Modified Rocking Engine

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NickG:
Do be totally honest, I'm not convinced whether it will run. After I started I got thinking about how i'd designed it. I'm not sure whether I've made the conrod too long, hence on the return stroke the piston might not rock to a large enough angle to vent sufficiently. The problem this could cause is that there is still too much force on the piston for the flywheel to carry it over to the next power stroke. The air should find the easiest route but it just depends on that balance of forces. Need :smart: really! This may be why the small bore ones are so effective too. You can see that if you put the pressure too high, it won't carry over so low pressure might be the order of the day.

Time will tell, :zap: it could be back to :coffee: :lol: to fix it I may be able to shorten the frame, reposition the bearing and shorten the piston rod - well, that means a new piston as it's 1 piece in my design. Unless I keep a plain diameter for the piston rod until I have it running instead of wasting away the section between the big end and the piston.

Nick

Stilldrillin:
Nick,

It WILL run! Relatively slowly, mebbe........ Have faith...... :thumbup:

David D

rleete:

--- Quote from: NickG on September 11, 2009, 03:57:13 AM ---I'm not convinced whether it will run.
--- End quote ---

I've found my rocker to be very forgiving, and actually runs a lot better not that it's loosened up. As long as the piston doesn't come out of the bore on the back stroke, or bottom out, it should be fine.

NickG:
Will have to see, because I've changed the parameters. I might not have heavy enough flywheel relative to the bore and stroke, and I might not have designed it to 'rock' the piston enough. I maybe should have scaled this part from a known working one, but I just did it where it looked right to me. I'm about 50% certain it'll run :lol:

Hopefully will get a bit more done tonight. Not sure what to start on though, should I tackle the crankshaft, probably the most complex turning job if doing it in 1 piece, should I do the inlet .. should be straight forward but quite interesting with the taper and the steps, should I do the 2 pedestals ... was a bit fiddley first time around. could do the piston I suppose, then I can turn the crankpin for a good fit in the big end. Or the wooden base?! Decisions decisions ...don't suppose it matters really, all needs to be done!!!

What will it be... come back tomorrow or very late tonight to find out! :lol:

Nick

NickG:
PS, forgot an important bit ... don't think it'll run without a flywheel! :lol: Not doing that tonight though, can't be @rsed to hand saw through 2" of steel, not sure how well it would part off.

NIck

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