Gail's version of Chuck's Horizontal single is alive

[GailInNM]

Chuck,
The valve is just a standard commercial one used for flow control in pneumatic systems. I have had it on my test regulator for probably 20 years, but it probably came from MSC or McMaster. It is 1/4 NPT female in and out and is hooked right in to my regulator. It has a big knob on it so it is easy to adjust. I have another one that I can put in line at the engine that is sold by home improvement stores around here for water control for evaporative coolers. As I recall, you are in a dry part of the country, so you probably have them in your area also. It is 1/4 compression tube in and out. When I want to run a conventional steam engine slow, I put it very near the steam chest and keep the pressure up high on the inlet side of it. I allows you to run conventional engines, particularly multi cylinder ones, much slower that way. Using it as a flow control, as the engine slows down, the pressure in the chest will increase to keep it going. It needs to have as little a volume between the valve and the engine for that to be effective.
Gail in NM,USA

 

[GailInNM]

Most of the essential modifications are complete. I still need to make a base plate and do some changes in the intake and exhaust fitting and piping, but I needed to check to see if the mods worked. Video is at 82 RPM.
[ame]http://www.youtube.com/user/nmsteam#p/u/6/ZYLc1-x4-F0[/ame]

 

[chuck foster]

gail...............thats one very nice sounding and very slow running engine you have :bow: 8)

didn't think and engine would run that slow

chuck

 

[bretk]

Gail,

Holy Crap ! That is SLOW ! :bow: :bow: :bow: :bow: :bow:

-Bret

 

[cfellows]

I love it! What are the specs on the spring you used for the piston slide valve (wire size, diameter, length)?

Chuck

 

[GailInNM]

The spring is from a Walgreen's Corner Office gel pen, but stretched out a little bit. Started off as 0.85 long from the pen and I stretched to 1 inch long. Specifications are: 0.20 Outside diameter, 0.015 carbon steel wire, with 8-1/2 active turns and two tight turns at each end.

My piston is 0.265 diameter instead of 0.25 that you had. My bore was a little bit rough at .25 so I reamed to .265 as I had a flex hone that size to smooth out the bore. I counter bored the piston 0.312 to provide extra room for the spring so the spring retainer is the bolt on flange at the end of the cylinder with a 3/16 hole through it.

The real key to making it run slow it to get rid of all the friction possible. The only plain bearings are the rod small end, which is 2024 teamed .1255 running on a dowel pin, and the cam gear which is bronze 660 on a 12L14 shaft. I may change out the cam gear bearing to a ball bearing sometime in the future.

Th main cause of friction on small engines is Oil! My piston and cylinder are cast iron. They were lapped independently of each other with 600 mesh (25 micron) diamond using brass laps. I lapped to a clearance at 0.0005 inch. At these speeds, cast iron against cast iron has a very low friction coefficient and is quite happy running dry. As soon as you put even the lightest loin on it, the viscosity of the oil at least triples the drag. The real problem is that if the air is moist, it will rust very quickly. I will probably make another piston and lap it for 0.0010 to 0.0015 clearance so I can use light oil and still have fairly good slow running. For the video, I removed the cylinder and cleaned the piston and cylinder with brake cleaner and dry compressed air. After the video, I ran it for about 2 hours and it picked up enough oil from my air line that the low RPM increased to about 100 RPM.

I can get a really good "bark" form it by running the RPM up to about 1000 by increasing the air flow, then load the engine down with a rag on the flywheel to about 150 RPM That makes the air pressure build up in the cylinder and then gives a sharp report when it exhausts.

Gail in NM,USA

 

[rake60]

I'd say there are TWO :bow:'s in order here.

:bow: #1 to Chuck for his design and sharing it here.

:bow: #2 to Gail for showing just how far that design
could be taken.

I LOVE slow runners!
Great work on BOTH fronts!

Rick

 

[GailInNM]

Thanks Rick.
Don't leave Bret out. I stole a lot of ideas from him and got a good bit of information from him also. And mine will never get dressed up like his !! And his is a good runner too.

http://www.homemodelenginemachinist.com/index.php?topic=2422.0
Gail in NM,USA

 

[rake60]

And a :bow: to Bret as well!

THIS is the type of a hobby community I'd dreamed could happen.
YOU people have proved it's possible!

Rick