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[south steyne]

Hi everyone I am interested in building a unaflow engine and wondering if anyone has experience with this type of engine any advise would be most welcome.
John

[ooyah/2]

Hi John,
Have a look at this, is this what you wish to build.
http://www.modelboatmayhem.co.uk/forum/index.php?topic=24568.0
George

[south steyne]

 )Thanks for the links and some very good info, I am looking to build the uniflow engine to power a large tug and wondered if there was any advantage over a slide valve engine of similar size to Stuart d10.
John

[ooyah/2]

Hi John.
DISADVATAGES OF UNIFLOW.

1--Not self starting,
2--non reversible
3--Usually working under high pressures therefore noisy and a silencer is required.
4-- Can't think of any advantages.

D10 or ANY OTHER TWIN DOUBLE ACTING ENGINE.(  Piston valve or Slide valve )

I-- Self starting.
2--Reversible
3-- Can be radio controlled
4-- Look more like a steam engine that would be fitted to full size boat.

Hope that this helps.
George.

[gondolier88]

It wouldn't be worth the bother trying to fit what was never a truly successful valve gear in full size into a model of that size, it would be seriously unreliable in service and as George says utterly horrible to listen to.

Go for slide valves, or if you want something different and contemporary to later tug engines; piston valves.

Greg

[kno3]

I've heard of a steam launch in England with uniflow engine, being in operation. Supposedly this kind of engine gives better performance than the slide valve design by having less thermal losses?
Anyway, here is the link to the steamboat with the uniflow:
http://www.youtube.com/watch?v=SuKzdm55FZ8

[gondolier88]

I've heard of a steam launch in England with uniflow engine, being in operation. Supposedly this kind of engine gives better performance than the slide valve design by having less thermal losses?
Anyway, here is the link to the steamboat with the uniflow:
http://www.youtube.com/watch?v=SuKzdm55FZ8

Spot on Kno3, that is the reason uniflow was invented, however, even the size of Elpenor's engine really limits the scale of efficiency that you gain by not having the inlet valve being also the exhaust, and just listen to the thing!

It does work though, very well, but it took some effort to get it running that well.

Greg