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Old 07-08-2010, 01:18 PM   #120 (permalink)
Dr. Jerryrigger
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Join Date: Jun 2010
Location: mass
Posts: 181

The Sh*t-Box - '99 Subaru Impreza Outback Sport
90 day: 27.81 mpg (US)
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Quote:
Originally Posted by LeakyIdeas View Post
Why worry about a boiler? i can see two options without one.

if you drip a small amount of water into a tube at 500F it expands to about 1600times it's volume,
effectively giving you a plusejet if the tube if small. requiring just a one way value and either a piston + conrod attached to a ratchet and flywheel, after the 'charge' is spent there is very little presure so the next drop can be added. but that requires a bit of metal work...and off the shelf microbore copper pipe.

another option,

if you heat small rc motor to 500-600F and small amount of water is injected a few degrees ATDC, it will expand 1600 times and force piston down....hey presto you have a tiny steam engine. you don't need much pressure to inject the water depending on the porting of the 2 stroke motor, as high compression is not required, and you don't have to worry about storing steam...just condensing the exhaust assuming you want to recycle the water.
small solenoids are easy to buy and time with a magnet and reed switch means nothing clever (pics etc) should be required.

I'm looking on ebay at the moment for something i can use...best should be a broken 2 stroke RC motor, 'diesel' should be good as it already has a threaded hole to the head in the form of a compression adjustment screw.
I seem to recall water to steam expiation is 1:1075, but that is likely not factoring in a large temp change. Anyway, that doesn't really matter at all...

If we are just trying to drive the alternator, then this drip boiler seems like it would really be quite sufficient. I feel like it would need a rather beefy fly wheel, which might have some trouble getting started, but popping the hood and giving it a spin start is not big deal.
Dose anyone have access to CNC machines? I'm willing to draw up a turbine/fly wheel. It seems like it would be best to just make the turbine directly connect to the alternator shaft, and be really heavy, though a easy to alter weight may be good....
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