Simple minded engine ideas-everyone may post.

[Kermit]

I'll start with one I think is rather simple but has a nice shape.

With all the trouble over copyrights and plans etc, etc, etc. I would rather work on my own designs. Perhaps I'm just using the copyright thing as an excuse . Yeah, pretty sure I am.

So anywho - anyone else with anything they want to share feel welcome to put it here. I already know I need lots and lots and lots of teaching, so no need to "be gentle" with me.

 

[Maryak]

Kermit,

Interesting concept.

How is the side thrust absorbed ???

Best Regards
Bob

 

[Kermit]

Okay, let the learning begin.

What exactly is side thrust?

 

[scoop]

Looks to me as if the sidethrust is contained by the slots that the pivot pins run up and down in.A sort of crosshead substitue.I reckon,for what its worth,that if you used a pair of ball races(one in the frame slot and one in the bellcrank)on a common pivot it would be a runner.It would need some care in the machining of all the slots to avoid slop but that should be easy enough as they are just straight slots.When do you start cutting?

best regards Steve C.

 

[Kermit]

Okay, so I think I understand the concept of side thrust then, and yes it will use slots in a side panel to constrain motion in a vertical line.

I've got most of the piece parts if I can manage to cut 1018 steel. I may have to check them with a file before using them since the shop manager told me some of them may be hardened already. I'll just take them back if thats the case and grab an armful off the shelf and try those. (Lots of rust on most of them. and the ones that don't rust I think I should leave alone till I get the hang of this hobby.)

So Here is another version that I might use if I want to increase the size of my flywheel assy, but it is not increased in the pic.

Kermit

 

[Kermit]

How will it be powered?

Steam I suppose, or rather "air" for starters. I'm not ready to embark on any IC engines yet.

Anyway, I think that using slots increases mechanical friction quite a lot.

I'm just learning so I'll be happy with it running friction or no friction. ;D

And I suppose I could use any kind of joint, but first I need to get something built. I could endlessly improve it on paper and never actually build anything for fear of building something that "could be better".

The idea of ball joints is a good one and so are ball races. I think I would need a mating plate for them to roll between. I also considered some round rod bearing housings(I have two left from previous job), but then I would need more of them to match.

Keep them suggestions and observations coming. Thanks,
Kermit

 

[mklotz]

How do you intend to do the valving? Will it be single or double acting?

 

[Captain Jerry]

Kermit

As you may have guessed, I really like offbeat stuff. This looks like fun. Do you think that the mechanism can be made visible or will it have to be enclosed?

Jerry

 

[Kermit]

How do you intend to do the valving? Will it be single or double acting?

They will be single acting pistons, but the reason there are two is for the double power stroke it gives in one rotation. The valve I was thinking could be a single rotary type that is always on and just place the inputs for the two cylinders on either side for a 180 degree seperation and then somehow get it hooked up to the shaft so that it turns once for every flywheel rotation. Seems easy enough in theory, but I suppose I'll find out. Unless someone has a better idea for a simple valve(hint hint)

Kermit

As you may have guessed, I really like offbeat stuff. This looks like fun. Do you think that the mechanism can be made visible or will it have to be enclosed?

Jerry

Jerry, what ever is the "easiest" to do will end up being my course of action. This being my first build and all.

I'm glad everyone so far finds it to be an interesting design,
Kermit

 

[gilessim]

Looks interesting Kermit, it looks to me that you could make it double acting with a carefully thought out slide valve between the two cylinders connected to your dogleg crank somehow,because using a rotary one would involve gears or a belt or something to turn it but if you think about it , two double acting cylinders give "4" power strokes so you can still have one rotation ,also using tiny dentist drill bearings in the slots you could overcome the possible friction problem.

Giles

P.S.you've got me thinking now ;D,

 

[Kermit]

Uhmmmm,,? Just how tiny is "tiny" around these parts. I hadn't envisioned any tiny bits of fumbly things for my numb hands to drop or lose under the heaviest shelf around. I was thinking of making slots around 3/4 of an inch or 16 to 17 mm in Euro length(I kinda like Euro for model making - 24 inch stroke becomes 24 mm stroke)

Lets say 2-56 screws are the tiniest thing I EVER want to work with and further state that I don't much care for 4-40's but I'll use em. Now that is out of the way, I'll clarify by telling everyone I understand models require tiny detail and sometimes eye loupes etc etc...I have built them for years and years I have just never built a model with "real" parts before. I'm kinda approaching this more as a "real" engine than a model one I suppose ??? No harm in that I guess.

So, here is where I change subjects on ya!

While reading about pumping engines I found something about a "compensator cylinder". They were attached in pairs to a cross head and would offer resistance to the power stroke as it began. The resistance then reversed and the cylinders offer an acceleration to the end of the power stroke. This was supposed to provide economy and was also spoken of as a flywheel replacement. One could use much less massive flywheels, making a motor lighter thereby providing more power to farmers who used mobile engine platforms(authors suppositions)

The cylinders are connected to a larger chamber and thereby offer a constant pressure. Compression does not take place as would be supposed by the drawing. The pressure in the large chamber being adjusted to whatever value was wanted to ensure smooth running under load. The air was communicated to the inside of the rotating spindle on which the cylinder was suspended no valving needed. A pressure of say 100 psi could be used first to resist the power stroke, then to assist the power stroke near its end.

Kermit

 

[Kermit]

No comment on the above pictured contraption, but everyone knows more about what I do for a living than I do.........Hmmmmm That's perfect par for the course, what have I got to complain about. ;D

Seems quiet enough inside this topic, I'll just leave this here for safekeeping.

Seems I don't know where to put a decimal point either,
Kermit

 

[joeby]

Kermit,

I can't say as I've seen an engine that actually had the compensating cylinders on it, and I would suppose that it would be a matter of simplicity and maintenance. It may sound good on paper, but you would be replacing flywheel mass with a reservoir and associated piping at least.

Also, I wonder, how would the reservoir be pressurized in actual use? I would think that over time, leakage would become an issue and the reservoir would have to be re-pressurized, which could be an issue in the field.

I'm not saying that it won't work, just that it may be more problems than it's worth. Then again, I could be completely misunderstanding your intention.

This looks like an idea hatched out back in the days when there existed no box in which to be constrained. There were many unusual ideas, some very interesting, but simplicity usually wins out.

Kevin

 

[Kermit]

Thanks for responding after my verbal flogging Kevin. Perhaps my doctor should increase my pain meds I've been an a$$2#% these past few days.

Flywheel placement idea.

Using same parts and slot length for all expect the length of the flywheel connecting Rod and the diameter of the Flywheel itself.

Kermit

 

[joeby]

Kermit,

I pay very little attention to arguments (my wife taught me that I can't win anyway), and I know next to nothing about the subject at hand, so I'm good here.

Back to the design, were you planning to try incorporating the compensators into your design? After a little more thought, I think you could make the engine framework work as a reservoir to keep things compact. Might be interesting to try.

Kevin

 

[Kermit]

You mean enclosing my dogleg crank on six sides and using it as the pressure reservoir?, sans the flywheel? Hmmm...

I think I might need to become a little better acquainted with making a piston that can drive an engine first. These compensators look like they need a closer precision fit than an ordinary steam engine piston might need. I would like to try that idea though. And Jerry asked somewhere way back in this thread if I planned to make the internal workings visible. That idea has stuck with me as well. A plexiglass body holding air pressure and containing those compensation cylinders all movement of the crank and piston rods being visible from all sides?? That would be VERY cool Jerry. 8) Although I don't think I'm in possesion of the the skills that I might need just yet.

Wow, I'm easy to entertain,
Kermit

 

[Kermit]

compensation cylinders added to sketch

 

[Kermit]

300 RPM will give me 3600 RPM. Perhaps to drive an electric generator or if smaller a grinder or sanding wheel or belt or....

Kermit

 

[Kermit]

This one isn't mine but I think it belongs

 

[Kermit]

more parts for the model engine.

And a drawing with explaination for the valve.