Steam rocket "release plug" question...

[Johansson]

What do they use to release the 1500 psi steam into the nozzle? It´s hard to believe that any small valve could handle the pressure and temperature. Is a burst-cap the answer?

//Anders

[Tom]

In the examples i've see, it's been a metal burst disk, but I don't know how they all work.

Tom

[marksteamnz]

In the book on steam rockets various schemes are shown. Most show a plug attached to the base launch plate pushed into the rocket nozzle. Various types of latchs hold a flange on the rocket nozzle to the base plate.

This site shows a balanced plug mechanism for his land speed attempt http://www.tecaeromex.com/

The steam dragster seens to use a large size ball valve.

[Johansson]

Ok, a ball valve would be nice if it can handle the pressure. By the way, what kind of pressure is needed? It shouldn´t have to be extremely high, because when the water is heated above 100 degrees C and the pressure drops the boiling water is what produces the thrust, right?

The engine will most certainly be more effective if the pressure/temperature in the engine is higher, but as long as the water is superheated the engine should work.

How is the water heated by the way? Simply by heating the tank with propane burners or perhaps by internal heating coils?

//Anders

[Tom]

Model Steam rocket http://www.inverseengineering.com/Pages/1999/Steam.html

Tom