Abstract: A vehicle for self-propelled travel through a body of water includes a hull, a propulsive element for engaging the water, an engine, and a fuel storage container. The engine includes a combustion chamber for receiving a monopropellant fuel and combusting the monopropellant fuel to form an energized gas. The engine includes responsive elements for drawing energy from expansion of the energized gas. The responsive elements are coupled to the propulsive element to drive the propulsive element. A fuel flow path extends from the container upstream to the combustion chamber downstream. A pump system pumps the fuel from the container. A port draws water from the body of water through the hull in at least a first mode of operation. A water flow path extends from the port upstream to the combustion chamber downstream in at least the first mode of operation.

Abstract: There is provided a system for expelling a liquid fuel component from a tank to a rocket engine utilizing a pressurized gas to displace the propellant. A pressurized high vapor pressure liquid is combined with the pressurized gas reducing the volume of pressurizing agent required to expel a desired volume of the liquid fuel component. Since the volume of pressurizing gas is less, the weight of the propelled craft may be reduced or additional fuel carried. In another embodiment of the invention, the vapor phase of the high vapor pressure liquid is used as a reference pressure to control other systems.

Abstract: There is provided a two-stage system for expelling a liquid fuel component from a main fuel tank to a rocket engine. A first vessel contains a first gas pressurized to the desired operating pressure at a minimum operating temperature. Since the first gas is subject to pressure increase due to environmental heating, opening a first valve exposes the pressurized first gas to a pressure relief valve, returning the pressure to the desired operating pressure. Subsequent opening of a second valve causes the pressurized first gas to displace a partition, such as a piston, expelling a desired quantity of the fluid. A gas generator converts the fluid to a second gas that expels a desired quantity of fuel from a main fuel tank. The two-stage system is at an equilibrium pressure. The only active control required for the system is a controller to meter the flow of fuel from the main fuel tank to the engine.

Abstract: There is provided a two-stage system for expelling a liquid fuel component from a main fuel tank to a rocket engine. A pressurized high vapor pressure liquid combined with the vapor of that liquid expel a desired volume of a gas forming liquid from a first stage fuel tank. A gas generator converts this liquid to a gas that expels a desired quantity of fuel from the main fuel tank. The two-stage system is at an equilibrium pressure. The only active control required for the system is a controller to meter the flow of fuel from the main fuel tank to the engine. The pressure drop in the system resulting from the discharge of fuel causes the high vapor pressure liquid to partially evaporate charging more gas into the system until equilibrium is achieved again.

Abstract: There is provided a system for expelling a liquid fuel component from a tank to a rocket engine utilizing a pressurized gas to displace the propellant. A pressurized high vapor pressure liquid is combined with the pressurized gas reducing the volume of pressurizing agent required to expel a desired volume of the liquid fuel component. Since the volume of pressurizing gas is less, the weight of the propelled craft may be reduced or additional fuel carried. In another embodiment of the invention, the vapor phase of the high vapor pressure liquid is used as a reference pressure to control other systems.