# Hit and miss STEAM ENGINE????



## Brian Rupnow

Okay, I know---seems like an oxymoron. I have been thinking the last few days of steam engines. I have built 4 steam engines (running them on air) and they all ran well. They also will drain an air tank in fairly short order, because of the high consumption of air. Now---a hit and miss i.c. engine runs on a type of inertial governor, that only lets the engine fire when the RPM's drop below a certain speed. Once it fires, the exhaust valve is held off its tappet untill RPMs fall off again. My idea would never work as a practical engine, but why couldn't one build a steam (air) engine with a pair of large flywheels, and the same type of inertial governor.--The engine would function in normal mode from zero speed and accelerate untill a desired speed was reached. At this speed, the inertial governor would shut off the steam/(air) and the large flywheels would give up their stored energy and keep the engine running untill the engine slowed beyond a critical RPM. When this critical low RPM range was reached, the inertial governor would open the steam/(air) valve again.--Like I said, not a practical engine, but an engine that would run a very long time on a given amount of compressed air.---Has anyone ever done this?


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## GailInNM

See what happens when you go away for a few weeks Brian.
 Is this sort of what you mean?

http://www.homemodelenginemachinist.com/index.php?topic=3732.0

Gail in NM,USA


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## Brian Rupnow

Son of a Gun!!! Thats a beauty. I guess I didn't have an original idea after all.---Brian


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## tel

I sort of, almost, did that a few years back Brian - well, it didn't stop the steam, just 'notch up' the cutoff til it was working with minimum steam admission. Worked rather well, if I do say so


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## tel

A couple of shots of the engine in question











The valve gear at speed


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## rickharris

Brian Rupnow  said:
			
		

> Hit and Miss on steam.---Has anyone ever done this?



John Toms site has plans for a compressed air hit and miss under IC engines http://www.john-tom.com/html/ICEngines.html


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## Brian Rupnow

Time on my hands and a curious mind are an evil combination----





View attachment FULL ASSY HIT AND MISS ENGINE.PDF


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## Brian Rupnow

Well, enough of this foolishness for a Saturday morning!! Not to disparage anyone elses drawings/plans, but there seems to be a lot of either missing dimensions or else downright wrong dimensions on the information I have dug up on this project. Of course, that could just be me. ;D ;D This is a fascinating little engine.--Brian


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## 10K Pete

OK, I gotta ask this question:

Doesn't the flyball governor on a steam engine 'sense' speed, like the governor on a hit and miss, and adjust the amount of steam going into the engine? I seems to me like the regular flyball governor does the same thing.

What am I missing here??

Thanks,
Pete


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## tel

> Doesn't the flyball governor on a steam engine 'sense' speed, like the governor on a hit and miss, and adjust the amount of steam going into the engine? I seems to me like the regular flyball governor does the same thing.



Well, yes it does, but it doesn't shut the steam off completely, which is what I think Brian is trying to achieve here. Mind you, the Ames type - shown in my pics - could be slightly modified to achieve the same end.


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## 10K Pete

Ahhhhh, I see. Thanks Tel, ya turned the light on for me! And I think I see where a modification could maybe do the shutoff trick.....maybe. The 'vision' is still fuzzy.

Thanks,
Pete


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## Brian Rupnow

10K Pete---To help understand the difference in the two systems---Yes, the flyball type governor does run off engine speed, and it does supply more steam or less steam, depending on the load on the engine and the RPM of the crankshaft. However, the valving on a conventional steam engine is ran independently of the governor, from a mechanical "cam" (eccentric). The valve which lets steam enter or exit the cylinder is going to operate the same regardless of how much or how little steam is entering the cylinder. Because of this, the engine will not "coast" very well.--For example, if the inlet valve was shut off completely, then the piston would have to"pull a vacuum " to go down on the power stroke , which makes for poor coasting. (Kinda like a Jake brake in reverse)
  On the hit and miss type of engine, the governor is also speed sensitive, but when hi speed and centrifugal force cause the weights to fly out, the steam inlet valve is rendered inoperative (it stays closed) and the exhaust valve remains open all the time, so that the engine can coast (freewheel) without pulling a vacuum.


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## Brian Rupnow

With all due respect to Chuck Fellows, who I believe is the originator of this unique valving system, there seem to be a lack of complete details on the valves inner workings. I have used the drawings posted in the download section, plus a bit of imagination, and the fact that the smallest taps and dies I care to work with are #5-40 to create 3D models of this valving system.--I am not finished yet, but have made a good start. (I have not shown the spring, clip, and washer that are on the bottom of the valve yet.) When I get this sorted out to my satisfaction, I will post complete details (my interpretation), but as I say, any credit for the original idea goes to Chuck Fellows. EDIT--EDIT--EDIT--In case you didn't notice, I had the port in the side of the valve facing the wrong direction. I have edited the .jpg and the .pdf files so that the port in the side of the valve faces in towards the cylinder and I put a #10-24 set screw thru the side of the cylinder head to keep the valve in place.










View attachment INLET VALVE CLOSED EXHAUST PORT OPEN.PDF


View attachment INLET VALVE OPEN--EXHAUST CLOSED.PDF


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## cfellows

Nice drawings, Brian. Wish I had your experience and ability with CAD!

This design is one of my earlier versions. Since then I've simplified the design to use a single hole from the head into the cylinder, instead of two, and to simply use a ball bearing for the slave valve instead of a cylindrical piston.

I only note this, because it's somewhat easier to build.

Chuck


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## Brian Rupnow

Chuck--are there any plans of this "later version" you speak of?-Where can I see more information about it? I am glad you have chimed in here, I always feel a bit cheesy about posting my interprestation of someone elses design.--Does the later version give the same performance and distinctive "popping" sound?


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## tel

this one?


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## Brian Rupnow

Yes, Tel---I guess that must be it, although Chuck metions a ball rather than a cylindrical slug as shown. --Do you have the link to whatever thread you got those pic's from please.---Brian


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## tel

Regretfully no mate, I just saved the images into my M.E. folder. Also these.


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## 10K Pete

Well I'll be dipped. Any of those are about the slickest valve setup.......

Sure are some clever folks around here! I'm like a fly on the wall just soakin' it up.

Thanks!
Pete


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## Brian Rupnow

Well, this is what it ends up looking like. I used 3 1/2" diameter flywheels to give as much inertial coasting as I could get, The bore is 3/4" and the stroke is 1.236 (Chuck will know why). I used a 1/4" diameter crankshaft with brass one peice bearing blocks. I kept everything as simple as I could, with a one peice crankcase hogged out of aluminum. I'm still not totally clear on the connection between the valve stem and the push rod which activates it, but that will come.





View attachment FULL ASSY HIT AND MISS ENGINE-DRAWING.PDF


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## Brian Rupnow

Okay---If I've remembered how to do this, we'll have a little video of an engine that doesn't exist yet----


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## tel

> I'm still not totally clear on the connection between the valve stem and the push rod which activates it, but that will come.



Shouldn't need a connection Brian, just a means of keeping them lined up with each other (think automotive valve rocker/push rod)

Looking good so far mate, time to start makin' chips!!!! ;D


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## Brian Rupnow

Due to bad economy, global warming, and the fact that I only have a small peice of brass and lots of aluminum, is their any real issue with making the cylinder from aluminum and the piston from brass? I have always done the reverse of this on previous engines, but I believe that for the small amount that these engines actually run, I will be old and dead before the aluminum cylinder wears enough to cause any running issues.---Opinions?????????


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## Brian Rupnow

tel  said:
			
		

> Shouldn't need a connection Brian, just a means of keeping them lined up with each other (think automotive valve rocker/push rod)
> 
> Looking good so far mate, time to start makin' chips!!!! ;D



Tel---As I dig deeper into this engine, it appears that there are three distinctly different springs that do different things. (Hey, that rhymes!!)  There is a spring in the cylinder head that operates the exhaust valve slug, there is a spring buried in the mechanism of the governor to return the weighted arms to the "parallel to crankshaft" position at low RPM. And a third spring which has the function of #1--keeping the intake valve seated, and also #2 keeping the fork which is activated by the "cam" seated against the rotating collar of the dog clutch.---Right?


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## Brian Rupnow

Allright!!! I've worked my way thru this thing with solid models. I may not build it untill fall, but since I have very little engineering work right now, I'm going to go ahead and detail the whole thing. Again, this is not meant to take away from any of the excellent work done by Chuck, superfast. putputman, Brent, nor anyone else that has built this. Its just that this is the way I have to work it out for myself before I can build anything, and if anyone else can benefit from it, then thats a good thing. If you see any mistakes or omissions, let me know and I will fix things and repost the corrected .pdf.---Brian

We will start with the crankcase, made from a solid block of aluminum---







View attachment CRANKCASE.PDF


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## Brian Rupnow

And then move on to the cylinder--





View attachment CYLINDER.PDF


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## Brian Rupnow

And a cylinder head---


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## Brian Rupnow

And a bearing (even though I called it a Bearing Support)





View attachment BEARING SUPPORT.PDF


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## Brian Rupnow

A plain flywheel--





View attachment PLAIN FLYWHEEL.PDF


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## Brian Rupnow

And a fancy flywheel (for the governor)---





View attachment FLYWHEEL FOR GOVERNOR SIDE.PDF


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## Brian Rupnow

And the exhaust gland---(I didn't know what else to call it).





View attachment EXHAUST GLAND.PDF


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## Brian Rupnow

Upper half of the intake valve housing--





View attachment UPPER HALF VALVE BODY.PDF


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## arnoldb

Shucks Brian, shouldn't this lot be moving to the "Plans" section  ??? ???

Looking VERY good !


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## tel

> Tel---As I dig deeper into this engine, it appears that there are three distinctly different springs that do different things. (Hey, that rhymes!!)  There is a spring in the cylinder head that operates the exhaust valve slug, there is a spring buried in the mechanism of the governor to return the weighted arms to the "parallel to crankshaft" position at low RPM. And a third spring which has the function of #1--keeping the intake valve seated, and also #2 keeping the fork which is activated by the "cam" seated against the rotating collar of the dog clutch.---Right?



Yep, that's how I see it as well. Plans are coming along nicely mate - another one for my 'future projects' folder


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## Brian Rupnow

When I get all the details finished I will post a complete file of .pdf's to the download section. I didn't really know that I was going to go this far when I started dabbling with the project last week. ---Thats why it started out in the "break room" section. This is the slowest year I have ever had for engineering work, and there are a 100 hours in every day when I have no work to do. I have been interested in this engine ever since Chuck Fellows built the first one. I looked thru all the threads posted by various builders of this engine, and one thing that struck me was that there was no file that was absolutely complete with details of every part. I do plan on building this engine, and I absolutely MUST have complete plans to work to. So---since I have to do it this way for my own benefit, I might just as well post all the plans for others out there who don't like to build engines "by the seat of their pants".----Brian


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## Brian Rupnow

Lower half of valve housing--


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## Brian Rupnow

And this morning we have the valve stem--





View attachment VALVE STEM.PDF


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## Brian Rupnow

And of course the valve spring and washer--









View attachment .093 WASHER.PDF


View attachment VALVE SPRING.PDF


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## Brian Rupnow

And the valve push rod--





View attachment SOLDERED ASSY OF VALVE PUSH ROD.PDF


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## Brian Rupnow

The valve actuator lever--






View attachment VALVE ACTUATOR LEVER.PDF


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## Brian Rupnow

CRANKSHAFT---






View attachment CRANKSHAFT FOR HIT AND MISS.PDF


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## Brian Rupnow

CONNECTING ROD---





View attachment CONNECTING ROD.PDF


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## Brian Rupnow

PISTON--






View attachment PISTON.PDF


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## Brian Rupnow

VALVE ACTUATOR BUSHING





View attachment VALVE ACTUATOR BUSHING.PDF


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## Brian Rupnow

SLIDING CAM--





View attachment SLIDING CAM.PDF


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## Brian Rupnow

SOLEDERED ASSY. OF BACKING PLATE THAT SUPPORTS COUNTERWEIGHT ARMS--





View attachment SOLDERED ASSEMBLY OF BACKING PLATE.PDF


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## Brian Rupnow

COUNTERWEIGHT ARM ASSEMBLIES---





View attachment SOLDERED ASSEMBLY OF WEIGHT ARMS AND WEIGHTS.PDF


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## Brian Rupnow

Well, I think thats it. if I missed anything, let me know. If you see any blatant mistakes let me know. If you like what I've done here, and/or want to download the files and use them yourself, please click on the "applaud" button under my name and give me a karma point.---Brian





View attachment FULL ASSY HIT AND MISS ENGINE.PDF


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## Brian Rupnow

If there is anything you don't understand (and there probably will be), please ask me and I will try to answer your questions.--There was a lot that I didn't understand when I started into this, and I think I have it pretty well figured out now.


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## mklotz

A detail (doesn't need to be a dimensioned drawing) of the spring location/arrangement on the governor might be useful.


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## Brian Rupnow

Good question, Marv---this should show it clearly--





View attachment ASSY TO SHOW 2 POSITIONS OF COUNTERWEIGHT ARMS.PDF


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## Brian Rupnow

A bit more explanation as to how the cam works for the hit and miss cycle---





NOTE: THE FOLLOWING NOTE ON THIS DRAWING HAS AN ERROR ON IT---

VALVE ACTUATOR BUSHING-THIS IS SET SCREWED TO
THE CRANKSHAFT AND CAN NOT MOVE. THE FORKED
END OF THE VALVE ACTUATOR LEVER RIDES ON IT, HELD
IN PLACE BY THE SPRING ON THE VALVE-STEM AND THE
CRANKSHAFT BEARING.(BEARING NOT SHOWN)-THERE
IS A SHOULDER ON THE "VALVE ACTUATOR BUSHING"
THAT KEEPS IT FROM MOVING TOWARDS THE FLYWHEEL

IT SHOULD READ

VALVE ACTUATOR BUSHING-THIS IS SET SCREWED TO
THE CRANKSHAFT AND CAN NOT MOVE. THE FORKED
END OF THE VALVE ACTUATOR LEVER RIDES ON IT, HELD
IN PLACE BY THE SPRING ON THE VALVE-STEM AND THE
VALVE ROD SPACER (SPACER NOT SHOWN)-THERE
IS A SHOULDER ON THE "VALVE ACTUATOR BUSHING"
THAT KEEPS IT FROM MOVING TOWARDS THE FLYWHEEL 

View attachment EXPLANATION OF HIT AND MISS CAM ACTION.PDF


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## Brian Rupnow

I have added a few more drawings and saved everything as .pdf files in the "Downloads" section.
http://www.homemodelenginemachinist.com/index.php?action=tpmod;dl=item198


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## Brian Rupnow

This is something I was thinking about last night, namely, how to put a bolt pattern in each end of a round cylinder when the two bolt patterns are offset at a 45 degree angle from each other. I came up with this answer as I was trying to drift off to sleep.





View attachment JIG FOR DRILLING CYLINDER.PDF


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## RobWilson

great post Brian :bow: looks like a lot of work went into them there plans, when dose the build start? ;D
Rob


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## Brian Rupnow

Well, actually it started about 15 minutes ago. I went over to see one of the companies that fabricate custom machinery for me this afternoon, and put a big whine on them about the high cost of aluminum, sob, sob. ---So being the great fellows that they are, and seeing as how I've put about $28,000 worth of work thru their shop this year so far, they let me go out back and launch a full scale raid on their "cut-off" bin. I came home with a big cardboard box full of about a zillion dollars worth of aluminum, and just started work on the cylinder.


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## RobWilson

Great stuff Brian ,there is nothing like a Zillion Dollars worth of stuff for free :big:
Hope to see lots of photos ,Thanks for sharing your drawings
Rob


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## Brian Rupnow

I have started to build this engine, so I have moved it over to"A work in progress".---Brian


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