Pondering different fuels and engine specs.

[Cyruscosmo]

Hello All

I been wandering around on the net and am accumulating more questions than answers.

I have been talking a fair amount with another member trying to iron out the wrinkles in my understanding of things. Thanks to him I have finally got a reasonable understanding of how the hot well works and why. Ingenious system I must say!

Lately I have wandered into unknown territory and am back here with a few questions for those of you in the know.

I have been reading of the many ways to supply fuel to the boiler and have a number of options open to me. First option is all the free wood I can carry away. The wood is in the form of one-time use pallets that are for the most part various types of hardwood.

I was pondering the idea of using the wood to make charcoal and then using the charcoal to make bricks of about 1.5 x 2 x 5 inches. The reason being is that the bricks stack much easier than the wood does from pallets that are all different sizes. The bricks would be wrapped in wax paper and sealed by dipping in wax. This idea was not mine I read about it on a website long ago. They were looking for ways to make and handle charcoal without making an almighty mess in the process.

Anyone have experience with this?

The other method is waste engine oil. The same company that gives me the pallets also has a 1500 gallon waste oil tank that they fill at least once a month and pay to empty.

I understand that there are some folks here who use, or have used waste oil as a fuel. Got any words of wisdom for me?

I service a lot of equipment where I work and a number of the tools are water heaters for pressure washer duty that burn fuel oil. I have been adjusting and tuning these things for over 10 years now and am wondering how well one would work in a steam launch?

Not the water heater just the burner part.

Last question has to do with engine specs. I am looking for numbers from engines that are three cylinder in a size range suitable to push a 30' Edwardian. I will be building my own engine from the ground up and want to make sure I have the rod and main journals the right size. Mike has been more than helpful in that area and has given me enough practical info that I am sure I can build the crank too. Only problem is most of the write-ups for engine specs cover the piston size but don't cover the diameter of the journals.

Anyone have info or links for this?


Cheers
Scott

[fredrosse]

Main and crank journal bearings should have a maximum bearing pressure of about 800 PSI. Bearing pressure is bearing force divided by bearing area. That is, piston area x maximum steam pressure giving the bearing force on the journal. Bearing area is the journal diameter x journal length. Bearing pressures can be lower with less lubrication issues, and some engines use higher pressures, but 800 is a good value for typical steam engines.

Note however that if you are designing a new engine, there are very many other calculations that need to be accounted for, and it is recommended that you copy successful engines to avoid having to hire an engine design engineer for all those details.

As far as fuels go, there have been lengthy discussions on this forum about all kinds of fuels, including all that you have mentioned. See those discussions for details.

[DetroiTug]

Keep in mind, whatever is burned, the smoke from it will also be inhaled.

I would avoid any sort of pre-engineered combustible products that may have been treated with preservatives or pesticides - many pallets are. Waste oil smoke is not something that should be inhaled either.

Stick with clean untreated firewood. The charcoal idea sounds pretty interesting. Although as most realize eventually, there is enough work in gathering and handling (splitting, loading) wood that adding another laborious process to this is not very practical. And wood fired systems on a large boat use a lot of wood. How much wood? It's relative to how much work the engine is doing - small boat, low horsepower - not so much. A large boat requiring more horsepower (more heat), more wood.

Oil burners: There are many different types and they all work, again though, how well depends on the BTU output. Any type of fire will make steam with fuels from sagebrush to clean burning propane.

Crank Rod and Journal sizes: From the engines I've looked at and in the sizes we typically use, around 1-1/4" on the crank mains and 1" or better on the crank pin diameter. 1" width on both. Steam engines have an advantage over their I/C counterparts with the absence of an explosion every one or two rotations. The requirements for the lower end are far less demanding. A steam engine with less than ideal crank tolerances can run reliably where the same crank ran under an I/C cylinder wouldn't last but a few minutes.

-Ron