Comber Rotary Engine

it is number 46 "rotary"

It is also spelt Comber

Jasonb said:

it is number 46 "rotary"

It is also spelt Comber

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Ah, thankyew. I have it, no wonder I couldn't find it. And thanx for the spelling lesson--I wasn't sure how to spell it.

Gordon,
Your foto doesn't show the section you are talking about. Could you be so kind as to take fotos from several angles of the section we are discussing? This is very intriguing and I would very much like to get to the top of it (bottom?). Do you have an idea of how many hours you have put into making it?

I am always looking for engines in which one can make it with only a lathe with a bit of fiddling maybe.

Why not draw it out yourself only a couple of mins work

the passage is at least covered by half the piston at full stroke so the air should be inclined to go where it is meant to at least when the engine is not under load so I'm not convinced that is the problem

Jasonb said:

Why not draw it out yourself only a couple of mins work

the passage is at least covered by half the piston at full stroke so the air should be inclined to go where it is meant to at least when the engine is not under load so I'm not convinced that is the problem

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You tawkin' to ME? WHO yew tawkin to? If me, then yes, I was intending to draw it up with Alibre but could not find the original Elmers. Thanx to you, I found it as 46 . . .

Yes, I meant draw it staight away rather than wait to see if Gordon would post images. Just as I did.

No better way to understand a design than to draw it out yourself rather than just look at pictures as it makes you think about what is happening. Though the sectional drawing that Gordon posted and the section shown on Elmers book are all you really need plus a bit of thought a sto where the piston travels.

Jasonb said:

Yes, I meant draw it staight away rather than wait to see if Gordon would post images. Just as I did.

No better way to understand a design than to draw it out yourself rather than just look at pictures as it makes you think about what is happening. Though the sectional drawing that Gordon posted and the section shown on Elmers book are all you really need plus a bit of thought a sto where the piston travels.

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GOT it. I was doing another drawing at the time but am almost finished with the Comber drawing. Still, I wold like to see Gordon's work, not the drawing. I might be able to spot something with a foto.

Jasonb said:

Why not draw it out yourself only a couple of mins work

the passage is at least covered by half the piston at full stroke so the air should be inclined to go where it is meant to at least when the engine is not under load so I'm not convinced that is the problem

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Maybe for you it is a few minutes work. For me that would be at least an hours work. I do not work with the program enough to actually become proficient with it. Also because I am old and retired I am easily distracted so I work on a project for a while and get sidetracked with something else.

Richard Hed said:

GOT it. I was doing another drawing at the time but am almost finished with the Comber drawing. Still, I wold like to see Gordon's work, not the drawing. I might be able to spot something with a foto.

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Believe me you would not see anything with a photo. This thing is only about 3" and whatever is wrong is happening internally and is not visible.

I do have a question for you. You said that you have eliminated all of the automatic features for dimensioning and it works much better. I am not seeing any setting which would eliminate and automatic features. Where are these settings?

Gordon said:

Maybe for you it is a few minutes work. For me that would be at least an hours work. I do not work with the program enough to actually become proficient with it. Also because I am old and retired I am easily distracted so I work on a project for a while and get sidetracked with something else.

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I've always been easily distracted--a result of ADHD. BTW, ADHD is NOT what you have been told it is. It is a survival mechanism that happens to be genetic. I'm sorry for those of you who do NOT have it.

Well the whole project takes a few hours but one part maybe 10 min.

You have the option to show or hide dimensions when creating a part. If you go to view and toggle "annotations" to off it will only show dimensions for the active 2D sketch not all the other sketches that make up the part.

When it comes to producing 2D drawings you can select to have all the dimensions for the creation of the part brought forward or to have none brought forward. I prefer not to bring them forward as they can be a bit of a mess so just add new dimensions to the drawing sheet.

I don't know if this is helpful because my coomber's is not an "elmers" but rather a Tubal Cain so design isn't the same. Pictures of my coomber' are posted somewhere on here. My comment is last I was playing with the engine, I could not get it to run on air, but ran fine on steam. Leaks like hell but always did because there are no seals. Good luck!

OK I finally got this thing to run. Opened up the intake and exhaust ports. Made the cam follower forks wider. Plans call for .130" to run on the .125 cam. opened it up to about .050. Seems to run better at about 5 to 10 PSI than it does at 20> PSI. It certainly is not a powerhouse. Any friction or bad spot makes it quit. It needs a lot of polishing to get it looking better but I think that I have seen enough of this thing for a while and will probably set it aside for a while and come back to it later. I think that making it with a slightly larger bore would help it to have more torque.

This reminds me of the Atkinson Differential that I built a few years ago. It runs but if the moon is in the wrong phase it will not run. Barely enough to keep itself running without doing any work. With both of these engines I was not alone with having problems with just barely running.