A container may be supplied with an incompressible fluid. For example, the container may be partially or completely prefilled with the incompressible fluid. The container may be supplied with a flow of compressible gas via a first valve. The first valve may regulate the flow of the compressible gas supplied to the container based on a pressure setting of the first valve. A second valve may release the incompressible fluid from the container as the container is filled with the compressible gas and in response to a pressure of the container being greater than a pressure setting of the second valve. The pressure setting of the first valve may be greater than the pressure setting of the second valve.

In an example, a drop tank for an aerial vehicle includes a body having an internal fuel reservoir configured to store fuel. The drop tank also includes an outlet coupled to the internal fuel reservoir for supplying the fuel from the internal fuel reservoir to a propulsion system of the aerial vehicle. Additionally, the drop tank includes a plurality of flight control surfaces extending outwardly from the body. The flight control surfaces are actuatable to adjust a flight attitude of the drop tank. The drop tank further includes a flight control system including a processor and configured to actuate the plurality of flight control surfaces to fly the drop tank to a target location when the drop tank is jettisoned from the aerial vehicle.

Apparatus and methods for training a machine learning algorithm (MLA) to control a first aircraft in an environment that comprises the first aircraft and a second aircraft are described. Training of the MLA can include: the MLA determining a first-aircraft action for the first aircraft to take within the environment; sending the first-aircraft action from the MLA; after sending the first-aircraft action, receiving an observation of the environment and a reward signal at the MLA, the observation including information about the environment after the first aircraft has taken the first-aircraft action and the second aircraft has taken a second-aircraft action, the reward signal indicating a score of performance of the first-aircraft action based on dynamic and kinematic properties of the second aircraft; and updating the MLA based on the observation of the environment and the reward signal.

A fuel pump system for an aerial refueling system including: a variable displacement motor operable to be driven by a hydraulic fluid pressure; a fuel pump operable to be driven by the variable displacement motor; and a drive system controller (DSC) connected to the variable displacement motor, wherein the DSC is operable to direct an operation of the fuel pump in modes comprising: a flow control mode operable to maintain an output fuel flow rate from the fuel pump to a predetermined maximum inlet pressure at a reception coupling for a receiver aircraft; a fuel pressure control mode operable to regulate the output fuel flow rate to not exceed the predetermined maximum inlet pressure; and a priority mode operable to reduce the output fuel flow rate in response to a decrease in the hydraulic pressure. Also a method of refueling a receiver aircraft.

A fuel pump system for an aerial refueling system including: a variable displacement motor operable to be driven by a hydraulic fluid pressure; a fuel pump operable to be driven by the variable displacement motor; and a drive system controller (DSC) connected to the variable displacement motor, wherein the DSC is operable to direct an operation of the fuel pump in modes comprising: a flow control mode operable to maintain an output fuel flow rate from the fuel pump to a predetermined maximum inlet pressure at a reception coupling for a receiver aircraft; a fuel pressure control mode operable to regulate the output fuel flow rate to not exceed the predetermined maximum inlet pressure; and a priority mode operable to reduce the output fuel flow rate in response to a decrease in the hydraulic pressure. Also a method of refueling a receiver aircraft.

An assembly comprising an aircraft door and auxiliary equipment. The aircraft door and the auxiliary equipment are connected by a flexible deformable bellows comprising creases. The door comprises a passing through hole and a support joinable to the first end of the bellows. The auxiliary equipment comprises a support joinable to the second end of the bellows and a projecting part. The projecting part is configured to have elevation movement and/or azimuth movement, and the projecting part crosses the interior of the bellows and the hole of the door and protrudes out of the door. At both ends of the bellows a clamp joins and tightens each end of the bellows with the corresponding support. There is a fixed joint between the first end of the bellows and the door and a movable joint between the second end of the bellows and the auxiliary equipment.

An assembly comprising an aircraft door and auxiliary equipment. The aircraft door and the auxiliary equipment are connected by a flexible deformable bellows comprising creases. The door comprises a passing through hole and a support joinable to the first end of the bellows. The auxiliary equipment comprises a support joinable to the second end of the bellows and a projecting part. The projecting part is configured to have elevation movement and/or azimuth movement, and the projecting part crosses the interior of the bellows and the hole of the door and protrudes out of the door. At both ends of the bellows a clamp joins and tightens each end of the bellows with the corresponding support. There is a fixed joint between the first end of the bellows and the door and a movable joint between the second end of the bellows and the auxiliary equipment.

A method for remotely guiding a refueling boom of a tanker to engage with a fueling receptacle of an aircraft while the tanker and the aircraft are in flight. The method comprising: transmitting a polarized RF scanning pattern from one of the refueling boom and refueling receptacle; detecting the polarized RF scanning pattern at one or more cavity sensors disposed on the other of the refueling boom and the refueling receptacle; and controlling a position of the refueling boom relative to a position of the refueling receptacle based on the detected polarized RF scanning pattern at the one or more cavity sensors.

A method for remotely guiding a refueling boom of a tanker to engage with a fueling receptacle of an aircraft while the tanker and the aircraft are in flight. The method comprising: transmitting a polarized RF scanning pattern from one of the refueling boom and refueling receptacle; detecting the polarized RF scanning pattern at one or more cavity sensors disposed on the other of the refueling boom and the refueling receptacle; and controlling a position of the refueling boom relative to a position of the refueling receptacle based on the detected polarized RF scanning pattern at the one or more cavity sensors.

A power spring passively applies tension to a cable connected to an aircraft refueling boom. The power spring has a first end engaging a fixed arbor and second end engaging a rotatable spooling drum around which a portion of the cable is wound. The power spring biases the drum to rotate in a winding direction to apply tension to the cable, and the power spring stores energy when the drum rotates in an unwinding direction. The power spring may be located inside the drum or outside the drum. The drum may be actively driven by a motor that may be uncoupled from the drum to permit freewheeling rotation of the drum, wherein the power spring continues to apply tension to the cable. The invention eliminates reliance on one or more powered motors for removing unwanted slack in the cable.