Systems and methods for controlling an unducted turbofan engine to limit noise. The unducted turbofan engine may include an unducted fan drivingly coupled with a low-pressure turbine and a plurality of unducted outlet guide vanes. The unducted fan may include a plurality of fan blades and a pitch angle of the fan blades may be variable. A pitch angle of the unducted outlet guide vanes may be variable. A controller is configured to control the engine to limit noise based on a noise sensitive condition.

An assembly of a pylon and of a wing of an aircraft, the pylon including a primary structure with a rear face and an upper spar. The assembly includes a rear fastening system including a pair of vertical shackles articulated between the rear face of the primary structure and a first shoe fastened to the wing, wherein the shackles are fastened to the primary structure by a clevis-type connection, and a pair of transverse shackles articulated between the rear face of the primary structure and a second shoe fastened to the wing, wherein the shackles are fastened to the primary structure by a clevis-type connection. With such an assembly, the bulk of the rear fastening system is reduced.

A propulsion system for an aircraft includes a gas turbine engine and a fuel tank, wherein the fuel includes at least a proportion of a sustainable aviation fuel—SAF—having a density between 90% and 98% of the density, ρ.sub.K, of kerosene and a calorific value between 101% and 105% the calorific value CV.sub.K, of kerosene. The engine includes a combustor; and a fuel pump arranged to supply a fuel thereto at an energy flow rate, C, the pump being arranged to output fuel at a volumetric flow rate, Q, the percentage of fuel passing through the pump not provided to the combustor being referred to as a spill percentage. The fuel include X % SAF, where X % is in the range from 5% to 100%, and has a density, ρ.sub.F, and a calorific value CV.sub.F. The propulsion system is arranged so: the fuel-change spill ratio, R.sub.s, of: $R_s=\frac{\mathrm{spill}\mathrm{percentage}\mathrm{at}\mathrm{cruise}\mathrm{using}\mathrm{kerosene}}{\mathrm{spill}\mathrm{percentage}\mathrm{at}\mathrm{cruise}\mathrm{using}\mathrm{the}\mathrm{fuel}\mathrm{with}X\%SAF}$ is equal to: $\frac{Q-\left(C/\left({\mathrm{CV}}_K\times {\rho }_K\right)\right)}{Q-(C/({\mathrm{CV}}_F\times {\rho }_{}}$

An aircraft gas turbine engine (110) comprises first and second non-coaxial propulsors (113a, 113b), each propulsor (113a, 113b) being driven by a common gas turbine engine core (176) comprising a propulsor drive turbine (143) arranged to drive the first and second propulsors (113a, 113b) via a propulsor drive coupling (127). The core (176) further comprises a first core module (190) comprising a first compressor (129) and a first turbine (131) interconnected by a first shaft (177), and a second core module (191) comprising a second compressor (128) and the propulsor drive turbine (143) interconnected by a second shaft (127), the first and second core modules (190, 191) being axially spaced.

An aircraft gas turbine engine (110) comprises first and second non-coaxial propulsors (113a, 113b), each propulsor (113a, 113b) being driven by a common gas turbine engine core (176) comprising a propulsor drive turbine (143) arranged to drive the first and second propulsors (113a, 113b) via a propulsor drive coupling (127). The core (176) further comprises a first core module (190) comprising a first compressor (129) and a first turbine (131) interconnected by a first shaft (177), and a second core module (191) comprising a second compressor (128) and the propulsor drive turbine (143) interconnected by a second shaft (127), the first and second core modules (190, 191) being axially spaced.

The present disclosure is directed to an aerodynamic stabilizer assembly for stabilizing an aft fan mounted to a fuselage of an aircraft. For example, the stabilizer assembly includes one or more generally horizontal stabilizers for mounting to a nacelle of the aft fan and the fuselage so as to stabilize the aft fan. Each of the generally horizontal stabilizers includes an inner portion and an outer portion. As such, the inner portions are mounted to a nacelle of the aft fan and the fuselage at a predetermined downward angle with respect to a central axis of the aft fan so as to direct airflow upwards and into the aft fan, the outer portion being mounted to the inner portion.

The present disclosure is directed to an aerodynamic stabilizer assembly for stabilizing an aft fan mounted to a fuselage of an aircraft. For example, the stabilizer assembly includes one or more generally horizontal stabilizers for mounting to a nacelle of the aft fan and the fuselage so as to stabilize the aft fan. Each of the generally horizontal stabilizers includes an inner portion and an outer portion. As such, the inner portions are mounted to a nacelle of the aft fan and the fuselage at a predetermined downward angle with respect to a central axis of the aft fan so as to direct airflow upwards and into the aft fan, the outer portion being mounted to the inner portion.

An assembly having a pylon with an upper spar and four lateral scoops, a wing with a skin, longitudinal spars and fittings, and, for each lateral scoop, two fastening assemblies, wherein the skin and the fitting each have a first bore and wherein the upper spar and the lateral scoop each have a second bore, wherein each fastening assembly has a screw passing through the first and the second bores, a nut, two eccentric rings, threaded onto one another and onto the screw, and a system for stopping the eccentric rings rotating. The assembly makes it possible to dispense with the use of the spigots while also ensuring the reaction of the shear forces contained in the XY plane by the bolts on account of the reduced tolerances between the various bores, the external and internal surfaces of the eccentric rings and the plain zones of the screws.

An aircraft propulsion system comprises first and second thrust producing gas turbine engines. The system comprises a controller configured to determine a required overall propulsion system thrust level, and determine an engine core power level contribution from each aircraft gas turbine engine such that the overall propulsion system produces a minimum overall noise level and meets the required overall propulsion system thrust level. In meeting the minimum overall noise level, at least the first and second gas turbine engines are operated at different engine core power settings.

An aircraft propulsion system configured to be supported from an aircraft wing having a leading edge and opposing upper and lower surfaces. The aircraft propulsion system broadly comprises an engine having a core, a fan case, and a nacelle including a plurality of access panels, and an attachment assembly for securing the engine to the aircraft wing. The attachment assembly broadly comprises an upper support section including a number of spars and a number of ribs connected between the spars, a lower support section, and an aft section. The attachment assembly aerodynamically melds the nacelle and the aircraft wing together via the upper support section so that air flowing over the engine flows over the aircraft wing along the upper surface and air flowing laterally alongside the nacelle flows under the aircraft wing along the lower surface.