy,

Gil







[ Guests cannot view attachments ]



[ Guests cannot view attachments ]



[ Guests cannot view attachments ]



[ Guests cannot view attachments ]

Here is the AI answer:
 
The Murdoch oscillating steam engine has significantly fewer moving parts than a D-valve steam engine because it eliminates the need for complex external
valve gear.
 
Murdoch Oscillating Steam Engine
Mechanism: In this design, the cylinder itself is pivoted on a trunnion (pivot point) and oscillates (rocks back and forth) as the piston moves the crank. The oscillation causes ports in the cylinder to align alternately with fixed steam intake and exhaust ports in the engine frame.
Key Moving Parts (single-acting, basic model):
 
Piston
Cylinder assembly (which moves/oscillates)
Crankshaft
Flywheel (often included for momentum)
Connecting rod (in some designs; "wobbler" type engines can eliminate this too)
 
Advantage: The critical feature is the elimination of the separate, complex valve mechanism. This simplicity leads to low manufacturing costs and makes it popular for models and simple applications.
 
D-Valve Steam Engine
Mechanism: The cylinder is fixed. A separate D-shaped sliding valve moves back and forth within a steam chest to control the flow of steam into and out of the fixed cylinder ports.
Key Moving Parts (single-cylinder, basic model):
 
Piston
Piston rod
Crosshead (guides the piston rod's linear motion)
Connecting rod
Crankshaft
Flywheel
D-slide valve
Valve rod/stem
Eccentric assembly (used to drive the valve)
 
Advantage: While more complex, D-valve systems offer better control over steam admission and exhaust timing (cutoff), leading to greater efficiency, especially at higher speeds or for reversing applications (which usually involve even more complex valve gear like Stephenson linkage).
In summary, the oscillating engine integrates the valve function into the primary motion of the cylinder, dramatically reducing the total number of dedicated moving components compared to a D-valve engine which requires a separate valve, eccentric, and associated rods and linkages.