here's another one for you guys... This would be for a marine triple-expansion steam engine 3-1/2"HP, 5-1/4"IP, 8-3/4"LP X 4" or 5" stroke, piston valves on all three cylinders.. I want it to look just like cliff blackstaffe's triple (if any of you road guys are familiar with it) just on a MUCH larger scale...

My question is, what do you think of this?;

constructing the majority of the engine out of steel plate and piping (with cast iron liners).. what i'm trying to really get my head around is how to arrange the steam passages from valve to cylinder..

I know this is out of the car territory, but it's steam and i know that many steam enthusiasts cannot just settle on one form of steam powered vehicle. Any information or pictures on fabricating steam engines from scratch would be MUCH appreciated.

thanks,

Wes



Edited 1 time(s). Last edit at 07/23/2007 09:07PM by 87gn@tahoe.

You should start by reading about triple expansion engines. Study the work of Herreshoff; most of his work is available at the Hart nautical museum at MIT. You can get any of his planes, they are now on microfilm.
One thing you want to be careful of is the power stroke, a triple is set up High Low, Intermediate. The rod journals are not always 120 degrees. The high comes to TDC then the low and then the Intermediate. The steam goes from the H to I to L. Since the valve is not open for the steam exhausting from the H you need a large manifold to store the expanded steam till the valve opens. This is three to four times the cylinder volume of the cylinder it is being exhaust from.

I know where you can get a set of casting for a compound 3-1/5 X 7 X 5 all piston valve.

This is a three-cylinder compound I designed, not a triple.
[ourworld.cs.com]

Rolly

Some will call this design antiquainted,,,However please note the old method of using the long hi tensile rods to secure the block to the mainbearing caps in a straight line is far superior and stronger than a heavier "modern" casting,,Mercedes used this on the big cars,,1925--31 head bolts ended at the main caps,,and the blower boost was around 8psi,,Hey,,is this thing gonna be for constant output,,,??? ,,Hmmm Ben

Rolly Wrote:
-------------------------------------------------------
> You should start by reading about triple expansion
> engines. Study the work of Herreshoff; most of his
> work is available at the Hart nautical museum at
> MIT. You can get any of his planes, they are now
> on microfilm.
> One thing you want to be careful of is the power
> stroke, a triple is set up High Low, Intermediate.
> The rod journals are not always 120 degrees. The
> high comes to TDC then the low and then the
> Intermediate. The steam goes from the H to I to L.
> Since the valve is not open for the steam
> exhausting from the H you need a large manifold to
> store the expanded steam till the valve opens.
> This is three to four times the cylinder volume of
> the cylinder it is being exhaust from.
>
> I know where you can get a set of casting for a
> compound 3-1/5 X 7 X 5 all piston valve.
>
> This is a three-cylinder compound I designed, not
> a triple.
>

I waiting on the book "Thermodynamics of the steam engine and other heat engines" By Cecil Peabody.. should be here soon.. hopefully this book will help me with establishing valve events as well as port volume, etc. if not, it should still be quite an interesting read..

It is going to be difficult to design in a manifold of that size.. especially with the valve arrangement i'd like to go with; stephenson link, HP cylinder then the HP and IP valves adjacent to eachother, inside emission on both, and then the IP cylinder after which would be the LP valve (inside emission also) then the LP cylinder.. i guess the back pressure could fight the HP piston at high RPM's.. will have to think this over..

what would you say to nickel-aluminum-bronze valves and slippers (other than the expense)?

Herreshoff triple

Rolly

Herreshoff undoubtedly had some VERY good and powerful designs. Unfortunately (depending on how you look at it) I have found them to be amongst the ugliest steam engines I have aver seen.. That isn't to say I wouldn't own one, I just wouldn't spend the time and money to replicate one.. They are some of the best designed engines of their time and I respect that.

I want something that looks like a traditional ships engine, just on a small scale i.e. cast back columns turned front columns, maybe an inboard condenser, stephenson link valve gear, crossover passages non-visible... i could make it relatively light by making the bed plate out of aluminum (oxy-fuel weld it together) make the front columns out of sc 80 pipe or maybe even anodized aluminum bar... if i go with "box" style rear columns maybe out of aluminum, and build the condenser out of aluminum (does copper + aluminum = electrolysis? do you think that aluminum tubes would provide sufficient heat transfer?).. i could make it so the only things really made out of ferrous material would be the cylinder block, and the reciprocating parts (which i hope to somehow equalize all of the corresponding parts' weights to each other).

You’re talking about a very large engine. That size will push a fifty-foot boat. You can go to Connecticut and visit Mystic Seaport. My friend donated a complete collection of Navy steam engines to them. I’m not sure there on display but if you ask in advance some one will show them to you.
Other American engines were George Lawley South Boston, Davis boat and Ore Co.
Some nice English engines were made by W.Sission & Co, Simpson & Strickland Co, The Lune Valley Engineering,
If you’re going to design and built it your self you should at least get a book published by Lindsay Publication, Steam Engine design. If you use it wisely at least your engine may run well.

Rolly

thank you very much.. i have ordered the book...

i would like to build the boat for this engine on the lines of a panetela out of aluminum, but enlarged to 30 feet (like John York did) and add a 6-foot canoe stern on top of that.. so about 36-feet long and 6-foot wide, on a hard chine hull (less rolling) should cut cleanly enough through the water with a length to breadth ratio of 6:1.. a 42 foot version would be better, but not very trailer-able, not to mention trying to get a berth at the local marina or steamboat meet...

with this and a lightweight water-tube or the "lamont" (whoever invented it LOL) it would fairly scream...

i could possibly even make the cylinder block out of aluminum with cast iron liners... though, differences in expansion in materials, not to mention if moisture gets in-between the liners and the block.. HMMM

Maybee a steel tube cylender like the 1893 Maxim airplane engine ??? Ben