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| The Artful Bodger's nutating engine! |
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| bogstandard:
Very ingenious thoughts and ways of doing things John, and you are showing that you are not the simpleton you make yourself out to be. I can't wait to see how this is going to turn out. They are having a bit of a discusssion over on the 'other site' about sleeve valve engines, which is 180 degrees out from what you are doing, rotating the cylinder instead of the piston to obtain port timing. This might be a bit of an interesting read for you. I have a friend who has one of the horizontal versions, very compact and innovative. Lots of easily understood principles are shown the deeper you search. http://www.rcvengines.com/ John |
| John Hill:
John, OK the idea was original to me but I am not the first to think of it! I found reference to an engine in a museum somewhere c1878 which by the description operates on a similar principle except the piston was rotated by some sort of cam and lever. There is a current oscillating piston model steam/air engine online which gets the rotation via a 90 degree lever connection to the crank. So far as I have found mine is the only one where the piston motion is controlled by the wonky big end. The designs that use ports in the piston itself require a rather heavy piston which would have to be solid for the length of the stroke whereas mine uses a minimum weight piston and an attached sleeve that works in a space in the upper cylinder formed by the outer cylinder and a 'displacer' which is a loose fit inside the piston sleeve. That form of sleeve-in-head is not original as the Junkers diesel aircraft engines of WWII used the same arrangement. I believe some sleeve valve cars used the same thing where it was called a 'junk head'. Rotating the sleeve independant of the piston is essential for four stroke operation (as far as I can see). Obviously I am however not as smart as I thought as examination of my engine as it is so far has shown that the cylinder is too short and the piston ports would be exposed at the bottom of the stroke! :doh: Oh dear, another 3 inches of water pipe will have to go in the lathe! |
| Darren:
--- Quote from: John Hill on August 08, 2009, 05:25:26 PM --- Oh dear, another 3 inches of water pipe will have to go in the lathe! --- End quote --- Otherwise known as R&D, perfectly normal chain of events..... :thumbup: It's looking good btw.... :clap: |
| John Hill:
Exhaust ports drilled in the piston sleeve, I had intended to cut a slot until at the last moment I remembered this is just cold rolled pipe and with unknown internal stresses I might have lost the shape by cutting too much out, so a row of holes it is. The inlet port is the same sort of thing on the other side of the sleeve but there are only 3 or 4 holes. All complete, and it runs..... :ddb: :ddb: :ddb: :ddb: :ddb: :ddb: :ddb: :ddb: :ddb: :ddb: :ddb: :ddb: Yes, yes, I know a video would be nice but no camera right now.. |
| Stilldrillin:
It RUNS!!! :clap: :clap: :clap: :clap: Blummin well done John! :thumbup: David D |
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