FLASH STEAM ENGINES?

[PJ]

Can somebody please explain to me what a "Flash Steam Engine" is and how it works.  I have heard there is a model boat application for these.

PJ
Victoria, BC Canada

[steamboatmodel]

Hi PJ,
It's not the engine thats flash steam any engine will run with it. What Flash Steam is a coil of tubing heated to a high heat with a burner, usually to a red heat, and then you pump water into it, which  turns into steam. Hope this simple explanation is clear enough.
Regards,
Gerald

[Eddy Matthews]

Hi Paul,

As Gerald said, basically it's a coil of copper tube forming the "Boiler". This is normally heated using a paraffin flame thrower - The sort of thing used for clearing weeds from garden paths. The paraffin tank is pressurised using a handpump so that it burns as a gas.

The water that is fed into the "Boiler" is instantly turned to steam (it's flashed), and develops incredibly high pressures.

This type of powerplant was used extensively in model hydroplanes, so it's definately not suitable for a paddler, unless you want two HUGE rooster tails of course! :-)

[Khephre]

One of our club members brought a vintage flash steam tethered hydroplane to our monthly club night a few months ago.

The flash steam boiler consisted of three copper tubes each around 40 ft long and 3/8 inch diameter, each bent into tight spring-like coils of around 3" internal diameter. These coils were heated by two pressurised parrafin blow torches. The inlets were connected to a water pump and tank, while the outlets were connected to a two cylinder homebuilt steam engine.

As water was pumped into the boiler, it turned to steam very quickly, within the first foot or so of the coiled tubes. That steam was then superheated to very high temperatures as it passed through the length of the three coils, and gaseous expansion did the rest.

We were told that the engine would run up to 10,000 or more rpm and was capable of propelling the hydroplane at speeds in excess of 70 mph. That's hearsay but having read up a bit on the subject since, I can quite believe it.

The prop was something else - a piece of brass strip around 3 inches long by 3/4 inch across and at least 1/8 thick, with a simple twist either end - completely capable of taking off an unwary finger, and that was how she was started - with a smart flick of the finger, followed by a quick count of the hand to ensure each little piggy ws still there.

I'm told that stopping was just as dramatic - relying on snaring a length of piano wire on the hydroplane with a form of 'boathook'. The snare tripped the drive to the water pump and cut off the flow of water to the boiler. If the skipper were to attempt to trip the wire with his bare hand then the piggy counting task would have been shortened by several fingers.

Scary stuff indeed!

Tony

[frankmcneilll]

Little tin boats with flash boiler steam engines were one of the hottest toys available when I was a kid back before WW2. They were called "pop-pop" boats because they had diaphragm boilers with thin panels that would make a popping sound when they were filled with water and heated by little wafer candles. There is a simpler version in the form of a copper tube with a coil in the middle and ends projecting from a boat's stern below the water line. I have never seen one, but anyone who is interested can learn how to build toy boats with the simplest of all steam engines because you can't get much simpler than an engine that has no moving parts. Go to: The Pop-pop pages at: http://tinyurl.com/1nnz for more information than you probably want, and don't blame me for not warning you!

Best wishes,
Frank McNeill

[steamboatmodel]

Hi All,
They are great at Shows were due to radio conflicts you can't run (ie the Car guys are running).
Regards,
Gerald

[kiwimodeller]

Came across a photo in a magazine I was skimming through recently, I think a Marine Modelling of the mid 90's, of a flash steam hydro setting off on a run on which it set a record at 118 Miles per Hour !!! Apparently the other notable thing about a flash steam setup was the noise - they were much louder than an I.C. engine. I have a book from the 50's all about building the boilers etc if anybody wants to have a go.