Help on building a steam engine,boiler for a sidewheeler

[granath]

Hello, as the topic says, I'm new to this and i need some help, first of, I've got some general mechanics knowledge and I've always loved things that makes some kind of sound.. therefor i want to go with steam rather than electric.

the boat, will be a sidewheeler tug boat in approx 600-800mm in length, it will be my own design presumably. so therefor no problem building the boat after the engine size..

i would like to reverse with the boat(and go forward offcourse!;) ).

what will be the effect of having a long vs short stroke engine in my type of setup.

and I've got access to milling, cnc cutting machine's and a bunch of people willing to help me with that part.

i hope someone out there can help me were to start, what type of engine i should go for. and hopefully a nice set of plans. I've checked in the plans section but it's a jungle if you don't know what to look for.. so please help me out, and sorry for my bad English I'm from Sweden

Cheers!

[kno3]

Hello!

First, whatever engine type you choose, make sure it has 2 cylinders at least, to be self-starting and to run forwards/backwards.

If you want to keep it simple, an oscillating engine is recommended. It has fewer parts than a slide valve engine, is easier to make and usually very reliable.
Slide valve engines are very good, but of course require more work to build them.

I would recommend a long stroke engine, because it can run slower and you could drive the paddlewheels directly, as was done in most real life steamboats.

For plans, look at the downloads section, there's plenty to choose from.

[granath]

Okey! thanks alot, 2cylinder it is, and long stroke.. how do i know what engine size will be good for a 600-800mm ship?

how is power on a oscillation vs slide valve engine?

Cheers! 

[kno3]

I think power is mostly comparable if the have the same capacity. The slide valve engines can be operated at high pressures though, which on the oscillators would cause the cylinders to lift from the steam ports and leak. This shouldn't be a concern though, unless you plan on operating above approx. 3 bar pressure.

Some say that the oscillators consume more steam. I'm not sure about that, but my observation is that they tend to turn faster than some slide valve engines.
This depends on many construction aspects so it can't be generalised.

I can't really recommend an engine size, as I haven't tested enough. For a 60 cm boat a small one with bore up to 10 mm should be enough.
For instance, my 57 cm tugboat has a Wilesco D49 engine whose bore is somewhere around 9 mm and 20 mm or less stroke (I'm estimating here) and provides more power than needed to my tug. You can see it here:
http://www.modelboatmayhem.co.uk/forum/index.php?topic=11688.50

[philbutton]

My 'John H Amos' paddle tug (a much-modified Graupner 'Glasgow') is similar in size to your proposed tug and is fitted with a two-cylinder, double-acting oscillating engine of 10mm bore and 11mm stroke.  This is geared down approximately 7.5:1 to drive the standard Graupner paddle wheels and the arrangement works fine for me using a gas-fired vertical boiler.

A picture of the 'John H Amos and its power plant is posted in my gallery on this website.

[andy]

Hi,
today I would not construct an engine myself if there was not a need to a very special arrangement or so. In my actual model, I use the machine from Anton Vapeur, which is a very delicate mechanic. They also have horizontal engines, too. And why a steam engine has to be geared down- I do not know. i prefer power and never would gear down, but let her run as she wants to run. Steam engine are as well as electrical engines in this using. Take enough power and all will be ok.

Andreas

http://fabrice.bretagne.club.fr/Index.htm