2 cylinder inside-out steam engine

[metalmad]

looking great Chuck :bow:
Pete

 

[cfellows]

Thanks, guys, for the comments. I originally made that flywheel for another project 4 or 5 years ago that never got completed. I carved it out of a solid piece of brass six inches in diameter and 1" thick. As I recall, the blank cost me $40 at Speedy Metals. Now the same piece is priced at $98!

I'm not generally a big fan of flywheels with 8 spokes, but this one looks pretty good. I agree with you Harld, that the larger mass makes it look more victorian and has better proportions.

Chuck

 

[sawyer massey]

cool that is on fantastic design

 

[cfellows]

After a brief hiatus to work on my mill / drill and add DRO's on the x and y axes, I got back to work on my engine today. I finished up the two connecting rods. Here in the first picture you can see the fixture I made to hold each connecting rod for machining.

I first milled the edge of one side, then took out the screws, flipped the rod over and did the opposite side. After finishing the edges on both rods, I changed end mills to a 3/16" and milled the groove down the center of each side. Finally, I rounded the outside edge of the small end.

Here are the finished rods...

And an idea of what they will look like on the engine...

The whole process was a good exercise in using DRO's for positioning. Makes for much more precise locating than trying to machine up to scribed lines and marks.

I think I only need to make and install the crank arms to be able to test the engine. And of course I'll need to make a base for it sooner or later.

Chuck

 

[cfellows]

Well, the good news is that I got the engine together enough to try running it...

The bad news, it doesn't run... at all. Doesn't even look like it's trying. I suspect there is too much binding and too many air leaks.

Chuck

 

[flatbelter]

Sorry Chuck

Some times even the pretty ones don't run.

It it does look pretty stunning, I'm sure you'll get it straitened out real soon.

If making motors was easy, it wouldn't feel like much of an accomplishment.

Best of luck, and congrats on the DRO. (I've got one to hookup some time too that I just never seem to get to)

FB

 

[cfellows]

Sorry Chuck

Some times even the pretty ones don't run.

It it does look pretty stunning, I'm sure you'll get it straitened out real soon.

If making motors was easy, it wouldn't feel like much of an accomplishment.

Best of luck, and congrats on the DRO. (I've got one to hookup some time too that I just never seem to get to)

FB

Thanks, FB. I think I'm going to convert over to a D-Valve arrangement driven by an eccentric off the crankshaft. That will help me control the are leaks and reduce the binding.

I had my DRO's in a drawer for close to a year. When I finally tore down my mill/drill a couple of weeks ago to replace the x-axis lead screw nut, I decided it was time to install them. I've used the DRO's a few times now and it really makes things a lot more accurate with less time involved. I would highly recommend them to anyone who hasn't installed them yet.

Chuck

 

[napoleonb]

Not that i am a model engine expert but it looks to me that your design could be improved upon.
When the conrod pushes the cylinder forward the forces are also up/downwards, perhaps it leeds to a slight rotation of the cylinder which in terms can leed to higher friction.
Perhaps if you were to offset the conrods or prevent the rotation of the cylinder, as is the case in the movie on the first page, there is less friction to overcome.

Really love the design of your engine by the way, please fix it!

 

[cfellows]

Not that i am a model engine expert but it looks to me that your design could be improved upon.
When the conrod pushes the cylinder forward the forces are also up/downwards, perhaps it leeds to a slight rotation of the cylinder which in terms can leed to higher friction.
Perhaps if you were to offset the conrods or prevent the rotation of the cylinder, as is the case in the movie on the first page, there is less friction to overcome.

Really love the design of your engine by the way, please fix it!

Thanks for the comments. Actually, there are crosshead guides on the bottom of each cylinder comprised of a ball bearing race fixed to the cylinder which rides in a square groove attached to the base. This keeps the cylinders from trying to rotate.

Chuck

 

[cfellows]

Got the engine running! Here's a short video...

[ame=http://www.youtube.com/watch?v=GFW1I0_33XM]http://www.youtube.com/watch?v=GFW1I0_33XM[/ame]

Still got some air leaks to fix but I know where they are and how to fix them. Also gotta build the base.

Chuck

 

[Captain Jerry]

Chuck

Don't give up. That thing will run! If I understand the valving, it ought to oscillate without even needing the crank and flywheel. You said it was leaky, but without a load, even a leaky cylinder should show some reaction if there is any pressure at all. If a cylinder doesn't move, it makes me think that there is no pressure in the cylinder, (both ports closed) or equal pressure on both sides of the piston, (both ports open or really bad piston ring).

If it were me, I would take the con rods off and isolate the cylinders so that air was going to only one. I would reduce the pressure so that leaks are minimized and then manually slide the piston to the limit of its travel to check the valve action. If you don't see any reaction from the cylinder, then I would take the cylinder off and test the valve action by moving the rod manually. This should give you a clue to the problem.

It may not be the most effective valve setup. There are lots of opportunity for leaks but it should run some.

I'm just thinking out loud, you have probably thought of these things.

Good luck,
Jerry

 

[Captain Jerry]

Chuck

While I was typing, you got it running! See, I told you it would. Congratulations. Nice action and nice "outside the box" design. Thm: :bow:

Jerry

 

[cfellows]

Thanks, Jerry. The problem was massive air leaks in supply side and some binding. I redesigned to the air supply but still have some leaks to fix. I managed to fix the binding so it turns over pretty freely now.

The only way the cylinders would oscillate without the flywheel is if the cylinders had enough mass to move the valve rod with it's momentum at the end of the stroke. The cylinders are brass and pretty thick walled, so they may have enough mass. The whole engine oscillates back and forth pretty good at high rpm's.

Chuck

 

[ozzie46]

I knew you'd get it Chuck. Good job. Nice looking engine. :bow: :bow:

Ron

 

[bearcar1]

Way to go Chuck, BRAVO!! A very unique and interesting engine to say the very least.


BC1
Jim

 

[archer3d]

WoW that looks great I love the way the motion looks. The noise at the end of the video is a bit dis-concerning.

Wonderful work Chuck Thm:

tom

 

[rudydubya]

Nice, Chuck. And I always learn something by following along with your projects. :bow:

Regards,
Rudy

 

[Captain Jerry]

??? So now that it is running, is it reversible? How? Seems like it ought to go either way ???

Jerry

 

[arnoldb]

:bow: Nicely done Chuck - it looks great Thm:
I love the way it sounds like a big steam locomotive pulling a heavy load ;D

Kind regards, Arnold

 

[cfellows]

??? So now that it is running, is it reversible? How? Seems like it ought to go either way ???

Jerry

Yes, it's reversible. If you turn the air off, then turn it back on, the engine will self start in the same direction. If you turn the air off, then manually spin the engine in the opposite direction, it will start up in reverse. In other words, the engine will start up in whatever direction it was last spinning.

:bow: Nicely done Chuck - it looks great Thm:
I love the way it sounds like a big steam locomotive pulling a heavy load ;D

Kind regards, Arnold

Thanks, Arnold, I think it will sound even better once I get all the air leaks in the supply side fixed.

Chuck