Single cylinder steam engine handling

[Spencer M]

Yesterday I had a little throttle time on the show's Case 75. Being used to twin cylinders with perpendicular cranks I frequently found myself foundering in crank angle purgatory. I rocked the reverser back and forth and was very gentle on the throttle but just didn't want to move after the piston had moved past 75% of the stroke from a standstill. I understand that this has to do with the non adjustable minimum cutoff of the engine. The valve even on minimum cutoff shuts before the piston reaches dead center, in my case it seemed that it shut after 75% of the stroke.
Not realizing this, and thinking that the steam admission continued up to around the 90% range I found myself frustrated and baffled.

I never actually got the engine on dead center.

Is the minimal cutoff factory set to improve steam economy?

[Jerry Christiansen]

Hi Spencer,

You looked like you were having a good time on Sunday.

I believe another one of the reasons for the cutoff is to keep a little steam in the cylinder to act as a 'cushion' for the piston as it goes to bottom (or top) dead center.

Someday when you are steaming around, we can belt up to the Prony Brake and let you practice firing under load.

See you at Breakfast On The Farm?

later,
Jerry Christiansen

[Spencer M]

That would be great! Thanks for the reply:)

[Mike McKnight]

Spencer,
After having ran and owned singles and doubles, you're correct in saying there's quite a difference between running a double and a single. Oh man, do I love my little 18 HP Gaar-Scott double! ;)

You might already know this, but there's quite a bit that can contribute to hard-starting on a single. Lower steam pressure (the lower you get below 100 psi the worse they get....try belting an engine on 75 psi!!!!) makes 'em harder to handle. More steam pressure gives 'em more "oomph" to get 'em started the first time. Timing set not quite right....leaking throttle....all can contribute to harder handling.

Like anything else, practice makes it all easier. More time on the throttle will help make all the difference in the world. Flip the reverser the other way, give 'er just enough throttle to roll about 1/4 turn, flip the reverser again, then throttle and she usually will go. I've gotta say though, if you're NOT hitting TDC constantly, you're definitely doing something right!

Good luck!
Mike

[Goat Boy]

Actually the Case engines are probably on the easier side to handle for a single. The Russel or the Rumely with the shifting eccentric are probably the easiest... Try a 24 or 28 Minnie on Soft Ground Sometime...:eek:

The closer to the center the reverse lever is the quicker they cut off. Yes even with the reverse in the corner they will cut off at about 60% to 70% of the stroke. So when starting out put the lever in the corner. After a while you will get the hang of it. Then your Ready for the Teeter Totter...:D