CliShay/Big Bertha question

[ChipsAhoy]

I am making the pattern to cast cylinders for the Big Bertha, An engine designed to go into the CliShay. I have no experience with vertical steam, and next to none with horizontal beyond building up a pair of Allens cylinders to put on my Wendy.
In drawing up the cylinder, I don't see any accomodations for cylinder cocks. I dug around a bit, mostly looking at Stuarts, but I haven't seen any with drains for condensate. Closest thing I see is pin hole ports on Allens brake cylinders.
Anybody have any ideas, experience, first hand knowledge re; drains for vertical steam? Are they even necessary?
Scotty

[K. Browers]

Hi Scotty,
Until the cylinders are warmed up you will have condensation in the cylinder. If there will be enough enough to cause a problem I can not say for sure. A slide valve engine will force condensation past the valve where as a piston valve engine might be damaged. Since you are making your own patterns why not add the bosses for the fittings it is only a little extra work. If you do not need the cylinder cocks machine them off the castings later..

One thing I do not think that can be denied is cylinder cocks will add a certain bling factor...

Cheers
Karel

[bill4227]

I am building the Clishay/Big Bertha from the Modeltec plans and am planning on adding the cylinder cocks. Also adding piston rings on the piston.

Bill

[NP317]

I would add cylinder cocks.
My steam launch engine is a vertical steeple compound. It has cylinder cocks for both cylinders and at the bottom of the steam chest.
And they are needed.
RussN

[ChipsAhoy]

We also are using the modeltec plans, going to follow advice from here and pour Bronze cylinders, so I can put the boss where needed.
I can guess on locating the cocks for the bottom. But on the top...just above the piston at the bottom of the stroke? That simple?
Wouldn't happen to have any photos handy?
Ya, didn't even think about the steam chests.
Thanks
Scotty

[Bill Shields]

An alternative to cylinder cocks is a way to pour cylinder oil into the top cylinder head then turn the engine over by hand to displace the condensate.

This is what I described in Tom Thumb article and have done for 15 years on my personal tom thumb loco.

Yes...it is messy as all that oil comes out the stack but clears cylinders and steam chests.

A drain line on the exhaust pipe would be of benefit if you do not like having your engineers cap lubricated.

[Builder01]

We also are using the modeltec plans, going to follow advice from here and pour Bronze cylinders, so I can put the boss where needed.
I can guess on locating the cocks for the bottom. But on the top...just above the piston at the bottom of the stroke? That simple?
Wouldn't happen to have any photos handy?
Ya, didn't even think about the steam chests.
Thanks
Scotty

The location for the drain valves should be toward the ends of the cylinders. Ideally, the drain holes would be drilled In the space between the piston and cylinder cover when the piston is closest to the cylinder cover. One hole at each end. You don't want the piston to ever cover the drain holes.

[ChipsAhoy]

Let's ponder on that one a bit.
On Horizontal cylinders, gravity would deliver the condensate to the port...where steam would exhaust it.
On vertical cylinders, the same would happen to the bottom, but on the top, the 'piston' would have to deliver
the condensate to the port, where the steam could once again do it's duty. On the top end it may not get total evacuation, but
the balance should "cook" off in short order.... I would think. First blush... that should work...why not?
Russ and Bill, where are your ports located on the top side cylinders?

[Bill Shields]

Top center. Pipe plug on each head. I put the piston on BDC, fill cylinder to top by eyeball..insert plug and turn engine over by hand. .SLOWLY

Gravity does not flush out the steam chest since the 'lower edge ' of the chest is above the port. Hence my idea to use the moving piston to flush oil through.

[Builder01]

I think the important thing, for cylinder drains to be effective, is that the piston does not ever cover the drain hole at either end of the cylinder, otherwise, the water cannot exit the drain cocks. If the drains are mechanical, you leave them open until only steam comes out.

[NP317]

Chips:
Here's a photo for my older, unrestored, steeple compound engine and boiler. Cliff Blackstaffe designs.
You can see the cylinder cocks at both top and bottom of each cylinder, and at the bottom of the steam chest.
In operation, the engine is run slowly to warm it up, and the cylinder cocks remain open until steam only is exiting the cylinders.
RussN

[ChipsAhoy]

Great pic...I can clearly see the piping. great treasure also!
Thx
Scotty