These here rocking engines

[Mo deller]

I seem to have missed the plot regarding these so called rocking engines.
I have tried hard not to let anything else distract me from all the unfinished projects I have but am failing miserably.

I have searched for an explanation of how the rockers work and why they are called such but can't find anything.
Would a kind person explain or post a link for me please.

Mo ???

 

[putputman]

Mo, try this link: http://www.homemodelenginemachinist.com/index.php?topic=5461.0
It gets a little long but eventually get into the rocker style engine, although he does not call it that. You will see the rocking action of the piston take the place of normal valving. There are no valves in this engine.

 

[Mo deller]

I had looked at this thread but I could not work out why it worked. Now you have said that there is no valve I think I am begining to understand the principle but I can't fathom how it works. If the piston is so thin it can rock in the bore why doesn't it get stuck?
Is it made so the piston only rocks on the exhaust stroke so the air escapes? Am I getting warm? ;D

Mo.

 

[arnoldb]

Mo, I'll try to explain:
On this engine, the drive shaft center is not on in line with center line of the bore; it is above it - unlike most "normal" engines
As the con rod is directly connected to the crank:
This means that while the con rod link is below center, the piston travels in a "sort of straighter line" with minimal play in the piston angle in the bore - giving a power stroke.
When the link is above center for the other half of the stroke, the piston is angled a lot in the bore, allowing the air/steam to escape at top and bottom through most of the stroke.
This engine will NEVER run with too-thick a piston - it needs the piston to "swivel" or "ROCK" (hence it's name) up and down in the cylinder, and also, it can only run in one direction; not in reverse.
Like Marv noted, this is a terribly inefficient engine - as there are no valves, you get a "power stroke" while the con-rod is "sort of in line with the cylinder bore (lower than center), while at exhaust, the engine must exhaust, as well as exhausting the incoming air/steam which is not shut off.

Hope this lot made sense :big: - regards, Arnold

 

[Mo deller]

That sounds like the way I was imagining it but hadn't worked out which bit was controlling the rocking.

Thanks,
Peter.