"Valveless" steam engine

[mklotz]

Some years ago, there was a series in "Model Engineer" devoted to building 'valveless' steam engines. The idea intrigued me and I built my own version of the simplest design shown in that series.

The piston is a length of 1/4" drill rod that extends out of the bottom of the cylinder. Attached to the bottom of the piston is a complicated linkage that links the piston to the crankshaft. As the crankshaft rotates, this linkage forces the piston to turn through an angle of +/- 45 degrees or so as the piston moves up and down. A flat milled into the portion of the piston inside the cylinder alternately uncovers the intake and exhaust ports as this oscillation occurs. Like the elbow engine, this engine is completely symmetrical so it can be reversed by simply interchanging the inlet and exhaust ports.

It's an interesting engine and fun to watch when operating. The gyrations of the linkage are particularly eye-catching.

 

[Bogstandard]

Marv,
You are really tantalising us aren't you, showing us engines that we would love to build and then tell us it came from M.E. mags.
I'm sure you did it to make me go and look for the articles in my old mags, and hopefully I just might happen to drop onto the steam hammer articles while I'm at it. Shame on you.
Just joking of course, but a lovely interesting little engine. But as you were saying about us Brits, if it can be made with a lot more parts, we will do it, just to show it can be done.
Maybe I should send out a challenge to make a Heath Robinson (Rube Goldberg) steam engine.

John

 

[mklotz]

Well, John, I could have offered to scan the plans and put them up for grabs, but I imagine that they have copyright laws in England just as we do here.

Aside: How does that site with all the Elmer Verburg plans get away with it?
I have the book and the copyright date is 1988.

Of course, fortune has smiled on me and I am not a lawyer, so maybe all the copyrights have expired and this material is in the public domain.

Here's a bit more tantalizing - Philip Duclos' "Huff 'n Puff", published in "Projects in Metal" before it morphed into "Machinist's Workshop". The engine is breath-powered, piston valve, double-acting. The head bolts are 0-80 and the connecting rod link pins are 1/16" drill rod turned down to 0.040", then split on the ends with a 0.010" slitting saw so they can be spread to keep them in place.
For scale, the American penny shown is 0.75" diameter.

Now, what's really tantalizing about this engine is that, a few issues after it appeared in the mag, a follow-up article showed a half-scale version of it built by an Australian fellow. While I enjoy building miniatures, that's way beyond my patience level.

 

[Bogstandard]

I am the same as you Marv, I don't put mag articles on the net just in case. You never know what is still copyright, and I suppose it varies from country to country. Not worth taking the chance.
I see you like big engines then. Did you see my build in the post 'My Tiny', I took Tubal Cains port spacing and designed my own around that, only a 'wobbler' though. Half a turn on the nut holding the salvaged cigarette lighter spring is enough to stop it running, and what is the first thing people do when you hand it to them to look at? Must get it locked in position before I take it for display tomorrow.
I think you are on about the Aussie who builds Z gauge live steamers, he has a thing about small steam engines. Doing it once to satisfy a curiosity is one thing, doing it all the time could be classed as a fetish.
Lovely engine build by the way.

John

 

[rake60]

That copyright issue is one that we need to keep in mind!

The copyright for Elmer's Engines IS still quite in force.
IF you can find a copy of the book, expect to pay somewhere in the range
of $500.
The current copyright holder is a 65 year old shop owner from Texas.
He does however make all the plans available to the public for free
downloads from his Yahoo Groups "Elmers_Engines_ 1 thru 4"

If you are an Elmer fan as I am I'd suggest you join one or all of Dirk's
Elmer's Engines Yahoo Groups. It is the only place where you can
legally download the plans.

Rick

 

[mklotz]

John:

"Big engines" indeed. Like winding the Yanks up, do you? Your Tiny is tinier than Verburg's, which I've built - camera batteries on recharge or I'd provide a snap. There's one (Minikin by James Senft IIRC) that's about finger tip size and another by the same fellow that's soldered to the top of a thimble which acts as its boiler. I'd like to try the latter but I don't think my skills are up to it.

Although I've built several oscillators, I'm not overly fond of them since, being 'wobblers' (an Americanism), they, well, wobble. This makes them awkward and noisy at shows. On Verburg's double-acting, reversible wobbler,

I used a solid brass flywheel and a heavy steel base so that one stays in place rather well.

I checked my notebook of completed projects and the Valveless engine article(s) were by Ted Pepper and appeared in the May-June 1992 era in ME. That should shorten your search.

I can't tell you how envious I am of you being able to build miniature engines for people and getting paid for doing it. Usually, I have to be satisfied with finding people who know what an engine is and have some inkling of how it works.

 

[Bogstandard]

Hi Marv,
Its all done in jest. Would I wind anyone up :roll:
Thanks for the info on M.E., should shorten my search a lot.
Skills to do things whether large or small is all in the mind, it shouldn't be 'I can't do that' it should read 'how am I going to do that', if you don't try you will never know. If you fail, OK, but at least you tried, but on the other hand, when you succeed, total mind blowing satisfaction.
We have a large following for model steam engines for model boats here in the UK, and when I make a batch (usually six off, twice a year) they are snatched up by usually the same people or their friends, who appreciate quality rather than the quantity from commercial suppliers.
This all goes to finance my little workshop and its associated activities.
I never make more than six of any one design, the last ones I called the square engine, maybe the next ones will be triangular, all using the same basic port layout of a French long stroke engine design, but with my own modifications to it. I also only ever dispose of four, the other two stay with me for my collection or are given to friends as gifts, there is even one of my engines in Moscow, gracing the shelves of a good German friend of mine.
It isn't done for profit, it is done for the love of model engineering and keeping me active. What a wonderful life.

John

 

[tattoomike68]

Well, John, I could have offered to scan the plans and put them up for grabs, but I imagine that they have copyright laws in England just as we do here.

Aside: How does that site with all the Elmer Verburg plans get away with it?
I have the book and the copyright date is 1988.

Of course, fortune has smiled on me and I am not a lawyer, so maybe all the copyrights have expired and this material is in the public domain.

Here's a bit more tantalizing - Philip Duclos' "Huff 'n Puff", published in "Projects in Metal" before it morphed into "Machinist's Workshop". The engine is breath-powered, piston valve, double-acting. The head bolts are 0-80 and the connecting rod link pins are 1/16" drill rod turned down to 0.040", then split on the ends with a 0.010" slitting saw so they can be spread to keep them in place.
For scale, the American penny shown is 0.75" diameter.

Now, what's really tantalizing about this engine is that, a few issues after it appeared in the mag, a follow-up article showed a half-scale version of it built by an Australian fellow. While I enjoy building miniatures, that's way beyond my patience level.

My goodness, thats a little devil. It would be worth buying some books if they have plans like that.