Subject: steam turbines

From: [email-masked] (Richard Hal Buxton)
Date: Tue, 10 Dec 1996 20:49:12 GMT

Hi everyone,
Some time ago I started on a Tiny Power 5HP steam engine.  At
the same time I started on a 5 HP boiler.  Of late I have
shifted my efforts to the boiler as I reconsider the engine.  A
friend of mine suggested I build a five HP steam turbine
instead of the piston drived engine.  I have seen the 5 HP
steam turbines offered by an outfit in Florida I believe.  It
had four vanes in the turbine set at right angles to the
shaft.  I wondered if there was a better arrangement for the
blades and if there was an advantage to having more blades?  I
also wondered if someone had built something like this before
and had some ideas or plans.  Suggestions on any of the above
issues is appreciated.  By the way, the boiler has no
superheaters so it will provide saturated steam at about 100
psi.  I plan to power a generator with it.  Another reason for
the turbine in that it turns at a speend closer to that of a
generator.
TIA
Rick

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From: [email-masked] (Jonathan M. Elson)
Date: 10 Dec 1996 23:53:10 GMT

Richard Hal Buxton ([email-masked]) wrote:
: Hi everyone,
: Some time ago I started on a Tiny Power 5HP steam engine.  At
: the same time I started on a 5 HP boiler.  Of late I have
: shifted my efforts to the boiler as I reconsider the engine.  A
: friend of mine suggested I build a five HP steam turbine
: instead of the piston drived engine.  I have seen the 5 HP
: steam turbines offered by an outfit in Florida I believe.  It
: had four vanes in the turbine set at right angles to the
: shaft.  I wondered if there was a better arrangement for the
: blades and if there was an advantage to having more blades?  I

What you want is to look up the Scientific American article on the
breakthrough steam turbine built by (and now my memory is blocked with
Whittle, but that's gas turbines, not steam).  It had a few very good
photos and analysis of how the turbine was built (with simple machine
tools).  I've seen the original unit in the Smithsonian.  I'll try to
get the correct name and the date of the article.  This unit was apparently
the first high speed (18000 RPM) turbine ever built.  This thing looks
eminently buildable in the home shop, but not in one weekend :) !

						Jon

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From: "PyroWare" <[email-masked]>
Date: Wed, 11 Dec 1996 09:06:00 -0600

Richard, there is an exciting element of model internal combustion engine
construction which is pretty new; that is, gas turbine construction. 
While the principles are a bit different, the two books I have are loaded
with practical, hands-on development of precision turbine blades, angles,
shafts, bearings, and the math and balancing of such a beast.  Consider:

Gas Turbine Engines for Model Aircraft by Kurt Shreckling; and,
Model Jet Engines by Thomas Kamps

If youy need them, I can post publishers and such.  Really fascinating
reading.

Kurt Bjorn

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From: [email-masked] (Edward Haas)
Date: 12 Dec 1996 10:41:20 -0800

--Steam turbines *are* lotsa fun: they make nice noises and they 
aren't all that hard to build once you get the hang of it, BUT. The "but" 
is that they aren't as efficient as steam reciprocating engines, until 
they get upwards of (I think) 25 HP or thereabouts. Below that value they 
are extreme steam hogs. For experimenting purposes, make sure that you 
have a steam feed pump hooked up to put water back in your boiler. My 
friends Roger McGuire and Todd Guldenbrein have a rotary-vane vacuum pump 
hooked up to a 6HP Scotch boiler, up in Vallejo, CA and when they turn on 
the steam, the pump makes a dandy noise and rotates at a fair clip (but 
nothing to write home about). You can see the water level declining, tho, 
and it makes you wonder...
	--I run little experimental 3/8" thick, 2" diameter modified deLaval 
turbines using the Coles Power Models 5" dia. VFT boiler, altho any large 
"model" boiler would probably do, again so long as there  is a steam feed 
pump in the system... 
	--More info. on my experiments with steam turbines will appear on 
my "cob-web" -page sometime early next year (no, really!)
-- 
	"Steamboat Ed" Haas	:	Duravi, ergo	
	COMING EVENTUALLY	:	Impavidus Sum
	http://www.west.net/~steamer  	
		---Decks a-wash in a sea of words---

---

From: [email-masked] (Jonathan M. Elson)
Date: 12 Dec 1996 19:08:25 GMT

: Richard Hal Buxton ([email-masked]) wrote:
: : Hi everyone,
: : Some time ago I started on a Tiny Power 5HP steam engine.  At
: : the same time I started on a 5 HP boiler.  Of late I have
: : shifted my efforts to the boiler as I reconsider the engine.  A
: : friend of mine suggested I build a five HP steam turbine
: : instead of the piston drived engine.  I have seen the 5 HP
: : steam turbines offered by an outfit in Florida I believe.  It
: : had four vanes in the turbine set at right angles to the
: : shaft.  I wondered if there was a better arrangement for the
: : blades and if there was an advantage to having more blades?  I

: What you want is to look up the Scientific American article on the
: breakthrough steam turbine built by (and now my memory is blocked with
: Whittle, but that's gas turbines, not steam).  It had a few very good
: photos and analysis of how the turbine was built (with simple machine
: tools).  I've seen the original unit in the Smithsonian.  I'll try to
: get the correct name and the date of the article.  This unit was apparently
: the first high speed (18000 RPM) turbine ever built.  This thing looks
: eminently buildable in the home shop, but not in one weekend :) !

The article is in the April 1985 issue of Scientific American, PP. 132 to
139.  It was for the 100th anniversary of the development by Charles
Parsons of the axial flow steam turbine.  He had to invent the whole
science of high speed rotating machinery, critical speed, vibration,
lubrication, seals, regulation, etc.  He completed his first practical
turbine in 1884!  One of the features of this turbine is that the 15
stages are all the same diameter.  This certainly made it easier to
construct the blade rings, which were made of BRASS!  All the blades
are at 45 degrees, with just a filed (or milled) chamfer at the leading
edge!  You could make these easily with a dividing head in a mill.

 						Jon

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From: Jay Hayes <[email-masked]>
Date: Thu, 12 Dec 1996 02:55:40 -0800

> the turbine in that it turns at a speend closer to that of a

As a marine engineer I have seen a lot of different arangements for
steam turbines. Most steam turbines have many turbine blades of a rather
complex geometery. There are usually multiple stages of varing sizes on
a single shaft. Steam turbines also like dry superheated steam. 

One style that comes to mind that may be what you are looking for is a
tangential-flow type turbine. This style has semicircular buckets
machined into the rim of a single turbine wheel. This type of turbine is
often called a "Terry Turbine".

I've built some small models of steam turbines but can't imagine four
vanes being very efficient. Unless you are talking about four rows of
blades.

If you want to read up on the subject see if you can locate a copy of
Modern Marine Engineer's Manual by Osbourne from Cornell Maritime Press.
It has a lot of info on boilers also.

Hope this helps,

Jay