Engine choice

[TahoeSteam]

I believe I read an article or series of letters written by Cliff Blackstaff outlining his experiments with his series of engines, including his personal triple. If I recall correctly he found that even in those small engines there were gains in efficiency to be realized. After hearing stories about Cliff and his attention to detail, I'm willing to be he even put an indicator on them to confirm his findings.

If we wanted to be the most efficient we'd all put diese'ls in our launches

[Lopez Mike]

About twice a year, Cliff would show up at our house and my dad and he would stay up until all hours talking and arguing about one thing and another. Needless to say, one junior high aged person stayed up too! Thus I have a lot of respect for his practical and theoretical opinions.

That said, If I did decide to run a compound in my boat, I would arrange some sort of automatic simpling valve that operated when reversing or operating at low r.p.m.

I hate hitting docks.

And I still think that few of us pay enough attention to other ways to reduce fuel consumption to bother with compounding. It's been ages since I've seen insulation on cylinder heads. I know, it's a pain and we (I) like to look at the top head and polish the bolts. But if you can't touch it without burning your fingers, it's wasting fuel.

I burn about a apple box of wood per hour dorking around having fun so my little single does the trick for me.

Do continue building beautiful and complicated engines, though. I love looking at them and watching them run!

Mike

[Rainer]

Of course a compound will save fuel/need less steam even in our small plants. I know someone, who used a single as replacement for his broken compound. Both with same HP bore/stroke. He reported a measurable higher wood consumption during one year of operation.

Additional I knew someone who converted his plant from a twin to a compound because his boiler was not able to feed the hungry twin(s). After that he could keep up with the other boats without changing the boiler.

And yes, even if the LP only gets 1 to 0.5 bar it lives from the vacuum too.

And - OK - if you don't like to operate a simpling valve - you could run in trouble with a compound - but you have the same (bigger?) problem with a single.

All this questions - as ever with steam boating - must be balanced by the boat owner/builder with his limitations (financial/technical/operational/...) in mind. The problem of the newbie is that he don't know which question to ask and what to compare...

With now limitations I! would use a compound with a suitable boiler to save weight and fuel and have fun watching all that moving gear.

[Lopez Mike]

Yes Ranieer, my single requires watching when reversing quickly. I sit next to the flywheel so a quick kick will move it.

I was comparing a simple twin to a similar rated compound. Also one needs a vacuum pump with the compound. One more thing to act up.

I truly appreciate complicated power plants but mostly in other people's boats. I fell in love with the African Queen years ago and have never recovered. I ride with Wes and spend much of my time marveling at his engine and systems. But then I go back to Folly and throw in another chunk of wood and toot the whistle.

Mike

[PeteThePen1]

Hi Folks

Whilst following this thread I idly wondered if the John Winn vee twin (2.125 X 2.25 X 2) in Frances Ann would be modifiable into a compound. The engine is built of stock steel/cast iron rather than castings, so I imagine that one could possibly bore out one cylinder if there is enough metal, or replace it with a fatter lump. To my non-engineer's mind, I presume that one could get away with the same valve setting and reversing mechanism simply by plumbing the HP exhaust to the new LP inlet.

Or, is it a whole lot more complicated than that?

(This, by the way, is idle speculation as we have yet to run her under steam...)






Regards

Pete

[farmerden]

Mike Reverse? I just push the lever down and it reverses-everytime! I've watched you guys with singles kicking the flywheel and thought that might be considered abusive and it would scratch my chrome As for insulation-I have very little-Stupid me Check out Oesa for a well insulated engine
http://www.youtube.com/watch?v=sp6Xj6Fr0HU

[Rainer]

Hello Pete,

it depends on the settings/timing of your valves.

For the same output a compound need "more steam" in the HP than one HP of a twin. Therefore you have to change the timing and/or the valve shape.

Same thing with the expansion. You want to divide the expansion phase into two cylinder. Therefore you also have to change the timing and valve.

Next is the valve size. The partly expanded steam has more volume and so needs bigger steam canals - When you are lucky the canals of your twin are over dimensioned and you can use them anyway?...

[Lopez Mike]

Den,
Good info that your engine reverses fine. I had been fed all full of stories about compounds having startup problems. On big locomotives it quite necessary to run the engine as a simple at low speeds to get enough pull to start a train. Not that many hills on the water.

Ranier,
I agree that converting a simple twin to compound would be almost as much work as starting from scratch. I guess Pete could keep most of the engine though.

Mike

[TahoeSteam]

John- check your PM's concerning availability of an AVL compound.

[artemis]

About twice a year, Cliff would show up at our house and my dad and he would stay up until all hours talking and arguing about one thing and another. Needless to say, one junior high aged person stayed up too! Thus I have a lot of respect for his practical and theoretical opinions.

That said, If I did decide to run a compound in my boat, I would arrange some sort of automatic simpling valve that operated when reversing or operating at low r.p.m.

I hate hitting docks...

Mike

A number of engine manufacturers incorporated throttle valves that utilized a "starting" position which cross-connected steam to the LP valve chest. The engine in Burma Queen did/does. Davis of Toronto(?) also had a throttle valve that did the same. Al Rustad had a Davis engine in Cyrene and he made a drawing for me a few years back (which I've lost) that showed the interior of the casting and pieces with dimensions. Oceanid had a steam line that connected to the steam line to the HP valve chest and dumped into the LP valve chest with a valve in between, but it was a globe valve and VERY easy to forget that it was open leading to noticeable increase in fule consumption. The ones I mention above did away with this drawback.