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Coomber Style
Elliptical Rotary Cylinder Steam Engine |
USA - Manufacture date:
2006 Bore = 1.25", Stroke 1.75
", Flywheel diameter
= 8"
Style: Elliptical , Rotary
Cylinder
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13" length x 9" width
x 11" height
(includes base) |
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The Coomber Elliptical Style Engine |
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This collection is obviously made up of engines
with unusual designs and a wide variety
of different mechanical functions.
As you might have noticed, I try to
collect machines with the widest
variety of mechanical movements in mind.
The Coomber Elliptical Rotary design
is a perfect example of this tendency. The original Coomber design
is a kit which came from specifications
provided by the legendary steam engine
guru, Tubal Caine. This particular engine
is based on Caine inspired drawings
offered by A-1 Machining, of Flushing
Michigan, which later were adapted for CNC
by Carl Hoyer, in California. The
CNC adaptation allowed him to add the
wonderfully smooth contours, curves and beautifully
executed brass inlays to an already
very nice design. |
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As with many things in my life,
this engine came to the collection in
an unexpected way. I had seen the
builder of this engine offer his creations
on Ebay at a time when my toy funds
were less than flush. I figured they
would sell off quickly, so I continued
searching for the "casting kit"
version I was more familiar with. A fellow collector and
friend had recently bought this
engine for less than it was
offered on Ebay, but now he was looking
to pick up a more desirable,
engine and wanted to sell this one to
free up his own toy funds. A deal was
struck and after some clean up and a
bit of work to fix a few minor alignment
problems, mostly due to shipping, this
well made bar stock engine is now
the perfect display partner for
the ever flamboyant Rectilinear
engine. |
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Detail of Curves, Contours and Inlays |
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View of the Cylinder Details |
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The cylinder of this engine is mounted
on the centerline of its axis
and rotates inside a fixed ring which is
offset above the centerline. This offset
guide ring acts to control the cylinder
rod's travel. By the ring being
located above the centerline, one
end of the cylinder rod is allowed to
extending as it rotates to the top of
the circular guide. As one end of the
rod extends, the other fully collapses
as it reaches the bottom of the circle.
This action provides the cylinder with
a cyclical stroke which turns the
motor's shaft and flwheel to provide
its motive force. Switching is via a
pair of fixed ports running inside the
length of the main shaft. To say it
has an unusual mechanical action
is a bit of an understatement. It is
really quite entertaining to watch in
action.
This engine will soon
undergo a tear down and it will then
be polished up a bit. Nothing is wrong
with Carl's workmanship, but the engine
has been shipped around enough to acquire
a few small nicks and dings. These will
be removed and the engine will once
again look just as fine as the skills
that brought it to life. |
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