An oil tank system (100) for a gas turbine engine is provided. The oil tank system (100) includes an oil tank (102) having an upper tank portion (112) and a lower tank portion (114), a waisted section (118) being provided between the upper tank portion (112) and the lower tank portion (114). Oil is received by a de-aerator (104) of the system (100) which supplies de-aerated oil to the upper tank portion (112). The waisted section (118) includes an upper face (119) configured to catch oil drips from above the waisted section (118) and to guide oil to a lower face (121) of the waisted section (118).

An electric machine (101) for use in an aircraft is shown. The electric machine comprises a casing (104) containing electromechanical components, a shaft (106) which extends outside of the casing, a seal (107) to seal the casing around the shaft, and a depressurisation system (102) configured to depressurise the casing below an external pressure to prevent electrical breakdown within gas in the casing.

An electric machine (101) for use in an aircraft is shown. The electric machine comprises a casing (104) containing electromechanical components, a shaft (106) which extends outside of the casing, a seal (107) to seal the casing around the shaft, and a depressurisation system (102) configured to depressurise the casing below an external pressure to prevent electrical breakdown within gas in the casing.

In the method for propelling an aircraft, to obtain electric energy, a fuel is combusted, and an electric machine is used, wherein the fuel is used to cool at least one part of the electric machine and contains natural gas. The propulsion system is configured to propel an aircraft, in particular according to the above-mentioned method. The propulsion system has an electric machine configured to obtain electric energy by combusting a fuel. The propulsion system further includes a natural gas tank configured to supply the fuel formed with natural gas, and a cooling device configured to cool at least one part of the electric machine. The aircraft has such a propulsion system.

In the method for propelling an aircraft, to obtain electric energy, a fuel is combusted, and an electric machine is used, wherein the fuel is used to cool at least one part of the electric machine and contains natural gas. The propulsion system is configured to propel an aircraft, in particular according to the above-mentioned method. The propulsion system has an electric machine configured to obtain electric energy by combusting a fuel. The propulsion system further includes a natural gas tank configured to supply the fuel formed with natural gas, and a cooling device configured to cool at least one part of the electric machine. The aircraft has such a propulsion system.

An aircraft hybrid propulsion system (5) comprising an inboard gas turbine engine (10a, 10c) and an outboard gas turbine engine (10b, 10d), each comprising a propulsor (12a, 12b) and a respective electric machine (32a, 32b) coupled to one or more engine shaft (24a, 24b). An electrical interconnection (34) is provided between the electric machine (32a) of the inboard gas turbine engine (10a) and the electric machine (32b) of the outboard gas turbine engine (10b). A controller (36) is configured to transfer electrical power between the inboard gas turbine engine electrical machine and the outboard gas turbine engine electrical machine when a thrust setting change is selected.

An aircraft hybrid propulsion system (5) comprising an inboard gas turbine engine (10a, 10c) and an outboard gas turbine engine (10b, 10d), each comprising a propulsor (12a, 12b) and a respective electric machine (32a, 32b) coupled to one or more engine shaft (24a, 24b). An electrical interconnection (34) is provided between the electric machine (32a) of the inboard gas turbine engine (10a) and the electric machine (32b) of the outboard gas turbine engine (10b). A controller (36) is configured to transfer electrical power between the inboard gas turbine engine electrical machine and the outboard gas turbine engine electrical machine when a thrust setting change is selected.

The invention is directed to an aerial vehicle with a hybrid drive unit (10) and with a rotor unit (1, 1′) wherein the hybrid drive unit (10) comprises at least a combustion engine (11), a generator (12) and a first electric motor (7) and the rotor unit (1, 1′) comprises a first rotor (1), wherein the combustion engine (11) is configured to drive the generator (12) to produce electricity, the generator (12) is coupled to the first electric motor (7) in such a way that the first electric motor (7) is feedable with electricity from the generator (12). The rotor unit (1, 1′) comprises a second rotor (1) and the hybrid drive unit (10) comprises a second electric motor (7′), wherein the generator (12) is coupled to the second electric motor (7′) in such a way that the second electric motor (7′) is feedable with electricity from the generator (12), and wherein the first rotor (1) is driven by the first electric motor (7) and the second rotor (1′) is driven by the second electric motor (7′).

The invention is directed to an aerial vehicle with a hybrid drive unit (10) and with a rotor unit (1, 1′) wherein the hybrid drive unit (10) comprises at least a combustion engine (11), a generator (12) and a first electric motor (7) and the rotor unit (1, 1′) comprises a first rotor (1), wherein the combustion engine (11) is configured to drive the generator (12) to produce electricity, the generator (12) is coupled to the first electric motor (7) in such a way that the first electric motor (7) is feedable with electricity from the generator (12). The rotor unit (1, 1′) comprises a second rotor (1) and the hybrid drive unit (10) comprises a second electric motor (7′), wherein the generator (12) is coupled to the second electric motor (7′) in such a way that the second electric motor (7′) is feedable with electricity from the generator (12), and wherein the first rotor (1) is driven by the first electric motor (7) and the second rotor (1′) is driven by the second electric motor (7′).

The propulsion system have a load change detecting unit detecting a load change and an operating point control unit controlling power operating points defined using a torque T and a rotation number Ne. The operating point control unit calculates target power operating points 44 and 54 corresponding to the load after change for first power operating points 41 and 51 that are current power operating points in a case in which a change in the load is detected by the load change detecting unit. By changing the fuel flow in a range not exceeding a predetermined fuel line, the operating point control unit moves the power operating points from first power operating points 41 and 51 to second power operating points 42 and 52, third power operating points 43 and 53, and target power operating points 44 and 54 in order.