Steam rocket

A hot water rocket, or steam rocket uses water held in a pressure vessel at a high temperature, such that its saturated vapor pressure is significantly greater than ambient pressure. The water is allowed to escape as steam through a rocket nozzle to produce thrust.

They are best known for their use in rocket-powered car and bikes.

Sometimes a hydrogen peroxide monopropellant rocket is called a 'steam rocket', but this is not quite accurate, as the propellant is not water, and the exhaust is a mixture of steam and oxygen.

Principle of operation

The water in the pressure vessel is heated up to a high temperature (approx. 250-500 °C). At launch the water turns to steam at the nozzle (usually a de Laval nozzle) leaving at high speed. By the recoil the rocket accelerates against the direction of the steam. The water tank of hot water rockets must be able to withstand high pressure and high temperature.

Applications of hot water rockets

• Evel Knievel's Skycycle X-2 used for the Snake River Canyon jump used a steam rocket designed by Robert Truax
• Art Arfons's "Neptune I" dragster[1]
• Thunderbolt III dragster
• Hot water rockets are used occasionally as auxiliary launch aids and for experimentation purposes..

Proposed uses of steam rockets

Solar or nuclear heated steam rockets have been proposed for use in interplanetary travel. Although the performance is low (~190 seconds I_sp), high mass fractions are easy to achieve, and water is expected to be very easy to extract and purify from ice deposits that are found around the solar system.

See also

• Water rocket
• Rocket engine
• Jet engine

External links

• Steam Rockets of Tecnologia Aeroespacial Mexicana
• Time article about possible applications
• Aquarius Hot Water Rocket Propulsion Systems site
• Technical papers ordering