Horizontal Single

[cfellows]

I'm drawing up plans for the horizontal single I just rebuilt and am at a bit of loss as to how and where to post them. At this point I plan to save them as PNG files as shown in the accompanying link. Anybody got any other ideas?

 

[Brass_Machine]

Did you try the upload/download section? If that doesn't work, I can host them for you.

Eric

 

[Bogstandard]

If I could make a suggestion Chuck.

When all the plans are completed, Zip or Rar all the files together, and as Eric suggested, post it in the downloads/uploads section.

Doing it that way ensures whoever wants to build, can get all the pages in one go, and not have the discomfort of finding and downloading individual pages.

John

 

[shred]

I will be happy to convert them to PDF if you want as well.

 

[cfellows]

John, I'll take your suggestion and compile all the drawings into a single document when I'm finished.

Shred, I may take you up on your offer to convert it to PDF.

In the meantime, I will continue to post single pages here as I complete them. That way people can be scrounging for material and/or starting a build without waiting for the completed document, which could take awhile.

Here is the Cylinder. Pretty simple...

 

[cfellows]

Here are the drawings of the valve assembly. I'm sure most of you realize by now that I'm not a draftsman by trade! These drawings are are little busy and I'm sure they're not even close to standard drafting protocol. I guess I would as if they are good enough to build the assembly from... Any constructive feedback would be appreciated.

Most of the dimensions are not real critical.

Chuck

 

[Bogstandard]

Your spoiling 'em Chuck.

Just do rough sketches like I do, make them work for it.

But honestly, nice job on the plans, you can never have too much information showing.

I gather the valve seat could be almost any angle.

John

 

[chuck foster]

chuck: nothing wrong with the look of these drawings, and thanks for posting them here for all to enjoy ;D 8)

chuck foster

 

[cfellows]

Here is the drawing of the engine frame. Any preference as to what I draw up next?

 

[tel]

Not really Chuck, you do 'em as it suits you and we'll all tag along behind. ;D

 

[cfellows]

Here's the crankshaft

Chuck

 

[Brian Rupnow]

Chuck---I just finished my first ever steam engine, a simple wobbler. I may try and build the engine covered in this thread next. I see other people making reference to the sound of the poppet valve. Do you have a video/audio clip of this engine running somewhere?--Brian

 

[cfellows]

Brian, here's the video:

[ame=http://www.youtube.com/watch?v=CXH2nNLmBXo]http://www.youtube.com/watch?v=CXH2nNLmBXo[/ame]

There are also a bunch of pictures here:

http://www.homemodelenginemachinist.com/index.php?topic=2088.0

Chuck

 

[Brian Rupnow]

Fantastic!!! I love it. This will definitly be my next build. Thank you for the video.---Brian

 

[cfellows]

Here is a drawing of an idea I had for a hit n miss governor setup for a compressed air engine. On a traditional internal combustion hit n miss engine, the governor has to hold the valve open when the engine is freewheeling.

On a compressed air engine, the governor has to hold the (inlet) valve closed when the engine is freewheeling. With this design, most of the governor mechanism is the same as those found on a traditional internal combustion engine. However, the sliding sleeve has a tongue (boss?) which engages a slot in the primary timing gear when the engine is to fire. When the engine is freewheeling, the governor pulls the sleeve to the left, disengaging the boss from the slot in the primary timing gear. Since the primary timing gear is not pinned to the crankshaft, it should stop turning as soon as the push rod comes up against the bottom of the spring loaded valve.

When the engine slows enough, springs pull the flyballs back in and pushe the sleeve to the right, engaging the primary timing gear. This cause the cam gears to turn and the cam to push the pushrod up opening the inlet valve. The sliding sleeve would have to be keyed to the crankshaft. Anybody see any issues with this approach?

 

[Bogstandard]

Chuck,

Not much of an opinion, but that definitely should work. You are just using the one locating pawl to keep the timing correct?

Because there is very little load on the firing gear train, maybe to keep the wear to a minimum, and keep the extraction friction to as low as possible, I personally would try a pawl with a half round end to it, with only a small straight sided drive area.

Just a suggestion.

John

 

[GailInNM]

Chuck,
Dog clutches work best when they either fully engaged or disengaged so anything you can do to improve this will be helpful. I have designed a few and here are a couple of things that have helped.

Make the slot in the timing gear much wider than the tongue on the sleeve. Maybe even to the point that the slot is most of the way around the gear with only a tongue sticking out to engage the other tongue. It is only driving one one face anyway so this will not change the operation. This allows time for the tongue to engage the slot more fully.

Keep the edges of the slot and tongue sharp with only a very slight breaking of the edge for wear purposes. This reduces the tendency for the sleeve and gear to cam away from each other. Harden the tongue and slot to reduce wear.

Dog clutches really like a digital, on-off, type input and not a slow analog input like the movement of the flyballs varying with RPM. Anything you can do to provide a break-over-center action in the movement of the sleeve will be helpful. One way to visualize this is to extent the pawl that engages the groove in the sliding sleeve on the opposite side of the bearing that the flyball arm pivots on. Hook a compression spring between these two extensions. When the flyballs are in mid position the spring will be at it's maximum extension and exerting no torque on the flyball arms. If the flyballs move either outward or inward the spring will try to move them in that direction. This is of course in addition to the regular springs in the governor. This is not a good working solution as the mass of the flyballs will slow the action down, but might work on a low speed engine if it could be fitted in. A much better solution would to make the groove wide and apply the break-over-center action to only the sleeve. What I described was only to visualize the desired action.

One other possible problem is if the clutch disengages part way through the cycle, say when the inlet valve is open. The valve would then stay open until the engine slowed down, shortly I am sure, before the clutch would reengage and allow the valve to close.

Chuck,I am not trying to be negative about it. I think it will work, but that it may get a little more complicated to work the way you want it to.

Gail in NM

 

[cfellows]

Gail, thanks for all the good input. You've made a lot of good points.

Chuck

 

[GailInNM]

Chuck,
I have designed five,I think, dog clutches so all that I know about it is the mistakes that you can make on five designs.

I just looked at my old punch press (1938 model) that uses a dog clutch to engage the crank to a free running energy storage flywheel. It has the same problem that operating a valve would have in that it must always stop the crank, think cam, with the punch at the uppermost part of the ram travel. On it the dog is retracted by a cam on the crankshaft at the uppermost point. If in continuous mode the dog is allowed to reengage during the next 1/4 revolution if the operating lever is held down. In single stroke mode the operating lever is disengaged until the lever is released and then it reengages when the lever is is again depressed.

If the flyballs only engaged the dog clutch and a cam disengaged the clutch somewhere around bottom dead center then the valve would never be held open except when desired. The disengagement cam could just be a ramp that the tongue could ride up on if the tongue were extended beyond the diameter of slotted hub of the valve gear with the slot in it.

I know, it gets complicated in a hurry. Easy for me to talk about it as I am not the one building it.

Gail in NM

 

[cfellows]

Here's another installment. This shows the Connecting Rod and the Piston. The piston doesn't require a ring and it really doesn't need to be all that snug a fit in the cylinder. A thou under the ID of the cylinder would be fine.