A fluid tank for integration into a structure of an unmanned aircraft includes a shell having a first axial wall, an oppositely arranged second axial wall, an upper side, a lower side, and an enclosed interior, at least one receiving chamber in the interior for storing fluid, and a collection chamber, which is arranged on the lower side and which is fluidically connected to the at least one receiving chamber. The collection chamber includes a bottom surface, through which there extends a drain, wherein a covering surface is arranged above the bottom surface and covers at least a portion of the collection chamber. At least one flow opening could be arranged on an upper side of the collection chamber, which flow opening allows gas bubbles to escape in the direction of the upper side of the fluid tank.

Provided is a fuel system that can reduce the amount of fuel in a second tank before the amount of fuel in a first tank. A fuel system includes: a first tank and a second tank that respectively store fuel; a fuel supply pump that supplies at least the fuel in the first tank out of the first and second tanks to a fuel consuming section; a transfer pump that transfers the fuel in the second tank into the first tank; and a fuel passage having an inlet in communication with an inner portion of the first tank, and an outlet in communication with an inner portion of the second tank. The fuel in the first tank overflows into the second tank through the fuel passage.

Provided is a fuel system that can reduce the amount of fuel in a second tank before the amount of fuel in a first tank. A fuel system includes: a first tank and a second tank that respectively store fuel; a fuel supply pump that supplies at least the fuel in the first tank out of the first and second tanks to a fuel consuming section; a transfer pump that transfers the fuel in the second tank into the first tank; and a fuel passage having an inlet in communication with an inner portion of the first tank, and an outlet in communication with an inner portion of the second tank. The fuel in the first tank overflows into the second tank through the fuel passage.

A tank configured to store a liquid and that includes at least one capture device which includes at least a first portion of a line situated at the bottom of the tank, close to its first end, and at least a second portion of the line situated at the bottom of the tank, close to its second end, each of the first and second portions including at least one orifice situated on the upper face thereof, a floating shut-off device for each orifice, the floating shut-off device being movable between an open position in which the floating shut-off device is spaced apart from the orifice and a closed position in which the floating shut-off device shuts off the orifice, the floating shut-off device having a density lower than that of the liquid stored in the tank.

An aircraft engine having an oil circuit and a transmission that can be supplied with oil via the oil circuit. Oil fed to the transmission can be directed out of the transmission into an oil reservoir, from which oil can be introduced directly back into the transmission via a hydraulic line path. According to the invention, the oil fed to the oil reservoir can only be fed to the hydraulic line path below a defined filling level of the oil reservoir. When the defined filling level of the oil reservoir is reached, oil can also be introduced into a further hydraulic line path.

An aircraft engine having an oil circuit and a transmission that can be supplied with oil via the oil circuit. Oil fed to the transmission can be directed out of the transmission into an oil reservoir, from which oil can be introduced directly back into the transmission via a hydraulic line path. According to the invention, the oil fed to the oil reservoir can only be fed to the hydraulic line path below a defined filling level of the oil reservoir. When the defined filling level of the oil reservoir is reached, oil can also be introduced into a further hydraulic line path.

An aircraft fuel system having a fuel tank and a baffle dividing the fuel tank into a primary fuel containing space and a secondary fuel containing space. A fuel drain is provided through which fuel flows from the primary fuel containing space into the secondary fuel containing space. A primary fuel outlet draws fuel from the primary fuel containing space and a secondary fuel outlet draws fuel from the secondary fuel containing space, wherein fuel flow through the primary fuel outlet causes fuel flow through the secondary fuel outlet. The mass flow rate of fuel through the fuel drain is restricted so that the allowable mass flow rate of fuel through the secondary fuel outlet is configured to be greater than the allowable mass flow rate of fuel through the fuel drain in the baffle.

An aircraft fuel system having a fuel tank and a baffle dividing the fuel tank into a primary fuel containing space and a secondary fuel containing space. A fuel drain is provided through which fuel flows from the primary fuel containing space into the secondary fuel containing space. A primary fuel outlet draws fuel from the primary fuel containing space and a secondary fuel outlet draws fuel from the secondary fuel containing space, wherein fuel flow through the primary fuel outlet causes fuel flow through the secondary fuel outlet. The mass flow rate of fuel through the fuel drain is restricted so that the allowable mass flow rate of fuel through the secondary fuel outlet is configured to be greater than the allowable mass flow rate of fuel through the fuel drain in the baffle.

Aspects of the disclosure are directed to a system comprising: a tank that stores a fluid, and a conduit that includes a first end and a second end, where the conduit is configured to convey at least a portion of the fluid stored in the tank from the second end of the conduit to the first end of the conduit, where a first end region of the conduit coinciding with the second end of the conduit has a first end region density and the fluid has a fluid density, where the first end region density is greater than or equal to the fluid density such that the first end region of the conduit remains immersed in the fluid stored in the tank when the fluid in the tank is under negative gravity conditions.

Aspects of the disclosure are directed to a system comprising: a tank that stores a fluid, and a conduit that includes a first end and a second end, where the conduit is configured to convey at least a portion of the fluid stored in the tank from the second end of the conduit to the first end of the conduit, where a first end region of the conduit coinciding with the second end of the conduit has a first end region density and the fluid has a fluid density, where the first end region density is greater than or equal to the fluid density such that the first end region of the conduit remains immersed in the fluid stored in the tank when the fluid in the tank is under negative gravity conditions.