Valveless pulse-jet engine with forward facing intake duct

A self starting, self-aspirating valveless jet engine, comprising:

• (a) a combustor tube consisting of a combustion chamber closed at its forward end by a flat or covex face, said combustion chamber communicating with an exhaust tail tube by way of an intermediate reducing cone, said exhaust tail tube open to the atmosphere at its aft end and of a smaller diameter than the combustion chamber, with the combustion chamber, reducing cone, and exhaust tail tube all arranged on a common longitudinal axis,
• (b) an intake duct to capture air, and mix it into the vaporized fuel, and feed the fuel-air mixture to the combustion chamber, said intake duct penetrating the forward face of the combustion chamber at its center, said intake duct positioned on a common longitudinal axis with the combustor tube, and comprising of three to five intake tubes of varying diameters, wherein each tube is flared at its forward end to form an enlarged mouth which faces the direction of flight, said intake tubes arranged in order of increasing diameter with the smaller diameter tubes at the forward end of the intake duct and each intake tube, except the last two aft intake tubes, partially inserted inside the forward end of the intake tube behind and to the aft of it, with the last tube in the sequence being the primary intake tube having a length equal to the diameter of the combustion chamber, and a cross-section area of 25-100% of the cross-section area of the exhaust tail tube, said primary intake tube penetrating the forward face of the combustion chamber at its center and integrally joined to the forward face of the combustion chamber around the circumference of said primary intake tube, said primary intake tube extending into the combustion chamber to a length approximately equal to 50% of the diameter of the combustion chamber, with the adjacent intake tube just forward of the primary intake tube having a length of 1.25-2.0 times the length of said primary intake tube, a diameter of 85-95% of the said primary intake tube, and inserted inside the primary intake tube and extending into the combustion chamber to a length of 25-37.5% of the diameter the combustion chamber, each remaining intake tube in the intake duct, forward of the last two aft intake tubes, having a length equal to one-half to one times the intake tube behind and to the aft of it, and all the intake tubes in the intake duct arranged with their centers aligned,
• (c) a flame holder, comprising a coiled wire or suitable solid surface of minimum cross section, positioned inside the combustion chamber, adjacent to the aft end of the primary intake tube so said flame holder comes in contact with the fuel-air mixture as it enters the combustion chamber to ignite it,
• (d) a fuel supply means comprising a fuel tank capable of retaining liquified gaseous hydrocarbon fuel, a suitable means to fill the tank and draw liquid from the tank, a fuel supply or tank valve leading to a fuel line of lesser diameter than a vaporizer tube and vaporizer coils downstream, said fuel line feeding to a throttle valve to vary the liquid fuel feed rate to the vaporizer tube, said vaporizer tube penetrating the wall of the combustion chamber and extending inside the combustion chamber where said vaporizer tube is coiled to form a series of vaporizer coils which superheat the liquid fuel, transforming it into a vapor which flows through a straight section of the vaporizer tube, said straight section of the fuel line extending out the combustion chamber to the atmosphere through a small hole in the combustion chamber, where it is fitted at its end with a supersonic fuel nozzle which is positioned directly in front and at the center of the mouth of the first forward intake tube and,
• (e) a spark plug for igniting the fuel-air mixture, said spark plug located anywhere on the combustor tube, and activated by a suitable electrical source.