“Potty” radial engine

[Eric CoxParticipant @ericcox50497]

In ME 4397 the general arrangement on page 197 shows the component list but the identification numbers are missing from the drawing.

 

Why make the crankcase out of 1 3/4″ A/F when the largest available stock size appears to be 1 1/2″ A/F.

 

[Eric CoxParticipant @ericcox50497]

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Eric, I guess thats why it was machinced from round bar stock. Don;t know about the I D numbers.

 

Regards Nick.

[Eric CoxParticipant @ericcox50497]

Obvious when you think about it.

 

Also, the photo no 2 shows the surface between the two under cuts where the cylinder hole breaks through appears to be curved and not flat or am I interpreting the drawing wrong.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Eric, you are looking at a cross section, where the outside is flat and the inside is a round bore. If you actually cut the piece thruogh and looked at it in this way, that is how it will look at a point blank view.

 

Regards Nick

[Stewart HartParticipant @stewarthart90345]

Hi

 

My assembly drawing did show the part numbers but for some reason they were left off at the editing bench, I also spotted that they show some holes on the crank case as 3mm when they sould be M3 also changed at editing.

 

Any one wanting a set of my own un edited drawing can send me a PM with email adress and I’ll send them a copy.

 

Stew (Potty)

 

 

 

 

[Tony Case 1Participant @tonycase1]

No credit given to ET Westbury ? (Cygnet Royal)

[Maurice Cox 1Participant @mauricecox1]

Hi,

I echo Tony Case’s reference to E.Westbury,s Cygnet Royal. I also have a question about Potty. Why does a steam engine need cooling fins?

Coxy.

[John OlsenParticipant @johnolsen79199]

I will make a wild guess that it is because Stewart wanted it to look like an aircraft engine. The fins are of course a disadvantage when running on steam, but will be of benefit when running on compressed air, and I suspect that many engines of this type (eg small stationary engines.) spend more time on air than steam, so maybe it is not a bad idea.

 

regards

John

[Stewart HartParticipant @stewarthart90345]

The rotary valve is based on the great ET Westbury,s Cygnet Royal along with the overall scale, I modified the crank to ease manufacture and redesigned the con rods and crank case, and sculpted the cylinders to look like an aircraft engine, as John said the finning has no practical use.

 

There are a number of similar designs of engines about, I was also influenced by an engine on John Tom http://www.john-tom.com/ :-there are very few things that don’t evolve from what has gone before.

 

I tried to show in the article an engine that could be made from bar stock without the use of castings.

 

I answered all question from ME honestly about the design.

 

I doubt that as a steam engine the concept would have any practical use, however if you turn it on its head and coupled it up to an electric motor the concept is used for compresors/pumps.

 

Stew

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