Steam weapons?

[Faeelin]

Okay, looking over information on Leonardo, it turns out that he developed the idea for a cannon, based on Archimedes, using steam.

Could a steam cannon be effective?

[David S Poepoe]

Not without a reliable and easily transportable means of continually supplying steam to it. It could probably be used in either fixed fortifications or on warships (in limited number). As far as I know the only 'appearance' in popular culture that a steam cannon has made was in the movie "The Fearless Vampire Hunters".

[Diamond]

Originally Posted by David S Poepoe

As far as I know the only 'appearance' in popular culture that a steam cannon has made was in the movie "The Fearless Vampire Hunters".

Really? That's that old Roman Polanski movie, isn't it? I don't remember a steam cannon. Granted, its been about ten years since I've seen the movie...

I tend to agree about the impracticability of having mobile steam cannon; fixed positions seem your best bet.

But if you had a steam engine big enough to power a proto-tank, maybe it could siphon off some power to fire a cannon as well?

[Ward]

Originally Posted by Faeelin

Okay, looking over information on Leonardo, it turns out that he developed the idea for a canon, based on Archimedes, using steam.

Could a steam cannon be effective?

The British Navy used a steam Cannon in WWII on Small Ships it ran off the steam from the bolliers of the ship . It was use to shoot Handgernades at German aircraft and also against German patrol boats .

[Archangel Michael]

How small of a steam engine can you build without losing efficencey?

[DuQuense]

Stanly Steamers Cars & aircraft

[Faeelin]

Apparently a greek historian by the name of Lazos built a copy of archimedes weapon. Fired a 40kg rock about a kilometer, or an 88 pound rock half a mile.

[NHBL]

I read a book or two, overall fairly bad, but a steam machine gun is put into use against the Mongol hoardes. It seemed practical to me at the time, but I don't remember the details. If not a machine gun, a semi-automatic should be possible for castle defense and ships.
The small calliber needs less steam than large rounds.