Rotary Steam Engines: Page 3.

Updated: 18 Sept 2008
Simpson & Shipton updated
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ROTARY ENGINES IN THE 1850s & 1860s
CONTENTS OF THIS PAGE

SIMPSON & SHIPTON'S SECOND ENGINE: 1851

Simplified diagram of the second Simpson & Shipton engine
Left: Simplified diagram of the second Simpson & Shipton engine.

This intriguing engine was introduced by two Manchester engineers, Joseph Simpson and James Alfred Shipton. It should not be confused with a similar machine that was patented by them in 1848; see Page 2.

Here it can be seen that the rotor a rotates around an axle 2, which is fixed to the arm b, which pivots around the central axis of the crankshaft 3. The other two arms are attached to cranks set at 90 degrees to each other on the crankshaft, and transmit the rotation of the rotor to it.

This engine was shown driving textile machinery at the London Great Exhibition of 1851, and "attracted no little attention" according to Reuleaux. It was driving cotton machinery supplied by Parr, Curtis & Madeley of Manchester, and by Masons of Rochdale. (The Self Site brings you the details)

But he also said: "In the form before us, however, the machine is in the highest degree impractical, in no respect as advantageous as the common direct-acting engine."

Side view of the second Simpson & Shipton engine
Left: Side view of the second Simpson & Shipton engine, with the cylinder part-sectioned.

Note the heavy flywheel to the left, more than twice as big as the engine.

 Section of the second Simpson & Shipton engine
Left: Section of the second Simpson & Shipton engine.

g is the eccentic driving the valvegear.

This simplified section does not make the modus operandi any clearer. (to me, anyway)

From "The Steam Engine- Its History & Mechanism" by Robert Scott Burn,

End view of the second Simpson & Shipton engine
Left: End view of the second Simpson & Shipton engine.

The slide valves are driven by the eccentric, via a bellcrank on layshaft Z at the left. Note once again that enormous flywheel; did this engine have particularily variable torque in its cycle?

It is very clear is that the number of moving parts is not much less than a conventional steam engine.

Left: Animation of the Simpson & Shipton rotary steam engine.

Here it can be seen clearly how the axle of the rotor slides back and forth in the slot on the side of the casing, allowing rotation. It is also very clear that there is a line contact between the rotor and the inside of the casing, one that looks particularly difficult to seal, as the line contact is not in a fixed position on either rotor or casing.

While it is not readily visible here, the horizontal slot is actually an arc of a circle centred on the crankshaft.

This superb animation is kindly provided by Bill Todd

The Simpson & Shipton engine is one of the few engines for which detailed drawings exist. And even better, you can build your own!

A model of Simpson & Shipton's second engine
Left: A model of Simpson & Shipton's second engine.

Parts to build this model are sold by pollymodelengineering.co.uk, who very kindly provided this image.

See the model here

They also sell parts for several other unusual steam engines, such as
Murray's Hypocycloidal Engine


THE NAPIER ROTARY ENGINE: 1851

Napier Rotary Engine: 1851
Left: The Napier Rotary Engine: 1851

"An eccentric mounted cylinder on a shaft concentric with the shell. There are two sliding wings in slots in the shell, held to their bearings by springs or cam wheels on the shaft outside with connecting bars. There are two pair of ports."

In the diagram, it appears that on the right side of the two sliding doors, the upper pipe is the steam inlet and the lower is the exhaust. However, in the left part of the casing there appears to be direct communication between the steam inlet and outlet ports, which would hardly be conducive to economy. This could be prevented by the addition of valve gear to cut off the steam admission on the non-working side of the casing, and probably this is what Napier intended. If so, it would detract from the beautiful simplicity that most rotary engine designers aimed for.

Diagram from "Mechanical Movements, Devices and Appliances" Hiscox, 1899

According to Reuleaux, this form of engine was first invented by Bahrens of Cologne in 1847; Napier made improvements in 1851, and Bompard of Piedmont reinvented it in 1867.


THE HARDY ROTARY ENGINE: 1859

Hardy Rotary Engine: 1851
Left: The Hardy Rotary Engine: 1859

The subject of US patent 24,388. There is a single rotating vane with sealing provided by doors that slide out of the way to let the vane pass. The idea goes back to the Bramah & Dickenson Rotary Engine of 1790.

Nothing is known of its history apart from the existence of the patent.

Hardy took out another rotary engine patent (No77,373) in 1868.

Hardy Rotary Engine: 1851
Left: The Hardy Rotary Engine: 1859

It appears that the doors were moved in and out by face cams on the plates mounted on either side of the engine casing.


THE HOLMES ROTARY ENGINE: 1860

Holmes Rotary Engine: 1851
Left: The Holmes Rotary Engine: 1860

The subject of US patent No 29,787 by Perry Holmes of Cincinnati, Ohio. There is an eccentric rotor with two hinged doors attached. Note the packing at D, adjusted by two screws.

Nothing is known of its history apart from the existence of the patent.


THE NORTON ROTARY ENGINE: 1866

Norton Rotary Engine: 1866
Left: The Norton Rotary Engine: 1866

The subject of US patent No 54,006. There are two interlocking rotors synchronised by external spur gearing. The engine appears to be reversible.

Nothing is known of its history apart from the existence of the patent.

The story of the Rotary Steam Engine continues on Page 4 of this gallery.

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