I particularly like that he expects all the punters to pay for a
licence to build one.
Play "I betcha" ?
It's a neat enough design, and would look good on a tabletop, but I
would not hold real high hopes for longevity in real use. Maybe I'm wrong.
I happen to have in front of me a Siemens engine design of about 1860
with the same layout (with 4 cylinders), the only difference is that
this one uses a bendy coupling, whereas the 1860 version used a rigid
coupling with a ball pivot in the centre. As far as I can see,
anything else claimed (and there is a lot) is either baloney or
irrelevant to the patent, which is just the bendy bit. Siemens was
trying to invent the IC engine, the drive system wasn't the novel part
of his design, it probably dates way back to the days when there was a
patent on the crankshaft.
On Thu, 6 Mar 2008 01:55:59 -0800 (PST), Cheshire Steve
This cropped up 6 months or maybe a year ago, I imagine his later
development will be a Perpetual Motion Machine coupled to an anti
gravity system for time travel.
Curious perhaps it is, cheap, reliable, efficient or ecological etc it
Purely on the basis of Carnot's theorem - an engine running on low pressure
steam at low inlet temperture can never be more than a few percent efficient
given that the exhaust temperature has to be above 100C and the inlet
temperature is probably not a lot higher.
You are right, the bendy bit returns no energy. The mechanism doesn't
have the friction that might arise in a ball swivel, but the main
thing is that it might just be novel enough to gain a patent, unless
you can show someone used a bendy rod before. To patent something it
doesn't have to be useful, just novel, and on your own web page you
can claim anything else you like.
You don't even need a patent, but some people will add one to the
other and think the patent backs up the misleading claims - which it
doesn't - it just applies to the bendy bit.
Max efficiency of a heat engine is temperature difference divided by
the higher temperature (and we are talking degrees absolute here).
Minor variations in friction within engines is tiny compared to that
Its amazing how much money people must have spare. Patents are
not cheap (Ive looked into it for something Im developing), and
using a spring might be 'novel' the engineer in me cringes at the
on the website....
Ive not built a swashplate engine, but I cant see how you even need
'bendy bit' There must be a pivot / bearing in the flywheel, which has
take the thrust. And as for not needing 'crossheads' whats that bolted
the back of the cylinders?
(glass of wine in hand, grumpy old man hat firmly on!)
I like the grumpy old man with glass of wine attitude - can go for
I have bunged a copy of the Siemens engine drawing from 1860 on the
You will see the similarity (assuming the link works)
On Thu, 6 Mar 2008 21:52:59 -0000, "James Lugsden"
Also see David Urwick, patentee of the triangular gib key and designer of
the Metalmaster machine tool. His passion was stirling engines and the last
one I saw described in ME was a Siemens Drive with lots of tiny ball
joints. He'd used all manner of devices from z-crank, swashplate/wobble
plate and lots of others in earlier engines. Just not content to watch
wheels go round, that man.
The volume of a pizza of thickness 'a' and radius 'z' is given by pi*z*z*a.
Love the equation for the pizza, but was surprised to hear about this
being referred to as the Siemens drive, and I am also not sure if the
correct term is swashplate as I thought that had a sliding angled
plate, whereas this more of a wobbler.
Back to the Siemens drive..I came across the design of this engine in
a book called The Theory of The Gas Engine by Dugald Clerk published
in about 1882 (though possibly reprinted from an earlier magazine). It
is interesting in stating the Siemens had worked out all about the
need for compression in the cylinders by 1860, and then built the
engine in the drawing (for which I provided a link in an earlier
message). Clearly Sir/Dr Siemens was at the leading edge of the
theory, and I have extracted this bit...
"With reference to the early engine which Dr. Siemens constructed in
1860, the author had stated
that it combined other elements, which were entirely wanting in the
gas engines of the present day. The gas engine of
the present day, taking either of the three types, was, in his
opinion, in the condition of the steam engine at the time of
"In the engine which he constructed in 1860 all those points were
fully taken into account. The combustion of the
gases took place in a cylinder without working a piston, and in a
cylinder that could be maintained hot, and the gases
after having completed expansive action, communicated their heat by
means of a regenerator to the incoming gases before explosion took
place. Although the engine was not worked with ordinary gas used for
illumination, but by a cheaper kind made in a gas producer, he then
thought that a gas engine constructed on that principle would prove to
be the nearest approach to the theoretical limits which could never be
exceeded, but which might exceed the limits of the steam engine four
or five fold. The engine promised to give very good results, but about
the same time he began to give his attention to the production of
intense heat in furnaces, and having to make his choice between the
two subjects, he selected the furnace and the metallurgic process
leading out of it ; and that was why the engine had remained where it
was for so long a time."
So - the big item here is that there is not even a mention of the
drive system - not a peep. So although we know Siemens had it as part
of his design for an internal combustion engine he built in 1860,
surely it would have been remarked on if it was novel. I suspect it
had been around for some time.
On Fri, 7 Mar 2008 15:16:36 -0800 (PST), Cheshire Steve
I forgot where I pinched it from and it's getting boring now.
<snipped very interesting stuff>
I'm not sure either. Mr Urwick called it a nutator, attributing the basis
of the idea to Siemens' work.
The Green engine has perhaps a slightly novel feature in that the cylinder
block itself moves in a cone-like motion, obviating the need for jointed
connecting rods. The cable looks a bit like a Hillman Imp gearshift rod
A step further might be to rotate the block with the shaft as in Rexroth
bent axis hydraulic pumps.
Some models offer variable capacity by straightening out the bend. Porting
appears to be simple by comparison :)
Cognito ergo sum - I think I think, therefore I may be. (R Robinson)
I had overlooked the fact that the cylinders move. It would appear to
be a blessing as regard the linkage, but a nuisance as regards balance
and the connections for the inlet and outlet.
I have had no success in find any earlier example of the 'Siemens
drive', but have found the swashplate principle illustrated in a list
of mechanical movements from 1842 - that mechanism may date back to
There is much in the original Siemens engine design that I do not
understand from the drawing. I wonder if the patent is available
somewhere, or whether some ancient text gives more details of this
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