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February 26, 2003
Fark Fest
All that is old is new. Steam powered ships. Nothing new you say. Well, what about a steam powered jet boat (see the story here)? It seems an Australian inventor sold the design of such an engine to a British company who is trying to make a commercial product out of it. I don't know whether this thing actually works but it is an interesting twist on an old power source. The article says it works like this:
A separate boiler heats water to generate steam, which is pushed at about four times normal atmospheric pressure through a hollow tube submerged in the water.
When the steam hits the water, it immediately condenses to 1,600th of its previous volume. The resulting effect is a dramatic drop in pressure, essentially a vacuum, that sucks water from the front to the back of the tube and thus produces thrust to move.
Speaking of old modes of power. How about paper airplanes? No, they haven't discovered a way to build 747s out of paper. I'm talking about the kind you make out of folded paper and toss over to the cubicle across the aisle. Follow this link here to the WRPA Fliers Club and learn how to fold'em and how to hold'em. Included at the site is the 1994 record holding plane that stayed aloft for 18.8 seconds.
Aloha!
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Comments
Not so new as they may think. The dingus they have which "forces the steam and water to react with air drawn from the surface". Otherwise, I (and my parents before me, which puts it back at least to the '30s) used to play with these in the bathtub as kids. IIRC, my Cub Scout handbooks had directions on how to make one with a coil of metal tubing and a candle in a boat hull. We called them "pop-pop" boats. Basically, a candle under a chamber (or coil) would boil the contained water, forcing the steam out the tube openings in the back of the boat. New water was then pulled in, and the whole process repeated itsself. Actually, not too different from Hero of Alexandria's steam turbine (couple of hundred AD?).
For more: http://www.nmia.com/~vrbass/pop-pop/buildpop.htm
Posted by: Jon at February 27, 2003 06:10 AM
Thanks for the follow-up. I guess it confirms that all that is new, is old. But I'm not so sure this is a practical device because, barring a way of creating large quantities of steam without the weight needed in fuel and other assorted mechanisms, this can only work in larger ships. The question then is can this type of propulsion scale up large enough to be used to efficiently move ships?
Aloha - Dan
Posted by: Dan at February 27, 2003 06:52 AM