First run on steam

[SAM in LA]

Very nice.

Did you make the bucket too?

SAM

 

[zeeprogrammer]

That is beautiful.
I love detail...the bucket is great.

 

[mcr]

Few more bits to do but at least its coming together
[ame]http://www.youtube.com/watch?v=Gr1HPlVLBYs[/ame]

 

[SAM in LA]

Looks like it runs very well.

It sure makes a lot of noise.

Is that because its sitting on the counter?

Great job.

SAM

 

[mcr]

Thanks if you look closely you should see that the base plate is supported by two lumps of wood this might be the reason.

 

[Blogwitch]

Sam,

Steam engines like this do make a lot of noise as there is no loading on it, and of course running a lot faster than it would do when fitted into a boat and loaded with a prop.

When on the water, they only run very slowly, maybe just a couple of hundred revs rather than over 1K it is doing in the vid. You will hardly be able to hear it when on the water.

Lovely engine BTW Mcr, I especially like the water pump.

Bogs

 

[mcr]

Thanks for the nice comments it means a lot when your peers seem as happy as you are.
By the way I am looking for a by pass valve to return water to the tank any plans or pictures would be most welcome.
Mark

 

[Blogwitch]

Mark,

Where a lot of people go wrong is that they attempt to keep the boiler topped up so that you can have continuous steaming, say for hours.

That is the wrong way to go unless you are into endurance competitions, and then you have a special setups for boiler top up.

What you should aim for is to only extend the normal steaming time say from 20 mins to 40 mins. So the boiler water is going down at a slower rate. If you attempt to keep the boiler full, you will find that the amount of water you are trying to put in actually cools down the water in the boiler and steam generation is compromised.

I can't find any water bypass valves in my archive, and I am trying to remember the setup I used many years ago.

I am sure it worked on a principle that had a metering needle for feeding say one drop per 10 engine revs to the boiler thru a clack valve, and the rest of the pumped water went thru an adjustable spring ball valve (similar to a safety valve) that was set so that the back pressure generated by the pump was enough to counteract boiler pressure.

I always remember it was a real PITA to set up correctly and was a fine balance between feeding too much or too little. Eventually, I took it off and came in for a fag break more often when steaming.

I can do a C-o-C sketch if needed.


Bogs

 

[HS93]

all cheddar do is put a T piece on the output and then a tap valve with a fine adjust (standard Cheddar tap) in the bypass line that then runs back to the water tank, you can then set the about going to the engine and how much to the boiler, in fact you could use a servo and just top up every now and then depending on the type of running you have done. picture shows the valve on the T piece

Peter

 

[Blogwitch]

Peter,

There must be some sort of restriction to the water going back to the feed tank, otherwise all the water will just take the path of least resistance, back to the tank, and won't feed thru the boiler feed needle valve and so overcome boiler pressure.

I hope the C-o-C schematic explains it a little better.


John

 

[HS93]

Peter,

There must be some sort of restriction to the water going back to the feed tank, otherwise all the water will just take the path of least resistance, back to the tank, and won't feed thru the boiler feed needle valve and so overcome boiler pressure.

I hope the C-o-C schematic explains it a little better.


John

there is , if you just open it a very small amount only part of the water is diverted, this has been standard on most of Cheddar plants and works fine , it does take some fiddling to set up. that's why they use a valve with a fine adjustment

Peter

 

[mcr]

I can see the logic in both approaches John does that second valve have a spring a bit like a safety valve?

 

[Blogwitch]

Mcr,

Yes, it is adjusted until it is just above boiler pressure before allowing water bypass.

The needle valve then controls/allows pressurised pump water to overcome the boiler pressure thru the clack valve. (lower sketch)

If that restriction wasn't there, all the water would flow back to the tank because the pump water cannot overcome boiler pressure. (upper sketch)

The setting of the bypass spring could in fact be quite a bit higher than boiler pressure because of the differential pressures on either side of the clack valve ball. It just depends on how the ball is positioned against it's seat, if it is low down, the clack ball will lift easier than if it sits higher up on the seat.

I never really had much luck with a metal ball in the clack, they always seemed to leak, I did have some success once it was changed to a viton ball.

The way the Cheddar system worked, like Peter showed (but doesn't show the actual needle valve on the drawing), does only use one needle valve, but on their pumps, I found them very hit or miss and you could very easily flood the boiler. See schematic sketch.

You pay your money, you make your choice

John

 

[HS93]

Mcr,.

The way the Cheddar system worked, like Peter showed (but doesn't show the actual needle valve on the drawing), does only use one needle valve, but on their pumps, I found them very hit or miss and you could very easily flood the boiler. See schematic sketch.

You pay your money, you make your choice

John

I included the picture as it has the valve in it attached to the T piece, it is standard on all the range that has pumps i have used it on the Gemini and Proteus until I upgraded to the ABC on the Proteus worked fine the same system is used on the Monahan engines and the engines by John Hemmens (spit)

peter

 

[Blogwitch]

Peter,

Next time you come over I will put you over my knee. Rof}
The photo was so small I couldn't make out the needle valve.

I'm not trying to cause conflict, just trying to show Mcr that there are different systems that can be used quite effectively, just that some are more effective and controllable than others.

I am sure that there are many more mechanical systems that could be used. In fact I think I have an electronics kit somewhere that uses a burned out glo plug in the boiler as a sensor (more reliable than a sight glass sensor), which then sparks up a small electric pump.

Topping up a boiler has always been a very debateable issue.

My personal view, before I gave up model steam boats a few years ago, was that 20-30 mins (normal boiler running time without topping up) was enough time for steaming.

By that time the lubricator was usually needing to be topped up, the engine needed external lube and the gas tank was due for filling, plus I was ready for a fag and coffee break.

Others seem to want to sail forever and will go to any lengths to make it possible.

Just fitting an extra needle control valve between engine and boiler can usually extend normal sailing times by up to 50%. But that would be another discussion.


John

 

[HS93]

John woodruff from Cheddar models hated pumps and as you said , once the oil has run out you need to bring it in, Brian martin of MHB would not fit them to his engines or boats for the same reason you gave, the only reason i like them is you don't have to let the boiler cool to re fill and why use a hand pump when it can do it itself.

Peter

 

[mcr]

Progress update looks a bit like a scene from the African Queen ;D I must get that pond cleaned out.
I still have water tanks to make any advice would be most welcome I have add a couple of goes with little success so far.

 

[SAM in LA]

Progress update looks a bit like a scene from the African Queen ;D I must get that pond cleaned out.
I still have water tanks to make any advice would be most welcome I have add a couple of goes with little success so far.

mcr

Beautiful.

SAM

 

[mcr]

I figured that I would need the pump as I thought the multitubular boiler had a low capacity for the size.
I also thought that the engine might be steam greedy and consume large amounts of water when running.
Now that I have made the thing I think it looks rather cool when it runs 8)
I must admit that it is the whole fuss about steam engines which attracts me to them.

 

[mcr]

Placed the plant in the launch and tried it out pleased with the result so far.
Issues to be resolved include:
cooling of Gas tank
location of water tank
Using condensate to warm gas perhaps
make a some more fixtures and fittings
[ame]http://www.youtube.com/watch?v=dLMWGrIGjHA[/ame]