TURBOFAN ENGINE WITH OIL TANK FILLING SYSTEM
FIG1 is a sectional side view of a gas turbine engine
FIG1 illustrates a gas turbine engine 10, more particularly a turbofan engine, having a principal rotational axis 9. The engine 10 comprises an air intake 12 and a propulsive fan 23 that generates two airflows: a core airflow A and a bypass airflow B. The gas turbine engine 10 comprises a core 11 that receives the core airflow A. The engine core 11 comprises, in axial flow series, a low pressure compressor 14, a high pressure compressor 15, combustion equipment 16, a high-pressure turbine 17, a low pressure turbine 19 and a core exhaust nozzle 20. A fan nacelle 21 surrounds the fan case of the gas turbine engine 10 and defines a bypass duct 22 and a bypass exhaust nozzle 18. The bypass airflow B flows through the bypass duct 22. The fan 23 is attached to and driven by the low pressure turbine 19 via a shaft 26 and an epicyclic gearbox 30. Other turbofan engines to which the present disclosure may be applied may have alternative configurations. For example, such engines may have an alternative number of compressors and/or turbines and/or an alternative number of interconnecting shafts. By way of further example, the gas turbine engine shown in FIG1 has a split flow nozzle 18, 20 meaning that the flow through the bypass duct 22 has its own nozzle 18 that is separate to and radially outside the core engine nozzle 20. However, this is not limiting, and any aspect of the present disclosure may also apply to engines in which the flow through the bypass duct 22 and the flow through the core 11 are mixed, or combined, before (or upstream of) a single nozzle, which may be referred to as a mixed flow nozzle. One or both nozzles (whether mixed or split flow) may have a fixed or variable area. In some arrangements, the gas turbine engine 10 may not comprise a gearbox 30. The geometry of the gas turbine engine 10, and components thereof, is defined by a conventional axis system, comprising an axial direction (which is aligned with the rotational axis 9), a radial direction (in the bottom-to-top direction in FIG1), and a circumferential direction (perpendicular to the page in the FIG1 view). The axial, radial and circumferential directions are mutually perpendicular.
sectional side view
28
sun gear
30
gearbox
34
planet carrier
16
combustion equipment
10
engine
26
shaft
21
fan nacelle
36
linkages
23
fan
['1. A turbofan engine (10) that has a core (11), an aft core cowl, and an oil tank filling system (50), the oil tank filling system comprising: an oil tank (52) that has an oil tank top (66) and an oil tank bottom (68) and is located within the core (11) of the turbofan engine (10); and an oil access port (55); characterized in that : the oil access port (55) is located on the aft core cowl; and in that  the oil tank filling system has an oil tank filling pipe (56) that leads from the oil access port (55) to a tank filling port (58) located at or adjacent the oil tank bottom (68), and oil that is supplied to the oil access port (55) flows to and into the oil tank (52) using gravitational force.', '12. The turbofan engine of any preceding claim wherein the core (11) comprises a turbine (17,19), a compressor (14,15), and a core shaft (26) connecting the turbine to the compressor; a fan (23) located upstream of the core, the fan comprising a plurality of fan blades and a gearbox (30) that receives an input from the core shaft and outputs drive to the fan so as to drive the fan at a lower rotational speed than the core shaft.']