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Yesterday was just one of those days!Thanks Derek, yes, it is great to see so much interest. I have always thought we were a bit too reluctant to get really technical, let alone the maths. Our aero modeller colleagues include quite a bit of aerodynamics in their literature, so I don't know why we have to apologise before including a bit of thermodynamics. It is my intention to show how relevant it all is to our engine making.But yesterday? It was not a good day. If you found yesterday's post a bit hard to follow, please don't despair, it did not do much for me either when I read again today.Just as in building we sometimes don't get a part up to our standard and have to consign it to the scrap bin, in trying to build a knowledge base, the same thing happens. I assume that is what the "modify" button is for? I will try it in the next few days and let everyone know when it is ready to read again. I have at least given thought to how I should have approached it.But that is not the complete reason for my heading. Earlier in the day, I was working on the brown stuff, when my jigsaw went bang, and all the lights went out. The machine was not even warm, and I did not see any smoke get out. So I reset the breakers, restored the lights and tried to start and again bang and no lights. It was only about 25 years old, but clearly a trip to the tool shop was required. The man did not miss a beat. What a pity you did not bring it in last Friday, he said. It might have still been on warranty! I was not quick enough to point out it was not broken then. It was really disappointing. Despite using power tools since primary school, that is the first I have ever broken. But the new one is really nice. To top it all off I found that my belt sander was so old that the correct size belts do not seem to be available. (Much older than the jigsaw, it was my Dad's.) Looks like more tool shopping required. What a blow! I never saw what others see I retail therapy, then one day I happened on a really good tool store. Now I get it.I have resolved some internet technologies this week, so I will prepare a diagram to illustrate where we are up to, as I should now be able to communicate with the scanner. But it has been a long day, and it is late, I will be very lucky to to get any thinking time tomorrow so it may be Saturday.Thank you for all the interest.MJM460
The lower side of a single acting cylinderOn our single acting cylinder, atmospheric air pressure does work on the underside of the piston on the up stroke, and the piston does work on the air on the down stroke,
The conventional presentations do not easily show both sides of the piston at the same time.
Thank you Maryak for a really great example of an indicator diagram showing top and bottom faces of a double acting cylinder. It appears to be very realistic. Did you by any chance take it yourself?