double acting wobbler

[chuck foster]

i was looking "under the bench" and found this little engine i built about 20 years ago.
the plans are in some 1967 model engineer mags i have, i believe edgar westbury designed this one.
it is a simple little engine and when i built it i ran it with an aquarium air pump. it ran for about 3 to 4 years using the aquarium pump. looking at it now i can see it will have to be torn apart and cleaned, to get it to run on the 2 or 3 pounds of pressure that the pump puts out.
i think the bore and stroke are 1/2" and it is double acting.

any one else got a model from model engineer plans???

chuck

 

[mklotz]

This "Simple Simon" is built from ME plans.

The engine has no valves as such. The piston is a solid rod with a flat on one side.
As the flywheel revolves, the complex linkage forces the piston to rotate from side to side as it goes up and down. This causes the flat to alternately connect the top of the piston with the inlet and exhaust ports, thus providing the valving action. Because of the symmetry, the engine rotation can be reversed by simply swapping the air/steam supply between the two ports.

Incidentally, Elmer Verburg has a design for a double-acting wobbler.

His design incorporates a reversing valve.

I'm not a great fan of wobblers because, well... they wobble and tend to walk off the display table. However, this one, with a heavy base and flywheel plus the double acting tends to stay put. If I were going to put a wobbler in a model boat (something I wouldn't consider), I would choose this design.

 

[slink74659]

Can you tell me what issue that Simple Simon was in. That looks like a engine I might want to build.

 

[mklotz]

Can you tell me what issue that Simple Simon was in. That looks like a engine I might want to build.

I don't have a complete set of all the articles but the photocopies of the plans I do have indicate that it was covered in a series of articles starting in May 1992. The author was Ted Pepper and the name of the engine in the article was "Simon Junior" if you have access to a searchable ME Index.

 

[slink74659]

Thanks, that gives me a place to start.

 

[Brass_Machine]

You dont know how many times I have flipped through Elmer's book and never thought about looking at the double acting wobbler he did. Now that I see one, I may have to give it a go.

Eric

 

[b.lindsey]

The PM Research wobbler is double acting if you want to go the casting route...and it is one of the best running engines I have...quiet, smooth and runs on 2-3 psi quite nicely.

Here is my take on the Simple Simon concept though it really evolved from learning to use Solid Works. I made a running "virtual" version on the computer first...wasn't even sure it would work once built..but so far so good. Is ME still published...I have never seen one?

Bill

 

[mklotz]

Model Engineer is still published but it's hardly the magazine it used to be. Some years ago they seem to have abandoned most all subject matter except model (live steam) railroading. When they did, I let my subscription lapse.