Beeton's Model Steam-boat engine 1869

[The_Paso_Kid]

My grandfather came across this engine many years ago in one of the English model boating magazines. I recently was able to get a copy of the entire article from its original source: Beeton's Boys' Annual for 1869. However it left a lot to be guessed at. It is quite interesting in its design. However I'm in doubt about whether it will actually run as drawn. The driving piston and the piston valve are shown sharing the same position on the cam shaft, rather than being off-set, so that the actual timing of the intake cycle to power the driving piston would be rather short and the valve would be opening as the driving piston is still in its upward movement before reaching top-dead center and beginning its downward stroke. The drawing also shows the valve and driving piston have the same stroke distance, however the drawing shows between fig 3 and fig 4 that there appears to be less distance traveled by the valve than it actually would if it shared the same stroke distance as that of the driving piston.

My grandfather and I have been working on several wooden prototypes with the valve and piston exposed so that we could experiment with adjusting the positions of the piston valves. In one of the models I used a "floating" piston valve to both shorten the travel distance of the valve and to provide the necessary lag between the movements of driving piston and valve to obtain the proper intake and exhaust cycles for the engine. That prototype actually ran.

Just wondering if anyone else has come across this engine or has attempted to build it, or has any advice. Thanks

 

[The_Paso_Kid]

This is a link to a video clip on YouTube showing my wooden prototype running.

[ame]https://www.youtube.com/watch?v=F6SaQdcHM-g[/ame]

 

[Blogwitch]

You might find it will run a lot better if you have the cranks with 90 degrees between them rather than them going up and down in unison.

John

 

[10K Pete]

See the original post, John. The small one is a piston valve. The trick is that it runs on the same throw as the power piston!

Pete

 

[The_Paso_Kid]

Thank you John and Pete for your input. I was trying to stay as true to the original design concept as possible, with the exception of the floating piston valve instead of the fixed linkage in the original which I found to be unworkable. I have posted several photos in the photo section. I also put together another prototype engine while experimenting with this concept but used the 90-degree offset for the valve which of course will work. The author of the article was not too fond of oscillating engines as he believed them to be less reliable in a boat rocking around in rough water, so I decided to make the prototype, again with a piston valve but would simulate the motion of an oscillating steam engine.

 

[Blogwitch]

Pete,
I had realised that already. I was talking about the power pistons being 90 degrees apart, which usually gives a self starting engine.

But anyway PK, what you are doing is great work, looking at old designs and proving they work, keep it up.

With regards to oscillators, I remember seeing an old print of an oscillator in a fairly well known steam ship (can't remember at this time), it had a, I hope it is the right way around, 7ft diameter bore with a 14ft stroke twin cylinder and it powered the ship for many years.

John