There's a well-known engine modeler in the community from the Netherlands: Jan Ridders. Jan has his own design but has built several others like the one I've built. He has a web page dedicated to them and talks about getting them running. One of the observations I've seen somewhere is that it might take as long to get it running as it did to make all the parts, in which case I should be working on this until around Halloween.
One of the many tests.
Among the things I've done is get some 3' lengths of music wire and wind springs, ordered a higher percentage ethanol version of denatured alcohol than I started with, and worked at minimizing friction. As I've asked various forum members for help, I've ended up running several tests. They all say it should be working.
I can't say this is how I spent my weekend. It's much more than that. More like the last three weeks.
Still, it's late August (today is August 47th, after all), so there's no problem staying out of the heat to work on the engine.
It spins over freely?
ReplyDeleteI wonder if it could be some sort of "timing" problem caused by the spring?
I'm at the rather annoying point where I've run at least a dozen tests and everything says it should be working. Nothing is wrong, but something must be wrong, because it won't work.
DeleteI have three different springs to go back and forth between. None seem to make any difference.
Isopropyl alcohol is available @ 99%. I haven't read everything, so I don't know if ethanol is req'd for some reason. 99% ethanol is available as Everclear, which is expensive.
ReplyDelete_revjen45
I tried to find a comparison of temperatures they burn at, but the recommended stuff was 95% ethanol, 5% methanol denatured (methylated spirits). I started out with something that was more like 50-50, and ended up with 90.5% ethanol, the rest being isopropanol and n-propyl acetate (if I recall). I have to say I probably had the attitude that it can't be the differences in temperature of the flame. The engine runs on the difference between the flame temperature and the room's. It can't be that different between fuel types.
DeleteIf they're that fussy, they're the wrong thing to build.
Hmmm....wonder if a hotter flame, like from Butane or Propane, would work better.
DeleteMaybe try "Flicking Your Bic" at the intake port and see if that helps?
Graphite intake door?
ReplyDeleteIt's currently a small piece of steel, as the designer called out for. Not sure if you're asking if it is one or if I could make one. I would say I could make one, but just another delay to get some graphite.
DeleteI'm at the point of considering everything.
Hi SiGraybeard, How is it supposed to start? Do you manually turn the flywheel or can you take a roller in a drill to get it to operational rpm to see if it would run? Does it matter if it is a clockwise or counter clockwise runner? Curious Al.
ReplyDeleteHey SiG, Al Again.Having watched a you tube on this to see how it operates,I presume the sliding valve is the intake valve and there is no exhaust, just the cooled combustion dissipates the exhaust? If so it would seem like the timing is off or the rotation direction is wrong. I may be totally off base cause all my experience is on automotive applications.
ReplyDeleteI think you answered your questions, Al, but from this side we're looking at in the picture, you run the flywheel to the right (clockwise). These things are so low power that while I could make it rotate continuously with my drill, it doesn't tell me anything. When they run right, it should start working with the alcohol lamp just by flicking the flywheel.
DeleteWhat you see is what there is, so there's the one valve that both takes in the hot air, valve shuts and the expanding hot gas expands, it pushes the piston down to bottom dead center. Flywheel comes around and the valve opens as the piston pushes the now cooled air out of the cylinder.
If I put the alcohol lamp a little in front of that position in the pic, the air coming out of the engine will blow the flame out.
How they work - you will have to click on the frame at the top for the English version.
Video of one working properly
DeleteInteresting how he "throttles" it by adjusting the position of the flame.
DeleteSiG, Since this is a low power engine did you correct the friction, binding concern? Also do you use a similar lamp?Seems the positioning of the lamp and the wetness of the wick would contribute to the fueling of the engine. All things the same still seems like a timing issue. On the video at 26 seconds you can see the position of the piston connecting rod to the flywheel relevant to the sliding valve.Yours look the same? Sorry if I'm no help. A lifetime of diagnosing cars makes me wonder if you have 5 lined up and 4 runs whats different with the one that doesn't. Discovered your blog yesterday and found your engine conundrum.A ingrained curiosity.
ReplyDeleteSiG So you know my names Allan under my wifes email.
ReplyDeleteSiG, Damn diagnostician in me,can't let it go. Looking at your flame and wick placement,your flame is more orange and thus less hotter than comparable flame on you tube Roger Crolls engine. Could this be the issue? If you want me to go away just say. Al
ReplyDeleteAl, since I've been working on this nonstop for a few weeks, I've tried lots and lots of things. More than I can think of, I'm sure. Plus, I'm still working on it and will continue until it runs.
DeleteDid I go after the friction and anything binding? Several times. Is it fixed now and right? I'm not sure. It definitely moves better than it did. I can spin the engine clockwise easily. One guy says it should turn easier CW than CCW and that's the case. When spinning CCW, the action should suck the valve against the cylinder and have form a seal. When I spin it CCW it won't even go half a turn. Is it right now? I'm not sure.
Is the cylinder face smooth enough? I don't know how to tell. I'd guess if it seals when the piston vacuum pulls the valve against the cylinder, that's probably good enough.
The cam has a curved slot in it that sets the timing. The instructions say to set it in the center to get the engine running, and other forum members say they have it centered and it runs. Mine is centered.
The piston should be hard to pull out of the cylinder if you put your finger over the opening. It's not quite the limit of what I can lift with one hand, but it takes quite a pull. Same for pushing it into the cylinder. Is it good enough? I'm not sure.
The latest thing I'm going after is the sound it makes when turning the flywheel without a fire. It should make a farting sound - call it a quacking sound if you prefer. It does. Is it the right farting sound? Long enough? Loud enough? I'm not sure.
This is a well known design. Lots of them are out there: search YouTube for "Duclos flame eater" and you'll see a small sample. It's not the design, it's something I did wrong.
I've been working on this engine since February. I should put together a separate page for the project, like my page on converting my milling machine to CNC. It's almost embarrassing it has taken me to make it and it's not even working. My excuse is that I've never had a formal class in any of this and I'm learning as I go as well as fixing or making other things.
SiG I think I read that the piston to wall clearance was 5/10000. Is that correct? If so thats really snug. Have you tried putting light machine oil on the piston /cylinder wall? that would help seal it just to see if thats an issue.Al
ReplyDeleteThat number isn't from me, and I don't have a way of measuring that accurately enough.
DeleteThe conventional wisdom is not to use oil in these engines. Dry graphite is essentially the only thing people accept. Jan Ridders (that Dutch web page I link to) says a little WD-40 on clean rag is acceptable, but only to help clean out the cylinder if it accumulates some ash and what he calls "pollution". The cylinder is 6061-T6 aluminum and the piston is graphite.
I did a test video where I show how the piston moves freely with the valve open and is hard to move by grabbing the push rod when the valve is closed. The few guys I talk with on a forum who have built these say it looks good.